CN114189040A - Dual-power switching circuit and power supply equipment - Google Patents
Dual-power switching circuit and power supply equipment Download PDFInfo
- Publication number
- CN114189040A CN114189040A CN202111444623.4A CN202111444623A CN114189040A CN 114189040 A CN114189040 A CN 114189040A CN 202111444623 A CN202111444623 A CN 202111444623A CN 114189040 A CN114189040 A CN 114189040A
- Authority
- CN
- China
- Prior art keywords
- power supply
- mos tube
- load
- mos transistor
- main power
- 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.)
- Pending
Links
- 238000005070 sampling Methods 0.000 claims description 22
- 238000001514 detection method Methods 0.000 claims description 21
- 230000009977 dual effect Effects 0.000 claims description 11
- 239000003990 capacitor Substances 0.000 claims description 8
- 230000001133 acceleration Effects 0.000 claims description 3
- 230000002262 irrigation Effects 0.000 abstract description 6
- 238000003973 irrigation Methods 0.000 abstract description 6
- 230000005669 field effect Effects 0.000 description 10
- 239000004065 semiconductor Substances 0.000 description 10
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 7
- 230000014509 gene expression Effects 0.000 description 7
- 229910052744 lithium Inorganic materials 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 230000006978 adaptation Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 229910052739 hydrogen Inorganic materials 0.000 description 4
- 239000001257 hydrogen Substances 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000012212 insulator Substances 0.000 description 2
- 229910052987 metal hydride Inorganic materials 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 230000003993 interaction Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
- H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
- H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/36—Arrangements using end-cell switching
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Charge And Discharge Circuits For Batteries Or The Like (AREA)
- Direct Current Feeding And Distribution (AREA)
Abstract
The invention relates to a double-power-supply switching circuit and power supply equipment, wherein the circuit comprises a main power supply branch and an auxiliary power supply branch; the MOS tube Q4 is a P-channel MOS tube, and the MOS tube Q6 is an N-channel MOS tube; the drain electrode of the MOS tube Q4 is connected with a main power supply, the source electrode is connected with a load, and the grid electrode is connected with the drain electrode of the MOS tube Q6; a first body diode is arranged on the MOS tube Q4, the anode of the first body diode is connected with a main power supply, and the cathode of the first body diode is connected with a load; the grid electrode of the MOS tube Q6 is connected to a main power supply, and the source electrode is grounded; the auxiliary power supply branch comprises a MOS tube Q1, the MOS tube Q1 is a P-channel MOS tube, the grid electrode of the MOS tube Q1 is connected to the main power supply, the drain electrode is connected to the auxiliary power supply, and the source electrode is connected to the load. Seamless switching between the main power supply and the auxiliary power supply is realized, the main power supply preferentially supplies power, the main power supply branch and the auxiliary power supply branch can effectively prevent reverse irrigation, and the power efficiency is hardly reduced.
Description
Technical Field
The application relates to the field of power supplies, in particular to a dual-power switching circuit and power supply equipment.
Background
Many electronic products currently have a main power supply (via various power supplies such as an external adapter or a USB) and an auxiliary power supply (a backup battery) for supplying power. The power supply selection switching circuit has the following problems and disadvantages:
1) time is required for mechanical switching;
2) the power selection circuit is usually isolated by using a diode to prevent the power supply and the battery from flowing backwards, but the diode generates larger voltage drop when being conducted in the forward direction, so that the power supply efficiency or the service life of the battery is undoubtedly reduced;
3) the standby power supply is narrow in battery voltage adaptation range and only suitable for a single lithium battery (the power supply voltage is 3.6-4.2 v);
4) the current consumed by the load is not accurately detected in real time, and if short circuit, overcurrent or mismatching of voltage and power and the load is found, a power supply loop is cut off in time;
5) the prior partial technical scheme improves the partial defects, but is difficult to fully consider all the defects.
As shown in fig. 1, in the technical solution of the conventional power switching circuit, when the voltage of the VBAT battery is greater than 5V, the switching circuit fails; the USB 5V branch is connected with schottky diodes (the diodes generate a large conduction voltage drop) to reduce the power efficiency.
The technical scheme of ZL 201910554942.7 has the following defects:
1) the USB 5V power supply branch needs to pass through a diode D1 and then supplies power to a load through a Q2, obviously, the diode D1 has certain conduction voltage drop, and the service efficiency of a power supply is reduced;
2) when the voltage of the VBAT battery is more than 5V, the switching circuit is invalid;
3) in the technical scheme, the USB voltage is sampled in real time only indirectly through resistance voltage division, whether the load is overloaded or not is judged (namely, when the load is started or exceeds the current provided by the USB instantly in the working process, the USB voltage is reduced), and the load current is not measured dynamically in real time.
Disclosure of Invention
In view of the above problems, the present application provides a dual power supply switching circuit and a power supply device, which solve the problem that in the existing power supply switching circuit, a diode is needed to supply power to a load in a USB 5V power supply branch, and the diode generates a large conduction voltage drop, so that the power supply use efficiency is reduced.
