CN109256939B - Current selection circuit and drive circuit - Google Patents

Current selection circuit and drive circuit Download PDF

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Publication number
CN109256939B
CN109256939B CN201710566052.9A CN201710566052A CN109256939B CN 109256939 B CN109256939 B CN 109256939B CN 201710566052 A CN201710566052 A CN 201710566052A CN 109256939 B CN109256939 B CN 109256939B
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current
current selection
resistor
selection circuit
circuit
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CN109256939A (en
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冯辉萍
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Chidonic Co ltd
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Chidonic Co ltd
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Priority to CN201710566052.9A priority Critical patent/CN109256939B/en
Priority to PCT/CN2018/094839 priority patent/WO2019011193A1/en
Publication of CN109256939A publication Critical patent/CN109256939A/en
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    • 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
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/33507—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of the output voltage or current, e.g. flyback converters
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
    • G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
    • G05F1/10—Regulating voltage or current
    • G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
    • G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
    • 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
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • 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
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0009—Devices or circuits for detecting current in a converter
    • 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
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0012—Control circuits using digital or numerical techniques
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/375—Switched mode power supply [SMPS] using buck topology
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/38—Switched mode power supply [SMPS] using boost topology
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • H05B45/30—Driver circuits
    • H05B45/37—Converter circuits
    • H05B45/3725—Switched mode power supply [SMPS]
    • H05B45/385—Switched mode power supply [SMPS] using flyback topology

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Automation & Control Theory (AREA)
  • Dc-Dc Converters (AREA)
  • Power Conversion In General (AREA)

Abstract

The application provides a current selection circuit and drive circuit, current selection circuit selects output current's gear according to the resistance of predetermined current selection resistance, and current selection circuit has input and output, and the input is connected with current selection resistance, and the output is connected with power converter, current selection circuit basis current selection resistance's resistance makes with the resistance that has predetermined resistance value that output current's gear corresponds via the output with power converter connects, power converter basis the selected resistance output current of current selection circuit. According to the present application, flexible current selection is possible, and the number of input terminals of the current selection device does not increase with an increase in the number of steps of the output current.

