WO2024055869A1

WO2024055869A1 - Current compensation circuit, quasi-resonant power supply, and charging device

Info

Publication number: WO2024055869A1
Application number: PCT/CN2023/116952
Authority: WO
Inventors: 卢好
Original assignee: 安克创新科技股份有限公司
Priority date: 2022-09-15
Filing date: 2023-09-05
Publication date: 2024-03-21
Also published as: CN218549563U

Abstract

The present application discloses a current compensation circuit, a quasi-resonant power supply, and a charging device. The current compensation circuit comprises a control module and a current providing module; the control module is configured to be connected to a rectifier and filter circuit and configured to receive an output voltage of the rectifier and filter circuit; the current providing module comprises a resistance-adjustable circuit and a resistance-fixed circuit connected to each other in parallel; one of parallel-connected ends of the resistance-fixed circuit and the resistance-adjustable circuit is configured to be connected to a pulse controller, and the other parallel-connected end of the resistance-fixed circuit and the resistance-adjustable circuit is grounded; the resistance-adjustable circuit is further connected to the control module; and the control module is configured to adjust the resistance of the resistance-adjustable circuit when the output voltage of the rectifier and filter circuit is greater than or equal to a set voltage, so as to reduce the current output by the current providing module to the pulse controller.

Description

A current compensation circuit, quasi-resonant power supply and charging device

This application claims priority to the Chinese patent application submitted to the China Patent Office on September 15, 2022, with the application number 202222448834.1 and the invention name "Current Compensation Circuit, Quasi-Resonant Power Supply and Charging Device", the entire content of which is incorporated by reference in in this application.

Technical field

The present application relates to the field of power supply technology, and in particular, to a current compensation circuit, a quasi-resonant power supply and a charging device.

Background technique

With the widespread use of new energy efficiency standards, the efficiency requirements for switching power supplies in the market are getting higher and higher. Compared with linear power supplies, switching power supplies have the advantages of easy control, high efficiency, small size, good reliability, and easy protection. They are widely used in equipment such as TV power supplies, mobile phone chargers, industrial instruments, power adapters, etc.

The quasi-resonant power supply is a type of switching power supply. The quasi-resonant power supply includes a rectifier filter circuit and a pulse controller. When the quasi-resonant power supply is at full voltage, when the output voltage of the rectifier filter circuit is large, the input pulse controller current is too large. , in order to enable the pulse controller to work normally under large current conditions, a pulse controller with high current resistance is often selected, resulting in a high overall selection cost of the resonant power supply. Therefore, how to effectively reduce the selection cost of quasi-resonant power supply has become an urgent problem to be solved.

Contents of the invention

Embodiments of the present application provide a current compensation circuit, a quasi-resonant power supply and a charging device, which can effectively reduce the overall selection cost of the quasi-resonant power supply.

In a first aspect, an embodiment of the present application provides a current compensation circuit of a quasi-resonant power supply, wherein the quasi-resonant power supply comprises a rectifier filter circuit and a pulse controller connected to each other; the current compensation circuit comprises a control module The control module is configured to be connected to the rectifier and filter circuit, and is configured to be connected to the output voltage of the rectifier and filter circuit; the current supply module includes an adjustable resistance circuit and a fixed resistance circuit connected in parallel with each other, one of the parallel ends of the fixed resistance circuit and the adjustable resistance circuit is configured to be connected to the pulse controller, the other parallel end of the fixed resistance circuit and the adjustable resistance circuit is grounded, and the adjustable resistance circuit is also connected to the control module; wherein the control module is configured to adjust the resistance of the adjustable resistance circuit when the output voltage of the rectifier and filter circuit is greater than or equal to the set voltage, so as to reduce the current output by the current supply module to the pulse controller.

Based on the current compensation circuit of the embodiment of the present application, the control module is configured to adjust the resistance of the adjustable resistance circuit to increase the total resistance of the current supply module when receiving the output voltage of the rectifier and filter circuit is greater than or equal to the set voltage. While the power of the pulse controller remains unchanged, reducing the current output from the current supply module to the pulse controller realizes a small current input to the pulse controller under high voltage conditions, which can effectively reduce the selection of the pulse controller. cost, thereby achieving the purpose of reducing the overall selection cost of the quasi-resonant power supply.

In the second aspect, embodiments of the present application provide a quasi-resonant power supply. The quasi-resonant power supply includes an interconnected rectifier filter circuit and a pulse controller, a circuit board and the above-mentioned current compensation circuit. The current compensation circuit is made on the circuit board, and the current The compensation circuit includes a control module and a current supply module. The control module is connected to the rectifier and filter circuit and is connected to the output voltage of the rectifier and filter circuit. The current supply module includes an adjustable resistance circuit and a fixed resistance circuit connected in parallel. The fixed resistance circuit One of the parallel terminals of the resistance-adjustable circuit is connected to the pulse controller, the other parallel terminal of the fixed-resistance circuit and the resistance-adjustable circuit is grounded, and the resistance-adjustable circuit is also connected to the control module; wherein, the control module is When it is received that the output voltage of the rectifier filter circuit is greater than or equal to the set voltage, the resistance of the adjustable resistance circuit is adjusted to reduce the current output by the current supply module to the pulse controller.