In order to achieve the above object, the inventor provides a dual power supply switching circuit, which includes a main power supply branch and a secondary power supply branch;
the main power supply branch comprises a MOS tube Q4 and a MOS tube Q6;
the MOS tube Q4 is a P-channel MOS tube, and the MOS tube Q6 is an N-channel MOS tube;
the drain electrode of the MOS tube Q4 is connected with a main power supply, the source electrode of the MOS tube Q4 is connected with a load, and the grid electrode of the MOS tube is connected with the drain electrode of the MOS tube Q6;
a first body diode is arranged on the MOS tube Q4, the anode of the first body diode is connected with a main power supply, and the cathode of the first body diode is connected with a load;
the grid electrode of the MOS tube Q6 is connected to a main power supply, and the source electrode of the MOS tube Q6 is grounded;
the auxiliary power supply branch comprises a MOS tube Q1, the MOS tube Q1 is a P-channel MOS tube, the grid electrode of the MOS tube Q1 is connected to the main power supply, the drain electrode of the MOS tube Q1 is connected to the auxiliary power supply, and the source electrode of the MOS tube Q1 is connected to the load.
Further preferably, the gate of the MOS transistor Q6 is connected in parallel with the accelerating capacitor C5.
Further preferably, the auxiliary power supply branch circuit further comprises an MOS transistor Q2, and the MOS transistor Q2 is a P-channel MOS transistor;
the gate of the MOS transistor Q2 is connected to the main power supply, the source of the MOS transistor Q2 is connected to the source of the MOS transistor Q1, and the drain of the MOS transistor Q2 is connected to the load.
Further optimizing, the device also comprises a current detection module, a switch module and a microcontroller;
the current detection module is arranged at the negative pole of the load and is used for detecting the current of the negative pole of the load and feeding the detected current back to the microcontroller;
the control end of the switch module is connected to the microcontroller, and the switch module is used for receiving a control signal of the microcontroller to switch off or switch on the load to supply power.
Further optimization, the current detection module comprises a sampling resistor and an operational amplifier;
the sampling resistor is connected in series with the negative electrode of the load, the input end of the operational amplifier is connected with the sampling resistor in parallel, and the output end of the operational amplifier is connected with the microcontroller.
Further optimization, the sampling resistor is formed by connecting four resistors with the resistance value of 0.1 ohm in parallel.
Further preferably, the switch module is arranged at the negative pole of the load.
Preferably, the switch module comprises a MOS transistor Q3, and the MOS transistor Q3 is an N-channel MOS transistor;
the gate of the MOS transistor Q3 is connected to the microcontroller, the source of the MOS transistor Q3 is grounded, and the drain of the MOS transistor Q3 is connected to the negative pole of the load.
Further preferably, the gate of the MOS transistor Q3 is connected in parallel with an accelerating capacitor C2.
Still provide another technical scheme, a power supply equipment, power supply equipment includes as above-mentioned two switching of power circuit.
Different from the prior art, according to the technical scheme, when a main power supply is connected, the load is achieved through the first body diode on the P-channel MOS tube Q4, and because the grid electrode of the MOS tube Q6 is connected with the main power supply, the MOS tube Q6 is conducted at the moment, the voltage difference between the source electrode and the grid electrode of the MOS tube Q4 is larger than Vgs (th) of the MOS tube Q4, the MOS tube Q4 is conducted, and because the conduction resistance of the MOS tube Q4 is very small, the conduction voltage drop generated on the MOS tube Q4 is very small, and the problem that the conduction voltage drop is large due to the single body diode is solved; when the main power supply and the secondary power supply are simultaneously connected, the MOS tube Q1 on the power supply branch of the secondary power supply is in a cut-off state, the load end is supplied with power by the main power supply, when the main power supply is powered off, the power is automatically switched to the secondary power supply, the secondary power supply supplies power to the load through the second body diode on the MOS tube Q1, and at the moment, the Q1 is in a conducting state, so that the problem of large voltage drop of the second body diode is solved. Seamless switching between the main power supply and the auxiliary power supply is realized, the main power supply preferentially supplies power, the main power supply branch and the auxiliary power supply branch can effectively prevent reverse irrigation, and the power efficiency is hardly reduced.
The above description of the present invention is only an overview of the technical solutions of the present application, and in order to make the technical solutions of the present application more clearly understood by those skilled in the art, the present invention may be further implemented according to the content described in the text and drawings of the present application, and in order to make the above objects, other objects, features, and advantages of the present application more easily understood, the following description is made in conjunction with the detailed description of the present application and the drawings.
Drawings
The drawings are only for purposes of illustrating the principles, implementations, applications, features, and effects of particular embodiments of the present application, as well as others related thereto, and are not to be construed as limiting the application.