Description

Current selection circuit and drive circuit
Technical Field
The present invention relates to the field of power supply technologies, and in particular, to a current selection circuit and a driving circuit having the current selection circuit.
Background
When driving an electronic device using a driving circuit, a user sometimes needs to adjust the magnitude of a driving current output from the driving circuit, which requires the driving circuit to have a function of current selection.
In the conventional driving circuit, a digital integrated circuit (digital IC) may be provided to realize the function of current selection, and the digital IC may output different current selection signals through 2 ports.
In the conventional driving circuit, an analog circuit may be provided to realize the function of current selection, and the analog circuit may have a plurality of output ports to output different current selection signals, so that the driving circuit outputs currents of different magnitudes.
It should be noted that the above background description is only for the convenience of clear and complete description of the technical solutions of the present application and for the understanding of those skilled in the art. Such solutions are not considered to be known to the person skilled in the art merely because they have been set forth in the background section of the present application.
Disclosure of Invention
The inventor of the present application finds that, in the existing technology of implementing the current selection function by providing a digital integrated circuit, the digital integrated circuit outputs a current selection signal in a direct current form, and the cost of implementing the current selection is high; in the conventional technique of implementing the current selection function by providing an analog circuit, if the number of current selection stages to be output is increased, the number of output ports of the analog circuit is also increased.
The embodiment of the application provides a current selection circuit and a driving circuit, wherein the resistance value of a resistor connected to a power converter is adjusted by changing the resistance value of a current selection resistor connected to an input end of the current selection circuit, so that the current value of the current output by the power converter is adjusted, thereby the flexible current selection can be carried out, and the number of output ports of the current selection circuit is not increased.
According to an embodiment of the present application, there is provided a current selection circuit that selects a gear of an output current according to a resistance value of a preset current selection resistor, the current selection circuit having an input terminal and an output terminal, the input terminal being connected to the current selection resistor, the output terminal being connected to a power converter (power converter), the current selection circuit causing a resistor having a predetermined resistance value corresponding to the gear of the output current to be connected to the power converter via the output terminal according to the resistance value of the current selection resistor, the power converter outputting a current (current) corresponding to the gear according to the resistor selected by the current selection circuit.
The beneficial effects of the embodiment of the application are that: the resistance value of the resistor connected to the power converter is adjusted by changing the resistance value of the current selection resistor connected to the input terminal of the current selection circuit, thereby adjusting the current value of the current output by the power converter.
Specific embodiments of the present invention are disclosed in detail with reference to the following description and drawings, indicating the manner in which the principles of the invention may be employed. It should be understood that the embodiments of the invention are not so limited in scope. The embodiments of the invention include many variations, modifications and equivalents within the spirit and scope of the appended claims.
Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments, in combination with or instead of the features of the other embodiments.
It should be emphasized that the term "comprises/comprising" when used herein, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps or components.
Drawings
The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:
fig. 1 is a schematic diagram of a current selection circuit according to embodiment 1 of the present application;
fig. 2 is a schematic diagram of a power converter in accordance with embodiment 2 of the present application, together with a current selection circuit.
Detailed Description
The foregoing and other features of the invention will become apparent from the following description taken in conjunction with the accompanying drawings. In the description and drawings, particular embodiments of the invention have been disclosed in detail as being indicative of some of the embodiments in which the principles of the invention may be employed, it being understood that the invention is not limited to the embodiments described, but, on the contrary, is intended to cover all modifications, variations, and equivalents falling within the scope of the appended claims.
Example 1
Embodiment 1 of the present application provides a current selection device. Fig. 1 is a schematic diagram of the current selection circuit.
As shown in fig. 1, the current selection device 100 may have a preset current selection resistor 101 and a current selection circuit 102, and the current selection circuit 102 may select a gear of the output current according to a resistance value of the current selection resistor 101.