The quasi-resonant power supply based on the embodiment of the present application has the above characteristics due to the design of the above-mentioned current compensation circuit. The quasi-resonant power supply of the current compensation circuit can effectively reduce the overall selection cost of the quasi-resonant power supply. In addition, the quasi-resonant power supply also has the effect of effectively improving the overall efficiency of the full-voltage input power supply and reducing temperature rise and electromagnetic interference.

In a third aspect, embodiments of the present application provide a charging device. The charging device includes a casing and the above-mentioned quasi-resonant power supply. The casing has an installation space. The quasi-resonant power supply is located in the installation space. The quasi-resonant power supply includes a rectifier filter circuit, a pulse control circuit, and a rectifier filter circuit. The controller, circuit board and current compensation circuit, the rectifier filter circuit and the pulse controller are connected to each other. The current compensation circuit is made on the circuit board. The current compensation circuit includes a control module and a current supply module. The control module is connected to the rectifier filter circuit and is connected to the rectifier. The output voltage of the filter circuit; the current supply module includes an adjustable resistance circuit and a fixed resistance circuit connected in parallel. One of the parallel terminals of the fixed resistance circuit and the adjustable resistance circuit is connected to the pulse controller, and the fixed resistance circuit is connected to the pulse controller. The other parallel terminal of the resistance-adjustable circuit is grounded, and the resistance-adjustable circuit is also connected to the control module; wherein, when the control module receives the output voltage of the rectifier and filter circuit is greater than or equal to the set voltage, it adjusts the resistance-adjustable circuit. resistor to reduce the current provided by the module output to the pulse controller.

Based on the charging device in the embodiment of the present application, the charging device with the above-mentioned quasi-resonant power supply can effectively reduce the overall selection cost of the charging device.

Description of drawings

In order to explain the embodiments of the present application or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only These are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic circuit structure diagram of the current compensation module when the number of resistance-adjustable circuits is one in the application embodiment;

Figure 2 is a schematic circuit structure diagram of the current compensation module when the number of resistance-adjustable circuits is multiple and the number of control modules is one in an embodiment of the present application;

FIG. 3 is a schematic circuit structure diagram of a current compensation module when the number of resistance-adjustable circuits is multiple and the number of control modules is multiple in an embodiment of the present application.

Reference signs: 10. Current compensation circuit; 11. Adjustable resistance circuit; Q1, first switching element; R39, first resistor; 12. Fixed resistance circuit; R44, fixed resistance resistor; 13. Control module; Q2, second switching element; R3, bias resistor; ZD11, Zener diode; 14, voltage dividing circuit; R27, first voltage dividing resistor; R41, second voltage dividing resistor; R62, third voltage dividing resistor; b1 , voltage dividing node; R7, second resistor; 20, rectifier filter circuit; V+, output voltage; 30, pulse controller.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

The quasi-resonant power supply is a type of switching power supply. The quasi-resonant power supply includes a rectifier filter circuit and a pulse controller. The quasi-resonant power supply operates at full voltage (that is, wide-band voltage. Generally, the identification range of wide-band voltage is AC AC: 85V-264V) In this case, when the output voltage of the rectifier filter circuit is large, the input pulse controller current is too large. In order to enable the pulse controller to work normally under large current conditions, a pulse controller that can withstand large currents is often selected, resulting in The overall selection cost of quasi-resonant power supply is relatively high.

Therefore, how to effectively reduce the selection cost of quasi-resonant power supply has become an urgent problem to be solved.

In order to solve the above technical problems, please refer to FIG. 1 . The first aspect of this application proposes a current compensation circuit 10 for a quasi-resonant power supply, which can effectively reduce the overall selection cost of the quasi-resonant power supply.

The quasi-resonant power supply includes a rectifier filter circuit 20 and a pulse controller 30. The current compensation circuit 10 includes a control module 13 and a current providing module. The current providing module includes an adjustable resistance circuit 11 and a fixed resistance circuit 12. The control module 13 is configured to connect input the output voltage V+ of the rectifier filter circuit 20, and when the output voltage V+ is greater than or equal to the set voltage, the control module 13 reduces the current output by the current supply module to the pulse controller 30 by adjusting the resistance of the adjustable resistance circuit 11 .

The specific circuit structure of the current compensation circuit 10 of the quasi-resonant power supply will be introduced below with reference to FIGS. 1 to 3 .

As shown in Figure 1, the quasi-resonant power supply includes a rectifier filter circuit 20 and a pulse controller 30.

The rectifier and filter circuit 20 is configured to rectify and filter the external power supply voltage to form an output voltage V+. Among them, the external power supply voltage can be understood as the mains voltage. It can be understood that the mains voltages in different regions or different countries are different, so different mains voltages will form different output voltages V+ after being processed by the rectifier and filter circuit 20 .