In the drawings of the specification:
FIG. 1 is a schematic circuit diagram of a prior art power switching circuit;
FIG. 2 is a schematic diagram of a dual power switching circuit according to an embodiment;
FIG. 3 is another schematic circuit diagram of the dual power switching circuit according to an embodiment;
FIG. 4 is another schematic circuit diagram of the dual power switching circuit according to an embodiment;
fig. 5 is a schematic diagram of a dual power switching circuit according to an embodiment.
The reference numerals referred to in the above figures are explained below:
110. a dual power supply switching circuit for switching the power supply,
120. the load is a load of the vehicle,
130. a main power source,
140. a secondary power supply for supplying power to the power supply,
150. a current detection module for detecting the current of the power supply,
160. a switch module, a power supply module and a power supply module,
170. a microcontroller.
Detailed Description
In order to explain in detail possible application scenarios, technical principles, practical embodiments, and the like of the present application, the following detailed description is given with reference to the accompanying drawings in conjunction with the listed embodiments. The embodiments described herein are merely for more clearly illustrating the technical solutions of the present application, and therefore, the embodiments are only used as examples, and the scope of the present application is not limited thereby.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase "an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or related to other embodiments specifically defined. In principle, in the present application, the technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution as long as there is no technical contradiction or conflict.
Unless defined otherwise, technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the use of relational terms herein is intended only to describe particular embodiments and is not intended to limit the present application.
In the description of the present application, the term "and/or" is a expression for describing a logical relationship between objects, meaning that three relationships may exist, for example a and/or B, meaning: there are three cases of A, B, and both A and B. In addition, the character "/" herein generally indicates that the former and latter associated objects are in a logical relationship of "or".
In this application, terms such as "first" and "second" are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
Without further limitation, in this application, the use of "including," "comprising," "having," or other similar expressions in phrases and expressions of "including," "comprising," or "having," is intended to cover a non-exclusive inclusion, and such expressions do not exclude the presence of additional elements in a process, method, or article that includes the recited elements, such that a process, method, or article that includes a list of elements may include not only those elements but also other elements not expressly listed or inherent to such process, method, or article.
As is understood in the examination of the guidelines, the terms "greater than", "less than", "more than" and the like in this application are to be understood as excluding the number; the expressions "above", "below", "within" and the like are understood to include the present numbers. In addition, in the description of the embodiments of the present application, "a plurality" means two or more (including two), and expressions related to "a plurality" similar thereto are also understood, for example, "a plurality of groups", "a plurality of times", and the like, unless specifically defined otherwise.
In the description of the embodiments of the present application, spatially relative expressions such as "central," "longitudinal," "lateral," "length," "width," "thickness," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used, and the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the specific embodiments or drawings and are only for convenience of describing the specific embodiments of the present application or for the convenience of the reader, and do not indicate or imply that the device or component in question must have a specific position, a specific orientation, or be constructed or operated in a specific orientation and therefore should not be construed as limiting the embodiments of the present application.
Unless specifically stated or limited otherwise, the terms "mounted," "connected," "secured," and "disposed" used in the description of the embodiments of the present application are to be construed broadly. For example, the connection can be a fixed connection, a detachable connection, or an integrated arrangement; it can be a mechanical connection, an electrical connection, or a communication connection; they may be directly connected or indirectly connected through an intermediate; which may be communication within two elements or an interaction of two elements. Specific meanings of the above terms in the embodiments of the present application can be understood by those skilled in the art to which the present application pertains in accordance with specific situations.
Referring to fig. 2-5, the present embodiment provides a dual power switching circuit 110, which includes a main power supply branch and a sub power supply branch;
the main power supply branch comprises a MOS tube Q4 and a MOS tube Q6;
the MOS tube Q4 is a P-channel MOS tube, and the MOS tube Q6 is an N-channel MOS tube;
the drain of the MOS transistor Q4 is connected to the main power supply 130, the source of the MOS transistor Q4 is connected to the load 120, and the gate of the MOS transistor is connected to the drain of the MOS transistor Q6;
a first body diode is arranged on the MOS transistor Q4, the anode of the first body diode is connected to the main power supply 130, and the cathode of the first body diode is connected to the load 120;
the gate of the MOS transistor Q6 is connected to the main power supply 130, and the source of the MOS transistor Q6 is grounded;
the secondary power supply branch comprises a MOS tube Q1, the MOS tube Q1 is a P-channel MOS tube, the grid electrode of the MOS tube Q1 is connected to the primary power supply 130, the drain electrode of the MOS tube Q1 is connected to the secondary power supply 140, and the source electrode of the MOS tube Q1 is connected to the load 120.
MOS transistor, is an abbreviation for MOSFET. A MOSFET Metal-Oxide Semiconductor Field Effect Transistor (MOSFET) is a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) for short. Typically a metal-oxide-semiconductor (semiconductor) field effect transistor, or so-called metal-insulator-semiconductor (insulator). G: a gate electrode; s: a source electrode; d: drain electrode. The source and drain of the MOS transistor can be reversed, and they are both N-type regions formed in the P-type back gate. The field effect transistor is divided into a PMOS (P channel type) transistor and an NMOS (N channel type) transistor, and belongs to an insulated gate field effect transistor.
