Voltage regulating circuit and switching power supply

Abstract

The utility model discloses a kind of voltage regulating circuit and switching power supply, voltage regulating circuit includes: signal preprocessing circuit, its input end is used to input first control signal, signal preprocessing circuit is used to output second control signal after filtering and anti-interference processing to first control signal;Signal amplification circuit, the output end of signal preprocessing circuit is connected, signal amplification circuit is used to output third control signal after amplification processing to second control signal;Signal feedback circuit, its first input end connects the output end of signal amplification circuit, second input end is used to input reference voltage, signal feedback circuit is used to output fourth control signal after comparing processing to third control signal and reference voltage, fourth control signal is used to connect to the cathode of photocoupler U1 emission end diode, the output voltage of the switching power supply is adjusted by control loop.The utility model can improve the operability of customer to power supply.

Description

Technical Field

[0001] This utility model belongs to the field of switching power supplies, and specifically relates to a voltage regulation circuit and a switching power supply. Background Technology

[0002] In practical applications, the load side often needs to control the power supply's output voltage. In traditional power supplies, although the output is adjustable, this is often done through an adjustable resistor. While this greatly increases the operability of output voltage adjustment, the load side cannot adjust it according to its own needs, limiting the power supply's use and reducing the user experience. This invention effectively solves this problem, significantly improving the user's operability. Users can adjust the power supply's output voltage according to their needs, requiring only the corresponding signal. Furthermore, this invention includes a signal preprocessing circuit, ensuring good compatibility with various control signals. Summary of the Invention

[0003] In view of this, the technical problem to be solved by this utility model is to provide a voltage regulating circuit and a switching power supply, which at least to some extent solves one of the technical problems existing in the prior art.

[0004] As a first aspect of this utility model, the embodiment of the voltage regulating circuit is as follows:

[0005] A voltage regulation circuit is applied to a switching power supply. The control loop of the switching power supply includes a main control chip, an optocoupler U1, and a resistor R7. One end of the resistor R7 is used to input the supply voltage, and the other end is connected to the anode of the emitter diode of the optocoupler U1. The cathode of the emitter diode of the optocoupler U1 is connected to the power supply ground. The collector of the receiver transistor of the optocoupler U1 is connected to the feedback pin FB of the main control chip, and the emitter is connected to the signal ground. The voltage regulation circuit includes:

[0006] A signal preprocessing circuit, the input terminal of which is used to input a first control signal, the signal preprocessing circuit is used to filter and anti-interference process the first control signal and then output a second control signal;

[0007] A signal amplification circuit is connected to the output terminal of the signal preprocessing circuit. The signal amplification circuit is used to amplify the second control signal and output a third control signal.

[0008] The signal feedback circuit has a first input terminal connected to the output terminal of the signal amplification circuit and a second input terminal for inputting a reference voltage. The signal feedback circuit is used to compare and process the third control signal and the reference voltage and output a fourth control signal. The fourth control signal is used to connect to the cathode of the diode at the emitter of the optocoupler U1 and adjust the output voltage of the switching power supply through the control loop.

[0009] Preferably, the signal preprocessing circuit includes a diode D1, a resistor R1, a Zener diode ZD1, and a capacitor C1. The anode of the diode D1 is the input of the signal preprocessing circuit, and the cathode is connected to one end of the resistor R1 and the cathode of the Zener diode ZD1. The other end of the resistor R1 and one end of the capacitor C1 are connected together to output the second control signal. The anode of the Zener diode ZD1 and the other end of the capacitor C1 are connected together to connect to the power supply ground.

[0010] Preferably, the signal amplification circuit includes resistor R3, resistor Rf, and operational amplifier OP1. One end of resistor Rf is connected to the non-inverting input of operational amplifier OP1 for inputting the second control signal. One end of resistor R3 is connected to the power supply ground and the other end is connected to the inverting input of operational amplifier OP1. The other end of resistor Rf is connected to the output of operational amplifier OP1 for outputting the third control signal.

[0011] Preferably, the signal feedback circuit includes an operational amplifier OP2, wherein the third control signal is input to the inverting input terminal, the reference voltage is input to the non-inverting input terminal, and the fourth control signal is output to the output terminal.

