CN209419314U - A dual power supply circuit - Google Patents

Abstract

The embodiment of the utility model discloses a dual power supply circuit. The dual power supply circuit includes: the first end of the one-way conduction module is electrically connected to the second power supply end, and the second end is electrically connected to the power supply output end, and the one-way conduction module is used for the voltage of the second power supply end to be higher than that of the power supply The voltage at the output end is turned on; the first end of the transistor is electrically connected to the first power supply end, and the second end is electrically connected to the power supply output end; the transistor drive module, the reference voltage input end of the transistor drive module is electrically connected to the power supply output end; The feedback voltage input end is electrically connected to the second power supply end; the drive output end is electrically connected to the control end of the transistor; the ground end is grounded. The embodiment of the utility model adopts a controllable transistor to realize the switching of two power supply sources, thereby avoiding the risk of power failure during the switching process, improving the reliability of the dual power supply circuit, and prolonging the service life of the dual power supply circuit .

Description

A dual power supply circuit

technical field

The embodiment of the utility model relates to the technical field of battery management, in particular to a dual power supply circuit.

Background technique

Dual power supply means that a load has two power supply circuits, and the two power supply circuits can be switched. In the case of one power supply failure, it can be switched to another power supply for power supply, or when both power supplies are available. In the case of electricity, you can choose one of the power supplies to supply power. With the wide application of electronic products, dual power supply circuits are widely used in fields such as electric vehicles equipped with batteries, battery cars, robots and drones.

In the prior art, the dual power supply circuit uses a single-pole double-throw mechanical relay to switch between the two power supply circuits. However, mechanical relays have problems of long conduction time, slow response speed, and easy aging of switch contacts. Therefore, the solution using mechanical relays has the problems of easy risk of power loss during switching, low reliability, and short life.

Utility model content

The utility model provides a dual power supply circuit to improve the reliability of the dual power supply circuit and prolong the service life of the dual power supply circuit.

The embodiment of the utility model provides a dual power supply circuit, and the dual power supply circuit includes: a first power supply terminal, a second power supply terminal and a power supply output terminal;

A one-way conduction module, the first end of the one-way conduction module is electrically connected to the power supply end of the second power supply, and the second end is electrically connected to the power supply output end, and the one-way conduction module is used for When the voltage of the power supply terminal of the second power supply is higher than the voltage of the power supply output terminal, it is turned on;

A transistor, the first terminal of the transistor is electrically connected to the first power supply terminal, and the second terminal is electrically connected to the power supply output terminal;

A transistor drive module, the transistor drive module includes a reference voltage input terminal, a feedback voltage input terminal, a drive output terminal and a ground terminal; the reference voltage input terminal is electrically connected to the power supply output terminal; the feedback voltage input terminal is connected to the The second power supply terminal is electrically connected; the driving output terminal is electrically connected to the control terminal of the transistor; the ground terminal is grounded.

Optionally, the transistor drive module also includes:

A voltage division sub-module, the first end of the voltage division sub-module is electrically connected to the power supply output end, the second end is grounded, the voltage division output end is electrically connected to the control end of the transistor, and the voltage division sub-module is used for controlling the transistor to turn on when the power supply at the second power supply terminal stops;

A cut-off sub-module, the first end of the cut-off sub-module is electrically connected to the power supply end of the second power supply, and the second end is electrically connected to the control end of the transistor, and the cut-off sub-module is used for switching on the second power supply When the power supply end supplies power, the transistor is controlled to be turned off.

Optionally, the voltage dividing sub-module also includes:

A first resistor, the first end of the first resistor is electrically connected to the first end of the voltage dividing sub-module, and the second end is electrically connected to the voltage dividing output end of the voltage dividing sub-module;

A second resistor, the first terminal of the second resistor is electrically connected to the voltage dividing output terminal of the voltage dividing sub-module, and the second terminal is grounded.

Optionally, the ratio of the resistance of the first resistor to the resistance of the second resistor is greater than or equal to 1.

Optionally, the resistance values of the first resistor and the second resistor are both greater than or equal to 200kΩ.

Optionally, the transistor is a MOS transistor.

Optionally, the cut-off sub-module further includes a first diode, an anode of the first diode is electrically connected to the second power supply terminal, and a cathode is electrically connected to the control terminal of the transistor.