The main function of the pulse controller 30 is to output a pulse signal to control the voltage of the primary coil of the quasi-resonant power supply coupled to the secondary coil. For example, the model of the pulse controller 30 may be, but is not limited to, SC3057.

The rectifier filter circuit 20 and the pulse controller 30 are connected to each other.

The current compensation circuit 10 includes a control module 13 and a current providing module.

The control module 13 is a circuit structure that controls the size of the current output by the current supply module to the pulse controller 30 according to the output voltage V+ of the rectifier and filter circuit 20 . The specific circuit structure of the control module 13 will be introduced below.

The current supply module serves as a circuit structure that outputs current to the pulse controller 30 . The current supply module includes an adjustable resistance circuit 11 and a fixed resistance circuit 12 .

The resistance value of the resistance-adjustable circuit 11 is adjustable, and the control module 13 adjusts the resistance value according to the rectified and filtered output voltage V+. Selectively adjust the resistance of the resistance-adjustable circuit 11. The specific circuit structure of the resistance-adjustable circuit 11 will be introduced below.

The resistance of the fixed resistance circuit 12 is fixed. The fixed resistance circuit 12 may include only one resistor, and the resistance of the one resistor is fixed (i.e., a fixed value resistor). The fixed resistance circuit 12 may also include multiple resistors. Resistors, multiple resistors can be connected in one of series, parallel, and mixed connections to form a resistor with a fixed resistance. The specific circuit structure of the resistance fixed circuit 12 will be introduced below.

As shown in Figure 1-3, the resistance-adjustable circuit 11 and the resistance-fixed circuit 12 are connected in parallel. It should be noted that the number of the resistance-adjustable circuit 11 can be one or more. When the number of the resistance-adjustable circuit 11 is one, the two ends of the resistance-adjustable circuit 11 are respectively connected with the resistance value. Both ends of the fixed circuit 12 are connected; when there are multiple resistance-adjustable circuits 11 , both ends of each resistance-adjustable circuit 11 are connected to two ends of the fixed-resistance circuit 12 respectively.

One of the parallel terminals of the fixed resistance circuit 12 and all the adjustable resistance circuits 11 is configured to be connected to the pulse controller 30 to output current to the pulse controller 30 , and the other end of the fixed resistance circuit 12 and all the adjustable resistance circuits 11 One parallel terminal is connected to ground.

The control module 13 is configured to be connected to the rectifier filter circuit 20 to access the output voltage V+. The control module 13 is also connected to the resistance-adjustable circuit 11. The control module 13 is configured to receive the output voltage V+ of the rectifier filter circuit 20 and is greater than or equal to the set value. When the voltage is constant, the control module 13 adjusts the resistance of the adjustable resistance circuit 11 to reduce the current output by the current supply module to the pulse controller 30 . Among them, the voltage corresponding to the overcurrent that affects the normal operation of the pulse controller 30 is the above-mentioned “set voltage”.

It can be understood that when the power of the pulse controller 30 remains unchanged, according to the formula P=I ² R, where I is the current output by the current providing module to the pulse controller 30, and R is the total power of the current providing module. resistance. To reduce the current I output by the current supply circuit to the pulse controller 30, the total resistance R of the current supply module can only be increased. The total resistance of the current supply module is equal to the fixed resistance circuit 12 connected in parallel and the resistance The sum of the resistances of the adjustable circuit 11, while the resistance of the fixed resistance circuit 12 is fixed. In order to increase the above total resistance R, it can be adjusted by directly increasing the resistance of the adjustable circuit 11. The resistance of the adjustable resistance circuit 11 can be increased to increase the total resistance R, or the resistance of the adjustable resistance circuit 11 can be adjusted to increase the resistance by disconnecting the adjustable resistance circuit 11 from the fixed resistance circuit 12. The above total resistance R. It should be noted that if the above-mentioned total resistance R is increased by disconnecting the resistance-adjustable circuit 11 from the fixed-resistance circuit 12, when the number of the resistance-adjustable circuit 11 is one, the resistance-adjustable circuit 11 can be directly connected. A resistance-adjustable circuit 11 is disconnected from a fixed-resistance circuit 12 so that the total resistance R is equal to the resistance of the fixed-resistance circuit 12; when there are multiple resistance-adjustable circuits 11, a reasonable Disconnect at least part of the resistance-adjustable circuit 11 from the fixed-resistance circuit 12 as long as the resistance of the total resistance R after disconnection is greater than the resistance of the total resistance R before disconnection.

Based on the current compensation circuit 10 in the embodiment of the present application, the control module 13 is configured to adjust the resistance of the adjustable resistance circuit 11 to increase the current supply when receiving the output voltage V+ of the rectifier filter circuit 20 which is greater than or equal to the set voltage. The total resistance of the module, thereby reducing the current output of the module to the pulse controller 30 when the power of the pulse controller 30 remains unchanged, realizes a small current input to the pulse controller 30 under large voltage conditions, The selection cost of the pulse controller 30 can be effectively reduced, thereby achieving the purpose of reducing the overall selection cost of the quasi-resonant power supply.