[0012] Furthermore, the signal feedback circuit also includes capacitor C3, capacitor C4 and resistor R4. One end of capacitor C3 and one end of capacitor C4 are both connected to the inverting input terminal of operational amplifier OP2. The other end of capacitor C4 is connected to one end of resistor R4. The other end of resistor R4 and the other end of capacitor C3 are both connected to one end of resistor R5.

[0013] Preferably, the first control signal is a DC voltage signal, or an AC voltage signal, or a PWM signal, or an SPWM signal.

[0014] As a first aspect of this utility model, the embodiment of the provided switching power supply is as follows:

[0015] A switching power supply, wherein the control loop of the switching power supply includes a main control chip, an optocoupler U1, and a resistor R7, one end of the resistor R7 is used to input the supply voltage, and the other end is connected to the anode of the emitter diode of the optocoupler U1, the cathode of the emitter diode of the optocoupler U1 is used to connect to the power supply ground, the collector of the receiver transistor of the optocoupler U1 is connected to the feedback pin FB of the main control chip, and the emitter is used to connect to the signal ground, wherein: the switching power supply includes the voltage regulation circuit described in any of the first aspects above.

[0016] Furthermore, the switching power supply also includes a soft-start circuit, which controls the degree of change between the output current and output voltage of the switching power supply to achieve soft-start of the switching power supply.

[0017] Preferably, the soft-start circuit includes a diode D2, a capacitor C5, and a resistor R6. The anode of the diode D2 is connected to the cathode of the emitter diode of the optocoupler U1, and the cathode is connected to one end of the capacitor C5 and one end of the resistor R6. The other end of the capacitor C5 and the other end of the resistor R6 are connected together to the power ground.

[0018] Compared with the prior art, this utility model has the following advantages:

[0019] (1) In this embodiment of the present invention, the first control signal is an externally provided signal. The load end customer can adjust the output voltage of the switching power supply according to actual needs. The whole process only requires the corresponding first control signal, which greatly improves the customer's operability of the power supply.

[0020] (2) The present invention includes a signal preprocessing circuit, which can be well compatible with various control signals. The first control signal can be a DC voltage signal, an AC voltage signal, a PWM signal, or an SPWM signal, etc. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the voltage regulation circuit of the first embodiment of this utility model applied in a power supply.

[0022] Figure 2 This is a circuit diagram of a switching power supply according to the second embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0024] It should be noted that the terms "comprising" and "having" and any variations thereof described in the specification and claims of this application are intended to cover non-exclusive inclusion. For example, including a series of components, unit circuits or control timings is not necessarily limited to those components, unit circuits or control timings that are explicitly listed, but may include components, unit circuits or control timings that are not explicitly listed or that are inherent to these circuits.

[0025] Furthermore, unless otherwise specified, the embodiments and features described in this application may be combined with each other.

[0026] It should be understood that, in the specification and claims, when an element is described as being "connected" to another element, that element may be "directly connected" to that other element or "connected" to that other element through a third element; when a step is described as being connected to another step, that step may be connected directly to that other step or connected to that other step through a third step.

[0027] First Embodiment

[0028] This embodiment provides a voltage regulation circuit applied to a switching power supply. Figure 1 This is a schematic diagram of the voltage regulation circuit of the first embodiment of this utility model applied in a power supply. The control loop of the switching power supply includes a main control chip, an optocoupler U1, and a resistor R7. One end of the resistor R7 is used to input the supply voltage VCC, and the other end is connected to the anode of the diode at the emitter end of the optocoupler U1. The cathode of the diode at the emitter end of the optocoupler U1 is connected to the power ground GND. The collector of the transistor at the receiver end of the optocoupler U1 is connected to the feedback pin FB of the main control chip, and the emitter is connected to the signal ground AGND. The voltage regulation circuit includes:

[0029] The signal preprocessing circuit has an input terminal for inputting a first control signal Ui, and the signal preprocessing circuit is used to filter and perform anti-interference processing on the first control signal Ui before outputting a second control signal.

[0030] The signal amplification circuit is connected to the output of the signal preprocessing circuit. The signal amplification circuit is used to amplify the second control signal and output the third control signal.

[0031] The signal feedback circuit has a first input terminal connected to the output terminal of the signal amplifier circuit, a second input terminal for inputting a reference voltage, and a fourth control signal output after comparing and processing the third control signal and the reference voltage. The fourth control signal is connected to the cathode of the diode at the emitter of the optocoupler U1 and adjusts the output voltage of the switching power supply through the control loop.