Optionally, the dual power supply circuit further includes a second diode, an anode of the second diode is electrically connected to the first power supply end, and a cathode is electrically connected to the power supply output end.

Optionally, the unidirectional conduction module further includes a third diode, an anode of the third diode is electrically connected to the second power supply terminal, and a cathode is electrically connected to the power supply output terminal.

Optionally, the voltage input to the second power supply terminal is higher than the voltage input to the first power supply terminal.

In the embodiment of the utility model, the first end of the transistor is electrically connected to the first power supply end, the second end is electrically connected to the power supply output end, the reference voltage input end of the transistor drive module is electrically connected to the power supply output end, and the feedback voltage input end is electrically connected to the power supply output end. The power supply terminal of the second power supply is electrically connected, and the driving output terminal is electrically connected to the control terminal of the transistor, that is, the embodiment of the utility model controls the switching between the first power supply and the second power supply by controlling the turn-on and turn-off of the transistor. Compared with the prior art, the embodiment of the utility model uses a controllable transistor to realize the switching of two power supply sources, thus avoiding the risk of power loss during the switching process, improving the reliability of the dual power supply circuit, and prolonging the The service life of the dual power supply circuit. In addition, when the power supply output terminal is powered by the first power supply, the voltage of the first power supply is transmitted to the power supply output terminal through the transistor. Power supply application requirements for automotive and energy storage battery management systems.

Description of drawings

Fig. 1 is a schematic structural diagram of a dual power supply circuit provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of another dual power supply circuit provided by an embodiment of the present invention.

Detailed ways

Below in conjunction with accompanying drawing and embodiment the utility model is described in further detail. It can be understood that the specific embodiments described here are only used to explain the utility model, rather than limit the utility model. In addition, it should be noted that, for the convenience of description, only some structures related to the present utility model are shown in the drawings but not all structures.

The embodiment of the utility model provides a dual power supply circuit. FIG. 1 is a schematic structural diagram of a dual power supply circuit provided by an embodiment of the present invention. Referring to FIG. 1 , the dual power supply circuit includes: a first power supply terminal 10 , a second power supply terminal 20 , a power supply output terminal 30 , a one-way conducting module 40 , a transistor Q1 and a transistor driving module 50 . Wherein, the first end of the unidirectional conduction module 40 is electrically connected to the second power supply end 20, and the second end is electrically connected to the power supply output end 30. The unidirectional conduction module 40 is used for the voltage of the second power supply end 20 to be higher than When the voltage of the power supply output terminal 30 is turned on. The transistor Q1 includes a first terminal, a second terminal and a control terminal. The first terminal of the transistor Q1 is electrically connected to the first power supply terminal 10 , and the second terminal is electrically connected to the power supply output terminal 30 . The transistor drive module 50 includes a reference voltage input terminal 51, a feedback voltage input terminal 52, a drive output terminal 53 and a ground terminal 54; the reference voltage input terminal 51 is electrically connected to the power supply output terminal 30; the feedback voltage input terminal 52 is connected to the second power supply terminal 20; the drive output terminal 53 is electrically connected to the control terminal of the transistor Q1; the ground terminal 54 is grounded.

Wherein, the first power supply terminal 10 is used to electrically connect with the power output terminal of the first power supply. The first power supply may be, for example, a constant power supply, that is, a main power supply during the use of electronic products. The second power supply terminal 20 is used to be electrically connected to the power output terminal of the second power supply. The second power supply can be, for example, an auxiliary power supply for charging, that is, the power supply when the power supply of the normal power supply is insufficient or needs to be charged for the normal power supply. power supply. Exemplarily, in the technical field of electric vehicles, the first power supply is a vehicle battery, the second power supply is an auxiliary power supply of a charging pile, and the ground terminal 60 of the vehicle battery is electrically connected to the ground terminal 54 of the transistor drive module 50, and the auxiliary power supply of the charging pile The ground terminal of the power supply is electrically connected to the ground terminal 54 of the transistor driving module 50 . The power supply output terminal 30 is used as a common output terminal of the first power supply and the second power supply to supply power to subsequent system circuits.

