CN216362285U - Power supply circuit and electronic equipment - Google Patents

Abstract

The application discloses power supply circuit, including switch module, isolation module and output module. The first end of the non-isolation end of the isolation module is connected with the positive electrode of the input power supply, the second end of the non-isolation end of the isolation module is connected with the first end of the switch module, the third end of the non-isolation end of the isolation module is connected with the second end of the switch module, the fourth end of the non-isolation end of the isolation module is connected with the first end of the output module and the load, the isolation end of the isolation module is used for being connected with the load, the third end of the switch module is connected with the second end of the output module, and the fourth end of the switch module is grounded. The isolation module is used for charging when the switch module is switched on and discharging when the switch module is switched off so as to output a first voltage at an isolation end of the isolation module, and the output module is used for outputting a second voltage according to the discharged electric energy of the isolation module. By the mode, the isolated positive power supply and the non-isolated negative power supply can be simultaneously provided through one circuit, and the cost is low.

Description

Power supply circuit and electronic equipment

Technical Field

The present disclosure relates to electronic circuits, and particularly to a power circuit and an electronic device.

Background

At present, two power supplies, namely an isolated power supply and a non-isolated power supply, are generally required to be arranged in a control board of a circuit. The isolated power source and the non-isolated power source may include a positive power source and a negative power source.

Generally, a non-isolated positive power supply can be used to conveniently control a part of a switching circuit, such as a thyristor, and an isolated negative power supply is mainly used to provide a safe low-voltage energy source to prevent a human body from getting an electric shock.

However, in the prior art, the isolated positive power supply and the non-isolated negative power supply generally need to be generated by different circuits, resulting in higher cost.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application aims to provide a power supply circuit and an electronic device, which can simultaneously provide an isolated positive power supply and a non-isolated negative power supply through one circuit, and have lower cost.

To achieve the above object, in a first aspect, the present application provides a power supply circuit comprising:

the device comprises a switch module, an isolation module and an output module;

the first end of the non-isolation end of the isolation module is connected with the anode of an input power supply, the second end of the non-isolation end of the isolation module is connected with the first end of the switch module, the third end of the non-isolation end of the isolation module is connected with the second end of the switch module, the fourth end of the non-isolation end of the isolation module is connected with the first end of the output module and a load, the isolation end of the isolation module is used for being connected with the load, the third end of the switch module is connected with the second end of the output module, and the fourth end of the switch module is grounded;

the isolation module is used for charging when the switch module is switched on and discharging when the switch module is switched off so as to output a first voltage at an isolation end of the isolation module;

the output module is used for outputting a second voltage according to the electric energy discharged by the isolation module.

In an alternative mode, the switch module comprises a first switch unit and a second switch unit;

the first end of the first switch unit is connected with the second end of the output module, the second end of the first switch unit is connected with the third end of the non-isolation end of the isolation module, the third end of the first switch unit is connected with the first end of the second switch unit, the second end of the second switch unit is connected with the second end of the non-isolation end of the isolation module, and the fourth end of the first switch unit and the third end of the second switch unit are both grounded;

the first switch unit is used for being switched on or switched off according to the second voltage so as to establish or disconnect the connection between the third end of the non-isolation end of the isolation module and the first end of the second switch unit;

the second switch unit is used for being switched on or off according to the switching on or off of the first switch unit so as to charge or discharge the isolation module.

In an optional mode, the first switching unit comprises a first switching tube and a first resistor;

the first end of the first switch tube is connected with the first end of the first resistor and the second end of the output module, the second end of the first switch tube is connected with the second end of the first resistor and the third end of the non-isolation end of the isolation module, and the third end of the first switch tube is connected with the first end of the second switch unit.

In an optional manner, the second switch unit includes a switch chip and a first capacitor, and the switch chip includes a drain pin, a source pin, a feedback pin, and a bypass pin;

the drain pin is connected with a second end of a non-isolation end of the isolation module, the feedback pin is connected with a third end of the first switch unit, the bypass pin is connected with the second end of the first switch unit, the third end of the non-isolation end of the isolation module and the first end of the first capacitor, and the source pin and the second end of the first capacitor are both grounded.