When the main power supply 130 is connected, the first body diode on the MOS tube Q4 of the P channel reaches the load 120, if the main power supply 130 is connected to the load 120 end only through the first body diode, the first body diode can generate voltage drop undoubtedly, the effect is the same as that of the direct connection diode, and because the grid electrode of the MOS tube Q6 is connected with the main power supply 130, the MOS tube Q6 is conducted at the moment, so that the voltage difference between the source electrode and the grid electrode of the MOS tube Q4 is larger than Vgs (th) of the MOS tube Q4, the MOS tube Q4 is conducted, and because the conduction resistance of the MOS tube Q4 is very small (dozens of milliohms), the conduction voltage drop generated on the MOS tube Q4 is very small, and the problem of large conduction voltage drop of a single body diode is solved; when the main power supply 130 and the secondary power supply 140 are simultaneously connected, the MOS transistor Q1 on the power supply branch of the secondary power supply is in a cut-off state, the power is supplied to the load 120 end by the main power supply 130, and after the main power supply 130 is powered off, the power is automatically switched to the secondary power supply 140 to supply power, the secondary power supply 140 supplies power to the load 120 through the second body diode on the MOS transistor Q1, and at this time, the Q1 is in a conducting state, so that the problem of large voltage drop of the second body diode is solved. Seamless switching between the main power supply 130 and the secondary power supply 140 is realized, the main power supply 130 supplies power preferentially, the main power supply branch and the secondary power supply branch can effectively prevent reverse irrigation, and the power supply efficiency is hardly reduced.
The main power source 130 may provide VCC 5V power for the load 120, and may provide the VCC 5V power through the USB interface, and the secondary power source 140 may provide power for the load 120 for a battery, where the battery may be a lithium battery or a nickel-metal hydride battery pack.
In some embodiments, to speed up the conduction of the MOS transistor Q6, the gate of the MOS transistor Q6 is connected in parallel with the accelerating capacitor C5.
Referring to fig. 3, in some embodiments, in order to increase the voltage adaptation range of the secondary power supply 140, a power supply with a voltage greater than that of the primary power supply 130 may be used to supply power to the load 120, the secondary power supply branch further includes a MOS transistor Q2, and the MOS transistor Q2 is a P-channel MOS transistor;
the gate of the MOS transistor Q2 is connected to the main power supply 130, the source of the MOS transistor Q2 is connected to the source of the MOS transistor Q1, and the drain of the MOS transistor Q2 is connected to the load 120.
When the main power source 130 and the secondary power source 140 are simultaneously connected, if the voltage of the main power source 130 is VCC 5V and the voltage of the secondary power source 140 is 5.5V, the voltage difference between the source and the gate of the MOS transistor Q2 is 5.5V-5V, which is 0.5V < vgs (th), the MOS transistor Q2 is not turned on, and the load 120 is still supplied with power through the main power source 130, so that the voltage adaptation range of the secondary power source 140 is increased, and if the voltage of the main power source 130 is VCC 5V, the secondary power source 140 may be applied to a single lithium battery (3.6V to 4.2V) or a nickel-hydrogen battery (4.8V to 5.5V).
Referring to fig. 5, in some embodiments, the apparatus further includes a current detection module 150, a switch module 160, and a microcontroller 170;
the current detection module 150 is disposed at the negative electrode of the load 120, and the current detection module 150 is configured to detect a current at the negative electrode of the load 120, and feed the detected current back to the microcontroller 170;
the control terminal of the switch module 160 is connected to the microcontroller 170, and the switch module 160 is configured to receive a control signal from the microcontroller 170 to turn off or turn on the load 120.
The current of the negative electrode of the load 120 is detected by the current detection module 150, and when the microcontroller 170 judges that the load 120 exceeds the range of the power supply capacity of the power supply or short circuit occurs according to the current fed back by the current detection module 150, the microcontroller 170 outputs a control signal to the switch module 160, disconnects the switch module 160, cuts off the power supply loop of the load 120, and avoids burning the power supply or the load 120.
Referring to fig. 4, in some embodiments, the current detection module 150 includes a sampling resistor and an operational amplifier;
the sampling resistor is connected in series with the negative electrode of the load 120, the input end of the operational amplifier is connected in parallel with the sampling resistor, and the output end of the operational amplifier is connected to the microcontroller 170. The sampling resistor is formed by connecting four resistors with the resistance value of 0.1 ohm in parallel.
