RCD absorption circuit

Abstract

The utility model discloses an RCD absorption circuit, which is arranged in a switching power supply circuit, the switching power supply circuit comprises a transformer and a power supply management chip, the RCD absorption circuit comprises a second resistor, a second capacitor and a first switching tube, the second resistor and the second capacitor are connected in parallel, one end of the second capacitor is connected with a synonym end of a primary winding of the transformer, and the other end of the second capacitor is connected with a secondary winding of the transformer. The other end of the second capacitor is connected with the input end of the first switch tube, the output end of the first switch tube is connected with the dotted terminal of the primary winding of the transformer and the power management chip, and the control end of the first switch tube is connected with the output end of the rectifier filter module electrically connected with the power supply winding of the transformer through the first resistor. According to the RCD absorption circuit, the first switch tube is arranged to replace a diode so as to reduce conduction impedance, loss and heating, the overall working efficiency of the circuit is ensured, the first switch tube is driven to be conducted through the voltage generated by the power supply winding of the transformer, and voltage spikes can be consumed.

Description

Technical Field

[0001] The utility model relates to the technical field of switching power supply circuits, and particularly relates to an RCD absorption circuit. Background Art

[0002] The existing RCD absorption circuit includes a resistor and a capacitor connected in parallel and a diode connected to the capacitor and the resistor. The greater the power of the power supply, the greater the working current on the RCD absorption circuit, and the greater the current flowing through the diode, resulting in greater losses of the diode and an increase in the temperature of the diode, affecting the overall working efficiency of the circuit. Summary of the Utility Model

[0003] The technical problem to be solved by the utility model is to provide an RCD absorption circuit to reduce losses, reduce heat generation, and ensure the overall working efficiency of the circuit.

[0004] To solve the above technical problem, the purpose of the utility model is achieved through the following technical solutions: providing an RCD absorption circuit provided in a switching power supply circuit, the switching power supply circuit including a transformer and a power management chip, the RCD absorption circuit including a second resistor, a second capacitor, and a first switching tube, the second resistor and the second capacitor being connected in parallel, one end of the second capacitor being connected to the opposite-named end of the primary winding of the transformer, the other end of the second capacitor being connected to the input end of the first switching tube, the output end of the first switching tube being connected to the same-named end of the primary winding of the transformer and the power management chip, and the control end of the first switching tube being connected to the output end of the rectification and filtering module of the power supply winding of the transformer through a first resistor.

[0005] The beneficial technical effect of the utility model lies in that: the RCD absorption circuit of the utility model replaces the diode with a first switching tube to reduce the conduction impedance, reduce losses, reduce heat generation, and ensure the overall working efficiency of the circuit. Moreover, the control end of the first switching tube is connected to the output end of the rectification and filtering module of the power supply winding of the transformer through a first resistor, so as to obtain an instantaneously stable voltage after rectifying and filtering the voltage generated by the power supply winding of the transformer, and then drive the first switching tube to conduct after passing through the first resistor, and then the loop between the first resistor and the rectification and filtering module is energized to consume the voltage spike. Description of the Drawings

[0006] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the utility model. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0007] Figure 1 The circuit diagram of the RCD absorption circuit provided by the embodiment of the present invention applied to a switching power supply circuit. Specific embodiments

[0008] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0009] Please refer to Figure 1 as shown Figure 1 The circuit diagram of the RCD absorption circuit provided by the embodiment of the present invention applied to a switching power supply circuit. The RCD absorption circuit 10 is provided in the switching power supply circuit. The switching power supply circuit includes a transformer and a power management chip U2. The RCD absorption circuit 10 includes a second resistor R2, a second capacitor C2, and a first switching transistor Q1. The second resistor R2 and the second capacitor C2 are connected in parallel. One end of the second capacitor C2 is connected to the opposite-named end of the primary winding T1A of the transformer. The other end of the second capacitor C2 is connected to the input end of the first switching transistor Q1. The output end of the first switching transistor Q1 is connected to the same-named end of the primary winding T1A of the transformer and the power management chip U2. The control end of the first switching transistor Q1 is connected to the output end of a rectification and filtering module 11 of the power supply winding T1C of the transformer through a first resistor R1.

[0010] Among them, the RCD absorption circuit 10 replaces a diode by setting a first switching transistor Q1 to reduce the conduction impedance, reduce the loss, reduce the heat generation, and ensure the overall working efficiency of the circuit. And the control end of the first switching transistor Q1 is connected to the output end of the rectification and filtering module 11 of the power supply winding T1C of the transformer through a first resistor R1, so as to obtain an instantaneously stable voltage after rectifying and filtering the voltage generated by the power supply winding T1C of the transformer through the rectification and filtering module 11, and then drive the first switching transistor Q1 to conduct after passing through the first resistor R1. Furthermore, the loop between the first resistor R1 and the rectification and filtering module 11 is energized to consume the voltage spike.

[0011] Specifically, in this embodiment, the rectifying and filtering module 11 includes a first capacitor C1, a first diode D1, and a fifth capacitor C5. Two ends of the first capacitor C1 are respectively connected to the same-named terminal of the power supply winding T1C of the transformer and the anode of the first diode D1. The cathode of the first diode D1 is connected to one end of the fifth capacitor C5 and one end of the first resistor R1. The other end of the fifth capacitor C5 is connected to the different-named terminal of the power supply winding T1C of the transformer and the power management chip U2. Among them, the capacitance values of the first capacitor C1 and the fifth capacitor C5 can be adjusted according to actual situations. The voltage generated by the power supply winding T1C of the transformer drives the first switching transistor Q1 to conduct, and then the loop of the first resistor R1 and the first capacitor C1 is powered on, thereby consuming the voltage spike.

[0012] Specifically, in this embodiment, the gate pin GATE of the power management chip U2 is connected to the control end of the first switching transistor Q1, the output end of the first switching transistor Q1, the different-named terminal of the power supply winding T1C of the transformer, and the same-named terminal of the primary winding T1A of the transformer through a third switching transistor Q3. The gate pin GATE of the power management chip U2 is connected to the control end of the first switching transistor Q1, the output end of the first switching transistor Q1, the different-named terminal of the power supply winding T1C of the transformer, and the same-named terminal of the primary winding T1A of the transformer through an eighth resistor R8 and an optocoupler U3. Among them, the gate pin GATE of the power management chip U2 is respectively connected to the third switching transistor Q3 and the optocoupler U3, so that when the power management chip U2 drives the third switching transistor Q3 to conduct, the optocoupler U3 is simultaneously driven to quickly pull down the control end of the first switching transistor Q1 to turn off and cut off the first switching transistor Q1, preventing mis-conduction.

[0013] Specifically, the gate pin GATE of the power management chip U2 is connected to one end of the eighth resistor R8. The other end of the eighth resistor R8 is connected to the light-emitting source of the optocoupler U3. The light-receiving device of the optocoupler U3 is a light-receiving triode. The emitter of the light-receiving triode is connected to the output end of the third switching transistor Q3, the control end of the first switching transistor Q1, the output end of the first switching transistor Q1, the different-named terminal of the power supply winding T1C of the transformer, and the same-named terminal of the primary winding T1A of the transformer. The collector of the light-receiving triode is connected to the control end of the first switching transistor Q1.

[0014] Specifically, in this embodiment, the third switching transistor Q3 is a MOS transistor. The gate of the third switching transistor Q3 is connected to the gate pin GATE of the power management chip U2 through the ninth resistor R9. One end of the eighth resistor R8 is electrically connected between the gate pin GATE of the power management chip U2 and the ninth resistor R9. The source of the third switching transistor Q3 is connected to the thirteenth grounding resistor R13. The drain of the third switching transistor Q3 is connected to the control end of the first switching transistor Q1, the output end of the first switching transistor Q1, the opposite-named end of the power supply winding T1C of the transformer, and the same-named end of the primary winding T1A of the transformer.

[0015] Specifically, the drain of the third switching transistor Q3 is connected to the control end of the first switching transistor Q1 through the fifth resistor R5. One end of the fifth resistor R5 is connected to the opposite-named end of the power supply winding T1C of the transformer, the emitter of the light-receiving triode of the optocoupler U3, and the drain of the third switching transistor Q3. The other end of the fifth resistor R5 is connected to the control end of the first switching transistor Q1 and the collector of the light-receiving triode of the optocoupler U3.

[0016] Specifically, the current detection pin CS of the power management chip U2 is connected to one end of the tenth resistor R10, the source of the third switching transistor Q3, and the thirteenth grounding resistor R13 through the eleventh resistor R11. The other end of the tenth resistor R10 is electrically connected between the ninth resistor R9 and the gate of the third switching transistor Q3.

[0017] Specifically, an eighth grounding capacitor C8 is electrically connected between the current detection pin CS of the power management chip U2 and the eleventh resistor R11.

[0018] Specifically, the switching power supply circuit includes a rectifier bridge BD1. The input end of the rectifier bridge BD1 is connected to an AC power supply. The positive output end of the rectifier bridge BD1 is connected to the opposite-named end of the primary winding T1A of the transformer, one end of the second resistor R2, and one end of the second capacitor C2 through the first inductor L1. The negative output end of the rectifier bridge BD1 is connected to the ground through the third inductor L3.

[0019] Specifically, the first switching transistor Q1 is a MOS transistor. The drain of the first switching transistor Q1 is connected to the second capacitor C2 and the second resistor R2. The gate of the first switching transistor Q1 is connected to the first resistor R1. The source of the first switching transistor Q1 is connected to the same-named end of the primary winding T1A of the transformer and the power management chip U2.

[0020] In summary, the RCD absorption circuit of the present utility model replaces the diode with a first switching tube to reduce the conduction impedance, reduce the loss, reduce the heat generation, ensure the overall working efficiency of the circuit, and the control end of the first switching tube is connected to the output end of the rectification and filtering module of the power supply winding of the transformer through a first resistor, so as to obtain an instantaneously stable voltage after rectification and filtering by the rectification and filtering module using the voltage generated by the power supply winding of the transformer, and then drive the first switching tube to conduct after passing through the first resistor, and then the loop between the first resistor and the rectification and filtering module is energized to consume the voltage spike.

[0021] The above is only the specific implementation manner of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope of the claims.

Claims

1. An RCD absorption circuit, characterized in that, It is provided in a switching power supply circuit. The switching power supply circuit includes a transformer and a power management chip. The RCD absorption circuit includes a second resistor, a second capacitor, and a first switching tube. The second resistor and the second capacitor are connected in parallel. One end of the second capacitor is connected to the opposite-named end of the primary winding of the transformer, and the other end of the second capacitor is connected to the input end of the first switching tube. The output end of the first switching tube is connected to the same-named end of the primary winding of the transformer and the power management chip. The control end of the first switching tube is connected to the output end of a rectification and filtering module of a power supply winding of the transformer via a first resistor.

2. The RCD absorption circuit according to claim 1, characterized in that, The rectification and filtering module includes a first capacitor, a first diode, and a fifth capacitor. Two ends of the first capacitor are respectively connected to the same-named end of the power supply winding of the transformer and the anode of the first diode. The cathode of the first diode is connected to one end of the fifth capacitor and one end of the first resistor. The other end of the fifth capacitor is connected to the opposite-named end of the power supply winding of the transformer and the power management chip.

3. The RCD absorption circuit according to claim 1, characterized in that, The gate pin of the power management chip is connected to the control end of the first switching tube, the output end of the first switching tube, the opposite-named end of the power supply winding of the transformer, and the same-named end of the primary winding of the transformer via a third switching tube. The gate pin of the power management chip is connected to the control end of the first switching tube, the output end of the first switching tube, the opposite-named end of the power supply winding of the transformer, and the same-named end of the primary winding of the transformer via an eighth resistor and an optocoupler.

4. The RCD absorption circuit according to claim 3, wherein, The gate pin of the power management chip is connected to one end of the eighth resistor. The other end of the eighth resistor is connected to the light-emitting source of the optocoupler. The light-receiving device of the optocoupler is a light-receiving triode. The emitter of the light-receiving triode is connected to the output end of the third switching tube, the control end of the first switching tube, the output end of the first switching tube, the opposite-named end of the power supply winding of the transformer, and the same-named end of the primary winding of the transformer. The collector of the light-receiving triode is connected to the control end of the first switching tube.

5. The RCD absorption circuit according to claim 4, wherein, The third switching tube is a MOS tube. The gate of the third switching tube is connected to the gate pin of the power management chip via a ninth resistor. One end of the eighth resistor is electrically connected between the gate pin of the power management chip and the ninth resistor. The source of the third switching tube is connected to a thirteenth grounding resistor. The drain of the third switching tube is connected to the control end of the first switching tube, the output end of the first switching tube, the opposite-named end of the power supply winding of the transformer, and the same-named end of the primary winding of the transformer.

6. The RCD absorption circuit according to claim 5, wherein, The drain of the third switching tube is connected to the control end of the first switching tube via a fifth resistor. One end of the fifth resistor is connected to the opposite-named end of the power supply winding of the transformer, the emitter of the light-receiving triode of the optocoupler, and the drain of the third switching tube. The other end of the fifth resistor is connected to the control end of the first switching tube and the collector of the light-receiving triode of the optocoupler.

7. The RCD absorption circuit according to claim 5, characterized in that, The current detection pin of the power management chip is connected to one end of the tenth resistor, the source of the third switching transistor, and the thirteenth grounding resistor through the eleventh resistor, and the other end of the tenth resistor is electrically connected between the ninth resistor and the gate of the third switching transistor.

8. The RCD absorption circuit according to claim 7, characterized in that, An eighth grounding capacitor is electrically connected between the current detection pin of the power management chip and the eleventh resistor.

9. The RCD absorption circuit according to claim 1, characterized in that, The switching power supply circuit includes a rectifier bridge. The input end of the rectifier bridge is connected to an AC power supply. The positive output end of the rectifier bridge is connected to the non - same - name end of the primary winding of the transformer, one end of the second resistor, and one end of the second capacitor through the first inductor, and the negative output end of the rectifier bridge is connected to the ground through the third inductor.

10. The RCD absorption circuit according to claim 1, characterized in that, The first switching transistor is a MOS transistor. The drain of the first switching transistor is connected to the second capacitor and the second resistor. The gate of the first switching transistor is connected to the first resistor. The source of the first switching transistor is connected to the same - name end of the primary winding of the transformer and the power management chip.

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