[0032] It should be noted that the power ground and signal ground are different grounds.

[0033] In this embodiment, the first control signal is an externally supplied signal. The load-side customer can adjust the output voltage of the switching power supply according to actual needs. The entire process only requires the corresponding first control signal, which greatly improves the customer's operability of the power supply. In addition, this embodiment is equipped with a signal preprocessing circuit, which can be well compatible with various control signals. The first control signal can be a DC voltage signal, an AC voltage signal, a PWM signal, or an SPWM signal, etc.

[0034] Please continue reading Figure 1 The signal preprocessing circuit includes diode D1, resistor R1, Zener diode ZD1, and capacitor C1. The anode of diode D1 is the input to the signal preprocessing circuit, and its cathode is connected to both one end of resistor R1 and the cathode of Zener diode ZD1. The other end of resistor R1 is connected to one end of capacitor C1 to output the second control signal. The anode of Zener diode ZD1 and the other end of capacitor C1 are connected together to the power supply ground. Setting up the signal preprocessing circuit ensures signal stability and accuracy, and avoids signal corruption.

[0035] Please continue reading Figure 1 The signal amplification circuit includes resistors R3 and Rf, and operational amplifier OP1. One end of resistor Rf is connected to the non-inverting input of operational amplifier OP1 to input the second control signal. One end of resistor R3 is connected to power ground, and the other end is connected to the inverting input of operational amplifier OP1. The other end of resistor Rf is connected to the output of operational amplifier OP1 to output the third control signal. By adjusting the parameters of resistors R1, R2, and Rf, the amplification factor can be controlled to meet the amplification requirements of different signals.

[0036] Please continue reading Figure 1 The signal feedback circuit includes operational amplifier OP2, which receives a third control signal at its inverting input, a reference voltage at its non-inverting input, and a fourth control signal at its output.

[0037] Please continue reading Figure 1 The signal feedback circuit also includes capacitors C3 and C4, and resistor R4. One end of capacitor C3 and one end of capacitor C4 are both connected to the inverting input of operational amplifier OP2. The other end of capacitor C4 is connected to one end of resistor R4, and the other ends of resistor R4 and capacitor C3 are both connected to one end of resistor R5. By adjusting their parameters, the stability of the switching power supply output voltage can be optimized.

[0038] Second Embodiment

[0039] This embodiment provides a switching power supply. The control loop of the switching power supply includes a main control chip, an optocoupler U1, and a resistor R7. One end of the resistor R7 is used to input the power supply voltage, and the other end is connected to the anode of the diode at the emitter end of the optocoupler U1. The cathode of the diode at the emitter end of the optocoupler U1 is used to connect to the power supply ground. The collector of the transistor at the receiver end of the optocoupler U1 is connected to the feedback pin FB of the main control chip, and the emitter is used to connect to the signal ground. The switching power supply includes any of the voltage regulation circuits in the first embodiment.

[0040] Since the switching power supply in this embodiment includes any of the voltage regulation circuits in the first embodiment, there is no need to sample the output voltage. The output voltage can be adjusted by an external signal according to one's own needs, which greatly improves the operability of the power supply. The external signal can be a DC voltage signal, an AC voltage signal, a PWM signal, or an SPWM signal, etc.

[0041] Figure 2 This is a circuit diagram of a switching power supply related to the second embodiment of this utility model. Please refer to [link / reference]. Figure 2 The switching power supply also includes a soft-start circuit, which controls the degree of change between the output current and output voltage of the switching power supply to achieve soft start. This helps protect the circuit from the impact during startup and improves the stability and reliability of the circuit.

[0042] Please continue reading Figure 2 The soft-start circuit includes diode D2, capacitor C5, and resistor R6. The anode of diode D2 is connected to the cathode of the diode at the emitter of optocoupler U1. The cathode is also connected to one end of capacitor C5 and one end of resistor R6. The other end of capacitor C5 and the other end of resistor R6 are connected together to the power ground. By modifying the parameters of capacitor C5 and resistor R6, the degree of current and voltage change can be controlled to achieve different soft-start levels.

[0043] The above are merely embodiments of this utility model. It should be particularly noted that the above embodiments should not be regarded as limitations on this utility model. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of this utility model, and these improvements and modifications should also be regarded as protection scope of this utility model.