The one-way conduction module 40 has a one-way conduction function, and the one-way conduction module 40 is arranged between the second power supply end 20 and the power supply output end 30. On the one hand, the voltage at the second power supply end 20 can be higher than the power supply output end When the voltage of 30 is turned on, it ensures that the second power supply can supply power normally; on the other hand, when the second power supply terminal 20 is not connected to the second power supply, it can prevent the voltage of the power supply output terminal 30 from being reversely conducted to the second power supply for power supply. End 20. Exemplarily, the one-way conduction module 40 includes a diode, an anode of the diode is electrically connected to the second power supply terminal 20 , and a cathode is electrically connected to the power supply output terminal 30 .

Transistor Q1 is a semiconductor device that has a switching function. Transistor Q1 is different from a mechanical relay. Transistor Q1 uses electrical signals to control its own on and off, and the switching speed can be very fast. In the embodiment of the utility model, a controllable transistor Q1 is adopted, and the transistor driving module 50 controls the turn-on and turn-off of the drive transistor Q1, which improves the reliability and service life of the dual power supply circuit. Optionally, the transistor Q1 is a MOS transistor, preferably an enhancement PMOS transistor. Exemplarily, the working principle of the dual power supply circuit is as follows:

When the first power supply terminal 10 outputs a high level (such as 12V), and the second power supply terminal 20 outputs a low level (such as 0V), the voltage of the feedback voltage input terminal 52 of the transistor drive module 50 is low level, and the single The conduction module 40 is in the cut-off state; the voltage of the first power supply terminal 10 is output to the reference voltage input terminal 51 of the transistor driving module 50 through the internal parasitic diode of the transistor Q1; the transistor driving module 50 is input according to the reference voltage input terminal 51 and the feedback voltage The voltage at the terminal 52 outputs the driving voltage at the driving output terminal 53, the driving transistor Q1 is turned on, and the power supply output terminal 30 is powered by the first power supply. When the second power supply terminal 20 outputs a high level (such as 13V), the voltage of the feedback voltage input terminal 52 of the transistor drive module 50 is a high level, and the unidirectional conduction module 40 is in a conduction state; the transistor drive module 50 according to the reference The voltage of the voltage input terminal 51 and the feedback voltage input terminal 52 outputs a driving voltage at the driving output terminal 53, the driving transistor Q1 is turned off, and the power supply output terminal 30 is powered by the second power supply.

In the embodiment of the utility model, the first terminal of the transistor Q1 is electrically connected to the first power supply terminal 10, the second terminal is electrically connected to the power supply output terminal 30, and the reference voltage input terminal 51 of the transistor driving module 50 is electrically connected to the power supply output terminal 30. , the feedback voltage input terminal 52 is electrically connected to the second power supply terminal 20, and the driving output terminal 53 is electrically connected to the control terminal of the transistor Q1, that is, the embodiment of the utility model controls the first power supply and the first power supply by controlling the on and off of the transistor Q1. Switching of the second power supply. Compared with the prior art, the embodiment of the utility model adopts the controllable transistor Q1 to realize the switching of two power supply sources, thereby avoiding the risk of power loss during the switching process, improving the reliability of the dual power supply circuit, and extending the Extend the service life of the dual power supply circuit. In addition, when the power supply output terminal 30 is powered by the first power supply, the voltage of the first power supply is transmitted to the power supply output terminal 30 through the transistor Q1. Compared with the diode, the transistor Q1 has a very low turn-on voltage drop, which is beneficial to boost conversion Efficiency to meet the power supply application requirements of electric vehicles and energy storage battery management systems.

FIG. 2 is a schematic structural diagram of another dual power supply circuit provided by an embodiment of the present invention. Referring to FIG. 2 , on the basis of the above implementations, optionally, the transistor driving module 50 further includes: a voltage dividing sub-module and a cut-off sub-module. The first end of the voltage dividing sub-module 50A is electrically connected to the power supply output end 30, the second end is grounded, the voltage dividing output end is electrically connected to the control end of the transistor Q1, and the voltage dividing sub-module 50A is used to supply power to the second power supply end 20 Control transistor Q1 is turned on when stopped. The first terminal of the cut-off sub-module 50B is electrically connected to the second power supply terminal 20, and the second terminal is electrically connected to the control terminal of the transistor Q1. The cut-off sub-module 50B is used to control the transistor Q1 to turn off when the second power supply terminal 20 supplies power. . Wherein, the voltage dividing sub-module 50A and the internal parasitic diode of the transistor Q1 form a voltage division, and when the divided voltage value is greater than the turn-on threshold voltage |VGS| of the transistor Q1, the transistor Q1 is turned on. The cut-off sub-module 50B can transmit the voltage of the second power supply terminal 20 to the control terminal of the transistor Q1 to drive the transistor Q1 to turn off. In the embodiment of the present invention, the voltage dividing sub-module 50A and the cut-off sub-module 50B are set to control the turn-on and turn-off of the transistor Q1, which is equivalent to driving the turn-on and turn-off of the transistor Q1 through the power supply of the first power supply and the second power supply. break, so that the structure of the driving module is simple, which is beneficial to reduce the cost of the circuit.

