Charging power supply control circuit

Abstract

The utility model relates to a control circuit of a charging power supply, which is applied to the technical field of charging power supplies and achieves the purpose of constant current output by adjusting a divider resistor through an optocoupler to control output voltage, for example, output current Iout is higher than reference current Iref, an optocoupler U2 is conducted after passing through a compensation network, output voltage Vout is reduced after a feedback signal Vfb is adjusted, and the output current Iout is reduced. And vice versa, when the output current Iout is lower than the reference current Iref, the optocoupler U2 is not conducted, the output voltage Vout rises, and the output current Iout rises; when the output current is suddenly reduced to 0A or the battery is suddenly disconnected, the integrator formed by the compensation network is slowly withdrawn, and the voltage loop works all the time in the whole switching process, so that the output overshoot is not too high; as the feedback signal Vfb and the output voltage Vout are associated through the resistor R7 and the resistor R8, the power supply can realize the lowest output voltage clamping, and meanwhile, the optocoupler is not conducted, and the highest output voltage clamping is realized through the resistor R7 and the resistor R8.

Description

Technical Field

[0001] This utility model relates to a charging power control circuit, and more particularly to a charging power control circuit applied in the field of charging power technology. Background Technology

[0002] In the current loop control method of charging power supply, a dual-loop competition mode is usually used, that is, the current loop and the voltage loop are used in parallel and compete with each other to make the output constant current.

[0003] Chinese patent CN203339785U discloses a charging power supply control circuit, including a chip, a clock signal generation circuit, a soft-start / shutdown control circuit, a voltage loop compensation circuit, a transformer primary peak current limiting control circuit, an output current overcurrent detection circuit, an adder circuit, and a dead-time setting circuit. It achieves constant voltage control through the output voltage feedback signal and the output voltage setting signal, constant current control through the output current feedback signal and the output current setting signal, and peak current limiting control through the transformer primary peak current feedback signal and a circuit-set limiting signal. Due to its constant voltage, constant current, soft-start, and power-on / off control, the controller has excellent compatibility and is extremely convenient to use.

[0004] The output regulation terminals of the feedback voltage loop and the feedback current loop are connected to the same network. They will interfere with each other during the switching between constant voltage mode and constant current mode, making the output of the charging power supply unstable. This is mainly manifested in one loop working while the other loop is saturated. Furthermore, the output result of the current loop is transmitted through an optocoupler before the feedback signal is obtained. This circuit only uses the current loop for regulation. During the regulation process, the Vfb potential may be low, making it impossible to clamp the minimum power supply output voltage. Utility Model Content

[0005] The technical problem that this utility model aims to solve in view of the above-mentioned prior art is that the output regulation terminals of the feedback voltage loop and the feedback current loop are connected to the same network, which will interfere with each other during the switching between constant voltage mode and constant current mode, making the output of the charging power supply unstable. In addition, the current loop output result is transmitted through an optocoupler before the feedback signal is obtained. This circuit only uses the current loop regulation, and during the regulation process, the Vfb potential may be low, making it impossible to clamp the minimum power supply output voltage.

[0006] To solve the above problems, this utility model provides a charging power supply control circuit, including a charging power supply current loop control circuit. The charging power supply current loop control circuit consists of a compensation network and an optocoupler adjustment. The compensation network consists of resistors R1, R2, R3, and R4, capacitors C1, C2, and C3, and an operational amplifier U1. The optocoupler adjustment consists of resistors R5, R6, R7, and R8, capacitor C4, optocoupler U2, and a diode D1.

[0007] The above-mentioned charging power supply control circuit solves the overshoot phenomenon caused by sudden changes in output current, realizes the function of stable and smooth switching of the output current of the charging power supply, and the function of clamping the minimum and maximum output voltage.

[0008] As a further improvement to this application, the operational amplifier U1 is a low-power operational amplifier to reduce the energy consumption of the entire circuit.

[0009] As a further improvement to this application, the resistors R1-R4 are high-precision metal film resistors, used to ensure the parameter accuracy of the compensation network.

[0010] As a further improvement of this application, the optocoupler U2 is a linear optocoupler, which can accurately transmit control signals.

[0011] As another improvement of this application, the capacitors C1-C4 are ceramic capacitors, which have high stability and low equivalent series resistance (ESR).

[0012] As a further improvement to this application, the diode D1 is a fast recovery diode, which can reduce the impact of reverse recovery time on circuit performance.

[0013] As a further improvement to this application, the resistors R5-R8 are surface mount resistors to reduce the circuit size.

