A switching power supply circuit for providing an instantaneous high current output

Abstract

The utility model provides a kind of switch power supply circuit for providing instantaneous large current output, including input rectification filter circuit, the transformer of the output end of connecting input rectification filter circuit, the output rectification filter circuit of connecting transformer and including rectifier diode group and energy storage capacitor, including feedback pin, current detection pin, drive pin and ground pin PWM controller;Three ends are connected drive pin, transformer primary coil, and the switch tube of current detection pin based on sampling circuit connection respectively;And including opto-coupler receiver and opto-coupler transmitter photoelectric isolation feedback loop.The switch power supply circuit PWM controller of the utility model can adjust the duty cycle of PWM signal output by drive pin in real time according to the output voltage signal transmission by photoelectric isolation feedback loop, control the conduction time of switch tube, when load needs instantaneous large current, energy storage capacitor releases stored energy, supplement load current, realize the instantaneous large current output of circuit.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a switching power supply circuit for providing instantaneous high current output. Background Technology

[0002] In switching power supply applications, devices such as audio amplifiers, motor drives, and pulsed lasers often require instantaneous high current output. Traditional solutions typically use parallel multi-stage power modules to increase the peak current capability of the power circuit. However, traditional solutions result in high system complexity and large size, making it difficult to meet miniaturization requirements.

[0003] Therefore, existing technologies still need to be improved and developed. Utility Model Content

[0004] This invention provides a switching power supply circuit for providing instantaneous high current output, aiming to solve the technical problems mentioned in the background art of existing switching power supply circuits.

[0005] The technical solution of this utility model is as follows: A switching power supply circuit for providing instantaneous high current output includes: The input rectifier and filter circuit is used to convert the AC input voltage into a pulsating DC voltage and then filter it. A transformer, wherein the first end of the primary coil of the transformer is connected to the output end of the input rectifier and filter circuit; The output rectifier and filter circuit is connected to the secondary coil of the transformer and includes a rectifier diode group and an energy storage capacitor. The rectifier diode group is used to convert the AC pulses of the secondary coil into DC, and the energy storage capacitor is used to store DC energy and supplement the load current by discharging when the load needs a large instantaneous current. A PWM controller, comprising a feedback pin, a current detection pin, a drive pin, and a ground pin; A switching transistor, the control terminal of which is connected to the drive pin, the first terminal of which is connected to the second terminal of the primary coil, and the second terminal of which is connected to the current detection pin through a sampling circuit; An opto-isolated feedback loop includes an optocoupler receiver and an optocoupler transmitter. The two ends of the optocoupler transmitter are respectively connected to the output terminal of the rectifier diode group and the output ground of the secondary coil. The optocoupler transmitter is used to detect the output voltage signal and emit an optical signal. The two ends of the optocoupler receiver are respectively connected to the feedback pin and the ground pin. The optocoupler receiver is used to receive the optical signal. In one optional embodiment of this utility model, the input rectifier filter circuit includes a fuse, an LC filter circuit, and a rectifier bridge connected in sequence, and the output terminal of the rectifier bridge is connected to the first terminal of the primary coil of the transformer. In one optional embodiment of this utility model, the switching transistor is an N-channel enhancement-mode MOS transistor, the control terminal of the switching transistor is the gate, the first terminal of the switching transistor is the drain, and the second terminal of the switching transistor is the source.

[0006] In one optional embodiment of this utility model, the optocoupler emitter is a light-emitting diode (LED), the anode of the LED is connected to the output terminal of the output rectifier filter circuit, and the cathode of the LED is connected to the output ground of the secondary coil. The optocoupler receiver is a phototransistor. The collector of the phototransistor is connected to the feedback pin, the emitter of the phototransistor is grounded, and the base of the phototransistor is used to receive the light signal from the light-emitting diode.

[0007] In one optional embodiment of this utility model, a first Zener diode is further provided on the line between the cathode of the light-emitting diode and the output ground of the secondary coil. The anode of the first Zener diode is connected to the output ground of the secondary coil, and the cathode of the first Zener diode is connected to the cathode of the light-emitting diode. In an optional embodiment of this utility model, the sampling circuit includes a first resistor, a second resistor, and a first capacitor. The two ends of the first resistor are respectively connected to the current detection pin and the second end of the switching transistor. The first end of the first capacitor is connected to the line between the first resistor and the current detection pin. The first end of the second resistor is connected to the line between the first resistor and the second end of the switching transistor. The second ends of the first capacitor and the second ends of the second resistor are both connected to the ground pin.