Continuing to refer to FIG. 2 , optionally, the voltage dividing sub-module 50A further includes: a first resistor R1 and a second resistor R2 . The first end of the first resistor R1 is electrically connected to the first end of the voltage dividing sub-module 50A, and the second end is electrically connected to the voltage dividing output end of the voltage dividing sub-module 50A. The first end of the second resistor R2 is electrically connected to the voltage dividing output end of the voltage dividing sub-module 50A, and the second end is grounded. In the embodiment of the utility model, the first resistor R1 and the second resistor R2 are connected in series to form a voltage dividing sub-module 50A, the circuit structure is simple, and it is beneficial to reduce the circuit cost.

On the basis of the above implementations, optionally, the ratio of the resistance value of the first resistor R1 to the resistance value of the second resistor R2 is greater than or equal to 1, thereby reducing the conduction loss of the transistor Q1, which is beneficial to reduce the dual power supply The static power consumption of the circuit.

On the basis of the above implementations, optionally, the resistance values of the first resistor R1 and the second resistor R2 are both greater than or equal to 200kΩ, thereby reducing the power consumption of the voltage divider module and helping to reduce the static power of the dual power supply circuit. consumption.

Continuing to refer to FIG. 2 , on the basis of the above implementations, optionally, the cut-off sub-module 50B further includes a first diode D1, the anode of the first diode D1 is electrically connected to the second power supply terminal 20, and the cathode is electrically connected to the second power supply terminal 20. The control terminal of the transistor Q1 is electrically connected. In the embodiment of the present invention, the cut-off sub-module 50B is formed by setting the first diode D1, and the circuit structure is simple, which is beneficial to reduce the cost of the dual power supply circuit.

Continuing to refer to FIG. 2, on the basis of the above implementations, optionally, the dual power supply circuit further includes a second diode D2, the anode of the second diode D2 is electrically connected to the first power supply terminal 10, and the cathode is electrically connected to the first power supply terminal 10. The power supply output terminal 30 is electrically connected. The embodiment of the utility model is set in this way, which ensures that the voltage of the first power supply terminal 10 can be transmitted to the reference voltage input terminal 51 of the transistor drive module 50 through the second diode D2, and avoids the connection between the second power supply and the first power supply. The series connection ensures the normal operation of the transistor driving module 50 and improves the reliability of the dual power supply circuit.

Continue referring to FIG. 2 , on the basis of the above implementations, optionally, the unidirectional conduction module 40 further includes a third diode D3, the anode of the third diode D3 is electrically connected to the second power supply terminal 20, and the cathode It is electrically connected with the power supply output terminal 30 .

In the above embodiments, optionally, the first diode D1, the second diode D2 and the third diode D3 are all Schottky diodes, which is beneficial to reduce the switching loss and cost.

Continue referring to FIG. 2 , the working principle of the dual power supply circuit is that when the first power supply terminal 10 outputs a high level (such as 12V), and the second power supply terminal 20 outputs a low level (such as 0V), the transistor drive module The voltage of the feedback voltage input terminal 52 of 50 is low level, the first diode D1 and the third diode D3 are in the cut-off state; the second diode D2 is in the conduction state, the voltage of the first power supply terminal 10 The second diode D2, the first resistor R1 and the second resistor R2 form a divided voltage. When the divided voltage value is greater than the turn-on threshold voltage |VGS| of the PMOS transistor, the PMOS transistor is turned on and the second diode D2 is bypassed. The power supply output terminal 30 is powered by the first power supply to achieve lower conduction voltage drop and higher conversion efficiency. When the second power supply terminal 20 outputs a high level (such as 13V), the voltage of the feedback voltage input terminal 52 of the transistor drive module 50 is a high level, and the first diode D1 and the third diode D3 are in conduction state; the high level of the second power supply terminal 20 is transmitted to the control terminal of the PMOS tube, and when the voltage difference between the control terminal of the PMOS tube and the second terminal is less than the turn-on threshold voltage |VGS| of the PMOS tube, the PMOS tube is turned off, and the second The diode D2 cuts off in reverse to realize reverse protection, and the power supply output terminal 30 is powered by the second power supply.

