Pulse power supply circuit

Abstract

The utility model belongs to the technical field of pulse power supplies, and particularly discloses a pulse power supply circuit, which comprises a power supply input module, a PWM (Pulse Width Modulation) signal input module, a feedback control module, a control chip and an output module, the power input module provides working power for the control chip and the whole circuit. The PWM signal input module is used for transmitting an external PWM signal to a signal input pin of the control chip; the feedback control module collects an electric signal in the circuit and transmits a processed feedback signal to the control chip; the control chip drives the output module to output a pulse power supply to provide electric energy for a load based on an input PWM signal and a feedback signal. According to the utility model, the feedback signal acquired by the feedback control module is compared with the reference voltage, the difference value is amplified, the control chip adjusts the duty ratio of the PWM signal according to the amplified error signal, the pulse waveform is effectively optimized, and the output stability and reliability of the pulse power supply are improved.

Description

Technical Field

[0001] This utility model belongs to the field of pulse power supply technology, and specifically relates to a pulse power supply circuit. Background Technology

[0002] With the vigorous development of my country's industry, pulse power supplies are widely used in industrial applications. A pulse power supply, also known as an AC-to-DC power supply, works by using semiconductor devices to rectify, filter, and regulate high-frequency AC power to obtain the required DC voltage and current. In a pulse power supply, the AC power generated by the AC power generator is first rectified into DC power by a transformer and rectifier bridge. Then, it passes through a filter capacitor to filter out the AC signal, making the actual output voltage and current closer to the DC voltage and current. Currently used laser pulse power supplies mainly consist of a constant current control circuit, a pulse width control circuit, and a protection control circuit.

[0003] Constant current control circuit such as Figure 1 As shown, it consists of a reference circuit, a sampling circuit, a comparator amplifier circuit, and a power output circuit. The principle of the pulse width control circuit is as follows: Figure 2 As shown, it consists of three parts: an anti-contact bounce circuit, a differentiating circuit, and a pulse width modulation circuit. The protection circuit is as follows: Figure 3 As shown, to eliminate the influence of transient peak currents, the following method was adopted. Figure 3 The protection circuit shown consists of capacitor C, Zener diode DZ, and protection switch K. Several problems arose during actual testing with the above scheme: firstly, the pulse leading edge overshoot oscillation was large, and the trailing edge began to decline before the required time; secondly, the overvoltage protection of the output laser diode currently uses a common Zener diode with a voltage regulation value of approximately 2.0V and a power of 1W, which is insufficient for the rated capacity of the protection shunt. Utility Model Content

[0004] The purpose of this invention is to overcome the defects in the existing technology and provide a pulse power supply circuit.

[0005] This utility model provides a pulse power supply circuit, including a power input module, a PWM signal input module, a feedback control module, a control chip, and an output module;

[0006] The power input module is connected to the power pin of the control chip, providing operating power to the control chip and the entire circuit.

[0007] The PWM signal input module is used to transmit external PWM signals to the signal input pins of the control chip.

[0008] The feedback control module collects electrical signals from the circuit and transmits the processed feedback signals to the control chip.

[0009] Based on the input PWM signal and feedback signal, the control chip outputs a control signal from the output pin to the output module, thereby driving the output module to output pulse power to provide electrical energy to the load.

[0010] A further embodiment is that the power input module includes a high-voltage power supply pin and a common voltage pin as power input ports. The high-voltage power supply pin and the common voltage pin are connected in series with several step-down resistors to form two step-down circuits. The two step-down circuits are respectively connected to a protection circuit composed of bidirectional diodes, and the protection circuit is connected to a capacitor for filtering. The power input module also includes a VCC pin to provide operating power to the control chip, which is connected to the power supply pin of the control chip.

[0011] A further embodiment is that the PWM signal input module includes an external PWM interface, which is connected to a filtering and shaping circuit composed of resistors and capacitors, and is connected to the current protection pin of the control chip.

