Light-load frequency conversion consumption reduction circuit and switching power supply

Abstract

The embodiment of the utility model discloses a light load frequency conversion consumption reduction circuit and a switching power supply, in the circuit, one end of a resistor R1 is connected with an output pin OUT of a pulse width modulation chip A1, the other end of the resistor R1 is connected with a base electrode of a triode E1, a reference pin of the pulse width modulation chip A1 is connected with one end of a resistor R2 and one end of a resistor R3, and the other end of the resistor R2 is connected with a base electrode of a triode E2. The other end of the resistor R2 is connected with a collector electrode of the triode E1, the other end of the resistor R3 is connected with an RT / CT pin of the pulse width modulation chip A1, an emitter electrode of the triode E1 and one end of the capacitor C1, and the other end of the capacitor C1 is connected with a GND pin of the pulse width modulation chip A1 and then is grounded. When the output power of the power supply is reduced, the PWM frequency time is shortened, the working frequency when the power supply is in light load is reduced, the switching loss of the switching tube is reduced, the energy consumption is reduced, the energy is saved, the efficiency is improved, and the device is suitable for popularization and application.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply, and in particular to a light-load frequency conversion and power-saving circuit and a switching power supply. Background Art

[0002] A switching power supply is a power supply that uses modern power electronics technology to control the ratio of the time when the switch is turned on and off to maintain a stable output voltage. As an energy supply device for industrial products, the switching power supply technology is constantly improving with the development and innovation of power electronics technology, and the advantages of low cost and high reliability of switching power supplies are becoming increasingly prominent. When the output power of the existing switching power supply using a fixed-frequency pulse width modulation (PWM) control chip is reduced, it is unable to reduce the operating frequency of the power supply when the power is lightly loaded, resulting in the switching loss of the switch tube not being reduced due to the reduction in output power, high energy consumption, and poor energy-saving and efficiency-enhancing capabilities. This problem needs to be solved urgently. Utility Model Content

[0003] In order to solve the related technical problems, the utility model provides a light-load frequency conversion and power consumption reduction circuit and a switching power supply to solve the problems mentioned in the above background technology part.

[0004] To achieve the above purpose, the embodiment of the utility model adopts the following technical solutions:

[0005] In the first aspect, an embodiment of the utility model provides a light-load variable frequency power consumption reduction circuit, comprising: a resistor R1, a resistor R2, a capacitor C2, a resistor R3, a transistor E1 and a pulse width modulation chip A1; wherein, one end of the resistor R1 is connected to the output pin OUT of the pulse width modulation chip A1, the other end of the resistor R1 is connected to the base of the transistor E1, the reference pin of the pulse width modulation chip A1 is connected to one end of the resistor R2 and one end of the resistor R3, the other end of the resistor R2 is connected to the collector of the transistor E1, the other end of the resistor R3 is connected to the RT / CT pin of the pulse width modulation chip A1, the emitter of the transistor E1, and one end of the capacitor C1, and the other end of the capacitor C1 is connected to the GND pin of the pulse width modulation chip A1 and then grounded.

[0006] As an optional implementation, the transistor E1 is an NPN transistor.

[0007] In a second aspect, an embodiment of the utility model provides a switching power supply, which adopts the light-load frequency conversion and power reduction circuit described in the first aspect.

[0008] The technical solution proposed in the embodiment of the utility model is aimed at a switching power supply using a conventional pulse width modulation chip. When the output power of the power supply increases, the PWM frequency time increases to improve the load capacity of the power supply. When the output power of the power supply decreases, the PWM frequency time decreases to reduce the operating frequency of the power supply when it is lightly loaded. The switching loss of the switching tube is reduced, the energy consumption is reduced, energy saving and efficiency improvement are achieved, and it is suitable for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate and understand the technical solutions in the embodiments of the present invention, the following briefly introduces the background technology of the present invention and the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0010] Figure 1 This is a structural diagram of a light-load frequency conversion and power-reduction circuit provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0011] In order to make the technical problems solved by the utility model, the technical solutions adopted and the technical effects achieved clearer, the technical solutions of the embodiments of the utility model will be further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0012] Embodiment 1