In an optional manner, the output module includes a first zener diode and a voltage dividing unit;

the anode of the first voltage stabilizing diode is connected with the first end of the voltage dividing unit and the fourth end of the non-isolation end of the isolation module, the reference end of the first voltage stabilizing diode is connected with the second end of the voltage dividing unit, and the cathode of the first voltage stabilizing diode is connected with the third end of the switch module;

the first voltage stabilizing diode is used for providing a reference voltage, and the voltage dividing unit is used for outputting a second voltage according to the reference voltage.

In an optional manner, the voltage dividing unit includes a second resistor and a third resistor;

the cathode of the first voltage stabilizing diode is connected with the third end of the switch module, the reference end of the first voltage stabilizing diode is connected with the first end of the second resistor and the first end of the third resistor, the second end of the second resistor is grounded, and the second end of the third resistor is connected with the anode of the first voltage stabilizing diode and the fourth end of the non-isolation end of the isolation module.

In an optional manner, the isolation module includes a first transformer, a fourth resistor, a fifth resistor, a sixth resistor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first diode, a second diode, a third diode, and a fourth diode, where the first transformer includes a primary winding, a first secondary winding, a second secondary winding, and a third secondary winding;

the different name end of the primary winding is connected with the anode of the input power supply, the first end of the second capacitor and the first end of the fourth resistor, the second end of the second capacitor is connected with the second end of the fourth resistor and the cathode of the first diode, and the same name end of the primary winding is connected with the anode of the first diode and the first end of the switch module;

the homonymous end of the first secondary winding is connected with the anode of the second diode, the cathode of the second diode is connected with the first end of the third capacitor, and the heteronymous end of the first secondary winding and the second end of the third capacitor are both grounded;

the dotted terminal of the second secondary winding is connected to the anode of the third diode, the cathode of the third diode is connected to the first terminal of the fourth capacitor and the first terminal of the fifth resistor, the dotted terminal of the second secondary winding is connected to the second terminal of the fourth capacitor and the dotted terminal of the third secondary winding, and the second terminal of the fifth resistor is connected to the second terminal of the switch module;

the dotted terminal of the third secondary winding and the first terminal of the fifth capacitor are both grounded, the synonym terminal of the third secondary winding is connected with the cathode of the fourth diode and the first terminal of the sixth capacitor, the second terminal of the sixth capacitor is connected with the first terminal of the sixth resistor, and the second terminal of the sixth resistor is connected with the anode of the fourth diode, the second terminal of the fifth capacitor and the first terminal of the output module;

the non-isolation end of the isolation module comprises the primary winding, the first secondary winding and the second secondary winding, and the isolation end of the isolation module comprises the third secondary winding.

In an optional manner, the power supply circuit further includes a preprocessing module, and the input power supply is connected to the non-isolated end of the isolation module through the preprocessing module;

the preprocessing module is used for carrying out current limiting, filtering and rectifying on the input power supply and then inputting the input power supply to the non-isolation end of the isolation module.

In an optional manner, the preprocessing module includes a seventh resistor, an eighth resistor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a fifth diode, a sixth diode, and a first inductor;

the first end of the seventh resistor is connected to the positive electrode of the input power supply, the second end of the seventh resistor is connected to the first end of the eighth resistor, the first end of the seventh capacitor and the anode of the fifth diode, the cathode of the fifth diode is connected to the anode of the sixth diode, the cathode of the sixth diode is connected to the first end of the first inductor and the first end of the eighth capacitor, the second end of the first inductor is connected to the first end of the ninth capacitor and the first end of the non-isolation end of the isolation module, and the second end of the eighth resistor, the second end of the seventh capacitor, the second end of the eighth capacitor and the second end of the ninth capacitor are all grounded.

In a second aspect, the present application provides an electronic device comprising a power supply circuit as described above.