As shown in FIGS. 1 to 3 , it can be understood that the number of the resistance-adjustable circuit 11 may be one or multiple. When the number of the resistance-adjustable resistors is one, the number of the control module 13 is one, and the control module 13 adjusts the resistance-adjustable circuit 11 when the output voltage V+ of the rectifier filter circuit 20 is greater than or equal to the set voltage. resistance. When the number of resistance-adjustable circuits 11 is multiple, the number of control modules 13 may be one or multiple. When the number of control modules 13 is one, the one control module 13 simultaneously adjusts the resistances of all the resistance-adjustable circuits 11 when the output voltage V+ of the rectifier filter circuit 20 is greater than or equal to the set voltage; when the number of control modules 13 is more than At this time, a control module 13 can correspondingly adjust an adjustable resistance when the output voltage V+ of the rectifier filter circuit 20 is greater than or equal to the set voltage. The resistance of the circuit 11 can also be a control module 13 that simultaneously adjusts the resistances of multiple (not all) resistance-adjustable circuits 11 when the output voltage V+ of the rectifier and filter circuit 20 is greater than or equal to the set voltage. For example, when the number of resistance-adjustable circuits 11 is three and the number of control modules 13 is two, one of the control modules 13 simultaneously controls the two resistances when the output voltage V+ of the rectifier filter circuit 20 is greater than or equal to the set voltage. The other control module 13 controls the resistance of the remaining adjustable value circuit 11 when the output voltage V+ of the rectifier and filter circuit 20 is greater than or equal to the set voltage. It should be noted that when the number of control modules 13 is multiple, the output voltages V+ of the rectifier and filter circuit 20 received by different control modules 13 may be the same or different, and the settings corresponding to different output voltages V+ The constant voltage is also different. For convenience of description, the following is an example in which the number of the resistance-adjustable circuit 11 is one and the number of the control module 13 is also one.

As shown in Figure 1, considering that the resistance of the fixed resistance circuit 12 is fixed and the resistance of the adjustable resistance circuit 11 is selectively changed under the control of the control module 13, in order to make the resistance of the fixed resistance circuit 12 and the resistance The value-adjustable circuit 11 has corresponding functions, so it is designed. In some embodiments, the resistance-fixed circuit 12 includes a fixed-value resistor R44, one end of the fixed-value resistor R44 is configured to be connected to the pulse controller 30, and the resistance is fixed. The other end of resistor R44 is connected to ground. The resistance-adjustable circuit 11 includes a first switching element Q1 and a first resistor R39. The first switching element Q1 has a first input terminal, a first output terminal and a first controlled terminal. The first input terminal is grounded, and the first output terminal The first controlled terminal is connected to the control module 13 through the first resistor R39 configured to be connected to the pulse controller 30 . That is to say, the first switching element Q1 and the first resistor R39 are connected in series to form a series branch. Both ends of the fixed resistance resistor R44 are connected in parallel with the series branch. The series branch is connected to one of the fixed resistance resistors R44. The parallel terminal is grounded, the other parallel terminal of the series branch and the fixed resistance resistor R44 is set to be connected to the pulse controller 30 , and the control module 13 is connected to the first controlled terminal of the first switching element Q1 . When the output voltage V+ of the rectifier and filter circuit 20 is greater than or equal to the set voltage, the control module 13 controls the first switching element Q1 to be turned off to increase the total resistance of the current supply module. Specifically, when the output voltage V+ of the rectifier and filter circuit 20 is greater than or equal to the set voltage, the control module 13 controls The first input terminal of the first switching element Q1 is disconnected from the first output terminal of the first switching element Q1 so that the first switching element Q1 is in an off state, and the first switching element Q1 is disconnected so that the connection with the first switching element Q1 The first resistor R39 connected in series is disconnected from the fixed resistance resistor R44. At this time, the resistance of the above total resistance is the resistance of the fixed resistance resistor R44. The current after the first switching element Q1 is disconnected provides the total resistance of the module. The resistance of the resistor increases relative to the total resistance of the current supply module before the first switching element Q1 is turned off. In this design, the first switching element Q1 is turned off so that the first resistor R39 is disconnected from the fixed resistance resistor R44. At this time, the resistance of the total resistance of the current supply module is the resistance of the fixed resistance resistor R44. Compared with Before the first switching element Q1 is turned off, the resistance value of the total resistance of the current supply module increases, thereby effectively reducing the current output by the current supply module to the pulse controller 30 and realizing the pulse controller 30 under large voltage conditions. The small current input can effectively reduce the selection cost of the pulse controller 30, thereby achieving the purpose of reducing the overall selection cost of the quasi-resonant power supply.