[0008] In an optional embodiment of this utility model, the opto-isolated feedback loop further includes a second Zener diode, a transistor, a third resistor, a fourth resistor, and a second capacitor. The base of the transistor is connected to the current detection pin through the third resistor, and the collector of the transistor is connected to the collector of the optocoupler receiver through the second Zener diode. The first end of the fourth resistor is connected to the line between the base of the transistor and the third resistor, and the first end of the second capacitor is connected to the line between the base of the transistor and the third resistor. The second end of the fourth resistor, the second end of the second capacitor, and the emitter of the transistor are all connected to the ground pin.

[0009] In an optional embodiment of this utility model, the output rectifier filter circuit further includes a fifth resistor, a sixth resistor, a seventh resistor, and a third capacitor. The fifth resistor and the sixth resistor are connected in series and then connected in parallel with the two ends of the energy storage capacitor. One end of the third capacitor is connected to the series connection line of the fifth resistor and the sixth resistor, and the other end of the third capacitor is connected to the cathode of the first Zener diode through the seventh resistor.

[0010] In one optional embodiment of this utility model, the energy storage capacitor of the output rectifier filter circuit is an electrolytic capacitor or a solid capacitor with low equivalent series resistance.

[0011] The beneficial effects are as follows: This utility model provides a switching power supply circuit for providing instantaneous high current output, including an input rectifier and filter circuit, a transformer connected to the output terminal of the input rectifier and filter circuit, an output rectifier and filter circuit connected to the transformer and including a rectifier diode group and an energy storage capacitor, a PWM controller including a feedback pin, a current detection pin, a drive pin, and a ground pin; a switching transistor with its three terminals respectively connected to the drive pin, the primary coil of the transformer, and the current detection pin based on a sampling circuit; and an opto-isolated feedback loop including an optocoupler receiver and an optocoupler transmitter. The PWM controller of this utility model can adjust the duty cycle of the PWM signal output from the drive pin in real time according to the output voltage signal transmitted by the opto-isolated feedback loop, controlling the conduction time of the switching transistor. When the load requires instantaneous high current, the energy storage capacitor releases the stored energy to supplement the load current, realizing the instantaneous high current output of the circuit. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a switching power supply circuit for providing instantaneous high current output according to the present invention.

[0013] Figure 2 This is a schematic diagram of an input rectifier filter circuit according to the present invention.

[0014] Figure 3 This is a schematic diagram of an output rectifier and filter circuit according to the present invention.

[0015] Figure 4 This is a schematic diagram of the control circuit of a PWM controller according to the present invention.

[0016] The icon numbers in the figure are as follows: 10 - Input rectifier and filter circuit; 20 - Transformer; 30 - Output rectifier and filter circuit; 40 - PWM controller; 50 - Switching transistor; 60 - Opto-isolated feedback loop; 70 - Fuse; 80 - LC filter circuit; 90 - Rectifier bridge; 100 - First Zener diode; 110 - First resistor; 120 - Second resistor; 130 - First capacitor; 140 - Second Zener diode; 150 - Transistor; 160 - Third resistor; 170 - Fourth resistor; 180 - Second capacitor; 190 - Fifth resistor; 200 - Sixth resistor; 210 - Seventh resistor; 220 - Third capacitor; 230 - Sampling circuit. Detailed Implementation

[0017] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present application 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.

[0018] It should be noted in advance that in the following description of this utility model, if there are any terms, the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0019] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0020] Throughout this specification, reference to "an embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Therefore, the phrase "in one embodiment" or "in some embodiments" appears in various places throughout the specification, and not all references refer to the same embodiment. Furthermore, in one or more embodiments, particular features, structures, or characteristics may be combined in any suitable manner.

[0021] See Figure 1This utility model provides a switching power supply circuit for providing instantaneous high current output, including an input rectifier and filter circuit 10, a transformer 20, an output rectifier and filter circuit 30, a PWM controller 40, a switching transistor 50, and an opto-isolation feedback loop 60.