In this embodiment, the current selection circuit 102 may have an input terminal connected to the current selection resistor 101 and an output terminal connected to a power converter (power converter).
In the present embodiment, the current selection circuit 102 may connect a resistor having a predetermined resistance value corresponding to the shift position of the output current to the power converter 200 via the output terminal, according to the resistance value of the current selection resistor 101; the power converter 200 can output a corresponding current (current) according to the resistance selected by the current selection circuit 102.
In this embodiment, the power converter 200 may have a current control terminal 201, and a resistance value between the current control terminal 201 and a ground terminal may control a driving current value output by the power converter 200. In one embodiment, a current sense resistor 2011(current sense resistor) may be connected between the current control terminal 201 and the ground terminal, and the resistor selected by the current selection circuit 102 may be connected in parallel with the current sense resistor 2011, so that the resistance value of the resistor selected by the current selection circuit 102 may be adjusted by adjusting the resistance value of the current selection resistor 101 at the input terminal of the current selection circuit 102, and thus the resistance value between the current control terminal 201 and the ground terminal of the power converter 200 may be adjusted, so as to adjust the output current value of the power converter 200.
According to the present embodiment, the resistance value of the resistor connected to the power converter is adjusted by changing the resistance value of the current selection resistor connected to the input terminal of the current selection circuit, so as to adjust the current value of the current output by the power converter, thereby enabling flexible current selection, for example, the resistance value of the current selection resistor may change in a sinusoidal manner with time, and thus the driving current output by the power converter 200 may also change in a sinusoidal manner with time, thereby improving flexibility of current selection; also, the number of output ports of the current selection circuit does not increase.
In this embodiment, the power converter 200 can convert the input voltage into the driving current and output the driving current, and the value of the output driving current can be controlled by the resistance value between the current control terminal 201 and the ground terminal. Reference is made to the prior art with respect to the structure and operating principles of the power converter 200.
For example, the power converter 200 may have a rectifying circuit, a smoothing circuit, a switching element, a transformer, an output-side rectifying circuit, a center control device, and the like, wherein the rectifying circuit and the smoothing circuit can rectify and smooth the input alternating current; the central control device may have an on/off control port that may output a control signal to control the on and off of the switching element so as to resonate the smoothed electrical signal; the transformer causes the resonant electric signal to be transmitted to the output side of the switching power supply; the output side rectifying circuit rectifies an electric signal transmitted to the output side of the switching power supply to form a driving current and outputs the driving current. The central control device may further have a control port, i.e., a current control terminal 201 of the power converter 200, and a resistance value between the control port and a ground terminal can control a driving current value of the output of the power converter 200.
The structure and operation of the current selection apparatus 100 will be described in detail with reference to the accompanying drawings.
As shown in fig. 1, the current selection circuit 102 may have two terminals X1 and X2, and the output terminal of the current selection circuit 102 may have two terminals X3 and X4, wherein the terminal X2 and the terminal X4 may be connected to the ground terminal of the current selection apparatus 100. The current selection resistor 101 may be connected between the terminals X1 and X2, and the terminal X3 may be connected to the current control terminal 201 of the power converter 200.
In this embodiment, as shown in fig. 1, the current selection circuit 102 may have a voltage dividing resistor R1, the current selection resistor 101 and the voltage dividing resistor R1 are connected in series between the power terminal Vcc and the ground terminal of the current selection circuit, and the voltage value across the current selection resistor 101 can be adjusted by adjusting the resistance value of the current selection resistor 101.
In the present embodiment, the current selection circuit 102 may further have at least one current sensing resistor string, and in fig. 1, 4 current sensing resistor strings 1021, 1022, 1023, and 1024 are shown.
In the present embodiment, each current sensing resistor string is connected to the output terminal, for example, each current sensing resistor string 1021, 1022, 1023, and 1024 is connected in parallel between terminals X3 and X4 of the output terminal of the current selection circuit 102.