As shown in Figure 1, considering that the control module 13 controls the first switching element Q1 to turn off when the output voltage V+ of the rectifier filter circuit 20 is greater than or equal to the set voltage, of course, the control module 13 controls the first switch element Q1 to turn off when the output voltage V+ of the rectifier filter circuit 20 is less than When setting the voltage, it is also necessary to control the conduction of the first switching element Q1. In order to enable the control module 13 to have corresponding circuit control functions, it is designed. In some embodiments, the control module 13 includes a second switching element Q2 and a zener diode ZD11. and bias resistor R3. The second switching element Q2 has a second input terminal, a second output terminal and a second controlled terminal. The second controlled terminal is set to be connected to the output voltage V+ of the rectifier and filter circuit 20, and the second output terminal is connected to the first controlled terminal. The cathode of the Zener diode ZD11 is connected to the second input terminal, and the anode of the Zener diode ZD11 is connected to the ground. One end of the bias resistor R3 is connected to the second controlled terminal, and the other end of the bias resistor R3 is connected to the second input terminal. Specifically, when the output voltage V+ of the rectifier and filter circuit 20 is greater than or equal to the set voltage, the larger output voltage V+ acts on the second controlled terminal of the second switching element Q2, and the larger output voltage V+ passes through the bias After the resistor R3 is set, it acts on the cathode of the Zener diode ZD11. Therefore, the voltage acting on the cathode of the Zener diode ZD11 is greater than the reverse breakdown voltage of the Zener diode ZD11, causing the Zener diode ZD11 to be reversely broken down. The Zener diode ZD11 reverse attack The voltage of the second input terminal of the second switching element Q2 is pulled down, so that the voltage of the second input terminal of the second switching element Q2 is less than the voltage of the second controlled terminal of the second switching element Q2, so that the second switching element Q2 is turned off. On, the second switching element Q2 is turned off, causing the first switching element Q1 to be turned off. The first switching element Q1 is turned off, causing the first resistor R39 to be disconnected from the fixed resistance resistor R44. At this time, the resistance of the above total resistance is The resistance value of the fixed resistor R44 is that the resistance value of the total resistance of the current supply module after the first switching element Q1 is disconnected is increased relative to the total resistance value of the current supply module before the first switching element Q1 is disconnected. big. On the contrary, when the output voltage V+ of the rectifier and filter circuit 20 is less than the set voltage, the smaller output voltage V+ acts on the second controlled terminal of the second switching element Q2, and the smaller output voltage V+ passes through the bias resistor. R3 then acts on the cathode of the Zener diode ZD11, so the voltage acting on the cathode of the Zener diode ZD11 is less than the reverse breakdown voltage of the Zener diode ZD11, so that the Zener diode ZD11 cannot be reversely broken down, and at this time the third The voltage of the second input terminal of the second switching element Q2 is greater than the voltage of the second controlled terminal of the second switching element Q2 (and the voltage difference between the two is greater than the conduction threshold value of the second switching element Q2), so that the second switching element Q2 is turned on. The second switching element Q2 is turned on, causing the first switching element Q1 to be turned on. The first switching element Q1 is turned on, making the first resistor R39 and the fixed resistance resistor R44 connected in parallel. At this time, the resistance of the above total resistance is The value of the total resistance after the fixed resistor R44 and the first resistor R39 are connected in parallel, the resistance of the total resistance of the current supply module after the first switching element Q1 is turned on is relative to the resistance of the current supply module before the first switching element Q1 is turned on. The total resistance value is reduced. In this design, when the output voltage V+ of the rectifier filter circuit 20 is greater than or equal to the set voltage, the second switching element Q2 is turned off, causing the first switching element Q1 to be turned off. The first switching element Q1 is turned off, causing the first resistor R39 to connect with the resistor. Fixed-value resistor R44 is disconnected. At this time, the resistance of the total resistance of the current supply module is the resistance of fixed-value resistor R44. Compared with the resistance of the total resistance of the current supply module before the first switching element Q1 is disconnected, has increased, thereby effectively reducing the current output by the current supply module to the pulse controller 30, realizing a small current input of the pulse controller 30 under a large voltage condition, and effectively reducing the selection cost of the pulse controller 30, thus The purpose of reducing the overall selection cost of quasi-resonant power supply is achieved. When the output voltage V+ of the rectifier filter circuit 20 is less than the set voltage, The second switching element Q2 is turned on, causing the first switching element Q1 to be turned on. The first switching element Q1 is turned on, making the first resistor R39 and the fixed resistance resistor R44 connected in parallel. At this time, the resistance of the total resistance of the current supply module is After the fixed resistor R44 and the first resistor R39 are connected in parallel, the resistance of the total resistance of the current supply module is reduced compared with before the first switching element Q1 is turned on, thereby effectively increasing the output of the current supply module. The current to the pulse controller 30 enables the pulse controller 30 to input a suitable large current under a small voltage, thereby ensuring the normal operation of the pulse controller 30 .