The beneficial effects of the embodiment of the application are that: the power supply circuit provided by the application comprises a switch module, an isolation module and an output module. The first end of the non-isolation end of the isolation module is connected with the positive electrode of the input power supply, the second end of the non-isolation end of the isolation module is connected with the first end of the switch module, the third end of the non-isolation end of the isolation module is connected with the second end of the switch module, the fourth end of the non-isolation end of the isolation module is connected with the first end of the output module, the isolation end of the isolation module is used for being connected with a load, the third end of the switch module is connected with the second end of the output module, and the fourth end of the switch module is grounded. The isolation module is used for charging when the switch module is conducted and discharging when the switch module is conducted so as to output a first voltage at an isolation end of the isolation module, and the output module is used for outputting a second voltage according to the electric energy discharged by the isolation module. Therefore, the power supply circuit can output a first voltage at the isolation end of the isolation module and output a second voltage at the non-isolation end of the isolation module, namely, the circuit can simultaneously provide an isolation positive power supply and a non-isolation negative power supply. Compared with the prior art that the isolated positive power supply and the non-isolated negative power supply need to be provided by different circuits respectively, the cost of the power supply circuit provided by the application is lower.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

Fig. 1 is a schematic structural diagram of a power supply circuit according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a power supply circuit according to another embodiment of the present application;

fig. 3 is a schematic circuit structure diagram of a power supply circuit according to an embodiment of the present disclosure.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a power circuit according to an embodiment of the present disclosure. As shown in fig. 1, the power circuit 100 includes a switch module 10, an isolation module 20, and an output module 30. Wherein, the first end of the non-isolation end of the isolation module 20 is connected with the positive electrode of the input power VIN, the second end of the non-isolation end of the isolation module 20 is connected with the first end of the switch module 10, the third end of the non-isolation end of the isolation module 20 is connected with the second end of the switch module 10, the fourth end of the non-isolation end of the isolation module 20 is connected with the first end of the output module 30 and the load 200, the isolation end of the isolation module 20 is used for being connected with the load 200, the third end of the switch module 10 is connected with the second end of the output module 30, and the fourth end of the switch module 10 is grounded GND.

The isolation module 20 is configured to be charged when the switch module 10 is turned on, and discharged when the switch module 10 is turned off, so as to output a first voltage at an isolation end of the isolation module 20. The output module 30 is configured to output a second voltage according to the electric energy discharged by the isolation module 20. Specifically, when the switch module 10 is turned on, the input power VIN charges the isolation module 20. When the switch module 10 is turned off, the input power VIN stops charging the isolation module 20, and at this time, the isolation module 20 discharges. The discharged electric energy is generated in the discharging process of the isolation module. On one hand, the isolation terminal of the isolation module 20 can output a first voltage according to the discharged electric energy; on the other hand, the output module 30 can output the second voltage according to the discharged electric energy, and since the output module 30 is connected to the non-isolated terminal of the isolation module 20, the second voltage output by the output module 30 is a non-isolated voltage. Therefore, by correspondingly configuring the electrical components in the power supply circuit 100, the first voltage can be a positive power supply, and the second voltage can be a negative power supply, that is, the power supply circuit 100 can simultaneously provide an isolated positive power supply and an isolated negative power supply, and compared with the related art that different circuits are required to respectively provide the isolated positive power supply and the isolated negative power supply, the cost is low.

In an embodiment, the switch module 10 includes a first switch unit 11 and a second switch unit 12. The first end of the first switch unit 11 is connected to the second end of the output module 30, the second end of the first switch unit 11 is connected to the third end of the non-isolation end of the isolation module 20, the third end of the first switch unit 11 is connected to the first end of the second switch unit 12, the fourth end of the first switch unit 11 is grounded GND, the second end of the second switch unit 12 is connected to the second end of the non-isolation end of the isolation module 20, and the third end of the second switch unit 12 is grounded GND.

The first end of the first switch unit 11 is the third end of the switch module 10, the second end of the first switch unit 11 is the second end of the switch module 10, the second end of the second switch unit 12 is the first end of the switch module 10, and the third end of the second switch unit 12 is the fourth end of the switch module 10.

The first switch unit 11 is configured to be turned on or off according to the second voltage output by the output module 30, so as to establish or break a connection between a third terminal of the non-isolated terminal of the isolation module 30 and the first terminal of the second switch unit 12. The second switching unit 12 is used to be turned on or off according to the turning on or off of the first switching unit 11 to charge or discharge the isolation module 30.

