CN116260107A - Buck circuit and DC-DC chip - Google Patents

Buck circuit and DC-DC chip Download PDF

Info

Publication number
CN116260107A
CN116260107A CN202310545627.4A CN202310545627A CN116260107A CN 116260107 A CN116260107 A CN 116260107A CN 202310545627 A CN202310545627 A CN 202310545627A CN 116260107 A CN116260107 A CN 116260107A
Authority
CN
China
Prior art keywords
output
module
control
transistor
input
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202310545627.4A
Other languages
Chinese (zh)
Other versions
CN116260107B (en
Inventor
樊茂
杨永华
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yingli Semiconductor Shanghai Co ltd
Original Assignee
Yingli Semiconductor Shanghai Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yingli Semiconductor Shanghai Co ltd filed Critical Yingli Semiconductor Shanghai Co ltd
Priority to CN202310545627.4A priority Critical patent/CN116260107B/en
Publication of CN116260107A publication Critical patent/CN116260107A/en
Application granted granted Critical
Publication of CN116260107B publication Critical patent/CN116260107B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
    • H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
    • H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
    • H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
    • H02H5/04—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature
    • H02H5/047—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature using a temperature responsive switch
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
    • H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
    • H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
    • H02M3/157—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators with digital control
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Protection Of Static Devices (AREA)

Abstract

The invention discloses a buck circuit and a DC-DC chip. The buck circuit comprises an over-temperature protection unit, wherein the input end of the over-temperature protection unit is connected with the first pole of the output transistor, the output end of the over-temperature protection unit is connected with the driving unit, and the over-temperature protection unit is used for forming an over-temperature protection signal according to the conduction voltage drop of the output transistor; the driving unit is also used for controlling the input control unit and the output transistor to be turned off according to the over-temperature protection signal. The first electrode potential of the output transistor is obtained through the over-temperature protection unit, and an over-temperature protection signal is formed according to the first electrode potential of the output transistor and the preset voltage, so that the correlation between the over-temperature protection signal and the temperature of the output transistor is improved, and the over-temperature protection precision and speed of the buck circuit are further improved.