A compact resistor in a milliohm level is connected between the negative electrode of the load 120 (namely the zero potential reference end of the load 120) and the power reference ground in series for current application, wherein the sampling resistor is formed by connecting four resistors with the resistance value of 0.1 ohm in parallel; the impedance between the negative pole of the load 120 and the power supply reference ground is negligible. When a large current is generated on the load 120, a weak voltage signal is generated on the sampling resistor, the voltage signal is amplified through the operational amplifier U1A, the operational amplifier outputs an Itest signal and sends the Itest signal to the microcontroller 170, and the microcontroller 170 accurately calculates the current magnitude through the Itest signal, so that a power supply is selected or the power consumption condition of the load 120 is calculated. When the load 120 is out of the range of the power supply capability of the power supply or a short circuit occurs, the controller immediately outputs a VOUT signal to turn off the switch module 160 to cut off the power supply loop of the load 120, thereby avoiding burning the power supply or the load 120.
In some embodiments, the switch module 160 is disposed at the negative terminal of the load 120. The power supply circuit of the load 120 may be disconnected by disconnecting the negative ground of the load 120, and in other embodiments, may be provided at the positive pole of the load 120, and the vault circuit of the load 120 may be disconnected by disconnecting the positive pole of the load 120 to turn on the power supply.
Referring to fig. 4, in some embodiments, the switch module 160 includes a MOS transistor Q3, the MOS transistor Q3 is an N-channel MOS transistor;
the gate of the MOS transistor Q3 is connected to the microcontroller 170, the source of the MOS transistor Q3 is grounded, and the drain of the MOS transistor Q3 is connected to the negative terminal of the load 120.
When the microcontroller 170 outputs VOUT signal to the gate of the MOS transistor Q3 according to the current fed back from the current detection, the MOS transistor 3 is turned off, and the power supply loop of the load 120 is cut off. In other embodiments, the switch module 160 may also employ a transistor or a relay.
In order to increase the conduction speed of the MOS transistor Q3, the gate of the MOS transistor Q3 is connected in parallel with an acceleration capacitor C2.
The seamless switching between the main power supply 130(VCC _5V) and the auxiliary power supply 140 (standby battery) is realized, the main power supply 130 has priority power supply, the two power supply branches can prevent reverse irrigation and hardly reduce the power supply efficiency (the minimum conduction voltage drop of the mos tube is small), the standby power supply has wide application range, and is suitable for a single lithium battery (3.6V-4.2V) and can be connected into a nickel-hydrogen battery pack (4.8V-5.5V). In addition, the current of the load 120 can be accurately detected in real time, a power supply mode is selected between the main power supply 130 and the standby battery according to the power consumption of the load 120, and if the load 120 is short-circuited or the carrying capacity of the power supply is not matched with the load 120, a power supply loop is cut off in time, so that the load 120 and the power supply are prevented from being damaged.
Referring to fig. 2-5, another technical solution is also provided, which is a power supply apparatus including the dual power switching circuit 110.
The dual power supply switching circuit 110 includes a main power supply branch and a sub power supply branch;
the main power supply branch comprises a MOS tube Q4 and a MOS tube Q6;
the MOS tube Q4 is a P-channel MOS tube, and the MOS tube Q6 is an N-channel MOS tube;
the drain of the MOS transistor Q4 is connected to the main power supply 130, the source of the MOS transistor Q4 is connected to the load 120, and the gate of the MOS transistor is connected to the drain of the MOS transistor Q6;
a first body diode is arranged on the MOS transistor Q4, the anode of the first body diode is connected to the main power supply 130, and the cathode of the first body diode is connected to the load 120;
the gate of the MOS transistor Q6 is connected to the main power supply 130, and the source of the MOS transistor Q6 is grounded;
the secondary power supply branch comprises a MOS tube Q1, the MOS tube Q1 is a P-channel MOS tube, the grid electrode of the MOS tube Q1 is connected to the primary power supply 130, the drain electrode of the MOS tube Q1 is connected to the secondary power supply 140, and the source electrode of the MOS tube Q1 is connected to the load 120.
MOS transistor, is an abbreviation for MOSFET. A MOSFET Metal-Oxide Semiconductor Field Effect Transistor (MOSFET) is a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) for short. Typically a metal-oxide-semiconductor (semiconductor) field effect transistor, or so-called metal-insulator-semiconductor (insulator). G: a gate electrode; s: a source electrode; d: drain electrode. The source and drain of the MOS transistor can be reversed, and they are both N-type regions formed in the P-type back gate. The field effect transistor is divided into a PMOS (P channel type) transistor and an NMOS (N channel type) transistor, and belongs to an insulated gate field effect transistor.