Specifically, when the second voltage increases, the first switching unit 11 is turned on to establish a connection between the third terminal of the non-isolated terminal of the isolation module 30 and the first terminal of the second switching unit 12. Then, the second switching unit 12 is turned on, the isolation module 30 starts to charge, and stops discharging, so that the second voltage is reduced. Conversely, when the second voltage decreases, the first switching unit 12 is turned off to disconnect the third terminal of the non-isolated terminal of the isolation module 30 from the first terminal of the second switching unit 12. Then, the second switching unit 12 is turned off, the isolation module 30 stops charging, and starts discharging to increase the second voltage. Therefore, the second voltage can be kept at a stable value, namely, the second voltage which is more stable can be output.

In an embodiment, referring to fig. 3 in combination with fig. 2, the first switch unit 11 includes a first switch Q1 and a first resistor R1. A first end of the first switch tube Q1 is connected to the first end of the first resistor R1 and the second end of the output module 30, a second end of the first switch tube Q1 is connected to the second end of the first resistor R1 and the third end of the non-isolated end of the isolation module 20, and a third end of the first switch tube Q1 is connected to the first end of the second switch unit 12. In this embodiment, the first resistor R1 is used to provide a turn-on voltage for the first switch Q1.

The first end of the first switch tube Q1 is the first end of the first switch unit 11, the second end of the first switch tube Q1 is the second end of the first switch unit 11, and the third end of the first switch tube Q1 is the third end of the first switch unit 11.

In one embodiment, the second switch unit 12 includes a switch chip U1 and a first capacitor C1, and the switch chip U1 includes a drain pin D, a source pin S, a feedback pin FB, and a bypass pin BP. The drain pin D is connected to the second end of the non-isolation end of the isolation module, the feedback pin FB is connected to the third end of the first switch unit 11, the bypass pin BP is connected to the second end of the first switch unit 11, the third end of the non-isolation end of the isolation module 20, and the first end of the first capacitor C1, and the source pin S and the second end of the first capacitor C1 are both grounded to GND. The feedback pin FB is a first end of the second switch unit 12, the drain pin D is a second end of the second switch unit 12, and the source pin S is a third end of the second switch unit 12.

In this embodiment, the bypass pin BP is used to connect an external bypass capacitor (in this embodiment, the first capacitor C1). During the normal operation of the switch chip U1, the on or off of the switch chip U1 is controlled by the signal input on the feedback pin FB, and specifically, when the signal input on the feedback pin FB is a high level signal, the switch chip U1 is on; when the signal inputted to the feedback pin FB is a low level signal, the switch chip U1 is turned off.

In one embodiment, referring to fig. 2 again, the output module 30 includes a first zener diode U2 and a voltage dividing unit 31. An anode of the first zener diode U2 is connected to the first end of the voltage dividing unit 31 and the fourth end of the non-isolated end of the isolation module 20, a reference end of the first zener diode U2 is connected to the second end of the voltage dividing unit 31, and a cathode of the first zener diode U2 is connected to the third end of the switch module 10. An anode of the first zener diode U2 is a first end of the output module 30, and a cathode of the first zener diode U2 is a second end of the output module 30.

Specifically, the first zener diode U2 is configured to provide a reference voltage, and the voltage dividing unit 31 is configured to output a second voltage according to the reference voltage. In one embodiment, the first zener diode U2 may be a three-terminal adjustable shunt reference source of model TL 431.

In one embodiment, as shown in fig. 3, the voltage dividing unit 30 includes a second resistor R2 and a third resistor R3. The cathode of the first zener diode U2 is connected to the third end of the switch module 10, the reference end of the first zener diode U2 is connected to the first end of the second resistor R2 and the first end of the third resistor R3, the second end of the second resistor R2 is grounded GND, and the second end of the third resistor R3 is connected to the anode of the first zener diode U2 and the fourth end of the non-isolation end of the isolation module 20. The second end of the third resistor R3 is the first end of the voltage divider 31, and the first end of the third resistor R3 is the second end of the voltage divider 31.