Description

Buck circuit and DC-DC chip
Technical Field
The embodiment of the invention relates to the technical field of voltage conversion, in particular to a buck circuit and a DC-DC chip.
Background
In an electronic apparatus using a direct current source, a voltage converter is required to convert the voltage of a power supply into a desired operating voltage. buck circuits, a widely used buck conversion circuit, are mainly used for direct current to direct current (DC-DC) buck conversion, and are generally applicable to the field of low-voltage and high-current applications.
Fig. 1 is a schematic structural diagram of a buck circuit provided in the prior art, and fig. 2 is a schematic layout of a buck circuit provided in the prior art. As shown in fig. 1 and 2, the buck circuit includes an analog module 101, an over-temperature protection unit 102, an N-type transistor Mn1, a P-type transistor Mp1, and a driving module 103, where the analog module 101 includes an analog circuit in the buck circuit, for example, includes a clock generator, a current sensing and compensating module, an error amplifier, a comparator, a zero point detector, and the like, and the driving module 103 includes a pulse width modulator, and the driving module 103 realizes conversion of a direct current source by controlling the N-type transistor Mn1 and the P-type transistor Mp1 to be turned on in a time-sharing manner. The over-temperature protection unit 102 is disposed around the N-type transistor Mn1 or the P-type transistor Mp1 for detecting the temperature of the N-type transistor Mn1 or the P-type transistor Mp 1. Fig. 3 is a schematic structural diagram of an over-temperature protection unit provided in the prior art, fig. 4 is a schematic diagram of a temperature coefficient versus temperature curve corresponding to the over-temperature protection unit provided in fig. 3, and fig. 5 is a schematic diagram of an over-temperature protection signal corresponding to the over-temperature protection unit provided in fig. 3. In fig. 4 and 5, the abscissa indicates the temperature temp, and the ordinate indicates the voltage V. As shown in fig. 3 to 5, the over-temperature protection unit 102 includes a comparator, a positive phase input terminal of which +inputs a constant temperature reference voltage, i.e., a constant temperature coefficient in fig. 4, and a negative phase input terminal of which-inputs a negative temperature coefficient. The voltage of the negative temperature coefficient gradually decreases along with the rise of the temperature, when the temperature is smaller than the preset temperature, namely, the temperature is smaller than the temperature corresponding to the intersection point of the negative temperature coefficient curve and the constant temperature coefficient curve, the voltage of the negative temperature coefficient is larger than the voltage of the constant temperature coefficient, the comparator outputs a low level and sends the low level to the driving module 103, and the driving module 103 does not perform over-temperature protection action. When the temperature is greater than or equal to the preset temperature, namely the voltage with the negative temperature coefficient is less than or equal to the preset temperature, the comparator outputs a high level and sends the high level to the driving module 103, so that the driving module 103 controls the N-type transistor Mn1 and the P-type transistor MP1 to be cut off according to the over-temperature protection signal, and the buck circuit stops working to avoid damage caused by overhigh temperature. In the above process, when detecting the temperature of the N-type transistor Mn1 or the P-type transistor Mp1, the over-temperature protection unit 102 needs to detect after the temperature of the N-type transistor Mn1 or the P-type transistor Mp1 is diffused to the surroundings, and the detection speed is slow, resulting in a slower over-temperature protection speed. And the temperature sensing capability is relatively poor, so that the accuracy of the over-temperature protection signal is relatively low, and the over-temperature protection accuracy of the buck circuit is further reduced.
Disclosure of Invention
The invention provides a buck circuit and a DC-DC chip, which are used for improving the over-temperature protection precision and speed of the buck circuit.
In a first aspect, an embodiment of the present invention provides a buck circuit, including a driving unit, an input control unit, an output transistor, an over-temperature protection unit, and an output storage unit;
the driving unit is respectively connected with the control end of the input control unit and the control electrode of the output transistor, the first end of the input control unit is connected with the power input end, the second end of the input control unit and the first electrode of the output transistor are connected with the first input end of the output storage unit, the second end of the output transistor and the second input end of the output storage unit are connected with the first potential end, and the output end of the output storage unit is used as the output end of the buck circuit; the driving unit is used for controlling the input control unit and the output transistor to conduct in a time-sharing way, the input control unit is used for providing electric energy for the output storage unit when conducting, and the output transistor is used for communicating a discharge loop of the output storage unit; the input end of the over-temperature protection unit is connected with the first pole of the output transistor, the output end of the over-temperature protection unit is connected with the driving unit, and the over-temperature protection unit is used for forming an over-temperature protection signal according to the conduction voltage drop of the output transistor; the driving unit is also used for controlling the input control unit and the output transistor to be turned off according to the over-temperature protection signal.
Optionally, the over-temperature protection unit comprises a mirror module, a reference module, a conversion module and a comparison module;
the first end of the mirror image module is connected with the power input end, the second end of the mirror image module is connected with the second potential end, and the mirror image module is used for mirroring the current of the main body branch circuit to the output end of the mirror image branch circuit; the first end of the reference module is connected with the output end of the mirror branch and the negative input end of the comparison module, the second end of the reference module is connected with the second potential end, and the reference module is used for forming a reference signal according to the current of the mirror branch;
the first control end of the conversion module is connected with the control end of the input control unit, the second control end of the conversion module is connected with the control electrode of the output transistor, the first input end of the conversion module is connected with the first electrode of the output transistor, the second input end of the conversion module is connected with the second potential end, the output end of the conversion module is connected with the positive input end of the comparison module and the output end of the mirror branch, and the conversion module is used for converting the first electrode potential of the output transistor or the potential of the second potential end according to the potential of the control end of the input control unit and the potential of the control electrode of the output transistor and then outputting a conversion signal;
The output end of the comparison module is connected with the driving unit, and the comparison module is used for comparing the reference signal with the conversion signal and then outputting the over-temperature protection signal.
Optionally, the conversion module includes a path selection sub-module and a conversion sub-module;
the first input end of the path selection submodule is connected with the control end of the input control unit, the second input end of the path selection submodule is connected with the control electrode of the output transistor, and the path selection submodule is used for forming a first control signal and a second control signal according to the potential of the control end of the input control unit and the potential of the control electrode of the output transistor; the first output end of the channel selection sub-module is connected with the first control end of the conversion sub-module, the second output end of the channel selection sub-module is connected with the second control end of the conversion sub-module, the first input end of the conversion sub-module is connected with the first pole of the output transistor, the second input end of the conversion sub-module is connected with the second potential end, and the output end of the conversion sub-module is connected with the positive input end of the comparison module and the output end of one mirror branch; the conversion sub-module is used for converting the first pole potential of the output transistor into the conversion signal or converting the potential of the second potential end into the conversion signal according to the first control signal provided by the first output end of the path selection sub-module and the second control signal provided by the second output end of the path selection sub-module.
Optionally, the path selection submodule includes a first inverter, an and logic operator, and a second inverter;
the first input end of the AND logic arithmetic unit is connected with the control end of the input control unit, the input end of the first inverter is connected with the control electrode of the output transistor, the output end of the first inverter is connected with the second input end of the AND logic arithmetic unit, the output end of the AND logic arithmetic unit is connected with the first control end of the conversion sub-module, the input end of the second inverter is connected with the output end of the AND logic arithmetic unit, and the output end of the second inverter is connected with the second control end of the conversion sub-module.
Optionally, the conversion submodule comprises a conversion resistor, a first switching tube and a second switching tube;
the control electrode of the first switching tube is connected with the first output end of the path selection submodule, the first electrode of the first switching tube is connected with the first electrode of the output transistor, the control electrode of the second switching tube is connected with the second output end of the path selection submodule, the first electrode of the second switching tube is connected with the second potential end, the second electrode of the first switching tube is connected with the first end of the conversion resistor, and the second end of the conversion resistor and the second electrode of the second switching tube are connected with the positive input end of the comparison module and the output end of the mirror image branch.
Optionally, the first switch tube and the second switch tube are the same type, and the levels of the first control signal and the second control signal are opposite.
Optionally, the reference module comprises a third switch tube and a reference resistor;
the control electrode of the third switching tube is used for being connected with a control voltage, and the control voltage is used for controlling the third switching tube to be in a long-turn-on state; the first pole of the third switching tube is connected with the first pole of the reference resistor, the second pole of the third switching tube is connected with the second potential end, and the second pole of the reference resistor is connected with the output end of one mirror branch.
Optionally, the body branch includes a bias current source and a body transistor, and the mirror branch includes a mirror transistor;
the first end of the bias current source is connected with the second potential end, the second end of the bias current source is connected with the second pole and the control pole of the main body transistor, the first pole of the main body transistor and the first pole of the mirror image transistor are connected with the power input end, the control pole of the mirror image transistor is connected with the control pole of the main body transistor, and the second pole of the mirror image transistor is used as the output end of the mirror image branch.