When the main power supply 130 is connected, the first body diode on the P-channel MOS transistor Q4 reaches the load 120, and if the main power supply 130 is connected to the load 120 only through the first body diode, the first body diode will generate a voltage drop, which is the same as the effect of the direct connection diode, but in the design, because the gate of the MOS transistor Q6 is connected to the main power supply 130, the MOS transistor Q6 is connected, so that the voltage difference between the source and the gate of the MOS transistor Q4 is greater than vgs (th) of the MOS transistor Q4, the MOS transistor Q4 is connected, and because the conduction resistance of the MOS transistor Q4 is very small (tens of milliohms), the conduction voltage drop generated on the MOS transistor Q4 is very small, and the problem of large conduction voltage drop due to the body diode alone is solved; when the main power supply 130 and the secondary power supply 140 are simultaneously connected, the MOS transistor Q1 on the power supply branch of the secondary power supply is in a cut-off state, the power is supplied to the load 120 end by the main power supply 130, and after the main power supply 130 is powered off, the power is automatically switched to the secondary power supply 140 to supply power, the secondary power supply 140 supplies power to the load 120 through the second body diode on the MOS transistor Q1, and at this time, the Q1 is in a conducting state, so that the problem of large voltage drop of the second body diode is solved. Seamless switching between the main power supply 130 and the secondary power supply 140 is realized, the main power supply 130 supplies power preferentially, the main power supply branch and the secondary power supply branch can effectively prevent reverse irrigation, and the power supply efficiency is hardly reduced.
The main power source 130 may provide VCC 5V power for the load 120, and may provide the VCC 5V power through the USB interface, and the secondary power source 140 may provide power for the load 120 for a battery, where the battery may be a lithium battery or a nickel-metal hydride battery pack.
In some embodiments, to speed up the conduction of the MOS transistor Q6, the gate of the MOS transistor Q6 is connected in parallel with the accelerating capacitor C5.
Referring to fig. 3, in some embodiments, in order to increase the voltage adaptation range of the secondary power supply 140, a power supply with a voltage greater than that of the primary power supply 130 may be used to supply power to the load 120, the secondary power supply branch further includes a MOS transistor Q2, and the MOS transistor Q2 is a P-channel MOS transistor;
the gate of the MOS transistor Q2 is connected to the main power supply 130, the source of the MOS transistor Q2 is connected to the source of the MOS transistor Q1, and the drain of the MOS transistor Q2 is connected to the load 120.
When the main power source 130 and the secondary power source 140 are simultaneously connected, if the voltage of the main power source 130 is VCC _5V and the voltage of the secondary power source 140 is 5.5V, the voltage difference between the source and the gate of the MOS transistor Q2 is 5.5V-5V which is 0.5V < vgs (th), the MOS transistor Q2 is not turned on, and the load 120 is still supplied with power through the main power source 130, so that the voltage adaptation range of the secondary power source 140 is increased, and if the voltage of the main power source 130 is VCC 5V, the secondary power source 140 is suitable for a single lithium battery (3.6V to 4.2V) and also can be connected to a nickel-hydrogen battery (4.8V to 5.5V).
Referring to fig. 4-5, in some embodiments, the apparatus further includes a current detection module 150, a switch module 160, and a microcontroller 170;
the current detection module 150 is disposed at the negative electrode of the load 120, and the current detection module 150 is configured to detect a current at the negative electrode of the load 120, and feed the detected current back to the microcontroller 170;
the control terminal of the switch module 160 is connected to the microcontroller 170, and the switch module 160 is configured to receive a control signal from the microcontroller 170 to turn off or turn on the load 120.
The current of the negative electrode of the load 120 is detected by the current detection module 150, and when the microcontroller 170 judges that the load 120 exceeds the range of the power supply capacity of the power supply or short circuit occurs according to the current fed back by the current detection module 150, the microcontroller 170 outputs a control signal to the switch module 160, disconnects the switch module 160, cuts off the power supply loop of the load 120, and avoids burning the power supply or the load 120.
In some embodiments, the current detection module 150 includes a sampling resistor and an operational amplifier;
the sampling resistor is connected in series with the negative electrode of the load 120, the input end of the operational amplifier is connected in parallel with the sampling resistor, and the output end of the operational amplifier is connected to the microcontroller 170. The sampling resistor is formed by connecting four precision resistors with the resistance value of 0.1 ohm in parallel, and the sampling resistor needs to bear large current, so that a larger package is adopted, such as 1206.
A milliohm-level precision resistor is connected in series between the negative pole of the load 120 (namely the zero potential reference end of the load 120) and the power reference ground for current sampling, wherein the sampling resistor is formed by connecting four resistors with the resistance value of 0.1 ohm in parallel; the impedance between the negative pole of the load 120 and the power supply reference ground is negligible. When a large current is generated on the load 120, a weak voltage signal is generated on the sampling resistor, the voltage signal is amplified through the operational amplifier U1A, the operational amplifier outputs an Itest signal and sends the Itest signal to the microcontroller 170, and the microcontroller 170 accurately calculates a current value through the Itest signal, so that a power supply is selected or the power consumption condition of the load 120 is calculated. When the load 120 is out of the range of the power supply capability of the power supply or a short circuit occurs, the controller immediately outputs a VOUT signal to turn off the switch module 160 to cut off the power supply loop of the load 120, thereby avoiding burning the power supply or the load 120.
In some embodiments, the switch module 160 is disposed at the negative terminal of the load 120. The power supply circuit of the load 120 may be disconnected by disconnecting the negative electrode of the load 120 from the ground, and in other embodiments, the power supply circuit of the load 120 may be disconnected by disconnecting the positive electrode of the load 120 and connecting the power supply.