Specifically, a constant voltage is provided between the reference terminal and the cathode of the first zener diode U2, which is also the voltage across the third resistor R3. Then, after the resistance values of the second resistor R2 and the third resistor R3 are determined, the voltage across the voltage dividing unit 31 composed of the second resistor R2 and the third resistor R3 can be obtained, so that the second voltage can be obtained.

In an embodiment, the isolation module 20 includes a first transformer T1, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4, and the first transformer T1 includes a primary winding L1, a first secondary winding L2, a second secondary winding L3, and a third secondary winding L4.

The different-name end of the primary winding L1 is connected to the positive electrode of the input power VIN, the first end of the second capacitor C2, and the first end of the fourth resistor R4 through the interface L, the second end of the second capacitor C2 is connected to the second end of the fourth resistor R4 and the cathode of the first diode D1, and the same-name end of the primary winding L1 is connected to the anode of the first diode D1 and the first end of the switch module 10. The dotted terminal of the first secondary winding L2 is connected to the anode of the second diode D2, the cathode of the second diode D2 is connected to the first terminal of the third capacitor C3, and the different-dotted terminal of the first secondary winding L2 and the second terminal of the third capacitor C3 are both grounded to GND. The dotted terminal of the second secondary winding L3 is connected to the anode of the third diode D3, the cathode of the third diode D3 is connected to the first terminal of the fourth capacitor C4 and the first terminal of the fifth resistor R5, the dotted terminal of the second secondary winding L3 is connected to the second terminal of the fourth capacitor C4 and the dotted terminal of the third secondary winding L4, and the second terminal of the fifth resistor R5 is connected to the second terminal of the switch module 10. The dotted terminal of the third secondary winding L4 and the first terminal of the fifth capacitor C5 are both grounded GND, the synonym terminal of the third secondary winding L4 is connected to the cathode of the fourth diode D4 and the first terminal of the sixth capacitor C6, the second terminal of the sixth capacitor C6 is connected to the first terminal of the sixth resistor R6, and the second terminal of the sixth resistor R6 is connected to the anode of the fourth diode D4, the second terminal of the fifth capacitor C5 and the first terminal of the output module 30. The non-isolation end of the isolation module 20 includes a primary winding L1, a first secondary winding L2, and a second secondary winding L3, and the isolation end of the isolation module 20 includes a third secondary winding L4.

In this embodiment, the ends of the primary winding L1, the first secondary winding L2, the second secondary winding L3 and the third secondary winding L4 with black dots are homonymous ends, and the ends without black dots are synonym ends. The primary winding L1 is charged by the input power VIN, and can discharge the charged power through the first secondary winding L2, the second secondary winding L3 and the third secondary winding L4. When the primary winding L1 is charged, the first secondary winding L2, the second secondary winding L3, and the third secondary winding L4 stop discharging; when the primary winding L1 stops charging, the first secondary winding L2, the second secondary winding L3, and the third secondary winding L4 discharge.

In an embodiment, the power circuit further includes a preprocessing module 40, and the input power VIN is connected to the non-isolated terminal of the isolation module 20 through the preprocessing module 40. The preprocessing module 40 is configured to perform current limiting, filtering and rectifying on the input power VIN, and then input the current to the non-isolated end of the isolation module 20.

In one embodiment, the preprocessing module 40 includes a seventh resistor R7, an eighth resistor R8, a seventh capacitor C7, an eighth capacitor C8, a ninth capacitor C9, a fifth diode D5, a sixth diode D6, and a first inductor L1. A first end of the seventh resistor R7 is connected to the anode of the input power VIN, a second end of the seventh resistor R7 is connected to a first end of the eighth resistor R8, a first end of the seventh capacitor C7, and an anode of the fifth diode D5, a cathode of the fifth diode D5 is connected to an anode of the sixth diode D6, a cathode of the sixth diode D6 is connected to a first end of the first inductor L1 and a first end of the eighth capacitor C8, a second end of the first inductor L1 is connected to a first end of the ninth capacitor C9 and a first end of the non-isolated end of the isolation module 20, and a second end of the eighth resistor R8, a second end of the seventh capacitor C7, a second end of the eighth capacitor C8, and a second end of the ninth capacitor C9 are all grounded.