[0014] In summary, the solution controls the output voltage by adjusting the voltage divider resistor through an optocoupler to achieve constant current output. For example, if the output current Iout is higher than the reference current Iref, the optocoupler U2 conducts after passing through the compensation network. After the feedback signal Vfb is adjusted, the output voltage Vout decreases, and the output current Iout decreases. Conversely, if the output current Iout is lower than the reference current Iref, the optocoupler U2 does not conduct, the output voltage Vout increases, and the output current Iout increases. When the output current suddenly drops to 0A or the battery is suddenly disconnected, the integrator composed of the compensation network will slowly exit. The voltage loop works continuously throughout the switching process, preventing output overshoot. Since the feedback signal Vfb and the output voltage Vout are related through resistors R7 and R8, the power supply can achieve minimum output voltage clamping, while the optocoupler does not conduct, achieving maximum output voltage clamping through resistors R7 and R8. Attached Figure Description

[0015] Figure 1 This is a circuit diagram of the charging power supply current loop control according to an embodiment of this application;

[0016] Figure 2 This is a schematic diagram of the compensation network circuit according to an embodiment of this application;

[0017] Figure 3This is a schematic diagram of the optocoupler adjustment circuit according to an embodiment of this application. Detailed Implementation

[0018] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0019] Implementation method:

[0020] Figure 1-3 A charging power supply control circuit is shown, including a charging power supply current loop control circuit. The charging power supply current loop control circuit consists of a compensation network and an optocoupler adjustment. The compensation network consists of resistors R1, R2, R3, and R4, capacitors C1, C2, and C3, and an operational amplifier U1. The optocoupler adjustment consists of resistors R5, R6, R7, and R8, capacitor C4, optocoupler U2, and a diode D1.

[0021] The operational amplifier U1 is a low-power operational amplifier to reduce the overall power consumption of the circuit. The resistors R1-R4 are high-precision metal film resistors to ensure the parameter accuracy of the compensation network. The optocoupler U2 is a linear optocoupler that can accurately transmit control signals. The capacitors C1-C4 are ceramic capacitors with high stability and low equivalent series resistance (ESR). The diode D1 is a fast recovery diode, which can reduce the impact of reverse recovery time on circuit performance. The resistors R5-R8 are surface mount resistors to reduce the circuit size.

[0022] This solution controls the output voltage by adjusting the voltage divider resistors using an optocoupler to achieve constant current output. For example, if the output current Iout is higher than the reference current Iref, the optocoupler U2 conducts after passing through the compensation network. After the feedback signal Vfb is adjusted, the output voltage Vout decreases, and the output current Iout decreases. Conversely, if the output current Iout is lower than the reference current Iref, the optocoupler U2 does not conduct, the output voltage Vout increases, and the output current Iout increases.

[0023] When the output current suddenly drops to 0A or the battery is suddenly disconnected, the integrator composed of the compensation network will slowly exit. The voltage loop works throughout the entire switching process, preventing the output overshoot from being too high.

[0024] Since the feedback signal Vfb is related to the output voltage Vout through resistors R7 and R8, the power supply can achieve the lowest output voltage clamping, while the optocoupler is not conducting, and the highest output voltage clamping is achieved through resistors R7 and R8.

[0025] This solution solves the overshoot phenomenon caused by sudden changes in output current, realizes the function of stable and smooth switching of the output current of the charging power supply, and the function of clamping the output voltage at the lowest and highest levels.

[0026] In light of current practical needs, the above-described embodiments adopted in this application are not limited to these. Any changes made within the scope of knowledge possessed by those skilled in the art without departing from the concept of this application still fall within the protection scope of this utility model.

Claims

1. A charging power supply control circuit, comprising a charging power supply current loop control circuit, characterized in that: The charging power supply current loop control circuit consists of a compensation network and an optocoupler adjustment. The compensation network consists of resistors R1, R2, R3, and R4, capacitors C1, C2, and C3, and an operational amplifier U1. The optocoupler adjustment consists of resistors R5, R6, R7, and R8, capacitor C4, optocoupler U2, and a diode D1.

2. The charging power supply control circuit according to claim 1, characterized in that: The operational amplifier U1 is a low-power operational amplifier to reduce the energy consumption of the entire circuit.

3. The charging power supply control circuit according to claim 1, characterized in that: The resistors R1-R4 are high-precision metal film resistors used to ensure the parameter accuracy of the compensation network.

4. The charging power supply control circuit according to claim 1, characterized in that: The optocoupler U2 is a linear optocoupler, which can accurately transmit control signals.

5. A charging power supply control circuit according to claim 1, characterized in that: The capacitors C1-C4 are ceramic capacitors, which have high stability and low equivalent series resistance.

6. The charging power supply control circuit according to claim 1, characterized in that: The diode D1 is a fast recovery diode, which can reduce the impact of reverse recovery time on circuit performance.

7. A charging power supply control circuit according to claim 1, characterized in that: The resistors R5-R8 are surface mount resistors to reduce the circuit size.

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