In this embodiment, each current sensing resistor string may have a first switching element and a first resistor connected in series, and the current selection resistor 101 controls whether the first switching element in each current sensing resistor string is turned on or not. For example, the current sensing resistor string 1021 has a first switching element Q1 and a first resistor R2, the current sensing resistor string 1022 has a first switching element Q2 and a first resistor R3, the current sensing resistor string 1023 has a first switching element Q3 and a first resistor R4, and the current sensing resistor string 1024 has a first switching element Q4 and a first resistor R5. In the present embodiment, the first switching element may be a Metal Oxide Semiconductor Field Effect Transistor (MOSFET), such as an N-type MOSFET, or may be another type of switching element.
In this embodiment, when the first switching element of a current sensing resistor string is turned on, the first resistor of the current sensing resistor string is connected to the power converter 200 through the output terminal, for example, the first resistor is connected between the current control terminal 201 and the ground terminal of the power converter 200 and connected in parallel with the current sensing resistor 2011.
In this embodiment, the first resistors of the current sensing resistor strings may have different resistance values, so that when different first switching elements are turned on, the first resistors with different resistance values may be connected in parallel with the current sensing resistor, so that the current control terminal 201 of the power converter 200 has different resistance values with the ground terminal.
In addition, the present embodiment may not be limited thereto, and the resistance values of the first resistors of the current sensing resistor strings may also be set to other values, for example, the resistance values of some first resistors may be the same.
In this embodiment, the current selection circuit 102 may further have at least one switch control circuit, and in fig. 1, 4 switch control circuits 1025, 1026,1027 and 1028 are shown, and the voltage across each switch control circuit can control whether the switch control circuit is turned on or not.
In this embodiment, each of the switch control circuits 1025, 1026,1027 and 1028 is connected in parallel to the current selection resistor 101, and therefore, the voltage across the current selection resistor 101 is the same as the voltage across each of the switch control circuits, and thus, by adjusting the resistance of the current selection resistor 101, the voltage across the current selection resistor 101 can be adjusted, thereby controlling whether each of the switch control circuits is turned on or off.
In this embodiment, the on threshold voltages required for turning on the respective switch control circuits may be different from each other, and thus, when the voltage across the current selection resistor 101 gradually increases, the switch control circuit having the lower on threshold voltage may be turned on first, and the switch control circuit having the higher on threshold voltage may be turned on later.
In the present embodiment, each of the switch control circuits 1025, 1026,1027 and 1028 may control whether or not the first switching elements Q1, Q2, Q3 and Q4 in the current sensing resistor strings 1021, 1022, 1023 and 1024 connected thereto are turned on, respectively, and thus the current selection resistor 101 controls whether or not the first switching elements Q1, Q2, Q3 and Q4 in the corresponding current sensing resistor strings 1021, 1022, 1023 and 1024 are turned on by controlling whether or not each of the switch control circuits 1025, 1026,1027 and 1028 is turned on.
In the present embodiment, each of the switch control circuits may have a second switching element (Q5, Q6, Q7, and Q8), a voltage stabilizing element (D1, D2, D3, and D4), and a second resistor (R6, R7, R8, and R9), wherein a current inflow terminal and a current outflow terminal of the second switching element, the second resistor, and the voltage stabilizing element are connected in series between a terminal X1 and a ground terminal, and a connection point between the second resistor and the voltage stabilizing element is connected to a control terminal, e.g., a gate, of the first switching element.
In the present embodiment, taking the switch control circuit 1025 as an example, in the case where the voltage across the switch control circuit 1025 causes the voltage stabilizing element D1 to break down, the second switching element Q5 is turned on, so that the voltage across the second resistor R5 rises, thereby turning on the first switching element Q1; in the case where the voltage across the switch control circuit 1025 is not enough to break down the voltage regulator D1, the second switch element Q5 is turned off, the voltage across the second resistor R5 is the same as the ground, and thus the first switch element Q1 is turned off.
In the present embodiment, each of the second switching elements Q5, Q6, Q7, and Q8 may be an npn bipolar transistor, but the present embodiment is not limited thereto, and the second switching elements may be other types of switching elements.
In this embodiment, the turn-on threshold voltage required for each switch control circuit to turn on may be related to the breakdown voltage of each voltage stabilization element, and the higher the breakdown voltage of the voltage stabilization element, the higher the turn-on threshold voltage required for the switch control circuit to turn on. In one embodiment, the breakdown voltage of each voltage stabilization element may be different.
In the present embodiment, the voltage regulator element may be a zener diode, for example, the breakdown voltage of the voltage regulator element D1 may be 6.2V, and its model may be BZX79-6V 2; the breakdown voltage of the voltage stabilizing element D2 can be 5.1V, and the model can be BZX79-5V 1; the breakdown voltage of the voltage stabilizing element D3 can be 3.9V, and the model can be BZX79-3V 9; the breakdown voltage of the voltage regulator element D4 may be 2.4V, and its model may be BZX79-2V 4. In addition, the voltage stabilizing elements can be of other types and models.