Specifically, the seventh resistor R7 can also function as a current limiting function to limit the inrush current input to the different-name terminal of the primary winding L1. The eighth resistor R8 is used for absorbing the input surge voltage. The first diode D1 and the second diode D2 form a half-wave rectifier circuit to perform rectification. The seventh capacitor C7, the eighth capacitor C8, the ninth capacitor C9 and the first inductor L1 play a role of filtering, wherein the seventh capacitor C7 can be used for eliminating electromagnetic interference, and the eighth capacitor C8, the ninth capacitor C9 and the first inductor L1 form a pi-type filter circuit.

It should be noted that, in the embodiment of the present application, any switching tube may be a switching device such as a triode, an MOS tube, or an IGBT switching tube, and each switching tube may be the same or different.

Specifically, the first switching tube Q1 is taken as an example. If the first switch tube Q1 is a triode, the base of the triode is the first end of the first switch tube Q1, the emitter of the triode is the second end of the first switch tube Q1, and the collector of the triode is the third end of the first switch tube Q1. If the first switch transistor Q1 is an MOS transistor, the gate of the MOS transistor is the first end of the first switch transistor Q1, the source of the MOS transistor is the second end of the first switch transistor Q1, and the drain of the MOS transistor is the third end of the first switch transistor Q1. If the first switch tube Q1 is an IGBT switch tube, the gate of the IGBT switch tube is the first end of the first switch tube Q1, and the emitter of the IGBT switch tube is the third end of the first switch tube Q1, which is the collector of the IGBT switch tube at the second end of the first switch tube Q1.

For a better understanding of the present application, the operating principle of the circuit arrangement shown in fig. 3 is described below.

When the switch chip U1 is turned on, the input power VIN charges the primary winding L1 after passing through the preprocessing module 40. At this time, the synonym terminal of the primary winding L1 is positive, and the synonym terminal thereof is negative, so that the synonym terminal of each secondary winding (including the first secondary winding L2, the second secondary winding L3, and the third secondary winding L4) is positive, and the synonym terminal thereof is negative, and each diode (including the second diode D2, the third diode D3, and the fourth diode D4) connected to each secondary winding is turned off in the reverse direction.

When the switch chip U1 is turned off, the primary winding L1 is disconnected from the loop in which the input power source VIN is located, and the primary winding L1 loses power. Then, when the primary winding L1 loses power, the current flowing through the primary winding L1 decreases, and the primary winding L1 resists the change of the current, so that the synonym terminal of the primary winding L1 is negative and the synonym terminal is positive to generate the current in the same direction as before the current decreases. At this time, the dotted terminal and the dotted terminal of each secondary winding are positive and negative, and the diodes connected to each secondary winding are conducted in the forward direction, and each secondary winding performs a discharge process.

At this time, on the one hand, the voltage output by the first secondary winding L2 is a positive voltage, i.e., a positive voltage can be output between the first output terminal VOUT1 and the second output terminal VOUT 2. And since the end of the first secondary winding L2 with the same name is positive, the first voltage V1 is an isolated positive power supply. The first output terminal VOUT1 and the second output terminal VOUT2 are used for connecting to a load.

On the other hand, since the positive electrode of the fifth capacitor C5 is connected to the ground PGND, i.e. the positive electrode of the fifth capacitor C5 is used as the ground PGND, the negative electrode of the fifth capacitor C5 can obtain a non-isolated negative power supply, which is the second voltage V2 and is output from the third output terminal VOUT3, and the third output terminal VOUT3 is used for being connected to the load. The voltage of the second voltage V2 is determined by the second resistor R2, the third resistor R3 and the first zener diode U2, and can be obtained by the following formula:

v2＝(Vref÷r5)×(r5+r6) (1)

v2 is the voltage value of the second voltage V2, Vref is the constant voltage between the reference terminal and the cathode of the first zener diode U2, R5 is the resistance value of the fifth resistor R5, and R6 is the resistance value of the sixth resistor R6.