In some embodiments, the switch module 160 includes a MOS transistor Q3, the MOS transistor Q3 is an N-channel MOS transistor;
the gate of the MOS transistor Q3 is connected to the microcontroller 170, the source of the MOS transistor Q3 is grounded, and the drain of the MOS transistor Q3 is connected to the negative terminal of the load 120.
When the microcontroller 170 outputs VOUT signal to the gate of the MOS transistor Q3 according to the current fed back from the current detection, the MOS transistor 3 is turned off, and the power supply loop of the load 120 is cut off. In other embodiments, the switch module 160 may also employ a transistor or a relay.
In order to increase the conduction speed of the MOS transistor Q3, the gate of the MOS transistor Q3 is connected in parallel with an acceleration capacitor C2.
The seamless switching between the main power supply 130(VCC _5V) and the auxiliary power supply 140 (standby battery) is realized, the main power supply 130 has priority power supply, the two power supply branches can prevent reverse irrigation and hardly reduce the power supply efficiency (the minimum conduction voltage drop of the mos tube is small), the standby power supply has wide application range, and is suitable for a single lithium battery (3.6V-4.2V) and can be connected into a nickel-hydrogen battery pack (4.8V-5.5V). In addition, the current of the load 120 can be accurately detected in real time, a power supply mode is selected between the main power supply 130 and the standby battery according to the power consumption of the load 120, and if the load 120 is short-circuited or the carrying capacity of the power supply is not matched with the load 120, a power supply loop is cut off in time, so that the load 120 and the power supply are prevented from being damaged.
Finally, it should be noted that, although the above embodiments have been described in the text and drawings of the present application, the scope of the patent protection of the present application is not limited thereby. All technical solutions which are generated by replacing or modifying the equivalent structure or the equivalent flow according to the contents described in the text and the drawings of the present application, and which are directly or indirectly implemented in other related technical fields, are included in the scope of protection of the present application.
Claims (10)
1. A double-power-supply switching circuit is characterized by comprising a main power supply branch and an auxiliary power supply branch;
the main power supply branch comprises a MOS tube Q4 and a MOS tube Q6;
the MOS tube Q4 is a P-channel MOS tube, and the MOS tube Q6 is an N-channel MOS tube;
the drain electrode of the MOS tube Q4 is connected with a main power supply, the source electrode of the MOS tube Q4 is connected with a load, and the grid electrode of the MOS tube is connected with the drain electrode of the MOS tube Q6;
a first body diode is arranged on the MOS tube Q4, the anode of the first body diode is connected with a main power supply, and the cathode of the first body diode is connected with a load;
the grid electrode of the MOS tube Q6 is connected to a main power supply, and the source electrode of the MOS tube Q6 is grounded;
the auxiliary power supply branch comprises a MOS tube Q1, the MOS tube Q1 is a P-channel MOS tube, the grid electrode of the MOS tube Q1 is connected to the main power supply, the drain electrode of the MOS tube Q1 is connected to the auxiliary power supply, and the source electrode of the MOS tube Q1 is connected to the load.
2. The dual-power-supply switching circuit of claim 1, wherein the gate of the MOS transistor Q6 is connected in parallel with an acceleration capacitor C5.
3. The dual-power-supply switching circuit of claim 1, further comprising a MOS transistor Q2 on the secondary power supply branch, wherein the MOS transistor Q2 is a P-channel MOS transistor;
the gate of the MOS transistor Q2 is connected to the main power supply, the source of the MOS transistor Q2 is connected to the source of the MOS transistor Q1, and the drain of the MOS transistor Q2 is connected to the load.
4. The dual-power-supply switching circuit of claim 1, further comprising a current detection module, a switch module and a microcontroller;
the current detection module is arranged at the negative pole of the load and is used for detecting the current of the negative pole of the load and feeding the detected current back to the microcontroller;
the control end of the switch module is connected to the microcontroller, and the switch module is used for receiving a control signal of the microcontroller to switch off or switch on the load to supply power.
5. The dual-power-supply switching circuit of claim 4, wherein the current detection module comprises a sampling resistor and an operational amplifier;
the sampling resistor is connected in series with the negative electrode of the load, the input end of the operational amplifier is connected with the sampling resistor in parallel, and the output end of the operational amplifier is connected with the microcontroller.
6. The dual-power-supply switching circuit of claim 5, wherein the sampling resistor is formed by connecting four resistors with a resistance value of 0.1 ohm in parallel.
7. The dual-power-supply switching circuit of claim 4, wherein the switch module is disposed at a negative pole of a load.
8. The dual-power-supply switching circuit of claim 7, wherein the switch module comprises a MOS transistor Q3, and the MOS transistor Q3 is an N-channel MOS transistor;
the gate of the MOS transistor Q3 is connected to the microcontroller, the source of the MOS transistor Q3 is grounded, and the drain of the MOS transistor Q3 is connected to the negative pole of the load.