Optionally, the input control unit includes an input transistor;
the control electrode of the input transistor is connected with the driving unit, the first electrode of the input transistor is connected with the power input end, and the second electrode of the input transistor is connected with the input end of the output storage unit.
In a second aspect, an embodiment of the present invention further provides a DC-DC chip, including the buck circuit according to the first aspect.
According to the technical scheme, the first pole potential of the output transistor is related to the conduction voltage drop of the body diode of the output transistor, the conduction voltage drop of the body diode of the output transistor is related to the temperature of the output transistor, the first pole potential of the output transistor is obtained through the over-temperature protection unit, and an over-temperature protection signal is formed according to the first pole potential of the output transistor and the preset voltage, so that the driving unit controls the input control unit and the output transistor to be turned off according to the over-temperature protection signal, and over-temperature protection of a buck circuit is achieved. The over-temperature protection signal is directly formed according to the first pole potential of the output transistor and the preset voltage, so that the speed of temperature detection can be improved, and the over-temperature protection speed can be improved. And the correlation between the over-temperature protection signal and the temperature of the output transistor can be improved, so that the over-temperature protection precision of the buck circuit is improved.
Drawings
Fig. 1 is a schematic diagram of a buck circuit according to the prior art;
FIG. 2 is a schematic diagram of a buck circuit according to the prior art;
FIG. 3 is a schematic structural diagram of an over-temperature protection unit according to the prior art;
FIG. 4 is a schematic diagram of a temperature coefficient versus temperature curve corresponding to the over-temperature protection unit shown in FIG. 3;
fig. 5 is a schematic diagram of an over-temperature protection signal corresponding to the over-temperature protection unit provided in fig. 3;
fig. 6 is a schematic structural diagram of a buck circuit according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a turn-on voltage drop of a body diode of an output transistor at 25 ° according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a turn-on voltage drop of a body diode of an output transistor at 150 ° according to an embodiment of the present invention;
fig. 9 is a schematic diagram of another buck circuit according to an embodiment of the present invention;
fig. 10 is a schematic diagram of another buck circuit according to an embodiment of the present invention;
FIG. 11 is a schematic diagram of another buck circuit according to an embodiment of the present invention;
fig. 12 is a schematic diagram of another buck circuit according to an embodiment of the present invention;
fig. 13 is a schematic diagram of another buck circuit according to an embodiment of the present invention;
Fig. 14 is a schematic diagram of an equivalent structure of a first switch tube turned on when the temperature of an output transistor is less than a preset temperature according to an embodiment of the present invention;
fig. 15 is a schematic diagram of an equivalent structure of a second switch tube turned on when the temperature of an output transistor is less than a preset temperature according to an embodiment of the present invention;
fig. 16 is a schematic diagram of an equivalent structure of a first switch tube turned on when a temperature of an output transistor is greater than or equal to a preset temperature according to an embodiment of the present invention;
fig. 17 is a schematic diagram of an equivalent structure of a second switch tube turned on when the temperature of an output transistor is greater than or equal to a preset temperature according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present invention are shown in the drawings.
Fig. 6 is a schematic structural diagram of a buck circuit according to an embodiment of the present invention. As shown in fig. 6, the buck circuit includes a driving unit 110, an input control unit 120, an output transistor 130, an over-temperature protection unit 140, and an output storage unit 150; the driving unit 110 is connected to the control terminal of the input control unit 120 and the control terminal of the output transistor 130, respectively, the first terminal of the input control unit 120 is connected to the power input terminal VDD, the second terminal of the input control unit 120 and the first terminal of the output transistor 130 are connected to the first input terminal of the output memory unit 150, the second terminal of the output transistor 130 and the second input terminal of the output memory unit 150 are connected to the first potential terminal V1, and the output terminal of the output memory unit 150 serves as the output terminal OUT of the buck circuit; the driving unit 110 is used for controlling the input control unit 120 and the output transistor 130 to conduct in a time-sharing manner, the input control unit 120 is used for providing electric energy for the output storage unit 150 when conducting, and the output transistor 130 is used for communicating with a discharge loop of the output storage unit 150; the input end of the over-temperature protection unit 140 is connected with the first pole of the output transistor 130, the output end of the over-temperature protection unit 140 is connected with the driving unit 110, and the over-temperature protection unit 140 is used for forming an over-temperature protection signal according to the conduction voltage drop of the output transistor 130; the driving unit 110 is further configured to control the input control unit 120 and the output transistor 130 to be turned off according to the over-temperature protection signal.
Specifically, during the operation of the buck circuit, the driving unit 110 may form a control signal according to the power supplied by the power input terminal VDD and the voltage required to be output by the output terminal OUT, so as to control the input control unit 120 and the output transistor 130 to be turned on in a time-sharing manner. When the driving unit 110 controls the input control unit 120 to be turned on, the output transistor 130 is turned off, and a power signal provided by the power input terminal VDD is transmitted to the output storage unit 150 through the input control unit 120, so that the output storage unit 150 can store electric energy. When the driving unit 110 controls the output transistor 130 to be turned on, the input control unit 120 is turned off, and the output transistor 130 may communicate with a discharge loop of the output memory unit 150 so that the output memory unit 150 may be discharged, thereby providing power through the output terminal OUT. In the above process, the driving unit 110 may control the electric energy stored in the output storage unit 150 by controlling the time of time-sharing turn-on of the input control unit 120 and the output transistor 130, and thus may control the voltage when the output storage unit 150 discharges, thereby implementing the conversion of the dc voltage. Therein, it is exemplarily shown in fig. 6 that the output storage unit 150 comprises an inductance and a capacitance for storing electrical energy, while the voltage signal may be filtered.
In addition, when the states of the input control unit 120 and the output transistor 130 are switched, there is an intermediate state in which the input control unit 120 and the output transistor 130 are simultaneously turned off, and at this time, the output memory unit 150 freewheels through the body diode D1 of the output transistor 130, and the first pole potential of the output transistor 130 is the first potential provided by the first potential terminal V1 minus the on-voltage drop of the body diode D1. Illustratively, when the first potential terminal V1 is the ground terminal, the first pole potential of the output transistor 130 is a negative value of the turn-on voltage drop of the body diode D1. And the on-voltage drop of the body diode D1 of the output transistor 130 is inversely related to the temperature, so that the first pole potential of the output transistor 130 is positively related to the temperature. After the over-temperature protection unit 140 obtains the first polar potential of the output transistor 130, the temperature of the output transistor 130 may be determined according to the first polar potential of the output transistor 130, when the temperature of the output transistor 130 is greater than the preset temperature, the first polar potential of the output transistor 130 is greater than the preset voltage, at this time, the over-temperature protection unit 140 forms an over-temperature protection signal according to the first polar potential of the output transistor 130 and outputs the over-temperature protection signal to the driving unit 110, and the driving unit 110 controls the input control unit 120 and the output transistor 130 to be turned off according to the over-temperature protection signal, so that the buck circuit stops working, and over-temperature protection of the buck circuit is realized. In the above-mentioned over-temperature protection process, the over-temperature protection unit 140 may directly form an over-temperature protection signal according to the first pole potential of the output transistor 130 and the preset voltage, that is, may form an over-temperature protection signal according to the on-voltage drop of the body diode D1 of the output transistor 130, so as to improve the speed of temperature detection, and further improve the speed of over-temperature protection. And the over-temperature protection signal can directly reflect the temperature change of the output transistor 130, so that the correlation between the over-temperature protection signal and the temperature of the output transistor 130 is improved, and the over-temperature protection precision of the buck circuit is further improved.
Fig. 7 is a schematic diagram of a conduction voltage drop of a body diode of an output transistor at 25 ° according to an embodiment of the present invention, and fig. 8 is a schematic diagram of a conduction voltage drop of a body diode of an output transistor at 150 ° according to an embodiment of the present invention. The abscissa is the time for acquiring the first polar potential of the output transistor, and the ordinate is the potential V of the first polar of the output transistor. As shown in fig. 7 and 8, when the first potential terminal V1 is the ground terminal. At the first sampling time t1 and the second sampling time t2, the driving unit 110 controls the input control unit 120 and the output transistor 130 to be turned off simultaneously, the body diode D1 of the output transistor 130 freewheels, and the first electrode potential of the output transistor 130 obtained at this time is a negative value of the on voltage drop of the body diode D1. As can be seen from fig. 7 and 8, the on-voltage drop of the body diode D1 of the output transistor 130 at 150 ° is 0.7V, the first pole potential of the output transistor 130 at 25 ° is-0.7V, the on-voltage drop of the body diode D1 of the output transistor 130 at 25 ° is 1V, the first pole potential of the output transistor 130 at 150 ° is-1V, the on-voltage drop of the body diode D1 of the output transistor 130 at 150 ° is smaller than the on-voltage drop of the body diode D1 of the output transistor 130 at 25 °, and the first pole potential of the output transistor 130 at 150 ° is greater than the first pole potential of the output transistor 130 at 25 °. The first polarity potential of the output transistor 130 is obtained by the over-temperature protection unit 140, and when the first polarity potential of the output transistor 130 is greater than the preset voltage, an over-temperature protection signal may be formed according to the preset voltage and the first polarity potential of the output transistor 130. The preset voltage may be set according to a conduction voltage drop of the body diode D1 of the output transistor 130 corresponding to the preset temperature of the over-temperature protection. For example, when the preset temperature of the over-temperature protection is 150 °, the preset voltage may be set according to an on-voltage drop of the body diode D1 of the output transistor 130 at 150 °. Then, the driving unit 110 controls the input control unit 120 and the output transistor 130 to be turned off according to the over-temperature protection signal, so that the buck circuit stops working, and over-temperature protection of the buck circuit is realized.