Further, as shown in fig. 1, each of the switch control circuits 1025, 1026,1027, and 1028 may further have a third resistor R10, R11, R12, and R13, and each of the third resistors may be connected between the base (base) of each of the second switching elements and the terminal X1.
In this embodiment, at a certain voltage, more than two switch control circuits may be turned on, for example, when the voltage across the current selection resistor 101 is higher than the turn-on threshold voltage of the switch control circuits 1027 and 1028, the switch control circuits 1027 and 1028 may be turned on, and thus, the first resistors R4 and R5 may be connected in parallel between the current control terminal 201 of the power converter 200 and the ground terminal.
For example, when one switch control circuit is turned on, the other switch control circuits may be turned off, thereby avoiding a case where two or more switch control circuits are simultaneously turned on.
As shown in fig. 1, the current selection circuit 102 may also have at least one additional control unit, in fig. 1, 3 additional control units 1031, 1032 and 1033 are shown.
In this embodiment, the additional control unit may control such that, in a case where the first switching element of one current sensing resistor string is turned on, the first switching elements of the other current sensing resistor strings are turned off, for example, the additional control unit may control such that, in a case where the switching control circuit having the higher on threshold voltage is turned on, the switching control circuit having the lower on threshold voltage is turned off.
In the present embodiment, each of the additional control units may be connected to other switch control circuits than the switch control circuit having the highest turn-on threshold voltage, respectively, for example, in fig. 1, the switch control circuit having the highest turn-on threshold voltage is 1025, and the other switch control circuits are 1026,1027 and 1028, and therefore, the additional control units 1031, 1032 and 1033 are connected to the other switch control circuits 1026,1027 and 1028, respectively. If the additional control units 1031, 1032 and 1033 are not provided, then when the switch control circuit 1025 with the highest conduction threshold voltage is turned on, the other switch control circuits 1026,1027 and 1028 will also be turned on, so that the present application can avoid the simultaneous conduction of more than two switch control circuits by connecting the additional control units 1031, 1032 and 1033 to the switch control circuits 1026,1027 and 1028, respectively, which have lower conduction thresholds.
In the present embodiment, as shown in fig. 1, each additional control unit may have third switching elements Q9, Q10, and Q11, which may be npn bipolar transistors or other types of switching elements.
In the present embodiment, the collector of each of the third switching elements (Q9, Q10, and Q11) may be connected to the base of the corresponding second switching element (Q6, Q7, and Q8), and the base of each of the third switching elements (Q9, Q10, and Q11) may be connected to the gate of the corresponding first switching element of the switch control circuit having a higher on-threshold voltage than the switch control circuit controlled by the third switching element via a third resistor (R20, R21, and R22).
For example, as shown in fig. 1, since the switch control circuit controlled by the third switching element Q9 is 1026 and the switch control circuit having a higher on-threshold voltage than the switch control circuit 1026 is 1025, the base of Q9 is connected to the gate of the first switching element Q1 corresponding to the switch control circuit 1025 via the third resistor R20, and thus, when Q1 is turned on, Q9 is also turned on, and the base potential of Q6 is lowered to turn off Q6, so that Q2 is turned off; similarly, the switch control circuit controlled by the third switching element Q10 is 1027, and the switch control circuits having higher on-threshold voltages than the switch control circuit 1027 are 1025 and 1026, so the base of Q10 is connected to the gate of the first switch Q1 corresponding to the switch control circuit 1025 via the third resistor R20, and the base of Q10 is also connected to the gate of the first switch Q2 corresponding to the switch control circuit 1026 via the third resistor R21, whereby, when Q1 or Q2 is on, Q10 is on, and thus Q7 is off, resulting in Q3 being off; similarly, the switch control circuit 1028 controlled by the third switching element Q11 is 1028, and the switch control circuits 1025, 1026, and 1027 having higher on-threshold voltages than the switch control circuit 1028, so the base of Q11 is connected to the gate of the first switch Q1 corresponding to the switch control circuit 1025 via the third resistor R20, the base of Q11 is also connected to the gate of the first switch Q2 corresponding to the switch control circuit 1026 via the third resistor R21, and the base of Q11 is also connected to the gate of the first switch Q3 corresponding to the switch control circuit 1027 via the third resistor R22, whereby, when Q1, Q2, or Q3 is turned on, Q11 is turned on, and Q8 is turned off, resulting in Q4 being turned off.