[0012] A further embodiment is that the feedback control module is an operational amplifier. The output voltage or output current is collected at the output terminal of the operational amplifier through a sampling resistor as a feedback signal, and the feedback signal is transmitted to the inverting input terminal of the operational amplifier. The non-inverting input terminal of the operational amplifier is connected to the reference voltage after voltage division. The operational amplifier compares the collected feedback signal with the reference voltage and amplifies the difference. The amplified error signal is connected to the inverting input pin of the control chip.

[0013] The reference voltage is output from the reference voltage output pin of the control chip.

[0014] A further option is that the control chip is a UC3823B chip.

[0015] A further embodiment is that the output module includes an output interface, the input end of which is connected to the control chip, and the output end of which is used to connect to the load and provide the load with the required pulse power.

[0016] A further option is that the operational amplifier is model LM358AMX.

[0017] A further embodiment involves mounting the power input module, PWM signal input module, feedback control module, control chip, and output module onto the circuit layer of an aluminum substrate.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] This invention uses a feedback control module to accurately acquire the output voltage or current signal as a feedback signal, compares it with a reference voltage, and amplifies the difference. Based on the amplified error signal, the control chip adjusts the PWM signal duty cycle, effectively optimizing the pulse waveform. This suppresses pulse leading-edge overshoot oscillation and ensures the trailing edge falls stably as designed, improving the stability and reliability of the pulse power supply output and meeting the needs of applications requiring high pulse waveform quality.

[0020] The power input module of this invention uses multiple step-down resistors connected in series on the high-voltage power pin and the common voltage pin to form a step-down circuit, which is then connected to a bidirectional diode to form a protection circuit. This effectively steps down and protects the input high-voltage power supply. Furthermore, in the overall circuit design, the control chip is connected to a current detection circuit. When an overcurrent or potentially overvoltage abnormality occurs, the chip can quickly reduce or cut off the PWM output, achieving overcurrent protection and indirectly enhancing the overvoltage protection capability of the load. Compared to existing technologies, this significantly improves the protection effect on the load, reduces the risk of load damage due to overvoltage, and extends the load's lifespan.

[0021] This invention uses a single-layer surface-mount aluminum substrate to mount the power devices on the circuit layer, ensuring that each power device can always remain within the normal operating temperature range during long-term operation, reducing circuit failures caused by temperature issues, and improving the reliability and stability of the entire pulse power supply circuit. Attached Figure Description

[0022] The following figures are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0023] Figure 1 : A constant current control circuit diagram for an existing laser pulse power supply;

[0024] Figure 2 : A circuit diagram of the pulse width control of an existing laser pulse power supply;

[0025] Figure 3 : Protection and control circuit diagram of existing laser pulse power supply;

[0026] Figure 4 : Schematic diagram of the pulse power supply connection structure of this utility model;

[0027] Figure 5 : Circuit diagram of the pulse power supply of this utility model;

[0028] In the diagram: 1. Power input module; 2. PWM signal input module; 3. Feedback control module; 4. Control chip; 5. Output module; 6. Load. Detailed Implementation

[0029] To make the objectives, technical solutions, design methods, 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 specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this utility model.

[0030] like Figure 4 and Figure 5 As shown, this utility model provides a pulse power supply circuit, which uses a single-layer surface-mount aluminum substrate. A power input module 1, a PWM signal input module, a feedback control module 3, a control chip 4, and an output module 5 are mounted on the circuit layer of the single-layer surface-mount aluminum substrate. The power input module 1 uses a high-voltage power supply pin (HVCC pin) and a common voltage pin (VOCM pin) as high-voltage power input ports. The high-voltage power supply pin is stepped down by resistors R173, R117, R116, and R115 connected in series. The common voltage pin is stepped down by resistors R172, R110, R109, and R108 connected in series. The circuits after the two voltage steps are connected to a protection circuit composed of bidirectional diodes D38 and D39, and then connected to capacitors C60, C61, and C62 for filtering. The power input module 1 also includes a VCC pin that provides operating power to the control chip 4, connected to pin 15 of the control chip 4, wherein the control chip 4 is a UC3823B chip.