On the basis of the above implementations, optionally, the voltage input by the second power supply terminal 20 is higher than the voltage input by the first power supply terminal 10, so that when the second power supply outputs a high level, the second power supply can be preferentially used. Mains powered.

Note that the above are only preferred embodiments of the present invention and the applied technical principles. Those skilled in the art will understand that the utility model is not limited to the specific embodiments described here, and various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the utility model. Therefore, although the utility model has been described in detail through the above embodiments, the utility model is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the utility model. The scope of the present invention is determined by the appended claims.

Claims (10)

1. A dual power supply circuit, characterized in that it comprises: a first power supply terminal, a second power supply terminal and a power supply output terminal; A one-way conduction module, the first end of the one-way conduction module is electrically connected to the power supply end of the second power supply, and the second end is electrically connected to the power supply output end, and the one-way conduction module is used for When the voltage of the power supply terminal of the second power supply is higher than the voltage of the power supply output terminal, it is turned on; A transistor, the first terminal of the transistor is electrically connected to the first power supply terminal, and the second terminal is electrically connected to the power supply output terminal; A transistor drive module, the transistor drive module includes a reference voltage input terminal, a feedback voltage input terminal, a drive output terminal and a ground terminal; the reference voltage input terminal is electrically connected to the power supply output terminal; the feedback voltage input terminal is connected to the The second power supply terminal is electrically connected; the driving output terminal is electrically connected to the control terminal of the transistor; the ground terminal is grounded. 2. The dual power supply circuit according to claim 1, wherein the transistor drive module further comprises: A voltage division sub-module, the first end of the voltage division sub-module is electrically connected to the power supply output end, the second end is grounded, the voltage division output end is electrically connected to the control end of the transistor, and the voltage division sub-module is used for controlling the transistor to turn on when the power supply at the second power supply terminal stops; A cut-off sub-module, the first end of the cut-off sub-module is electrically connected to the power supply end of the second power supply, and the second end is electrically connected to the control end of the transistor, and the cut-off sub-module is used for switching on the second power supply When the power supply end supplies power, the transistor is controlled to be turned off. 3. The dual power supply circuit according to claim 2, wherein the voltage divider sub-module further comprises: A first resistor, the first end of the first resistor is electrically connected to the first end of the voltage dividing sub-module, and the second end is electrically connected to the voltage dividing output end of the voltage dividing sub-module; A second resistor, the first terminal of the second resistor is electrically connected to the voltage dividing output terminal of the voltage dividing sub-module, and the second terminal is grounded. 4. The dual power supply circuit according to claim 3, wherein the ratio of the resistance of the first resistor to the resistance of the second resistor is greater than or equal to 1. 5. The dual power supply circuit according to claim 3, wherein the resistance values of the first resistor and the second resistor are both greater than or equal to 200 kΩ. 6. The dual power supply circuit according to claim 1, wherein the transistor is a MOS transistor. 7. The dual power supply circuit according to claim 2, wherein the cut-off sub-module further comprises a first diode, and the anode of the first diode is electrically connected to the second power supply terminal , the cathode is electrically connected to the control terminal of the transistor. 8. The dual power supply circuit according to claim 1, further comprising a second diode, the anode of the second diode is electrically connected to the first power supply terminal, and the cathode is electrically connected to the first power supply terminal. The power supply output end is electrically connected. 9. The dual power supply circuit according to claim 1, wherein the unidirectional conduction module further comprises a third diode, and the anode of the third diode is electrically connected to the second power supply terminal. connected, and the cathode is electrically connected to the power supply output terminal. 10. The dual power supply circuit according to claim 1, wherein the voltage input to the second power supply terminal is higher than the voltage input to the first power supply terminal.