In this embodiment, when the base of the third switching element is connected to the gates of two or more first switching elements, a diode may be further disposed on a connection path connected to the gate of each first switching element to avoid mutual interference of signals on different connection paths. For example, diodes D6 and D7 are provided in connection paths between the base of the third switching element Q10 and the gate of Q1 and the gate of Q2, respectively, and diodes D9, D10, and D11 are provided in connection paths between the base of the third switching element Q11 and the gate of Q1, the gate of Q2, and the gate of Q3, respectively.
In the present embodiment, by providing the additional control units (1031, 1032 and 1033), it is possible to avoid a situation where two or more switch control circuits are turned on at the same time, thereby allowing the current selection circuit 102 to select only one first resistance at a time to be connected to the power converter 200.
According to the embodiment of the present application, the resistance value of the resistor connected to the power converter is adjusted by changing the resistance value of the current selection resistor connected to the input terminal of the current selection circuit, thereby adjusting the current value of the current output by the power converter, thereby enabling flexible current selection; also, the number of output ports of the current selection circuit does not increase.
Example 2
Embodiment 2 of the present application provides a driving circuit, which may have the current selection device 100 described in embodiment 1, and the power converter 200 shown in fig. 1.
As shown in fig. 1, in the driving circuit 300, the power converter 200 may output a current according to the resistance selected by the current selection circuit 102 of the current selection device 100.
Fig. 2 is a schematic diagram of a power converter of the present embodiment, which is configured with a current selection circuit to form a driving circuit, and as shown in fig. 2, a driving circuit 300a has a current selection device 100 and a power converter 200a, where the structure of the current selection device 100 of fig. 2 is the same as that of fig. 1, and reference may be made to embodiment 1 for the description of the current selection device 100, and the power converter 200a of fig. 2 is a specific circuit structure of the power converter 200 of fig. 1.
Next, the driving circuit 300a of fig. 2 will be explained.
As shown in fig. 2, the power converter 200a may have a rectifier circuit BD1 and a smoothing capacitor C2, wherein the rectifier circuit BD1 may be, for example, a diode bridge circuit capable of rectifying an alternating voltage input from an alternating current power supply AC; the smoothing capacitor C2 can smooth the voltage rectified by the rectifying circuit BD1 to form a dc power supply.
The power converter 200a may also have a switching element Q21, and the central control unit U1 outputs a control signal from port 6 to control the switching element Q21 to turn on and off.
The power converter 200a may further have a transformer T1, the transformer T1 having a primary winding P1, a secondary winding S1 and an auxiliary winding Aux, the auxiliary winding Aux supplying an operating voltage to port 1 of the central control unit U1, and port 1 of the central control unit U1 being connected to the power supply terminal Vcc of the current selection device 100.
The power converter 200a may further have a rectifying diode D52 and smoothing capacitors C28, C29, wherein the rectifying diodes D52 are respectively connected to the secondary winding S1 for rectifying the sensing voltage of the secondary winding S1; the smoothing capacitors C28 and C29 are used for smoothing the rectified voltage to form a driving current for output.
As shown in fig. 2, the resistors R29, R211 and R212 are connected in series between the port 5 of the central control unit U1 of the power converter 200a and the ground, the ports X3 and X4 of the current selection device 100 are connected across the resistors R211 and R212, and the resistance values of the resistors connected in parallel with the resistors R211 and R212 via the ports X3 and X4 can be adjusted by adjusting the resistance value of the current selection resistor between the ports X1 and X2 of the current selection device 100, thereby adjusting the current value of the driving current output by the power converter 200 a.
In addition, as shown in fig. 2, the power converter 200a in fig. 2 may further include a voltage dependent resistor RV1, a fuse F1, an inductor L1, an inductor L2, a resistor R21, a resistor R22, capacitors CX1, CY1, a resistor R23, an inductor L3, resistors R24, R25, R26, R28, R210, R214, and R215, capacitors C23, C24, C25, C26, and C41, and diodes D32, D22, and D42.
Reference is also made to the prior art for the description of port 2, port 3 and port 4 of the central control unit U1 of fig. 2.
It should be noted that the power converter 200a in fig. 2 is only one embodiment of the power converter 200, and the present embodiment is not limited thereto, and the power converter may have another configuration.
In the drive circuit of the present embodiment, the resistance value of the resistor connected to the power converter is adjusted by changing the resistance value of the current selection resistor connected to the input terminal of the current selection circuit, thereby adjusting the current value of the current output by the power converter, and thus, flexible current selection is possible; also, the number of output ports of the current selection circuit does not increase.
The present application has been described in conjunction with specific embodiments, but it should be understood by those skilled in the art that these descriptions are intended to be illustrative, and not limiting. Various modifications and adaptations of the present application may occur to those skilled in the art based on the spirit and principles of the application and are within the scope of the application.