According to the technical scheme, the first pole potential of the output transistor is related to the conduction voltage drop of the body diode of the output transistor, the conduction voltage drop of the body diode of the output transistor is related to the temperature of the output transistor, the first pole potential of the output transistor is obtained through the over-temperature protection unit, and an over-temperature protection signal is formed according to the first pole potential of the output transistor and the preset voltage, so that the driving unit controls the input control unit and the output transistor to be turned off according to the over-temperature protection signal, and over-temperature protection of a buck circuit is achieved. The over-temperature protection signal is directly formed according to the first pole potential of the output transistor and the preset voltage, so that the speed of temperature detection can be improved, and the over-temperature protection speed can be improved. And the correlation between the over-temperature protection signal and the temperature of the output transistor can be improved, so that the over-temperature protection precision of the buck circuit is improved.
Fig. 9 is a schematic diagram of another buck circuit according to an embodiment of the present invention. As shown in fig. 9, the over-temperature protection unit 140 includes a mirroring module 141, a reference module 142, a conversion module 143, and a comparison module 144; the first end of the mirror module 141 is connected to the power input terminal VDD, the second end of the mirror module 141 is connected to the second potential terminal V2, and the mirror module 141 is configured to mirror the current of the main body branch 1411 to the output terminal of the mirror branch 1412; the first end of the reference module 142 is connected to the output end of the mirror branch 1412 and the negative input end IN of the comparison module 144, the second end of the reference module 142 is connected to the second potential end V2, and the reference module 142 is configured to form a reference signal according to the current of the mirror branch 1412; a first control end of the conversion module 143 is connected with the control end of the input control unit 120, a second control end of the conversion module 143 is connected with the control electrode of the output transistor 130, a first input end of the conversion module 143 is connected with the first electrode of the output transistor 130, a second input end of the conversion module 143 is connected with the second potential end V2, an output end of the conversion module 143 is connected with the positive input end in+ of the comparison module 144 and an output end of the mirror branch 1412, and the conversion module 143 is used for converting the potential of the first electrode of the output transistor 130 or the potential of the second potential end V2 according to the potential of the control end of the input control unit 120 and the potential of the control electrode of the output transistor 130 and outputting a conversion signal; the output end of the comparison module 144 is connected to the driving unit 110, and the comparison module 144 is configured to compare the reference signal and the conversion signal and output an over-temperature protection signal.
Specifically, the mirroring module 141 includes a main body branch 1411 and at least one mirroring branch 1412, and the current provided by the main body branch 1411 may be mirrored to the mirroring branch 1412, such that the current of the mirroring branch 1412 is directly proportional to the current of the main body branch 1411, and the currents of the different mirroring branches 1412 may be equal. As shown in fig. 9, the mirror module 141 illustratively includes two mirror branches 1412, and the output of the first mirror branch 1412 is coupled to a first end of the reference module 142 for providing current to the reference module 142. The output of the second mirror leg 1412 is coupled to the conversion module 143 for providing current to the conversion module 143. Both the reference signal and the converted signal may be voltage signals, where the currents of the two mirror branches 1412 may be set equal, and the change in the converted signal formed by the conversion module 143 is related to the input voltage. The conversion module 143 may convert the first polarity potential of the output transistor 130 to output as a converted signal or convert the second potential provided by the second potential terminal V2 to output as a converted signal under the control of the control terminal potential of the input control unit 120 and the control electrode potential of the output transistor 130, so that the change of the converted signal is related to the first polarity potential of the output transistor 130 and the potential of the second potential terminal V2.
Specifically, when the control terminal potential of the input control unit 120 and the control terminal potential of the output transistor 130 control the input control unit 120 and the output transistor 130 to be turned on in a time-sharing manner, the control terminal potential of the input control unit 120 may control the input control unit 120 to be turned off while the control terminal potential of the output transistor 130 controls the output transistor 130 to be turned on, or the control terminal potential of the input control unit 120 may control the input control unit 120 to be turned on while the control terminal potential of the output transistor 130 controls the output transistor 130 to be turned off. The conversion module 143 can convert the second potential provided by the second potential end V2 and output the converted second potential as a conversion signal, and at this time, the conversion signal output by the conversion module 143 is smaller than the reference signal, the comparison module 144 outputs a low-level signal according to the positive input end in+ and the negative input end IN-, i.e. the over-temperature protection signal is a low-level signal, and the driving unit 110 does not act according to the over-temperature protection signal. The second potential provided by the second potential end V2 is a fixed potential, and will not change with temperature, and the buck circuit works normally at this time. For example, the comparison module 144 may include a comparator for comparing the reference signal and the converted signal.
When the input control unit 120 is controlled to be turned off by the control terminal potential of the input control unit 120 and the output transistor 130 is controlled to be turned off by the gate potential of the output transistor 130, the body diode D1 of the output transistor 130 is in a freewheeling state, and the conversion module 143 converts the first electrode potential of the output transistor 130 under the control of the control terminal potential of the input control unit 120 and the gate potential of the output transistor 130 and outputs the converted first electrode potential as a conversion signal. When the temperature of the output transistor 130 is less than the preset temperature, the first electrode potential of the output transistor 130 is less than the preset voltage, at this time, the conversion signal formed by the conversion module 143 according to the first electrode potential of the output transistor 130 is less than the reference signal, the comparison module 144 outputs a low level signal according to the positive input terminal in+ and the negative input terminal IN-, i.e. the over-temperature protection signal is a low level signal, and the driving unit 110 does not act according to the over-temperature protection signal. When the temperature of the output transistor 130 is greater than or equal to the preset temperature, the first electrode potential of the output transistor 130 is greater than or equal to the preset voltage, at this time, the conversion signal formed by the conversion module 143 according to the first electrode potential of the output transistor 130 is greater than the reference signal, the comparison module 144 outputs a high-level signal according to the positive input terminal in+ and the negative input terminal IN-, i.e. the over-temperature protection signal is a high-level signal, and the driving unit 110 controls the input control unit 120 and the output transistor 130 to be turned off according to the over-temperature protection signal, so that the buck circuit stops working, and over-temperature protection of the buck circuit is realized.
Fig. 10 is a schematic diagram of another buck circuit according to an embodiment of the present invention. As shown in fig. 10, the conversion module 143 includes a path selection submodule 1431 and a conversion submodule 1432; a first input terminal of the path selection submodule 1431 is connected with a control terminal of the input control unit 120, a second input terminal of the path selection submodule 1431 is connected with a control electrode of the output transistor 130, and the path selection submodule 1431 is used for forming a first control signal and a second control signal according to a potential of the control terminal of the input control unit 120 and a potential of the control electrode of the output transistor 130; a first output terminal of the path selection submodule 1431 is connected with a first control terminal of the conversion submodule 1432, a second output terminal of the path selection submodule 1431 is connected with a second control terminal of the conversion submodule 1432, a first input terminal of the conversion submodule 1432 is connected with a first pole of the output transistor 130, a second input terminal of the conversion submodule 1432 is connected with a second potential terminal V2, and an output terminal of the conversion submodule 1432 is connected with a positive input terminal in+ of the comparison module 144 and an output terminal of the mirror branch 1412; the conversion submodule 1432 is configured to convert the first pole potential of the output transistor 130 into a conversion signal or convert the potential of the second potential terminal V2 into a conversion signal according to the first control signal provided at the first output terminal of the path selection submodule 1431 and the second control signal provided at the second output terminal of the path selection submodule 1431.