It can be seen that in this embodiment, the power supply circuit 100 is capable of providing both an isolated positive power supply, i.e., the first voltage V1, and a non-isolated negative power supply, i.e., the second voltage V2. Without employing a plurality of circuits to provide the isolated positive power supply and the non-isolated negative power supply, respectively, as in the related art, thereby contributing to cost reduction.

Meanwhile, the first switch tube Q1 can also perform a negative feedback regulation function to maintain the second voltage V2 as a stable output voltage. Specifically, when the voltage value of the second voltage V2 increases, the first zener diode U2 is turned on in the reverse direction, and the second secondary winding L3, the fifth resistor R5, the first resistor R1, the first zener diode U2, the fourth diode D4, and the third secondary winding L4 form a loop. The voltage difference exists between the first terminal and the second terminal of the first switch tube Q1, and the first switch tube Q1 is turned on. The feedback pin FB of the switch chip U1 inputs a high level signal, and the switch chip U1 is turned on. The primary winding L1 is charged and the secondary windings cease to discharge to reduce the voltage level of the second voltage V2. On the contrary, when the voltage value of the second voltage V2 decreases, the first zener diode U2 turns off, and the first switching tube Q1 turns off. The feedback pin FB of the switch chip U1 inputs a low level signal, and the switch chip U1 is turned off. The primary winding L1 stops charging and the secondary windings discharge to increase the value of the second voltage V2. Therefore, the second voltage V2 can be kept at a relatively stable voltage, which is beneficial to improving the stability of the circuit operation.

An embodiment of the present application further provides an electronic device, which includes the power supply circuit in any of the above embodiments.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; within the context of the present application, where technical features in the above embodiments or in different embodiments can also be combined, the steps can be implemented in any order and there are many other variations of the different aspects of the present application as described above, which are not provided in detail for the sake of brevity; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims (10)

1. A power supply circuit, comprising:

the device comprises a switch module, an isolation module and an output module;

the first end of the non-isolation end of the isolation module is connected with the anode of an input power supply, the second end of the non-isolation end of the isolation module is connected with the first end of the switch module, the third end of the non-isolation end of the isolation module is connected with the second end of the switch module, the fourth end of the non-isolation end of the isolation module is connected with the first end of the output module and a load, the isolation end of the isolation module is used for being connected with the load, the third end of the switch module is connected with the second end of the output module, and the fourth end of the switch module is grounded;

the isolation module is used for charging when the switch module is switched on and discharging when the switch module is switched off so as to output a first voltage at an isolation end of the isolation module;

the output module is used for outputting a second voltage according to the electric energy discharged by the isolation module.

2. The power supply circuit according to claim 1,

the switch module comprises a first switch unit and a second switch unit;

the first end of the first switch unit is connected with the second end of the output module, the second end of the first switch unit is connected with the third end of the non-isolation end of the isolation module, the third end of the first switch unit is connected with the first end of the second switch unit, the second end of the second switch unit is connected with the second end of the non-isolation end of the isolation module, and the fourth end of the first switch unit and the third end of the second switch unit are both grounded;

the first switch unit is used for being switched on or switched off according to the second voltage so as to establish or disconnect the connection between the third end of the non-isolation end of the isolation module and the first end of the second switch unit;

the second switch unit is used for being switched on or off according to the switching on or off of the first switch unit so as to charge or discharge the isolation module.

3. The power supply circuit according to claim 2,

the first switch unit comprises a first switch tube and a first resistor;

the first end of the first switch tube is connected with the first end of the first resistor and the second end of the output module, the second end of the first switch tube is connected with the second end of the first resistor and the third end of the non-isolation end of the isolation module, and the third end of the first switch tube is connected with the first end of the second switch unit.

4. The power supply circuit according to claim 2,

the second switch unit comprises a switch chip and a first capacitor, wherein the switch chip comprises a drain electrode pin, a source electrode pin, a feedback pin and a bypass pin;

the drain pin is connected with a second end of a non-isolation end of the isolation module, the feedback pin is connected with a third end of the first switch unit, the bypass pin is connected with the second end of the first switch unit, the third end of the non-isolation end of the isolation module and the first end of the first capacitor, and the source pin and the second end of the first capacitor are both grounded.