Further, the control module 13 also includes a voltage dividing circuit 14. One end of the voltage dividing circuit 14 is set to be connected to the output voltage V+ of the rectifier and filter circuit 20. The other end of the voltage dividing circuit 14 is grounded. The voltage dividing circuit 14 includes at least two series connected circuits. voltage dividing resistor, and the voltage dividing circuit 14 has a voltage dividing node b1 between any two voltage dividing resistors, and the voltage dividing node b1 is connected to the second controlled end. Specifically, the voltage dividing circuit 14 includes a first voltage dividing resistor R27, a second voltage dividing resistor R41 and a third voltage dividing resistor R62. The first end of the first voltage dividing resistor R27 is set to be connected to the output voltage of the rectifier filter circuit 20. V+, the second end of the first voltage dividing resistor R27 is connected to the first end of the second voltage dividing resistor R41, the second end of the second voltage dividing resistor R41 is connected to the first end of the third voltage dividing resistor R62, and the third The second end of the voltage dividing resistor R62 is connected to the ground, and the voltage dividing node b1 is located between the second end of the second voltage dividing resistor R41 and the first end of the third voltage dividing resistor R62. In this design, by designing the voltage dividing circuit 14, the output voltage V+ of the rectifier and filter circuit 20 is divided by the voltage dividing circuit 14 and then acts on the second controlled end of the second switching element Q2, which plays a good role in the second switching element Q2. protective effect.

Further, the control module 13 further includes a second resistor R7, the first end of the second resistor R7 is connected to ground, and the other end of the second resistor R7 is connected to the second output end. In this design, by designing the second resistor R7, the second resistor R7 plays a good voltage dividing role. When the second switching element Q2 is turned on, the gate of the first switching element Q1 is connected with the first switching element Q1. The voltage difference between the sources is greater than the conduction threshold of the first switching element Q1, ensuring the effective conduction of the second switching element Q2.

As shown in FIG. 1 , considering that when the output voltage V+ of the rectifier filter circuit 20 is greater than or equal to the set voltage, the second switch element Q2 is turned off, causing the first switch element Q1 to be turned off. When the output voltage V+ of the rectifier filter circuit 20 is When the voltage V+ is less than the set voltage, the second switching element Q2 is turned on, causing the first switching element Q1 to be turned on. In order to enable the first switching element Q1 and the second switching element Q2 to achieve the corresponding on-off functions, regarding the first switching element The specific expression forms of Q1 and the second switching element Q2 may include, but are not limited to, one or more of the following embodiments.

In the first embodiment, the first switching element Q1 is one of a field effect transistor and a triode. In this design, if the first switching element Q1 is designed as a field effect transistor, when the output voltage V+ of the rectifier filter circuit 20 is greater than or equal to the set voltage, the source of the field effect transistor and the gate of the field effect transistor are disconnected. When the output voltage V+ of the rectifier filter circuit 20 is less than the set voltage, the source of the field effect transistor and the gate of the field effect transistor are connected; if the first switching element Q1 is designed as a transistor, when the output voltage V+ of the rectifier filter circuit 20 When the voltage is greater than or equal to the set voltage, the collector of the triode and the emitter of the triode are disconnected. When the output voltage V+ of the rectifier filter circuit 20 is less than the set voltage, the collector of the triode and the emitter of the triode are connected.

In the second embodiment, the second switching element Q2 is one of a field effect transistor and a triode. In this design, if the second switching element Q2 is designed as a field effect tube, when the output voltage V+ of the rectifier filter circuit 20 is greater than or equal to the set voltage, the source of the field effect tube and the gate of the field effect tube disconnected, when the output voltage V+ of the rectifier filter circuit 20 is less than the set voltage, the source of the field effect transistor and the gate of the field effect transistor are connected; if the second switching element Q2 is designed as a transistor, when the rectifier filter circuit 20 When the output voltage V+ is greater than or equal to the set voltage, the collector of the triode and the emitter of the triode are disconnected. When the output voltage V+ of the rectifier filter circuit 20 is less than the set voltage, the collector of the triode and the emitter of the triode are connected.

Specifically, the first switching element Q1 is an NPN field effect transistor, and the second switching element Q2 is a PNP field effect transistor. The gate of the NPN field effect transistor serves as the first controlled terminal of the first switching element Q1, the source of the NPN field effect transistor serves as the first input terminal of the first switching element Q1, and the drain of the NPN field effect transistor serves as the first controlled terminal of the first switching element Q1. The first output terminal of the first switching element Q1 and the gate of the PNP field effect transistor serve as the second switching element The second controlled terminal of the component Q2, the source of the PNP field effect transistor serves as the second input terminal of the second switching element Q2, and the drain of the PNP field effect transistor serves as the second output terminal of the second switching element Q2.