Specifically, the path selection submodule 1431 may select the conversion submodule 1432 to convert the voltage signal input from the first input terminal or the second input terminal according to the control terminal potential of the input control unit 120 and the control electrode potential of the output transistor 130. When the control terminal potential of the input control unit 120 and the control electrode potential of the output transistor 130 control the input control unit 120 and the output transistor 130 to be turned on IN a time-sharing manner, the path selection submodule 1431 may control the conversion submodule 1432 to convert the potential of the second potential terminal V2 into a conversion signal according to the first control signal and the second control signal output by the control terminal potential of the input control unit 120 and the control electrode potential of the output transistor 130, and at this time, the conversion signal is smaller than the reference signal, and the comparison module 144 outputs a low level signal, i.e., the over-temperature protection signal is a low level signal according to the positive input terminal in+ and the negative input terminal IN-, and the driving unit 110 does not act according to the over-temperature protection signal. When the control terminal potential of the input control unit 120 controls the input control unit 120 to be turned off and the gate potential of the output transistor 130 controls the output transistor 130 to be turned off, the path selecting submodule 1431 may control the converting submodule 1432 to convert the first gate potential of the output transistor 130 into the converting signal according to the control terminal potential of the input control unit 120 and the first control signal and the second control signal outputted from the gate potential of the output transistor 130. When the temperature of the output transistor 130 is less than the preset temperature, the first electrode potential of the output transistor 130 is less than the preset voltage, the converted signal is less than the reference signal, the comparison module 144 outputs a low-level signal according to the positive input terminal in+ and the negative input terminal IN-, i.e. the over-temperature protection signal is a low-level signal, and the driving unit 110 does not act according to the over-temperature protection signal. When the temperature of the output transistor 130 is greater than or equal to the preset temperature, the first polar potential of the output transistor 130 is greater than or equal to the preset voltage, at this time, the conversion signal is greater than or equal to the reference signal, the comparison module 144 outputs a high-level signal according to the positive input terminal in+ and the negative input terminal IN-, that is, the over-temperature protection signal is a high-level signal, and the driving unit 110 controls the input control unit 120 and the output transistor 130 to be turned off according to the over-temperature protection signal, so that the buck circuit stops working, and over-temperature protection of the buck circuit is realized.
Based on the above technical solutions, fig. 11 is a schematic structural diagram of another buck circuit according to the embodiment of the present invention. As shown in fig. 11, the input control unit 120 includes an input transistor M1, a control electrode of the input transistor M1 is connected to the driving unit 110, a first electrode of the input transistor M1 is connected to the power input terminal VDD, and a second electrode of the input transistor M1 is connected to an input terminal of the output memory unit 150.
Specifically, the input transistor M1 is exemplarily shown as a P-type transistor and the output transistor 130 is an N-type transistor in fig. 11. When the driving unit 110 controls the input transistor M1 and the output transistor 130 to be turned on in a time-sharing manner, the same level of control signal may be supplied to the input transistor M1 and the output transistor 130 at the same time. Illustratively, during the charging process, the driving unit 110 outputs a low level to the control electrode of the input transistor M1 and the control electrode of the output transistor 130, such that the input transistor M1 is turned on, the output transistor 130 is turned off, and the power signal provided by the power input terminal VDD is transmitted to the output storage unit 150 through the input transistor M1, such that the output storage unit 150 can store electric energy. During the discharging process, the driving unit 110 outputs a high level to the control electrode of the input transistor M1 and the control electrode of the output transistor 130, so that the input transistor M1 is turned off, the output transistor 130 is turned on, and the output transistor 130 may be connected to the discharging circuit of the output memory unit 150, so that the output memory unit 150 may be discharged, and thus, power may be supplied through the output terminal OUT.
With continued reference to fig. 11, the path selection submodule 1431 includes a first inverter F1, an and logic operator G1, and a second inverter F2; the first input terminal of the logic operator G1 is connected to the control terminal of the input control unit 120, the input terminal of the first inverter F1 is connected to the control terminal of the output transistor 130, the output terminal of the first inverter F1 is connected to the second input terminal of the logic operator G1, the output terminal of the logic operator G1 is connected to the first control terminal of the conversion submodule 1432, the input terminal of the second inverter F2 is connected to the output terminal of the logic operator G1, and the output terminal of the second inverter F2 is connected to the second control terminal of the conversion submodule 1432.
Specifically, when the driving unit 110 controls the input transistor M1 and the output transistor 130 to be turned on in a time-sharing manner, the potentials of the control electrode of the input transistor M1 and the control electrode of the output transistor 130 are simultaneously high or low. The driving unit 110 outputs a low level to the control electrode of the input transistor M1 and the control electrode of the output transistor 130, the first input terminal of the logic operator G1 is input with a low level, the input terminal of the first inverter F1 is input with a low level, the first inverter F1 outputs a high level, the second inverter F2 outputs a low level, and the switching sub-module 1432 switches the potential of the second potential terminal V2 to a switching signal, the switching signal is smaller than the reference signal, the comparing module 144 outputs a low level signal, i.e., an over-temperature protection signal is a low level signal according to the positive input terminal in+ and the negative input terminal IN-, and the driving unit 110 does not operate according to the over-temperature protection signal. Alternatively, the driving unit 110 outputs a high level to the control electrode of the input transistor M1 and the control electrode of the output transistor 130, at this time, the high level is input to the first input terminal of the logic operator G1, the high level is input to the input terminal of the first inverter F1, the low level is output after passing through the first inverter F1, the low level is output to the logic operator G1, the high level is output to the second inverter F2, so that the converting sub-module 1432 converts the potential of the second potential terminal V2 into a converted signal, at this time, the converted signal is smaller than the reference signal, the comparing module 144 outputs a low level signal according to the positive input terminal in+ and the negative input terminal IN-, i.e. the over-temperature protection signal is a low level signal, and the driving unit 110 does not operate according to the over-temperature protection signal. When the driving unit 110 controls the input transistor M1 and the output transistor 130 to be turned off simultaneously, the potential of the control electrode of the input transistor M1 is at a high level, the potential of the control electrode of the output transistor 130 is at a low level, at this time, the high level is input to the first input terminal of the logic operator G1, the low level is input to the input terminal of the first inverter F1, the high level is output after passing through the first inverter F1, the high level is output to the logic operator G1, the low level is output to the second inverter F2, and the first electrode potential of the output transistor 130 is converted into a conversion signal by the conversion sub-module 1432. When the temperature of the output transistor 130 is less than the preset temperature, the first electrode potential of the output transistor 130 is less than the preset voltage, the converted signal is less than the reference signal, the comparison module 144 outputs a low-level signal according to the positive input terminal in+ and the negative input terminal IN-, i.e. the over-temperature protection signal is a low-level signal, and the driving unit 110 does not act according to the over-temperature protection signal. When the temperature of the output transistor 130 is greater than or equal to the preset temperature, the first polar potential of the output transistor 130 is greater than or equal to the preset voltage, at this time, the conversion signal is greater than or equal to the reference signal, the comparison module 144 outputs a high-level signal according to the positive input terminal in+ and the negative input terminal IN-, that is, the over-temperature protection signal is a high-level signal, and the driving unit 110 controls the input control unit 120 and the output transistor 130 to be turned off according to the over-temperature protection signal, so that the buck circuit stops working, and over-temperature protection of the buck circuit is realized.
Fig. 12 is a schematic diagram of another buck circuit according to an embodiment of the present invention. As shown in fig. 12, the conversion sub-module 1432 includes a conversion resistor R1, a first switching tube K1, and a second switching tube K2; the control pole of the first switching tube K1 is connected to the first output terminal of the path selection submodule 1431, the first pole of the first switching tube K1 is connected to the first pole of the output transistor 130, the control pole of the second switching tube K2 is connected to the second output terminal of the path selection submodule 1431, the first pole of the second switching tube K2 is connected to the second potential terminal V2, the second pole of the first switching tube K1 is connected to the first terminal of the switching resistor R1, and the second terminal of the switching resistor R1 and the second pole of the second switching tube K2 are connected to the positive input terminal in+ of the comparison module 144 and the output terminal of the mirror branch 1412.
Specifically, fig. 12 exemplarily shows that the first switching transistor K1 and the second switching transistor K2 are both N-type transistors, and the second potential terminal V2 is a ground terminal. When the driving unit 110 controls the input transistor M1 and the output transistor 130 to be turned on in a time-sharing manner, the potentials of the control electrodes of the input transistor M1 and the output transistor 130 are simultaneously high or low. At this time, the AND logic operator G1 outputs a low level, and the second inverter F2 outputs a high level, so that the first switching tube K1 is turned off, and the second switching tube K2 is turned on. The second switch tube K2 is connected to the second potential end V2 and the positive input end in+ of the comparison module 144, the second potential signal provided by the second potential end V2 is transmitted to the positive input end in+ of the comparison module 144 through the second switch tube K2, the potential of the positive input end in+ of the comparison module 144 is smaller than the reference signal, the comparison module 144 outputs a low-level signal according to the positive input end in+ and the negative input end IN-, that is, the over-temperature protection signal is a low-level signal, and the driving unit 110 does not act according to the over-temperature protection signal. When the driving unit 110 controls the input transistor M1 and the output transistor 130 to be turned off, the and logic operator G1 outputs a high level, and the second inverter F2 outputs a low level, so that the first switching transistor K1 is turned on and the second switching transistor K2 is turned off. The first switching transistor K1 is connected to the first pole of the output transistor 130, the switching resistor R1 and the positive input terminal in+ of the comparison module 144, and the first pole potential of the output transistor 130 is transmitted to the positive input terminal in+ of the comparison module 144 through the first switching transistor K1 and the switching resistor R1. The current on the path is a fixed current provided by the mirror image branch 1412, so that the voltage at two ends of the switching resistor R1 is fixed, and the conduction voltage drop of the first switching tube K1 is unchanged. When the temperature of the output transistor 130 is less than the preset