9. The dual-power-supply switching circuit of claim 8, wherein the gate of the MOS transistor Q3 is connected in parallel with an accelerating capacitor C2.
10. A power supply device characterized by comprising the dual power supply switching circuit according to any one of claims 1 to 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111444623.4A CN114189040A (en) | 2021-11-30 | 2021-11-30 | Dual-power switching circuit and power supply equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111444623.4A CN114189040A (en) | 2021-11-30 | 2021-11-30 | Dual-power switching circuit and power supply equipment |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114189040A true CN114189040A (en) | 2022-03-15 |
Family
ID=80603088
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111444623.4A Pending CN114189040A (en) | 2021-11-30 | 2021-11-30 | Dual-power switching circuit and power supply equipment |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114189040A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115054322A (en) * | 2022-05-25 | 2022-09-16 | 安速康医疗(苏州)有限公司 | Dual-mode power supply circuit, energy instrument for operation and ultrasonic operation system |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009254187A (en) * | 2008-04-09 | 2009-10-29 | Hitachi Ltd | Double system power source |
| CN101764388A (en) * | 2008-12-26 | 2010-06-30 | 环隆电气股份有限公司 | Over-current protection device and method thereof |
| CN203881841U (en) * | 2014-02-27 | 2014-10-15 | 快捷半导体(苏州)有限公司 | Over-current detection circuit, load switch and portable device |
| CN112467868A (en) * | 2020-12-03 | 2021-03-09 | 芜湖华沅微电子有限公司 | Multi-power supply switching circuit and method |
| CN113131606A (en) * | 2021-05-20 | 2021-07-16 | 浙江航芯科技有限公司 | Low-power consumption major-minor power supply automatic switching circuit |
-
2021
- 2021-11-30 CN CN202111444623.4A patent/CN114189040A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2009254187A (en) * | 2008-04-09 | 2009-10-29 | Hitachi Ltd | Double system power source |
| CN101764388A (en) * | 2008-12-26 | 2010-06-30 | 环隆电气股份有限公司 | Over-current protection device and method thereof |
| CN203881841U (en) * | 2014-02-27 | 2014-10-15 | 快捷半导体(苏州)有限公司 | Over-current detection circuit, load switch and portable device |
| CN112467868A (en) * | 2020-12-03 | 2021-03-09 | 芜湖华沅微电子有限公司 | Multi-power supply switching circuit and method |
| CN113131606A (en) * | 2021-05-20 | 2021-07-16 | 浙江航芯科技有限公司 | Low-power consumption major-minor power supply automatic switching circuit |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115054322A (en) * | 2022-05-25 | 2022-09-16 | 安速康医疗(苏州)有限公司 | Dual-mode power supply circuit, energy instrument for operation and ultrasonic operation system |
| CN115054322B (en) * | 2022-05-25 | 2024-05-17 | 安速康医疗(苏州)有限公司 | Dual-mode power supply circuit, surgical energy instrument and ultrasonic surgical system |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101552482B (en) | Charge and discharge control circuit and battery device | |
| US6690559B2 (en) | Charge/discharge type power supply | |
| KR100352403B1 (en) | Charge/discharge control circuit and chargeable electric power source apparatus | |
| CN101471579B (en) | Power supply switching circuit | |
| EP2190100A2 (en) | Overcurrent protection circuit of a rechargeable battery | |
| US20120056592A1 (en) | Charge/discharge control circuit and battery device | |
| KR20170100271A (en) | Battery protection circuit and battery pack including same | |
| CN102403756A (en) | Charge/discharge control circuit and battery device | |
| EP3817232B1 (en) | Nmos switch driving circuit and power supply device | |
| CN114189040A (en) | Dual-power switching circuit and power supply equipment | |
| CN108336810B (en) | Control circuit compatible with battery and external power supply for power supply | |
| CN109378876B (en) | Power supply parallel output circuit | |
| CN113131606A (en) | Low-power consumption major-minor power supply automatic switching circuit | |
| CN108258751B (en) | Charge/discharge control circuit and battery device | |
| CN216390578U (en) | Battery power supply circuit and terminal equipment | |
| CN217956749U (en) | Switch control circuit, battery management system, battery pack and electric equipment | |
| CN115360801B (en) | Charging control device and power supply apparatus | |
| CN218242990U (en) | Low-voltage detection circuit and solar equipment with same | |
| CN214314667U (en) | Integrated device and battery/battery pack management chip | |
| CN217363048U (en) | One-way conduction circuit | |
| CN114243870B (en) | Over-discharge protection circuit, battery protection board and electronic equipment | |
| CN214626342U (en) | Chip output short-circuit protection circuit | |
| CN217769535U (en) | Multi-channel battery power supply control circuit and power supply device | |
| CN213402555U (en) | Power supply path management circuit and true wireless earphone | |
| CN214045430U (en) | Optimized pre-discharge 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 | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20220315 |