Claims (7)

1. A current selection circuit is characterized in that the current selection circuit selects a gear of an output current according to the resistance value of a preset current selection resistor,
the current selection circuit has an input terminal and an output terminal,
the input end is connected with the current selection resistor,
the output end is connected with a power supply converter,
the current selection circuit connects a resistor having a predetermined resistance value corresponding to a tap position of the output current to the power converter via the output terminal in accordance with a resistance value of the current selection resistor,
the power converter outputs current according to the resistor selected by the current selection circuit,
the current selection circuit has at least one current sensing resistor string,
each of the current sense resistor strings is connected to the output terminal,
each of the current sensing resistor strings has a first switching element and a first resistor connected in series,
the current selection resistor controls whether the first switching element in the current sensing resistor string is turned on,
the current selection circuit also has at least one switch control circuit,
each of the switch control circuits is connected in parallel with the current selection resistor,
the current selection resistor controls whether the switch control circuit is conducted or not,
each of the switch control circuits controls whether the first switch element of the current sensing resistor string connected thereto is turned on.
2. The current selection circuit of claim 1,
the power converter is provided with a current control end which is connected with a current sensing resistor,
the resistance selected by the current selection circuit is in parallel with the current sensing resistance.
3. The current selection circuit of claim 1,
the resistance values of the first resistors of the current sensing resistor strings are different from each other.
4. The current selection circuit of claim 1,
the current selection circuit also has a voltage dividing resistor,
the current selection resistor and the voltage division resistor are connected in series between a power supply end and a grounding end of the current selection circuit.
5. The current selection circuit of claim 1,
the current selection circuit further has at least one additional control unit,
the additional control unit is configured to control such that, in a case where the first switching element of one current sensing resistor string is turned on, the first switching elements of the other current sensing resistor strings are turned off.
6. The current selection circuit of claim 5,
the additional control unit causes the switch control circuit having the lower turn-on threshold voltage to turn off in the case where the switch control circuit having the higher turn-on threshold voltage is turned on.
7. A driver circuit having a power converter, a preset current selection resistor and a current selection circuit as claimed in any one of claims 1 to 6, wherein the power converter outputs a current in accordance with the resistor selected by the current selection circuit.
CN201710566052.9A 2017-07-12 2017-07-12 Current selection circuit and drive circuit Active CN109256939B (en)

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CN104333933A (en) * 2013-07-22 2015-02-04 全汉企业股份有限公司 Light emitting diode driving device and light emitting diode illumination system applying same
CN105700606A (en) * 2016-01-22 2016-06-22 深圳微步信息股份有限公司 Power module and output voltage regulating method thereof

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CA2740631A1 (en) * 2010-05-20 2011-11-20 Rv Lighting Light emitting diode bulb
CN103547009B (en) * 2012-07-09 2016-09-14 登丰微电子股份有限公司 linear current regulator
CN104238609A (en) * 2013-06-14 2014-12-24 鸿富锦精密工业（深圳）有限公司 Voltage regulation circuit

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CN104333933A (en) * 2013-07-22 2015-02-04 全汉企业股份有限公司 Light emitting diode driving device and light emitting diode illumination system applying same
CN105700606A (en) * 2016-01-22 2016-06-22 深圳微步信息股份有限公司 Power module and output voltage regulating method thereof

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