temperature, the first electrode potential of the output transistor 130 is less than the preset voltage, and then the voltage conversion is performed through the first switch tube K1 and the conversion resistor R1, that is, the conversion signal is the sum of the first electrode potential of the output transistor 130, the on voltage drop of the first switch tube K1 and the voltages at two ends of the conversion resistor R1, so that the conversion signal of the positive input terminal in+ of the comparison module 144 is less than the reference signal of the negative input terminal IN-, the comparison module 144 outputs a low level signal according to the positive input terminal in+ and the negative input terminal IN-, that is, the over-temperature protection signal is a low level signal, and the driving unit 110 does not act according to the over-temperature protection signal. When the temperature of the output transistor 130 is greater than or equal to the preset temperature, the first electrode potential of the output transistor 130 is greater than or equal to the preset voltage, and then voltage conversion is performed through the first switch tube K1 and the conversion resistor R1, that is, the conversion signal is the sum of the conduction voltage drop of the first electrode potential of the output transistor 130 and the first switch tube K1 and the voltages at two ends of the conversion resistor R1, so that the conversion signal of the positive input terminal in+ of the comparison module 144 is greater than or equal to the reference signal of the negative input terminal IN-, the comparison module 144 outputs a high-level signal according to the positive input terminal in+ and the negative input terminal IN-, that is, the over-temperature protection signal is a high-level signal, the driving unit 110 controls the input control unit 120 and the output transistor 130 to be turned off according to the over-temperature protection signal, and the buck circuit stops working, and over-temperature protection of the buck circuit is realized.
On the basis of the above technical solution, optionally, the first switching tube K1 and the second switching tube K2 are the same type, and the levels of the first control signal and the second control signal are opposite.
Specifically, when the levels of the first control signal and the second control signal are opposite, the types of the first switching transistor K1 and the second switching transistor K2 may be set to be the same, so that the first switching transistor K1 and the second switching transistor K2 are turned on in a time-sharing manner, so that the first pole potential of the output transistor 130 may be obtained when the body diode D1 of the output transistor 130 freewheels, for characterizing the temperature of the output transistor 130. Fig. 12 exemplarily shows that the first switching transistor K1 and the second switching transistor K2 are both N-type transistors. In other embodiments, the first switching tube K1 and the second switching tube K2 may be P-type transistors, and at this time, the levels of the first control signal and the second control signal may be correspondingly set to be interchanged, which is not limited herein.
It should be noted that, in other embodiments, the types of the first switching tube K1 and the second switching tube K2 may be different, and at this time, the path selecting sub-module 1431 may only include the first inverter F1 and the and logic operator G1, and the control signal provided by the output end of the and logic operator G1 may simultaneously control the first switching tube K1 and the second switching tube K2 to be in an on or off state respectively.
Fig. 13 is a schematic diagram of another buck circuit according to an embodiment of the present invention. As shown in fig. 13, the reference module 142 includes a third switching tube K3 and a reference resistor R2; the control electrode of the third switching tube K3 is used for accessing a control voltage, and the control voltage is used for controlling the third switching tube K3 to be in a long-turn-on state; the first pole of the third switching tube K3 is connected to the first pole of the reference resistor R2, the second pole of the third switching tube K3 is connected to the second potential end V2, and the second pole of the reference resistor R2 is connected to the output end of a mirror branch 1412.
Specifically, the mirror branch 1412 is configured to provide a fixed current to the reference module 142, such that the reference resistor R2 has a fixed voltage drop across it. At the same time, the second pole of the third switching tube K3 is connected to the second potential terminal V2, so that the reference module 142 can output a desired reference signal by adjusting the reference resistor R2. Meanwhile, the potential at one end of the reference module 142 can be equal to the potential of the conversion submodule 1432 when the first-pole potential of the output transistor 130 is not acquired, so that the consistency of the reference module 142 and the conversion submodule 1432 is improved, and the over-temperature protection precision is improved. In addition, the third switching tube K3 is the same as the first switching tube K1 and the second switching tube K2 in the conversion submodule 1432, so that the structure of the reference module 142 is the same as the structure of the conversion submodule 1432, the second pole of the third switching tube K2 is connected with the second potential end V2, the first pole of the second switching tube K2 is connected with the second potential end V2, the branch current of the reference module 142 is the same as the branch current of the conversion submodule 1432, and the differential influence of interference factors on the reference signal provided by the reference module 142 and the conversion signal provided by the conversion submodule 1432 can be reduced as much as possible, so that the over-temperature protection precision is further improved.
For example, when the second potential end V2 is a ground end, the conduction voltage drop of the first switch tube K1, the second switch tube K2 and the third switch tube K3 is 0.5V, and the voltage across the switching resistor R1 is set to be 4V as required, and the voltage across the reference resistor R2 is 3.1V, the reference signal is the sum of the potential 0V of the ground end and the conduction voltage drop of the third switch tube K3 of 0.5V and the voltage across the reference resistor R2 of 3.1V, that is, 3.6V, and the input voltage of the negative input end IN-of the comparison module 144 is 3.6V. Fig. 14 is a schematic diagram of an equivalent structure of a first switch tube turned on when the temperature of an output transistor is less than a preset temperature, and fig. 15 is a schematic diagram of an equivalent structure of a second switch tube turned on when the temperature of the output transistor is less than the preset temperature. Fig. 16 is a schematic diagram of an equivalent structure of a first switch tube turned on when a temperature of an output transistor is greater than or equal to a preset temperature, and fig. 17 is a schematic diagram of an equivalent structure of a second switch tube turned on when the temperature of the output transistor is greater than or equal to the preset temperature. As shown in fig. 7, 8, and 14 to 17, when the temperature of the output transistor 130 is less than the preset temperature, for example, 25 °, the on-voltage drop of the body diode D1 of the output transistor 130 is relatively large, 1V, and the first pole potential of the output transistor 130 is relatively small, 1V. If the first switch K1 is turned on, the input voltage of the positive input terminal in+ of the comparison module 144 is-1V, the sum of the conduction voltage drop of the first switch K1 and the voltage 4V across the switching resistor R1 is 3.5V, the potential of the positive input terminal in+ of the comparison module 144 is less than the reference signal, the comparison module 144 outputs a low-level signal according to the positive input terminal in+ and the negative input terminal IN-, i.e. the over-temperature protection signal is a low-level signal, and the driving unit 110 does not act according to the over-temperature protection signal. If the second switch tube K2 is turned on, the sum of the input voltage of the positive input terminal in+ of the comparison module 144 and the conduction voltage drop of the first switch tube K1 is 0.5V, and is 0.5V, the potential of the positive input terminal in+ of the comparison module 144 is smaller than the reference signal, the comparison module 144 outputs a low-level signal according to the positive input terminal in+ and the negative input terminal IN-, i.e. the over-temperature protection signal is a low-level signal, and the driving unit 110 does not act according to the over-temperature protection signal. When the temperature of the output transistor 130 is greater than or equal to the preset temperature, for example, 150 °, the on-voltage drop of the body diode D1 of the output transistor 130 is smaller and is 0.7V, and the first pole potential of the output transistor 130 is larger and is-0.7V. If the first switch K1 is turned on, the input voltage of the positive input terminal in+ of the comparison module 144 is-0.7V, the sum of the conduction voltage drop 0.5V of the first switch K1 and the voltage 4V at two ends of the conversion resistor R1 is 3.8V, the conversion signal of the positive input terminal in+ of the comparison module 144 is greater than or equal to the reference signal of the negative input terminal IN-, the comparison module 144 outputs a high-level signal according to the positive input terminal in+ and the negative input terminal IN-, that is, the over-temperature protection signal is a high-level signal, the driving unit 110 controls the input control unit 120 and the output transistor 130 to be turned off according to the over-temperature protection signal, so that the buck circuit stops working, and over-temperature protection of the buck circuit is realized. If the second switch tube K2 is turned on, the sum of the input voltage of the positive input terminal in+ of the comparison module 144 and the conduction voltage drop of the first switch tube K1 is 0.5V, and is 0.5V, the potential of the positive input terminal in+ of the comparison module 144 is smaller than the reference signal, the comparison module 144 outputs a low-level signal according to the positive input terminal in+ and the negative input terminal IN-, i.e. the over-temperature protection signal is a low-level signal, and the driving unit 110 does not act according to the over-temperature protection signal.
With continued reference to fig. 13, body branch 1411 includes a bias current source I1 and a body transistor M2, and mirror branch 1412 includes a mirror transistor M3; the first terminal of the bias current source I1 is connected to the second potential terminal V2, the second terminal of the bias current source I1 is connected to the second pole and the control pole of the body transistor M2, the first pole of the body transistor M2 and the first pole of the mirror transistor M3 are connected to the power input terminal VDD, the control pole of the mirror transistor M3 is connected to the control pole of the body transistor M2, and the second pole of the mirror transistor M3 is used as the output terminal of the mirror branch 1412.
Specifically, the bias current source I1 is used to provide a mirror current. The main body branch 1411 and the mirror branch 1412 form a mirror circuit, and the current of the main body branch 1411 is equal to the current of the mirror branch 1412, so as to provide the same current for the reference module 142 and the conversion module 143, reduce the difference therebetween, and facilitate the improvement of the over-temperature protection precision.
The embodiment of the invention also provides a DC-DC chip. The DC-DC chip comprises the buck circuit provided by any embodiment of the invention.
The DC-DC chip comprises the buck circuit provided by any embodiment of the invention, so that the DC-DC chip has the beneficial effects of the buck circuit provided by any embodiment of the invention, and the description is omitted herein.
Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims (10)