Claims

1. A voltage regulating circuit applied to a switching power supply, a control loop of the switching power supply comprising a main control chip, an optocoupler U1 and a resistor R7, one end of the resistor R7 being used for inputting a supply voltage, the other end of the resistor R7 being connected to an anode of an emitting end diode of the optocoupler U1, a cathode of the emitting end diode of the optocoupler U1 being used for connecting a power supply ground, a collector of a receiving end triode of the optocoupler U1 being connected to a feedback pin FB of the main control chip, and an emitter of the receiving end triode being used for connecting a signal ground, characterized in that, The voltage regulation circuit includes: A signal preprocessing circuit, the input terminal of which is used to input a first control signal, the signal preprocessing circuit is used to filter and anti-interference process the first control signal and then output a second control signal; A signal amplification circuit is connected to the output terminal of the signal preprocessing circuit. The signal amplification circuit is used to amplify the second control signal and output a third control signal. The signal feedback circuit has a first input terminal connected to the output terminal of the signal amplification circuit and a second input terminal for inputting a reference voltage. The signal feedback circuit is used to compare and process the third control signal and the reference voltage and output a fourth control signal. The fourth control signal is used to connect to the cathode of the diode at the emitter of the optocoupler U1 and adjust the output voltage of the switching power supply through the control loop.

2. The voltage regulating circuit according to claim 1, characterized in that: The signal preprocessing circuit includes a diode D1, a resistor R1, a Zener diode ZD1, and a capacitor C1. The anode of the diode D1 is the input of the signal preprocessing circuit, and the cathode is connected to one end of the resistor R1 and the cathode of the Zener diode ZD1. The other end of the resistor R1 and one end of the capacitor C1 are connected together to output the second control signal. The anode of the Zener diode ZD1 and the other end of the capacitor C1 are connected together to connect to the power supply ground.

3. The voltage regulating circuit according to claim 1, characterized in that: The signal amplification circuit includes resistor R3, resistor Rf, and operational amplifier OP1. One end of resistor Rf is connected to the non-inverting input of operational amplifier OP1 for inputting the second control signal. One end of resistor R3 is connected to the power supply ground, and the other end is connected to the inverting input of operational amplifier OP1. The other end of resistor Rf is connected to the output of operational amplifier OP1 for outputting the third control signal.

4. The voltage regulating circuit according to claim 1, characterized in that: The signal feedback circuit includes an operational amplifier OP2, which receives the third control signal at its inverting input terminal, the reference voltage at its non-inverting input terminal, and outputs the fourth control signal at its output terminal.

5. The voltage regulating circuit according to claim 4, characterized in that: The signal feedback circuit also includes capacitors C3 and C4 and resistor R4. One end of capacitor C3 and one end of capacitor C4 are both connected to the inverting input terminal of operational amplifier OP2. The other end of capacitor C4 is connected to one end of resistor R4. The other end of resistor R4 and the other end of capacitor C3 are both connected to one end of resistor R5.

6. The voltage regulating circuit according to any one of claims 1 to 5, characterized in that: The first control signal is a DC voltage signal, or an AC voltage signal, or a PWM signal, or an SPWM signal.

7. A switching power supply, wherein the control loop of the switching power supply includes a main control chip, an optocoupler U1, and a resistor R7, one end of the resistor R7 is used for inputting the supply voltage, and the other end is connected to the anode of the emitting diode of the optocoupler U1; the cathode of the emitting diode of the optocoupler U1 is connected to the power supply ground; the collector of the receiving transistor of the optocoupler U1 is connected to the feedback pin FB of the main control chip, and the emitter is connected to the signal ground, characterized in that: The switching power supply includes the voltage regulation circuit according to any one of claims 1 to 6.

8. The switching power supply according to claim 7, characterized in that: The switching power supply also includes a soft-start circuit, which controls the degree of change between the output current and output voltage of the switching power supply to achieve soft start of the switching power supply.

9. The switching power supply according to claim 8, characterized in that: The soft-start circuit includes a diode D2, a capacitor C5, and a resistor R6. The anode of the diode D2 is connected to the cathode of the diode at the emitter of the optocoupler U1. The cathode is also connected to one end of the capacitor C5 and one end of the resistor R6. The other end of the capacitor C5 and the other end of the resistor R6 are connected together to the power ground.

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