Dual - tube active absorption flyback circuit

Abstract

The present invention discloses a dual - tube active absorption flyback circuit, which includes a C1 capacitor, a C2 capacitor and a transformer. The transformer is provided with a primary winding and a secondary winding. A C3 capacitor is connected between the high - voltage end and the low - voltage end of the secondary winding. The low - voltage end of the secondary winding is connected to a D3 diode. The C2 capacitor is sequentially connected with a Q3 transistor and a Q4 transistor near the grounding side. The primary winding is connected to a Q2 transistor near the power input end, and the other end is connected to a Q1 transistor. The drain of the Q2 transistor and the low - voltage end of the primary winding are connected in parallel with a D1 diode. The drain of the Q3 transistor and the high - voltage end of the primary winding are connected in parallel with a D2 diode.

Description

Technical Field

[0001] The present invention belongs to the technical field of flyback circuits, and particularly relates to a dual-switch active clamp flyback circuit. Background Art

[0002] In a traditional transformer circuit, as Figure 2 shown, when the drive Driver of Q1 is at a high level, Q1 conducts, VIN is applied to the primary winding 1-2 of T1. At the same time, the voltage of the secondary winding 3-4 is positive at pin 3 and negative at pin 4, D1 is cut off, and VOUT is maintained by discharging through C3. The current I1 in the 1-2 winding of T1 linearly increases under the action of VIN, and the energy in the winding gradually increases.

[0003] When the drive Driver of Q1 is at a low level, Q1 is cut off. The current I1 in the 1-2 winding of T1 cannot change suddenly. Since Q1 is cut off, the voltage at the drain of Q1 (pin 1) gradually increases. At the same time, the voltage of pin 4 of T1 relative to pin 3 also gradually increases until D1 conducts. At this time, due to the existence of the leakage inductance of T1, this part of the energy cannot be transferred to the secondary side. I1 continues to increase the voltage at the drain of Q1 and charges C2 through D1. C2 absorbs the energy in the leakage inductance of T1 to suppress the increase of the voltage at the drain of Q1, playing a role in absorbing spikes. The energy absorbed by C2 is then converted into heat energy through R1 and consumed, resulting in losses and reducing the overall efficiency of the machine. Summary of the Invention

[0004] Aiming at the problems proposed in the above background art, the object of the present invention is to provide a dual-switch active clamp flyback circuit.

[0005] To achieve the above technical object, the technical solution adopted by the present invention is as follows:

[0006] Dual - tube active absorption flyback circuit, including capacitor C1, capacitor C2 and a transformer. The transformer is provided with a primary winding and a secondary winding. A capacitor C3 is connected between the high - voltage end and the low - voltage end of the secondary winding. The low - voltage end of the secondary winding is connected to a diode D3. The capacitor C2 is sequentially connected with a triode Q3 and a triode Q4 near the grounding side. The primary winding is connected with a triode Q2 near the power input end and a triode Q1 at the other end. The drain of the triode Q2 and the low - voltage end of the primary winding are connected in parallel with a diode D1. The positive pole of the diode D1 is connected to the low - voltage end of the primary winding. The drain of the triode Q3 and the high - voltage end of the primary winding are connected in parallel with a diode D2. The positive pole of the diode D2 is connected to the drain of the triode Q3. When the triodes Q1, Q2, Q3, and Q4 are in the conducting state, the capacitor C1 and the capacitor C2 are connected in parallel and charge the primary winding of the transformer. When the triodes Q1, Q2, Q3, and Q4 are in the cut - off state, the primary winding of the transformer, the diodes D1, D2 and the capacitor C2 form a charging circuit.

[0007] Further defined, the drain of the triode Q3 is connected to the capacitor C2, the source is connected to the source of the triode Q4, the drain of the triode Q4 is grounded, the drain of the triode Q2 is connected to the power input end, the source is connected to the high - voltage end of the primary winding, the drain of the triode Q1 is connected to the low - voltage end of the primary winding, and the source is grounded.

[0008] Further defined, the sources of the triodes Q3 and Q4 are commonly connected to the negative end of the driver DriverA, and the gates of the triodes Q3 and Q4 are commonly connected to the positive end of the driver DriverA.

[0009] Further defined, the gate of the triode Q2 is connected to the driver DriverH.

[0010] Further defined, the gate of the triode Q1 is connected to the driver DriverL.

[0011] Further defined, the states of the driver DriverA, the driver DriverH, and the driver DriverL are synchronized.

[0012] Advantages of the present invention:

[0013] 1. After the leakage inductance energy of the transformer is absorbed, it returns to the capacitors C1 and C2, eliminating the loss of the absorption circuit in the flyback circuit and improving the efficiency of the whole machine. Description of the drawings

[0014] The present invention can be further illustrated by the non - restrictive embodiments given in the drawings;

[0015] Figure 1It is a schematic structural diagram of an embodiment of the dual - tube active absorption flyback circuit of the present invention;

[0016] Figure 2 It is a schematic structural diagram of a traditional transformer circuit;

[0017] The main component symbols are explained as follows:

[0018] C1 Capacitor 1, C2 Capacitor 2, Transformer 3, Q1 Transistor 4, Q2 Transistor 5, Q3 Transistor 6, Q4 Transistor

[0019] 7, D1 Diode 8, D2 Diode 9, D3 Diode 10, C3 Capacitor 11. Specific implementation manners

[0020] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below in conjunction with the drawings and embodiments.

[0021] As Figure 1 shown, the dual - tube active absorption flyback circuit of the present invention includes C1 Capacitor 1, C2 Capacitor 2 and Transformer 3. The transformer 3 is provided with a primary winding and a secondary winding. A C3 Capacitor 11 is connected between the high - voltage end and the low - voltage end of the secondary winding, and a D3 Diode 10 is connected to the low - voltage end of the secondary winding. It is characterized in that: Q3 Transistor 6 and Q4 Transistor 7 are sequentially connected to C2 Capacitor 2 near the grounding side, Q2 Transistor 5 is connected to the primary winding near the power input end, and the other end is connected to Q1 Transistor 4. The drain of Q2 Transistor 5 and the low - voltage end of the primary winding are connected in parallel with a D1 Diode 8. The positive pole of the D1 Diode 8 is connected to the low - voltage end of the primary winding. The drain of Q3 Transistor 6 and the high - voltage end of the primary winding are connected in parallel with a D2 Diode 9. The positive pole of the D2 Diode 9 is connected to the drain of Q3 Transistor 6. When Q1 Transistor 4, Q2 Transistor 5, Q3 Transistor 6, and Q4 Transistor 7 are in the conducting state, C1 Capacitor 1 and C2 Capacitor 2 are connected in parallel and charge the primary winding of the transformer 3. When Q1 Transistor 4, Q2 Transistor 5, Q3 Transistor 6, and Q4 Transistor 7 are in the cut - off state, the primary winding of the transformer 3 forms a charging loop with D1 Diode 8, D2 Diode 9, and C2 Capacitor 2;

[0022] The drain of Q3 Transistor 6 is connected to C2 Capacitor 2, the source is connected to the source of Q4 Transistor 7, the drain of Q4 Transistor 7 is grounded, the drain of Q2 Transistor 5 is connected to the power input end, the source is connected to the high - voltage end of the primary winding, the drain of Q1 Transistor 4 is connected to the low - voltage end of the primary winding, and the source is grounded;

[0023] The sources of transistor Q3 (6) and transistor Q4 (7) are commonly connected to the negative terminal of Driver A. The gates of transistor Q3 (6) and transistor Q4 (7) are commonly connected to the positive terminal of Driver A. The gate of transistor Q2 (5) is connected to Driver H, and the gate of transistor Q1 (4) is connected to Driver L. The states of Driver A, Driver H, and Driver L are synchronized.

[0024] In this embodiment, Driver L and Driver H supply power to transistor Q1 (4) and transistor Q2 (5) respectively for driving, and Driver A supplies power to transistor Q3 (6) and transistor Q4 (7) for driving. Driver A, Driver H, and Driver L are synchronized.

[0025] When the driving signals Driver A, Driver H, and Driver L for transistor Q1 (4), transistor Q2 (5), transistor Q3 (6), and transistor Q4 (7) are at high level, transistor Q1 (4), transistor Q2 (5), transistor Q3 (6), and transistor Q4 (7) are all turned on. Capacitor C1 (1) and capacitor C2 (2) are in parallel and have equal voltage. VIN is applied to the primary winding of transformer 3. At the same time, the voltage of pin 3 of the secondary winding is positive and the voltage of pin 4 is negative. Diode D1 (8) is cut off, and VOUT discharges through capacitor C3 (11) to maintain. The current in the primary winding of transformer 3 linearly increases under the action of VIN, and the energy in the winding gradually increases.

[0026] When the driving signals Driver A, Driver H, and Driver L for transistor Q1 (4), transistor Q2 (5), transistor Q3 (6), and transistor Q4 (7) are at low level, transistor Q1 (4), transistor Q2 (5), transistor Q3 (6), and transistor Q4 (7) are all cut off. The current in the primary winding of transformer 3 cannot change suddenly. Since transistor Q1 (4) is cut off, the drain voltage of transistor Q1 (4) gradually increases. At the same time, the voltage of pin 4 of transformer 3 relative to pin 3 also gradually increases until diode D1 (8) conducts. At this time, due to the existence of the leakage inductance of transformer 3, this part of the energy cannot be transmitted to the secondary winding. The current continues to increase the drain voltage of transistor Q1 (4) and charges capacitor C2 (2) through diode D1 (8) and diode D2 (9). Capacitor C2 (2) absorbs the energy in the leakage inductance of transformer 3 to suppress the increase of the drain voltage of transistor Q1 (4), playing a role in absorbing spikes. The energy absorbed by capacitor C2 (2) is sent back to capacitor C1 (1) when transistor Q3 (6) and transistor Q4 (7) are turned on, thus avoiding energy loss.

[0027] The above embodiments are only used to exemplarily illustrate the principles and effects of the present invention, rather than to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. Dual - tube active absorption flyback circuit, including capacitor C1 (1), capacitor C2 (2) and transformer (3). The transformer (3) is provided with a primary winding and a secondary winding. A capacitor C3 (11) is connected between the high - voltage end and the low - voltage end of the secondary winding, and a diode D3 (10) is connected to the low - voltage end of the secondary winding. It is characterized in that: The C2 capacitor (2) is sequentially connected with a Q3 transistor (6) and a Q4 transistor (7) near the grounding side. The primary winding is connected with a Q2 transistor (5) near the power input terminal, and the other end is connected with a Q1 transistor (4). The drain of the Q2 transistor (5) and the low-voltage end of the primary winding are connected in parallel with a D1 diode (8). The positive electrode of the D1 diode (8) is connected with the low-voltage end of the primary winding. The drain of the Q3 transistor (6) and the high-voltage end of the primary winding are connected in parallel with a D2 diode (9). The positive electrode of the D2 diode (9) is connected with the drain of the Q3 transistor (6). When the Q1 transistor (4), Q2 transistor (5), Q3 transistor (6), and Q4 transistor (7) are in the conducting state, the C1 capacitor (1) and the C2 capacitor (2) are connected in parallel and charge the primary winding of the transformer (3). When the Q1 transistor (4), Q2 transistor (5), Q3 transistor (6), and Q4 transistor (7) are in the cut-off state, the primary winding of the transformer (3), the D1 diode (8), the D2 diode (9), and the C2 capacitor (2) form a charging circuit.

2. The dual - tube active - absorption flyback circuit according to claim 1, wherein: The drain of the Q3 transistor (6) is connected to the C2 capacitor (2), and the source is connected to the source of the Q4 transistor (7). The drain of the Q4 transistor (7) is grounded. The drain of the Q2 transistor (5) is connected to the power input terminal, and the source is connected to the high-voltage end of the primary winding. The drain of the Q1 transistor (4) is connected to the low-voltage end of the primary winding, and the source is grounded.

3. The dual - tube active - absorption flyback circuit according to claim 2, wherein: The sources of the Q3 transistor (6) and the Q4 transistor (7) are commonly connected to the negative terminal of the driver DriverA. The gates of the Q3 transistor (6) and the Q4 transistor (7) are commonly connected to the positive terminal of the driver DriverA.

4. The dual - tube active absorption flyback circuit according to claim 3, wherein: The gate of the Q2 transistor (5) is connected to the driver DriverH.

5. The dual - tube active absorption flyback circuit according to claim 4, wherein: The gate of the Q1 transistor (4) is connected to the driver DriverL.

6. The dual - tube active absorption flyback circuit according to claim 5, wherein: The states of the driver DriverA, the driver DriverH, and the driver DriverL are synchronized.

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