As shown in Figure 1, the working principle of the current compensation circuit 10 is briefly introduced below:

When the output voltage V+ of the rectifier filter circuit 20 is larger, after the larger output voltage V+ is divided by the first voltage dividing resistor R27 and the second voltage dividing resistor R41, the voltage at point A is UA, and the second switching element Q2 (PNP Type field effect transistor) gate voltage is equal to the voltage at point A. Due to the existence of bias resistor R3, the voltage at point A acts on the cathode of Zener diode ZD11 through bias resistor R3. At this time, the voltage acting on the cathode of Zener diode ZD11 The reverse breakdown voltage of the Zener diode ZD11 causes the Zener diode ZD11 to be reversely broken down. The reverse breakdown of the Zener diode ZD11 causes the source voltage of the second switching element Q2 to be pulled down. At this time, due to the second switch The source voltage of the element Q2 is less than the gate voltage of the second switching element Q2, causing the second switching element Q2 to turn off. The turning off of the second switching element Q2 causes the first switching element Q1 (NPN type field effect transistor) to turn off. When one switching element Q1 is disconnected, the first resistor R39 is disconnected from the fixed resistance resistor R44. At this time, the total resistance of the current supply module is the fixed resistance resistor R44. After the first switching element Q1 is disconnected, the total resistance of the current supply module is The resistance has increased compared with the total resistance of the current supply module before the first switching element Q1 is turned off. The output power at point B is P. According to the formula P = I ² R, where P is a fixed value. As R increases , so I is reduced, so the current output by the current supply module to the pulse controller 30 is reduced, realizing a small current input of the pulse controller 30 under a large voltage, which can effectively reduce the selection cost of the pulse controller 30. This achieves the purpose of reducing the overall selection cost of the quasi-resonant power supply.

When the output voltage V+ of the rectifier filter circuit 20 is small, after the small output voltage V+ is divided by the first voltage dividing resistor R27 and the second voltage dividing resistor R41, the voltage at point A is UA'(UA'<UA), and the voltage at point A is UA'(UA'<UA). The gate voltage of the second switching element Q2 (PNP field effect transistor) is equal to the voltage at point A. Due to the existence of the bias resistor R3, the voltage at point A acts on the cathode of the Zener diode ZD11 through the bias resistor R3. At this time, it acts on the stabilizer. The voltage of the cathode of the voltage diode ZD11 is less than the reverse breakdown voltage of the Zener diode ZD11, so that the Zener diode ZD11 cannot be reversely broken down. At this time, because the source voltage of the second switching element Q2 is greater than the second switch The gate voltage of element Q2 turns on the second switching element Q2. The turning on of the second switching element Q2 causes the first switching element Q1 (NPN type field effect transistor) to turn on. The turning on of the first switching element Q1 causes the first resistor to turn on. R39 is connected in parallel with the fixed resistance resistor R44. At this time, the total resistance of the current supply module is the resistance after the first resistor R39 and the fixed resistance resistor R44 are connected in parallel. The total resistance of the current supply module after the first switching element Q1 is turned on Compared with the total resistance of the current supply module before the first switching element Q1 is turned on, the output power at point B is P. According to the formula P = I ² R, where P is a fixed value. As R decreases, Therefore, I increases, so the current output by the current supply module to the pulse controller 30 increases, realizing a suitable large current input to the pulse controller 30 under a small voltage, thereby ensuring the normal operation of the pulse controller 30 .

The second aspect of this application proposes a quasi-resonant power supply. The quasi-resonant power supply includes a circuit board and the above-mentioned current compensation circuit 10. The current compensation circuit 10 is fabricated on the circuit board. In this design, due to the design of the above-mentioned current compensation circuit 10, the quasi-resonant power supply having the above-mentioned current compensation circuit 10 can effectively reduce the overall selection cost of the quasi-resonant power supply. In addition, the quasi-resonant power supply also has the effect of effectively improving the overall efficiency of the full-voltage input power supply and reducing temperature rise and electromagnetic interference.

The third aspect of this application proposes a charging device. The charging device includes a housing (not shown in the figure) and the above-mentioned quasi-resonant power supply. The housing has an installation space, and the quasi-resonant power supply is located in the installation space. The charging device may include, but is not limited to, a charger. In this design, the charging device with the above-mentioned quasi-resonant power supply can effectively reduce the overall selection cost of the charging device.

What is disclosed above is only the preferred embodiment of the present application. Of course, it cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application still fall within the scope of the present application.

Claims

A current compensation circuit of a quasi-resonant power supply, wherein the quasi-resonant power supply includes a rectifier filter circuit and a pulse controller connected to each other, and the current compensation circuit includes:

A control module configured to be connected to the rectifier and filter circuit and to access the output voltage of the rectifier and filter circuit;

The current supply module includes an adjustable resistance circuit and a fixed resistance circuit connected in parallel. One of the parallel terminals of the fixed resistance circuit and the adjustable resistance circuit is configured to be connected to the pulse controller, and the The other parallel end of the fixed resistance circuit and the adjustable resistance circuit is grounded, and the adjustable resistance circuit is also connected to the control module;

Wherein, the control module is configured to adjust the resistance of the adjustable resistance circuit when receiving the output voltage of the rectifier filter circuit to be greater than or equal to the set voltage, so as to reduce the current supply module output to the The current of the pulse controller.
The current compensation circuit as claimed in claim 1, wherein,