[0013] Please refer to Figure 1 As stated, Figure 1 A structural diagram of a light-load frequency conversion and power-reduction circuit provided for an embodiment of the utility model. As shown in the figure, the light-load frequency conversion and power-reduction circuit in this embodiment includes: a resistor R1, a resistor R2, a capacitor C2, a resistor R3, a transistor E1, and a pulse width modulation chip A1. In this embodiment, one end of the resistor R1 is connected to the output pin OUT of the pulse width modulation chip A1, the other end of the resistor R1 is connected to the base of the transistor E1, the reference pin of the pulse width modulation chip A1 is connected to one end of the resistor R2 and one end of the resistor R3, the other end of the resistor R2 is connected to the collector of the transistor E1, the other end of the resistor R3 is connected to the RT / CT pin of the pulse width modulation chip A1, the emitter of the transistor E1, and one end of the capacitor C1, and the other end of the capacitor C1 is connected to the GND pin of the pulse width modulation chip A1 and then grounded.

[0014] In this embodiment, the transistor E1 is an NPN transistor.

[0015] When working, the conventional pulse width modulation chip presets the output frequency by the RC circuit of the RT / CT frequency control pin. In this embodiment, the 6th pin of the pulse width modulation chip A1 is used to adjust the RC parameters of the 4th pin oscillation through components such as resistor R2, transistor E1, and resistor R1 to change the fixed output frequency. When the output power of the power supply increases, the 6th pin PWM drive duty cycle of the pulse width modulation chip A1 increases, the conduction time of the transistor E1 increases, and the resistor R2 intervenes to increase the PWM frequency adjustment time, thereby improving the load capacity of the entire power supply; when the output power of the power supply decreases, the 6th pin PWM drive duty cycle of the pulse width modulation chip A1 decreases accordingly, the conduction time of the transistor E1 decreases, and the resistor R2 intervenes to reduce the PWM frequency adjustment time, thereby reducing the operating frequency of the power supply when lightly loaded, thereby reducing the switching loss of the switch tube.

[0016] The light-load variable frequency consumption reduction circuit proposed in the embodiment of the utility model is aimed at a switching power supply using a conventional pulse width modulation chip. When the output power of the power supply increases, the PWM frequency time increases to improve the load capacity of the power supply. When the output power of the power supply decreases, the PWM frequency time decreases to reduce the operating frequency of the power supply when it is lightly loaded. The switching loss of the switching tube is reduced, the energy consumption is reduced, energy saving and efficiency improvement are increased, and it is suitable for popularization and application.

[0017] Embodiment 2

[0018] This embodiment provides a switching power supply, which adopts the light-load frequency conversion and power reduction circuit described in the first embodiment.

[0019] The switching power supply proposed in the embodiment of the utility model increases the PWM frequency time when the power output power increases, thereby improving the load capacity of the power supply. When the power output power decreases, the PWM frequency time decreases, thereby reducing the operating frequency of the power supply when it is lightly loaded, reducing the switching loss of the switch tube, reducing energy consumption, and increasing energy conservation and efficiency.

[0020] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A light load frequency conversion and power reduction circuit, characterized in that: include: Resistor R1, resistor R2, capacitor C2, resistor R3, transistor E1 and pulse width modulation chip A1; wherein one end of the resistor R1 is connected to the output pin OUT of the pulse width modulation chip A1, the other end of the resistor R1 is connected to the base of the transistor E1, the reference pin of the pulse width modulation chip A1 is connected to one end of the resistor R2 and one end of the resistor R3, the other end of the resistor R2 is connected to the collector of the transistor E1, the other end of the resistor R3 is connected to the RT / CT pin of the pulse width modulation chip A1, the emitter of the transistor E1 and one end of the capacitor C1, and the other end of the capacitor C1 is connected to the GND pin of the pulse width modulation chip A1 and then grounded.

2. The light-load frequency conversion and power-reduction circuit according to claim 1, characterized in that: The transistor E1 is an NPN transistor.

3. A switching power supply, characterized in that: The switching power supply adopts the light-load frequency conversion and power reduction circuit according to any one of claims 1 or 2.

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