[0022] In this invention, the input rectifier and filter circuit 10 is used to convert the AC input voltage into a pulsating DC voltage and then filter it; see also Figure 2 The input rectifier and filter circuit may include a fuse 70 (F1), an LC filter circuit 80 (including an EMI filter capacitor C1 and a common mode inductor L1) and a rectifier bridge 90 (D1, model can be GBU608) connected in sequence. The output terminal of the rectifier bridge 90 is connected to the first terminal of the primary coil of the transformer. In this invention, the transformer 20 includes a primary coil and a secondary coil. The first end of the primary coil of the transformer 20 is connected to the output end of the input rectifier and filter circuit 10. The secondary coil of the transformer 20 is connected to the output rectifier and filter circuit 30. The secondary winding of the transformer 20 can use a coil with a thick wire diameter (e.g., 1.5mm²) and a small number of turns (primary:secondary = 60:1) to reduce copper loss and improve current transmission capability.

[0023] In this invention, the output rectifier filter circuit 30 includes a rectifier diode group (composed of two diodes connected in parallel) and an energy storage capacitor (the energy storage capacitor can be an electrolytic capacitor or a solid capacitor with low equivalent series resistance). The rectifier diode group is used to convert the AC pulses of the secondary coil into DC, and the energy storage capacitor is used to store DC energy and supplement the load current by discharging when the load needs a large instantaneous current. The energy storage capacitor is the core component of this invention to achieve a large instantaneous current output. In addition to storing charge (when the load suddenly needs a large current, the capacitor quickly releases the charge to supplement the power output and avoid excessive drop in output voltage), the energy storage capacitor can also filter out ripple (that is, convert pulsating DC into stable DC).

[0024] In this invention, the PWM controller 40 (model 0B2362) includes a feedback pin (FB), a current detection pin (CS), a drive pin (GATE), and a ground pin (GND); wherein, the feedback pin (FB) is used to receive a voltage feedback signal, the current detection pin (CS) is used to receive a current detection signal, and the drive pin (GATE) is used to output a PWM drive signal.

[0025] In this invention, the control terminal of the switching transistor 50 is connected to the drive pin, the first terminal of the switching transistor is connected to the second terminal of the primary coil, and the second terminal of the switching transistor is connected to the current detection pin through the sampling circuit 230. For example, the switching transistor 50 can be an N-channel enhancement-mode MOSFET, with the control terminal being the gate, the first terminal being the drain, and the second terminal being the source. The switching transistor 50 is driven by the GATE pin of the PWM controller 40, realizing the "on / off" energy transfer of the primary winding of the transformer 20 (peak current capability is crucial; it needs to withstand short-term high current during instantaneous large current surges).

[0026] See Figure 4 In an optional embodiment of this utility model, the sampling circuit 230 includes a first resistor 110 (R2), a second resistor 120 (R3), and a first capacitor 130 (C4). The two ends of the first resistor 110 are respectively connected to the current detection pin and the second terminal of the switching transistor 50. The first terminal of the first capacitor 130 is connected to the line between the first resistor 110 and the current detection pin. The first terminal of the second resistor 120 is connected to the line between the first resistor 110 and the second terminal of the switching transistor 50. The second terminals of both the first capacitor 130 and the second resistor 120 are connected to the ground pin. In the switching power supply circuit, the circuit composed of R2, R3, and C4 is essentially a conditioning network for the primary-side current detection signal. Its core function is to provide a high-precision, anti-interference current sampling signal for the peak current mode PWM controller. The core function of R2+R3 is signal voltage division protection, and the core function of C4 is high-frequency noise filtering.

[0027] The opto-isolated feedback loop 60 includes an optocoupler receiver (PC1B) and an optocoupler transmitter (PC1A). The two ends of the optocoupler transmitter are connected to the output terminal of the rectifier diode group and the output ground of the secondary coil, respectively. The optocoupler transmitter is used to detect the output voltage signal and emit an optical signal. For example, the optocoupler transmitter is a light-emitting diode (LED). The anode of the LED is connected to the output terminal of the output rectifier filter circuit, and the cathode of the LED is connected to the output ground of the secondary coil. The two ends of the optocoupler receiver are connected to the feedback pin and the ground pin, respectively. The optocoupler receiver is used to receive the optical signal. For example, the optocoupler receiver is a phototransistor. The collector of the phototransistor is connected to the feedback pin, the emitter of the phototransistor is grounded, and the base of the phototransistor is used to receive the optical signal from the LED.