1. The buck circuit is characterized by comprising a driving unit, an input control unit, an output transistor, an over-temperature protection unit and an output storage unit;
the driving unit is respectively connected with the control end of the input control unit and the control electrode of the output transistor, the first end of the input control unit is connected with the power input end, the second end of the input control unit and the first electrode of the output transistor are connected with the first input end of the output storage unit, the second end of the output transistor and the second input end of the output storage unit are connected with the first potential end, and the output end of the output storage unit is used as the output end of the buck circuit; the driving unit is used for controlling the input control unit and the output transistor to conduct in a time-sharing way, the input control unit is used for providing electric energy for the output storage unit when conducting, and the output transistor is used for communicating a discharge loop of the output storage unit; the input end of the over-temperature protection unit is connected with the first pole of the output transistor, the output end of the over-temperature protection unit is connected with the driving unit, and the over-temperature protection unit is used for forming an over-temperature protection signal according to the conduction voltage drop of the output transistor; the driving unit is also used for controlling the input control unit and the output transistor to be turned off according to the over-temperature protection signal.
2. The buck circuit according to claim 1, wherein the over-temperature protection unit includes a mirror module, a reference module, a conversion module, and a comparison module;
the first end of the mirror image module is connected with the power input end, the second end of the mirror image module is connected with the second potential end, and the mirror image module is used for mirroring the current of the main body branch circuit to the output end of the mirror image branch circuit; the first end of the reference module is connected with the output end of the mirror branch and the negative input end of the comparison module, the second end of the reference module is connected with the second potential end, and the reference module is used for forming a reference signal according to the current of the mirror branch;
the first control end of the conversion module is connected with the control end of the input control unit, the second control end of the conversion module is connected with the control electrode of the output transistor, the first input end of the conversion module is connected with the first electrode of the output transistor, the second input end of the conversion module is connected with the second potential end, the output end of the conversion module is connected with the positive input end of the comparison module and the output end of the mirror branch, and the conversion module is used for converting the first electrode potential of the output transistor or the potential of the second potential end according to the potential of the control end of the input control unit and the potential of the control electrode of the output transistor and then outputting a conversion signal;
The output end of the comparison module is connected with the driving unit, and the comparison module is used for comparing the reference signal with the conversion signal and then outputting the over-temperature protection signal.
3. The buck circuit according to claim 2, wherein the switching module includes a path selection sub-module and a switching sub-module;
the first input end of the path selection submodule is connected with the control end of the input control unit, the second input end of the path selection submodule is connected with the control electrode of the output transistor, and the path selection submodule is used for forming a first control signal and a second control signal according to the potential of the control end of the input control unit and the potential of the control electrode of the output transistor; the first output end of the channel selection sub-module is connected with the first control end of the conversion sub-module, the second output end of the channel selection sub-module is connected with the second control end of the conversion sub-module, the first input end of the conversion sub-module is connected with the first pole of the output transistor, the second input end of the conversion sub-module is connected with the second potential end, and the output end of the conversion sub-module is connected with the positive input end of the comparison module and the output end of one mirror branch; the conversion sub-module is used for converting the first pole potential of the output transistor into the conversion signal or converting the potential of the second potential end into the conversion signal according to the first control signal provided by the first output end of the path selection sub-module and the second control signal provided by the second output end of the path selection sub-module.
4. The buck circuit according to claim 3, wherein the path selection submodule includes a first inverter, an and logic operator, and a second inverter;
the first input end of the AND logic arithmetic unit is connected with the control end of the input control unit, the input end of the first inverter is connected with the control electrode of the output transistor, the output end of the first inverter is connected with the second input end of the AND logic arithmetic unit, the output end of the AND logic arithmetic unit is connected with the first control end of the conversion sub-module, the input end of the second inverter is connected with the output end of the AND logic arithmetic unit, and the output end of the second inverter is connected with the second control end of the conversion sub-module.
5. The buck circuit according to claim 3, wherein the switching submodule includes a switching resistor, a first switching tube, and a second switching tube;
the control electrode of the first switching tube is connected with the first output end of the path selection submodule, the first electrode of the first switching tube is connected with the first electrode of the output transistor, the control electrode of the second switching tube is connected with the second output end of the path selection submodule, the first electrode of the second switching tube is connected with the second potential end, the second electrode of the first switching tube is connected with the first end of the conversion resistor, and the second end of the conversion resistor and the second electrode of the second switching tube are connected with the positive input end of the comparison module and the output end of the mirror image branch.
6. The buck circuit according to claim 5, wherein the first switching tube and the second switching tube are of the same type, and the first control signal and the second control signal are of opposite levels.
7. The buck circuit of claim 5, wherein the reference module includes a third switching tube and a reference resistor;
the control electrode of the third switching tube is used for being connected with a control voltage, and the control voltage is used for controlling the third switching tube to be in a long-turn-on state; the first pole of the third switching tube is connected with the first pole of the reference resistor, the second pole of the third switching tube is connected with the second potential end, and the second pole of the reference resistor is connected with the output end of one mirror branch.
8. The buck circuit according to claim 2, wherein the body leg includes a bias current source and a body transistor, the mirror leg including a mirror transistor;
the first end of the bias current source is connected with the second potential end, the second end of the bias current source is connected with the second pole and the control pole of the main body transistor, the first pole of the main body transistor and the first pole of the mirror image transistor are connected with the power input end, the control pole of the mirror image transistor is connected with the control pole of the main body transistor, and the second pole of the mirror image transistor is used as the output end of the mirror image branch.
9. The buck circuit according to claim 1, wherein the input control unit includes an input transistor;
the control electrode of the input transistor is connected with the driving unit, the first electrode of the input transistor is connected with the power input end, and the second electrode of the input transistor is connected with the input end of the output storage unit.
10. A DC-DC chip comprising the buck circuit of any one of claims 1-9.
CN202310545627.4A 2023-05-16 2023-05-16 Buck circuit and DC-DC chip Active CN116260107B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310545627.4A CN116260107B (en) 2023-05-16 2023-05-16 Buck circuit and DC-DC chip