5. The power supply circuit according to claim 1,

the output module comprises a first voltage stabilizing diode and a voltage dividing unit;

the anode of the first voltage stabilizing diode is connected with the first end of the voltage dividing unit and the fourth end of the non-isolation end of the isolation module, the reference end of the first voltage stabilizing diode is connected with the second end of the voltage dividing unit, and the cathode of the first voltage stabilizing diode is connected with the third end of the switch module;

the first voltage stabilizing diode is used for providing a reference voltage, and the voltage dividing unit is used for outputting a second voltage according to the reference voltage.

6. The power supply circuit of claim 5, wherein the power supply circuit further comprises a power supply circuit

The voltage division unit comprises a second resistor and a third resistor;

the cathode of the first voltage stabilizing diode is connected with the third end of the switch module, the reference end of the first voltage stabilizing diode is connected with the first end of the second resistor and the first end of the third resistor, the second end of the second resistor is grounded, and the second end of the third resistor is connected with the anode of the first voltage stabilizing diode and the fourth end of the non-isolation end of the isolation module.

7. The power supply circuit according to claim 1,

the isolation module comprises a first transformer, a fourth resistor, a fifth resistor, a sixth resistor, a second capacitor, a third capacitor, a fourth capacitor, a fifth capacitor, a sixth capacitor, a first diode, a second diode, a third diode and a fourth diode, wherein the first transformer comprises a primary winding, a first secondary winding, a second secondary winding and a third secondary winding;

the different name end of the primary winding is connected with the anode of the input power supply, the first end of the second capacitor and the first end of the fourth resistor, the second end of the second capacitor is connected with the second end of the fourth resistor and the cathode of the first diode, and the same name end of the primary winding is connected with the anode of the first diode and the first end of the switch module;

the homonymous end of the first secondary winding is connected with the anode of the second diode, the cathode of the second diode is connected with the first end of the third capacitor, and the heteronymous end of the first secondary winding and the second end of the third capacitor are both grounded;

the dotted terminal of the second secondary winding is connected to the anode of the third diode, the cathode of the third diode is connected to the first terminal of the fourth capacitor and the first terminal of the fifth resistor, the dotted terminal of the second secondary winding is connected to the second terminal of the fourth capacitor and the dotted terminal of the third secondary winding, and the second terminal of the fifth resistor is connected to the second terminal of the switch module;

the dotted terminal of the third secondary winding and the first terminal of the fifth capacitor are both grounded, the synonym terminal of the third secondary winding is connected with the cathode of the fourth diode and the first terminal of the sixth capacitor, the second terminal of the sixth capacitor is connected with the first terminal of the sixth resistor, and the second terminal of the sixth resistor is connected with the anode of the fourth diode, the second terminal of the fifth capacitor and the first terminal of the output module;

the non-isolation end of the isolation module comprises the primary winding, the first secondary winding and the second secondary winding, and the isolation end of the isolation module comprises the third secondary winding.

8. The power supply circuit according to any one of claims 1 to 7,

the power supply circuit also comprises a preprocessing module, and the input power supply is connected with the non-isolated end of the isolating module through the preprocessing module;

the preprocessing module is used for carrying out current limiting, filtering and rectifying on the input power supply and then inputting the input power supply to the non-isolation end of the isolation module.

9. The power supply circuit according to claim 8,

the preprocessing module comprises a seventh resistor, an eighth resistor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a fifth diode, a sixth diode and a first inductor;

the first end of the seventh resistor is connected to the positive electrode of the input power supply, the second end of the seventh resistor is connected to the first end of the eighth resistor, the first end of the seventh capacitor and the anode of the fifth diode, the cathode of the fifth diode is connected to the anode of the sixth diode, the cathode of the sixth diode is connected to the first end of the first inductor and the first end of the eighth capacitor, the second end of the first inductor is connected to the first end of the ninth capacitor and the first end of the non-isolation end of the isolation module, and the second end of the eighth resistor, the second end of the seventh capacitor, the second end of the eighth capacitor and the second end of the ninth capacitor are all grounded.

10. An electronic device, characterized in that it comprises a power supply circuit according to any one of claims 1-9.

Images