[0028] In this invention, the PWM controller 40 adjusts the duty cycle of the PWM signal output from the drive pin (GATE) in real time based on the output voltage signal transmitted by the optocoupler transmitter and the switching transistor current signal detected by the sampling circuit 230, thereby controlling the conduction time of the switching transistor 50. This allows the transformer to transfer energy to the secondary side to maintain a stable output voltage. Simultaneously, when the load requires a large instantaneous current, the energy storage capacitor releases its stored energy to supplement the load current, achieving a large instantaneous current output without increasing the power device specifications.

[0029] See Figure 3 In an optional embodiment of this utility model, a first Zener diode (Z2) is further provided on the line between the cathode of the light-emitting diode and the output ground of the secondary coil. The anode of the first Zener diode 100 is connected to the output ground of the secondary coil, and the cathode of the first Zener diode 100 is connected to the cathode of the light-emitting diode. In this embodiment, the output rectifier filter circuit 30 may further include a fifth resistor 190 (R6), a sixth resistor 200 (R7), a seventh resistor 210 (R8), and a third capacitor 220 (C5). The fifth resistor 190 and the sixth resistor 200 are connected in series and then connected in parallel with the two ends of the energy storage capacitor. One end of the third capacitor 220 is connected to the series connection of the fifth resistor 190 and the sixth resistor 200, and the other end of the third capacitor 220 is connected to the cathode of the first Zener diode through the seventh resistor 210. In this invention, R6 and R7 form an output voltage sampling divider network, Z2 forms a voltage reference, R8 is used for Zener diode bias and loop gain adjustment, and C5 is used as a compensation capacitor for the output feedback loop. This network, through three-level regulation of precise voltage division (R6 / R7) → reference comparison (Z2) → dynamic compensation (C5+R8), enables the optocoupler feedback signal to quickly and accurately reflect load changes in coordination with primary PWM control.

[0030] See Figure 4In an optional embodiment of this utility model, the opto-isolated feedback loop further includes a second Zener diode 140 (Z1), a transistor 150 (Q1), a third resistor 160 (R4), a fourth resistor 170 (R1), and a second capacitor 180 (C3). The base of the transistor 150 is connected to the current detection pin through the third resistor 160, and the collector of the transistor 150 is connected to the collector of the optocoupler receiver through the second Zener diode 140. The first end of the fourth resistor 170 is connected to the line between the base of the transistor 150 and the third resistor 160. The first end of the second capacitor 180 is connected to the line between the base of the transistor 150 and the third resistor 160. The second ends of the fourth resistor 170, the second end of the second capacitor 180, and the emitter of the transistor 150 are all connected to the ground pin. In this invention, Z1, Q1, R4, R1, and C3 together constitute the primary-side optocoupler feedback signal processing and PWM control loop. Its core function is to convert the signal from the optocoupler receiver (PC1B) into a feedback voltage that can be recognized by the PWM controller (U1), while ensuring loop stability and transient response speed. Z1 is used for reference clamping and overvoltage protection, Q1 is used for feedback signal amplification and impedance conversion, R4 is the collector load resistor of Q1, R1 is the emitter negative feedback resistor of Q1, and C3 is used for phase compensation and noise filtering.

[0031] In summary, this invention provides a switching power supply circuit for providing instantaneous high current output, including an input rectifier and filter circuit, a transformer connected to the output terminal of the input rectifier and filter circuit, an output rectifier and filter circuit connected to the transformer and including a rectifier diode group and an energy storage capacitor, a PWM controller including a feedback pin, a current detection pin, a drive pin, and a ground pin, a switching transistor with its three terminals connected to the drive pin, the primary coil of the transformer, and the current detection pin based on a sampling circuit, respectively, and an opto-isolated feedback loop including an optocoupler receiver and an optocoupler transmitter. The PWM controller of this invention can adjust the duty cycle of the PWM signal output from the drive pin in real time according to the output voltage signal transmitted by the opto-isolated feedback loop, controlling the conduction time of the switching transistor. When the load requires instantaneous high current, the energy storage capacitor releases the stored energy to supplement the load current, realizing the instantaneous high current output of the circuit.

[0032] Although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A switching power supply circuit for providing instantaneous high current output, characterized in that, include: The input rectifier and filter circuit is used to convert the AC input voltage into a pulsating DC voltage and then filter it. A transformer, wherein the first end of the primary coil of the transformer is connected to the output end of the input rectifier and filter circuit; The output rectifier and filter circuit is connected to the secondary coil of the transformer and includes a rectifier diode group and an energy storage capacitor. The rectifier diode group is used to convert the AC pulses of the secondary coil into DC, and the energy storage capacitor is used to store DC energy and supplement the load current by discharging when the load needs a large instantaneous current. A PWM controller, comprising a feedback pin, a current detection pin, a drive pin, and a ground pin; A switching transistor, the control terminal of which is connected to the drive pin, the first terminal of which is connected to the second terminal of the primary coil, and the second terminal of which is connected to the current detection pin through a sampling circuit; An opto-isolated feedback loop includes an optocoupler receiver and an optocoupler transmitter. The two ends of the optocoupler transmitter are respectively connected to the output terminal of the rectifier diode group and the output ground of the secondary coil. The optocoupler transmitter is used to detect the output voltage signal and emit an optical signal. The two ends of the optocoupler receiver are respectively connected to the feedback pin and the ground pin. The optocoupler receiver is used to receive the optical signal.

2. The switching power supply circuit for providing instantaneous high current output according to claim 1, characterized in that, The input rectifier filter circuit includes a fuse, an LC filter circuit, and a rectifier bridge connected in sequence, and the output terminal of the rectifier bridge is connected to the first terminal of the primary coil of the transformer.

3. The switching power supply circuit for providing instantaneous high current output according to claim 1, characterized in that, The switching transistor is an N-channel enhancement-mode MOS transistor, the control terminal of the switching transistor is the gate, the first terminal of the switching transistor is the drain, and the second terminal of the switching transistor is the source.

4. The switching power supply circuit for providing instantaneous high current output according to claim 1, characterized in that, The optocoupler emitter is a light-emitting diode (LED), with the anode of the LED connected to the output terminal of the output rectifier filter circuit and the cathode of the LED connected to the output ground of the secondary coil. The optocoupler receiver is a phototransistor. The collector of the phototransistor is connected to the feedback pin, the emitter of the phototransistor is grounded, and the base of the phototransistor is used to receive the light signal from the light-emitting diode.

5. The switching power supply circuit for providing instantaneous high current output according to claim 4, characterized in that, A first Zener diode is also provided on the line between the cathode of the light-emitting diode and the output ground of the secondary coil. The anode of the first Zener diode is connected to the output ground of the secondary coil, and the cathode of the first Zener diode is connected to the cathode of the light-emitting diode.

6. The switching power supply circuit for providing instantaneous high current output according to claim 1, characterized in that, The sampling circuit includes a first resistor, a second resistor, and a first capacitor. The two ends of the first resistor are respectively connected to the current detection pin and the second end of the switching transistor. The first end of the first capacitor is connected to the line between the first resistor and the current detection pin. The first end of the second resistor is connected to the line between the first resistor and the second end of the switching transistor. The second ends of the first capacitor and the second ends of the second resistor are both connected to the ground pin.

7. The switching power supply circuit for providing instantaneous high current output according to claim 6, characterized in that, The opto-isolated feedback loop further includes a second Zener diode, a transistor, a third resistor, a fourth resistor, and a second capacitor. The base of the transistor is connected to the current detection pin through the third resistor, and the collector of the transistor is connected to the collector of the optocoupler receiver through the second Zener diode. The first end of the fourth resistor is connected to the line between the base of the transistor and the third resistor. The first end of the second capacitor is connected to the line between the base of the transistor and the third resistor. The second end of the fourth resistor, the second end of the second capacitor, and the emitter of the transistor are all connected to the ground pin.

8. The switching power supply circuit for providing instantaneous high current output according to claim 5, characterized in that, The output rectifier and filter circuit further includes a fifth resistor, a sixth resistor, a seventh resistor, and a third capacitor. The fifth resistor and the sixth resistor are connected in series and then connected in parallel with the two ends of the energy storage capacitor. One end of the third capacitor is connected to the series connection of the fifth resistor and the sixth resistor, and the other end of the third capacitor is connected to the cathode of the first Zener diode through the seventh resistor.

9. The switching power supply circuit for providing instantaneous high current output according to claim 1, characterized in that, The energy storage capacitor of the output rectifier filter circuit is an electrolytic capacitor or a solid capacitor with low equivalent series resistance.

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