[0031] PWM signal input module 2: The external PWM signal is first connected to resistor R91. One end of resistor R91 is connected to the external PWM signal, and the other end is connected to the anode of diode D68. The cathode of diode D68 is connected to a filtering and shaping circuit composed of resistors R4 and R97, capacitors C16 and C19, and resistor R98. Resistors R4, R97, and capacitor C16 form a first-order low-pass filter circuit. The connection method is as follows: one end of resistor R4 is connected to the cathode of diode D68, and the other end is connected to one end of resistor R97 and one end of capacitor C16; the other end of resistor R97 and the other end of capacitor C16 are grounded together. Capacitor C19 and resistor R98 further perform signal shaping and delay processing. The connection method is as follows: one end of capacitor C19 is connected to the connection node of resistor R97 and capacitor C16, and the other end is connected to one end of resistor R98; the other end of resistor R98 is connected to the relevant internal circuit of the UC3823B chip. The processed signal is connected to the UC3823B chip.

[0032] Feedback control module 3 is based on operational amplifier U3B (LM358AMX). At the output terminal, a sampling resistor is used to acquire the output voltage or current signal. One end of the sampling resistor is connected to the output terminal, and the other end is connected to one end of resistor R111. This signal is transmitted to the inverting input terminal (pin 2) of operational amplifier U3B via a circuit consisting of resistor R111, resistor R107, and capacitor C63. The connection method is as follows: the other end of resistor R111 is connected to one end of resistor R107 and one end of capacitor C63; the other end of resistor R107 and the other end of capacitor C63 are both connected to the inverting input terminal (pin 2) of operational amplifier U3B. The non-inverting input (pin 3) of operational amplifier U3B is connected to the reference voltage VREF, which is obtained by voltage division by resistors R119 and R120. The reference voltage VREF is the 5.1V reference voltage output from pin 16 of the UC3823B chip. The connection method is as follows: one end of resistor R119 is connected to the reference voltage VREF output from pin 16 of the UC3823B chip, and the other end is connected to one end of resistor R120; the other end of resistor R120 is grounded, and the connection point between resistors R119 and R120 is connected to the non-inverting input (pin 3) of operational amplifier U3B. Operational amplifier U3B compares the acquired feedback signal with the reference voltage VREF and amplifies the difference. The amplified error signal is transmitted to the inverting input terminal (pin 1, INV) of the UC3823B chip through a circuit composed of resistor R114 and capacitor C21. The connection method is as follows: the output terminal (pin 1) of operational amplifier U3B is connected to one end of resistor R114; the other end of resistor R114 is connected to one end of capacitor C21 and the inverting input terminal (pin 1, INV) of the UC3823B chip; the other end of capacitor C21 is grounded.

[0033] The peripheral circuit of the UC3823B chip is as follows: Pin 4 (CLK / LEB) of the UC3823B chip is connected to capacitor C13, with the other end of capacitor C13 grounded. Pin 5 (RT) is connected to resistor R92, with the other end of resistor R92 connected to the junction of capacitor C13 and pin 4. Pin 6 (CT) is connected to capacitor C18, with the other end of capacitor C18 grounded. Pin 7 (RAMP) outputs the internally generated sawtooth wave signal. Pin 9 (ILIM) is the current limiting pin. Pin 3 (EAOUT) is the error amplifier output pin. Pin 1 (INV) and pin 2 (NI) are the inverting and non-inverting inputs of the error amplifier, respectively. Pin 8 (SS) is connected to capacitor C17 to form a soft-start circuit, with the other end of capacitor C17 grounded. Pins 11 (OUTA) and 14 (OUTB) are PWM signal output pins, with pin 14 (OUTB) connected to subsequent circuitry. Pins 10 (GND) and 12 (PGND) are ground pins.