The fixed resistance circuit includes a fixed resistance resistor, one end of the fixed resistance resistor is configured to be connected to the pulse controller, and the other end of the fixed resistance resistor is grounded;

The resistance-adjustable circuit includes a first switching element and a first resistor. The first switching element has a first input terminal, a first output terminal and a first controlled terminal. The first input terminal is grounded. The first output terminal is configured to be connected to the pulse controller through the first resistor, and the first controlled terminal is connected to the control module;

Wherein, when the output voltage of the rectifier and filter circuit is greater than or equal to the set voltage, the control module controls the first switching element to be turned off to increase the total resistance of the current supply module.
The current compensation circuit of claim 2, wherein the control module includes:

The second switching element has a second input terminal, a second output terminal and a second controlled terminal. The second controlled terminal is configured to connect to the output voltage of the rectifier and filter circuit. The second output terminal Connected to the first controlled end;

A Zener diode, the cathode of the Zener diode is connected to the second input terminal, and the anode of the Zener diode is grounded;

A bias resistor, one end of the bias resistor is connected to the second controlled terminal, and the other end of the bias resistor is connected to the second input terminal.
The current compensation circuit of claim 3, wherein the control module further includes:

A voltage dividing circuit. One end of the voltage dividing circuit is configured to be connected to the output voltage of the rectifier and filter circuit. The other end of the voltage dividing circuit is grounded. The voltage dividing circuit includes at least two voltage dividing resistors connected in series. , and the voltage dividing circuit has a voltage dividing node between any two of the voltage dividing resistors, and the voltage dividing node is connected to the second controlled end.
The current compensation circuit of claim 4, wherein the voltage dividing circuit includes:

A first voltage dividing resistor, the first end of the first voltage dividing resistor is configured to be connected to the output voltage of the rectifier and filter circuit;

a second voltage dividing resistor, the first end of the second voltage dividing resistor is connected to the second end of the first voltage dividing resistor;

A third voltage dividing resistor, the first end of the third voltage dividing resistor is connected to the second end of the second voltage dividing resistor, and the second end of the third voltage dividing resistor is connected to ground; wherein, the voltage dividing resistor A node is located between the second end of the second voltage dividing resistor and the first end of the third voltage dividing resistor.
The current compensation circuit as claimed in claim 3, wherein,

The first switching element is one of a field effect transistor and a triode; and/or

The second switching element is one of a field effect transistor and a triode.
The current compensation circuit as claimed in claim 6, wherein,

The first switching element includes an NPN field effect transistor, and the second switching element includes a PNP field effect transistor.
The current compensation circuit of claim 3, wherein the control module further includes:

A second resistor, one end of the second resistor is connected to ground, and the other end of the second resistor is connected to the second output terminal.
The current compensation circuit as claimed in claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8, wherein,

The number of the resistance-adjustable circuits is multiple, and each of the resistance-adjustable circuits is connected in parallel with the fixed-resistance circuit; wherein, the control module is configured to receive the rectifier filter circuit When the output voltage is greater than or equal to the set voltage, the resistance of at least one of the adjustable resistance circuits is adjusted to reduce the current output by the current providing module to the pulse controller.
A quasi-resonant power supply, including:

Interconnected rectifier filter circuits and pulse controllers;

circuit boards; and

Current compensation circuit, the current compensation circuit is fabricated on the circuit board, and the current compensation circuit includes:

A control module, connected to the rectifier and filter circuit, and connected to the output voltage of the rectifier and filter circuit;

The current supply module includes an adjustable resistance circuit and a fixed resistance circuit connected in parallel. One of the parallel terminals of the fixed resistance circuit and the adjustable resistance circuit is connected to the pulse controller. The fixed circuit and the other parallel end of the resistance-adjustable circuit are grounded, and the resistance-adjustable circuit is also connected to the control module;

Wherein, when the control module receives that the output voltage of the rectifier filter circuit is greater than or equal to the set voltage, it adjusts the resistance of the adjustable resistance circuit to reduce the current supply module output to the pulse controller current.
A charging device, which includes:

An enclosure with space for installation; and

Quasi-resonant power supply. The quasi-resonant power supply is located in the installation space. The quasi-resonant power supply includes a rectifier filter circuit, a pulse controller, a circuit board and a current compensation circuit. The rectifier filter circuit and the pulse controller are connected to each other. , the current compensation circuit is fabricated on the circuit board, and the current compensation circuit includes:

A control module, connected to the rectifier and filter circuit, and connected to the output voltage of the rectifier and filter circuit;

The current supply module includes an adjustable resistance circuit and a fixed resistance circuit connected in parallel. One of the parallel terminals of the fixed resistance circuit and the adjustable resistance circuit is connected to the pulse controller. The fixed circuit and the other parallel end of the resistance-adjustable circuit are grounded, and the resistance-adjustable circuit is also connected to the control module;

Wherein, when the control module receives that the output voltage of the rectifier filter circuit is greater than or equal to the set voltage, it adjusts the resistance of the adjustable resistance circuit to reduce the current supply module output to the pulse controller current.