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310545627.4A CN116260107B (en) 2023-05-16 2023-05-16 Buck circuit and DC-DC chip

Publications (2)

Publication Number Publication Date
CN116260107A true CN116260107A (en) 2023-06-13
CN116260107B CN116260107B (en) 2023-08-01

Family

ID=86682925

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310545627.4A Active CN116260107B (en) 2023-05-16 2023-05-16 Buck circuit and DC-DC chip

Country Status (1)

Country Link
CN (1) CN116260107B (en)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1265539A (en) * 1998-12-28 2000-09-06 矢崎总业株式会社 Power supply control equipment and method
US20020021539A1 (en) * 2000-08-16 2002-02-21 International Business Machines Corporation Protective circuit against overheating of a semiconductor switching device
US20040042142A1 (en) * 2002-08-29 2004-03-04 Murata Manufacturing Co., Ltd. Overheat protection circuit
US20060028257A1 (en) * 2004-08-03 2006-02-09 Hong Huang System and method for over-temperature protection sensing employing MOSFET on-resistance Rds_on
CN102394237A (en) * 2011-12-06 2012-03-28 电子科技大学 Composite VDMOS device possessing temperature sampling and over-temperature protection function
JP2014007809A (en) * 2012-06-22 2014-01-16 Renesas Electronics Corp Semiconductor integrated circuit and operation method of the same
CN104980016A (en) * 2015-06-19 2015-10-14 西安三馀半导体有限公司 DC-DC converter with linear over-temperature protection circuit
CN109638774A (en) * 2018-12-24 2019-04-16 中国电子科技集团公司第五十八研究所 A kind of thermal-shutdown circuit

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1265539A (en) * 1998-12-28 2000-09-06 矢崎总业株式会社 Power supply control equipment and method
US20020021539A1 (en) * 2000-08-16 2002-02-21 International Business Machines Corporation Protective circuit against overheating of a semiconductor switching device
US20040042142A1 (en) * 2002-08-29 2004-03-04 Murata Manufacturing Co., Ltd. Overheat protection circuit
US20060028257A1 (en) * 2004-08-03 2006-02-09 Hong Huang System and method for over-temperature protection sensing employing MOSFET on-resistance Rds_on
CN102394237A (en) * 2011-12-06 2012-03-28 电子科技大学 Composite VDMOS device possessing temperature sampling and over-temperature protection function
JP2014007809A (en) * 2012-06-22 2014-01-16 Renesas Electronics Corp Semiconductor integrated circuit and operation method of the same
CN104980016A (en) * 2015-06-19 2015-10-14 西安三馀半导体有限公司 DC-DC converter with linear over-temperature protection circuit
CN109638774A (en) * 2018-12-24 2019-04-16 中国电子科技集团公司第五十八研究所 A kind of thermal-shutdown circuit

Also Published As

Publication number Publication date
CN116260107B (en) 2023-08-01

Similar Documents

Publication Publication Date Title
US11061422B2 (en) Low dropout linear regulator and voltage stabilizing method therefor
JP5101741B2 (en) Semiconductor device and inverter, converter and power conversion device using the same
US5440254A (en) Accurate low voltage detect circuit
US20150130428A1 (en) Level shift circuit and dc-dc converter for using the same
US9531259B2 (en) Power supply circuit
US11108325B2 (en) Electronic circuit and method of controlling three-level switching converters
KR100334363B1 (en) Power supply apparatus
CN203422692U (en) Low dropout regulator and soft start circuit of low dropout regulator
CN116260107B (en) Buck circuit and DC-DC chip
CN113659812B (en) Miller clamp control circuit
US20220147084A1 (en) Voltage regulator
CN112260370B (en) Battery protection circuit board
CN112558680B (en) Linear regulator and control circuit thereof
CN113241944A (en) True turn-off circuit and control method of synchronous boost DC-DC converter
CN114094660A (en) Linear charging system with high-voltage turn-off function
JP6185032B2 (en) Semiconductor device and inverter, converter and power conversion device using the same
US11689195B2 (en) Semiconductor device
JP5892772B2 (en) Semiconductor device and inverter, converter and power conversion device using the same
CN112242789B (en) Switching power supply chip and switching power supply converter suitable for polarity inversion
US20240223083A1 (en) Power supply circuit and control method thereof
CN215934724U (en) True turn-off circuit of synchronous boosting DC-DC converter
CN218482777U (en) External simulation soft start circuit
US20240186322A1 (en) Driving circuit having a negative voltage isolation circuit
CN109959836B (en) Electric leakage detection circuit
US11909369B2 (en) Low-pass filter circuit

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant