Control circuit based on high-power flyback circuit

Abstract

The utility model discloses a control circuit based on a high-power flyback circuit. The control circuit comprises an RCD peak absorption circuit. And at least one transformer; the transformer further comprises a packaging chip, a current detection circuit and a peripheral circuit, an RCD pin of the packaging chip is connected to the RCD peak absorption circuit, a D pin of the packaging chip is connected to a primary winding of the transformer, a CS pin of the packaging chip is connected to the current detection circuit, and the peripheral circuit is connected to the RCD peak absorption circuit, the packaging chip and the current detection circuit. According to the utility model, the heat dissipation design of the switching power supply is easier, the size of a product can be reduced, and the manufacturing cost and the material cost can be greatly reduced and the structure of a circuit can be simplified by adopting the sealed packaging chip.

Description

TECHNICAL FIELD

[0001] The utility model relates to a control circuit based on high -power flyback circuit. BACKGROUND

[0002] At present, the 100~200W flyback switching power supply all adopts the control chip plus the discrete MOS tube prevention, and the transformer's leakage inductance absorption diode is discrete device, which is very difficult in small volume product, not only affects the heat dissipation of switching power supply, but also increases the product manufacturing cost and material cost. UTILITY MODEL CONTENTS

[0003] The utility model discloses a control circuit based on high -power flyback circuit, which can make the heat dissipation design of switching power supply easier, reduce the volume of the product, and greatly reduce the manufacturing cost and material cost by using the sealing packaging chip, and simplify the structure of the circuit.

[0004] In order to solve the above technical problems, the utility model adopts the following technical scheme:

[0005] A control circuit based on high -power flyback circuit, comprising

[0006] RCD peak absorption circuit;

[0007] And at least one transformer;

[0008] Its characterized in that:

[0009] It further comprises a packaging chip, a current detection circuit and a peripheral circuit, the RCD pin of the packaging chip is connected to the RCD peak absorption circuit, the D pin of the packaging chip is connected to the primary winding of the transformer, the CS pin of the packaging chip is connected to the current detection circuit, and the peripheral circuit is connected to the RCD peak absorption circuit, the packaging chip and the current detection circuit, through the design of the above structure, the heat dissipation design of switching power supply can be made easier, the volume of the product can be reduced, the packaging chip can be sealed to greatly reduce the manufacturing cost and material cost, and the structure of the circuit can be simplified.

[0010] Further, the current detection circuit comprises resistors R31, R32 and R33 connected in parallel, and the resistors R31, R32 and R33 are connected to the CS pin of the packaging chip and the peripheral circuit.

[0011] Further, the peripheral circuit comprises a resistor R14, a resistor R15, a resistor R42, a capacitor C23 and a capacitor C26, the resistor R14 is connected to the VCC pin of the packaged chip through the resistor R15, the resistor R42 is connected to the DEM pin of the packaged chip, the capacitor C23 is connected to the VCC pin of the packaged chip, and the capacitor C26 is connected to the FB pin of the packaged chip.

[0012] Further, the output feedback circuit is further connected to the FB pin of the packaged chip.

[0013] Further, the primary side AC filtering rectifier circuit is connected to the peripheral circuit, the RCD peak absorption circuit and the transformer through the Pi filter circuit.

[0014] Further, the transformer comprises a first transformer T1 and a second transformer T3, the first transformer T1 is connected to the first RCD absorption circuit, and the second transformer T3 is connected to the second RCD absorption circuit.

[0015] Further, the secondary side filtering rectifier circuit is further connected to the transformer through the common mode inductor TF1.

[0016] Further, the secondary side filtering rectifier circuit comprises a first secondary side filtering rectifier circuit and a second secondary side filtering rectifier circuit, the first secondary side filtering rectifier circuit is connected to the first transformer T1, and the second secondary side filtering rectifier circuit is connected to the second transformer T3.

[0017] The utility model discloses a control circuit based on high -power flyback circuit, and the utility model discloses a kind of circuit, which comprises packaged chip, peripheral circuit, RCD peak absorption circuit, transformer and secondary side filtering rectifier circuit.

[0018] The utility model not only can make the heat dissipation design of switching power supply more easily, but also can reduce the volume of product, simultaneously, the packaged chip of sealing can greatly reduce manufacturing cost and material cost, simplify the structure of circuit. BRIEF DESCRIPTION OF DRAWINGS

[0019] The utility model will be further described in connection with the drawings:

[0020] Figure 1 It is the circuit diagram of the utility model for one transformer when adopting 1 control circuit embodiment 1 based on high -power flyback circuit.

[0021] Figure 2 It is the circuit diagram of the utility model for two transformers when adopting 2 control circuit embodiment 2.