[0034] Continue to refer to Figure 5 In power input module 1, the HVCC and VCOM pins are connected to a high-voltage power supply. The voltage is stepped down by resistors R173, R117, R116, R115, R172, R110, R109, and R108 connected in series. This voltage is then protected by bidirectional diodes D38 and D39 and filtered by capacitors C60, C61, and C62, providing a stable power supply to the UC3823B chip and other circuit modules via the VCC pin. PWM signal input module 2 processes the external PWM signal through current limiting, reverse voltage protection, and filtering and shaping before transmitting it to the UC3823B chip for subsequent adjustment of the pulse output characteristics.

[0035] Feedback control module 3 uses a sampling resistor at the circuit output to acquire voltage or current signals. These signals are then transmitted to operational amplifier U3B via a circuit composed of resistors and capacitors. The operational amplifier U3B compares the signal with the reference voltage VREF and amplifies the difference, transmitting the resulting error signal to the UC3823B chip. Based on this error signal and the sawtooth wave signal generated by its internal oscillation circuit, the UC3823B chip adjusts the duty cycle of the PWM signal.

[0036] When the circuit current is abnormal, the current detection circuit connected to pin 9 activates, controlling chip 4 to reduce or cut off the PWM output, thus achieving overcurrent protection. Capacitor C17 connected to pin 8 plays a role during circuit startup, gradually increasing the duty cycle of the PWM signal output by the chip, completing a soft start. Finally, the chip outputs the PWM signal through pins 11 (OUTA) and 14 (OUTB). Pin 14 (OUTB) drives output module 5, converting electrical energy into a pulsed power supply that meets the requirements and outputting it to load 6. Pins 10 (GND) and 12 (PGND) provide a stable reference ground potential for the chip, ensuring the stability of the coordinated operation of each module.

[0037] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A pulsed power supply circuit, characterized by, The application relates to a PWM signal input module, a feedback control module, a control chip and an output module. The power input module is connected with a power pin of the control chip to provide working power for the control chip and the whole circuit. The PWM signal input module is used for transmitting an external PWM signal to a signal input pin of the control chip. The feedback control module collects an electric signal in a circuit and transmits a processed feedback signal to the control chip. The control chip outputs a control signal to the output module from an output pin based on the input PWM signal and the feedback signal to drive the output module to output a pulse power source to provide electric energy for a load. The power input module comprises a high-voltage power pin and a common voltage pin as power input ports, and a plurality of voltage drop resistors are connected in series with the high-voltage power pin and the common voltage pin to form two voltage drop circuits; the two voltage drop circuits are connected with a protection circuit composed of bidirectional diodes, and the protection circuit is connected with a capacitor for filtering; the power input module further comprises a VCC pin for providing working power for the control chip and being connected with a power pin of the control chip.

2. A pulsed power supply circuit according to claim 1, wherein The PWM signal input module comprises an external PWM interface connected with a filtering and shaping circuit composed of resistors and capacitors and connected with a current protection pin of the control chip.

3. A pulsed power supply circuit according to claim 1, wherein The feedback control module is an operational amplifier, an output voltage or an output current is collected as a feedback signal through a sampling resistor at an output end of the operational amplifier, and the feedback signal is transmitted to an inverting input end of the operational amplifier; a reference voltage after voltage division is connected with a non-inverting input end of the operational amplifier, the operational amplifier compares the collected feedback signal with the reference voltage and amplifies a difference value, and an amplified error signal is connected with an inverting input pin of the control chip.

4. A pulsed power supply circuit according to claim 1, wherein The reference voltage is output from a reference voltage output pin of the control chip. The control chip is a UC3823B chip.

5. A pulsed power supply circuit according to claim 1, wherein The output module comprises an output interface, an input end of the output interface is connected with the control chip, and an output end of the output interface is used for connecting a load to provide required pulse electric energy for the load.

6. A pulsed power supply circuit according to claim 1, wherein The operational amplifier is an LM358AMX type.

7. A pulsed power supply circuit according to claim 4, wherein The power input module, the PWM signal input module, the feedback control module, the control chip and the output module are attached on a circuit layer of an aluminum substrate.

8. A pulsed power supply circuit according to claim 1, wherein, ​

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