[0022] In the diagram: 1-Primary-side AC filter and rectifier circuit; 2-Π-type filter circuit; 3-Packaged chip; 4-Current detection circuit; 5-RCD spike absorption circuit; 51-First RCD absorption circuit; 52-Second RCD absorption circuit; 6-Secondary-side filter and rectifier circuit; 61-First secondary-side filter and rectifier circuit; 62-Second secondary-side filter and rectifier circuit; 7-Output feedback circuit. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0025] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0026] Example 1

[0027] like Figure 1 As shown, this utility model discloses a control circuit based on a high-power flyback circuit, including an RCD spike absorption circuit 5 and at least one transformer. This embodiment uses one transformer T3.

[0028] The control circuit also includes packaged chip 3, current detection circuit 4 and peripheral circuit. The RCD pin of packaged chip 3 is connected to RCD spike absorption circuit 5. Packaged chip 3 can be a GBU-7 packaged chip. The GBU-7 packaged chip contains a flyback control chip, a diode and a power switch. The diode, capacitor C12, resistor R17 and resistor R18 form RCD spike absorption circuit 5.

[0029] The D pin of packaged chip 3 is connected to the primary winding of the transformer, and the CS pin of packaged chip 3 is connected to the current detection circuit 4. The current detection circuit 4 includes resistors R31, R32 and R33 connected in parallel. Resistors R31, R32 and R33 are connected to the peripheral circuit and the CS pin of packaged chip 3.

[0030] The peripheral circuit is connected to the RCD peak absorption circuit 5, the packaged chip 3 and the current detection circuit 4.

[0031] The peripheral circuit comprises a resistor R14, a resistor R15, a resistor R42, a capacitor C23 and a capacitor C26, the resistor R14 is connected to the VCC pin of the packaged chip 3 through the resistor R15, the resistor R42 is connected to the DEM pin of the packaged chip 3, the capacitor C23 is connected to the VCC pin of the packaged chip 3, and the capacitor C26 is connected to the FB pin of the packaged chip 3.

[0032] The control circuit further comprises an output feedback circuit 7 connected to the FB pin of the packaged chip 3.

[0033] The control circuit further comprises a primary side alternating current filtering rectification circuit 1 and a Pi type filtering circuit 2, the primary side alternating current filtering rectification circuit 1 is connected to the peripheral circuit, the RCD peak absorption circuit 5 and the transformer through the Pi type filtering circuit 2.

[0034] The control circuit further comprises a secondary side filtering rectification circuit 6 and a common mode inductor TF1, the common mode inductor TF1 is connected to the transformer through the secondary side filtering rectification circuit 6.

[0035] Through the design of the above structure, not only the heat dissipation design of the switching power supply is easier, but also the volume of the product can be reduced, and the adoption of the packaged chip 3 can greatly reduce the manufacturing cost and material cost and simplify the structure of the circuit.

[0036] The mains is filtered through TF3 / TF2 / DB1 / L1 and forms a DC voltage on C4, the positive end of which is connected to the primary winding of the transformer T3, and the other end of the primary winding is connected to the D pin of the packaged chip 3. The CS pin of the chip is connected to R31 / / R32 / / R33 and then returns to the negative pole of C4. The RCD pin of the chip is connected to C12 / / R17 / / R18. The chip controls the conduction of the D pin to the CS pin, thereby controlling the excitation of the transformer T3. When the current of the CS pin reaches the threshold value, the conduction of the D pin of the chip to the CS pin is turned off, and the transformer T3 begins to demagnetize. At this moment, the energy of the peak voltage generated by the leakage inductance of the transformer T3 at the D pin of the chip flows out to C12 / / R17 / / R18, and the cycle is repeated to realize control.

[0037] Embodiment 2

[0038] As shown in Figure 2 Fig. 1, it is a control circuit based on a high-power flyback circuit, which comprises an RCD peak absorption circuit 5 and at least one transformer. This embodiment adopts two transformers, which comprise a first transformer T1 and a second transformer T3, and the first transformer T1 is connected to a first RCD absorption circuit 51, and the second transformer T3 is connected to a second RCD absorption circuit 52.

[0039] The control circuit further comprises a package chip 3, a current detection circuit 4 and a peripheral circuit, the RCD pin of the package chip 3 is connected to the RCD peak absorption circuit 5, and the package chip 3 can adopt a GBU-7 package chip, the GBU-7 package chip is internally provided with a flyback control chip, a diode and a power switch tube, and the diode, the capacitor C12, the resistor R17 and the resistor R18 form the RCD peak absorption circuit 5.

[0040] The D pin of the package chip 3 is connected to the primary winding of the transformer T3, and the CS pin of the package chip 3 is connected to the current detection circuit 4, and the current detection circuit 4 comprises resistors R31, R32 and R33 which are connected in parallel with each other and connected to the CS pin of the package chip 3 and the peripheral circuit.

[0041] The peripheral circuit is connected to the RCD peak absorption circuit 5, the package chip 3 and the current detection circuit 4.

[0042] The peripheral circuit comprises resistors R14, R15, R42, a capacitor C23 and a capacitor C26, the resistor R14 is connected to the VCC pin of the package chip 3 through the resistor R15, the resistor R42 is connected to the DEM pin of the package chip 3, the capacitor C23 is connected to the VCC pin of the package chip 3, and the capacitor C26 is connected to the FB pin of the package chip 3.

[0043] Through the design of the above structure, the heat dissipation design of the switching power supply can be made easier, the volume of the product can be reduced, the manufacturing cost and material cost can be greatly reduced by using the sealed package chip 3, and the structure of the circuit is simplified.

[0044] The control circuit further comprises an output feedback circuit 7 connected to the FB pin of the package chip 3.

[0045] The control circuit further comprises a primary side AC filtering rectifier circuit 1 and a Π type filter circuit 2, and the primary side AC filtering rectifier circuit 1 is connected to the peripheral circuit, the RCD peak absorption circuit 5 and the transformer through the Π type filter circuit 2.

[0046] The control circuit further comprises a secondary side filter rectifier circuit 6 and a common mode inductor TF1, and the common mode inductor TF1 is connected to the transformer through the secondary side filter rectifier circuit 6. The secondary side filter rectifier circuit 6 comprises a first secondary side filter rectifier circuit 61 and a second secondary side filter rectifier circuit 62, the first secondary side filter rectifier circuit 61 is connected to the first transformer T1, and the second secondary side filter rectifier circuit 62 is connected to the second transformer T3.

[0047] The mains power is filtered by TF3 / TF2 / DB1 / L1 to form a DC voltage on C4, the positive terminal of which is connected to the primary winding of transformer T1, the other terminal of the primary winding of T1 is connected to the primary winding of T3, and the other terminal of the primary winding of T3 is connected to the D pin of the packaged chip 3. The CS pin of the packaged chip 3 is connected to R31 / / R32 / / R33 and then to the negative terminal of C4. The RCD pin of the packaged chip 3 is connected to C12 / / R17 / / R18. The packaged chip 3 controls the conduction between the D pin and the CS pin to control the excitation of the transformer T1 / T3, and when the current of the CS pin reaches a threshold value, the conduction between the D pin and the CS pin of the packaged chip 3 is disconnected, and the transformer T1 / T3 starts to demagnetize. At this moment, the energy of the spike voltage generated by the leakage inductance of the transformer T1 / T3 on the D pin of the packaged chip 3 flows out to C12 / / R17 / / R18 through the RCD pin of the chip, and the cycle is repeated to realize control.

[0048] The above is only a specific embodiment of the present application, but the technical features of the present application are not limited thereto. Any simple change, equivalent replacement or modification made on the basis of the present application to achieve basically the same technical effect is also covered by the protection scope of the present application.

Claims

1. A control circuit based on a high-power flyback circuit, comprising: RCD spike absorption circuit; and at least one transformer; Its features are: It also includes a packaged chip, a current detection circuit, and peripheral circuits. The RCD pin of the packaged chip is connected to the RCD spike absorption circuit, the D pin of the packaged chip is connected to the primary winding of the transformer, the CS pin of the packaged chip is connected to the current detection circuit, and the peripheral circuits are connected to the RCD spike absorption circuit, the packaged chip, and the current detection circuit.

2. The control circuit based on a high-power flyback circuit according to claim 1, characterized in that: The current detection circuit includes resistors R31, R32, and R33 connected in parallel. Resistors R31, R32, and R33 are connected to the peripheral circuit and the CS pin of the packaged chip.

3. The control circuit based on a high-power flyback circuit according to claim 1, characterized in that: The peripheral circuit includes resistors R14, R15, and R42, capacitors C23 and C26. Resistor R14 is connected to the VCC pin of the packaged chip through resistor R15. Resistor R42 is connected to the DEM pin of the packaged chip. Capacitor C23 is connected to the VCC pin of the packaged chip. Capacitor C26 is connected to the FB pin of the packaged chip.

4. The control circuit based on a high-power flyback circuit according to claim 1, characterized in that: It also includes an output feedback circuit, which is connected to the FB pin of the packaged chip.

5. A control circuit based on a high-power flyback circuit according to claim 1, characterized in that: It also includes a primary-side AC filter rectifier circuit and a Π-type filter circuit, wherein the primary-side AC filter rectifier circuit is connected to the peripheral circuit, the RCD spike absorption circuit and the transformer through the Π-type filter circuit.

6. The control circuit based on a high-power flyback circuit according to claim 1, characterized in that: The transformer includes a first transformer T1 and a second transformer T3. The first transformer T1 is connected to a first RCD absorption circuit, and the second transformer T3 is connected to a second RCD absorption circuit.

7. A control circuit based on a high-power flyback circuit according to claim 6, characterized in that: It also includes a secondary-side filter rectifier circuit and a common-mode inductor TF1, wherein the common-mode inductor TF1 is connected to the transformer through the secondary-side filter rectifier circuit.

8. A control circuit based on a high-power flyback circuit according to claim 7, characterized in that: The secondary-side filter rectifier circuit includes a first secondary-side filter rectifier circuit and a second secondary-side filter rectifier circuit. The first secondary-side filter rectifier circuit is connected to the first transformer T1, and the second secondary-side filter rectifier circuit is connected to the second transformer T3.

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