Low-cost high-voltage flyback conversion circuit

Abstract

The utility model aims to provide the low-cost high-voltage flyback conversion circuit which is simple in structure, does not need external reinforced insulation, and can be controlled by keys manually. The circuit comprises a fourth resistor (R4), a fifth resistor (R5), a high-voltage-to-low-voltage module (3), a third MOS tube (Q3) and a PWM controller (4), the fourth resistor, the fifth resistor and the high-voltage-to-low-voltage module are connected in series between the positive electrode and the negative electrode of a high-voltage power supply (1), and a primary side MOS tube (Q4) is arranged on a path between the negative electrode of the high-voltage power supply and the primary side of a transformer (2). The third MOS tube and the PWM controller are connected in series and then connected between the connection point of the fifth resistor and the high-voltage-to-low-voltage module and the connection point of the high-voltage-to-low-voltage module and the primary side MOS tube, the high-voltage-to-low-voltage module outputs a control signal to the grid electrode of the third MOS tube, and the PWM controller is connected with the grid electrode of the primary side MOS tube. The utility model relates to the technical field of high-voltage control.

Description

TECHNICAL FIELD

[0001] The utility model relates to high pressure control technical field, concretely is related to a low cost high voltage flyback conversion circuit. BACKGROUND

[0002] In high voltage system, because cannot achieve low cost insulation, so generally all use air switch to carry out power on operation. However, air switch has following very difficult to overcome problem: 1, air switch structure is complex, and the manufacturing cost is high; 2, air switch generally needs to be artificially pulled and closed gate operation, this not only exists risk to operating personnel, in addition, in high voltage system, when the voltage of high voltage module drops to a certain value, needs to cut off power supply, but air switch is unattended, very difficult to accurately grasp the gate pulling time point, this easily leads to high voltage battery overdischarge, and further causes unnecessary loss. In addition, for the case of small power supply, the cost of using other control topology mode is still high. Therefore, it is urgent to design a device without external strengthening insulation and manually key-controlled switch to realize the control of high voltage output. SUMMARY

[0003] In view of the deficiencies in the prior art, the utility model provides a low cost high voltage flyback conversion circuit which is simple in structure, does not need external strengthening insulation and can be manually key-controlled.

[0004] To achieve the above object, the technical scheme adopted by the utility model is as follows: a low cost high voltage flyback conversion circuit is arranged between the positive and negative poles of a high voltage power supply, and a transformer and a primary MOS tube are also connected in series between the positive and negative poles of the high voltage power supply, the secondary side of the transformer is provided with a load, the low cost high voltage flyback conversion circuit comprises a fourth resistor, a fifth resistor, a high voltage to low voltage module, a third MOS tube and a PWM controller, the fourth resistor, the fifth resistor and the high voltage to low voltage module are connected in series between the positive and negative poles of the high voltage power supply, the third MOS tube and the PWM controller are connected in series and then connected between the connection point of the fifth resistor and the high voltage to low voltage module and the connection point of the high voltage to low voltage module and the primary MOS tube, the high voltage to low voltage module outputs a control signal to the gate of the third MOS tube, and the PWM controller is connected with the gate of the primary MOS tube.

[0005] Further, the high-voltage-to-low-voltage module comprises a power supply, an eighth resistor, a ninth resistor, an eleventh resistor, a fourteenth resistor, a fifteenth resistor, a voltage stabilizing tube, a second MOS tube and a switch, the eighth resistor and the ninth resistor are connected in series across the power supply, the voltage stabilizing tube is connected across the eighth resistor, the eleventh resistor and the fifteenth resistor are connected in series and then connected across the voltage stabilizing tube through the second MOS tube, the fourteenth resistor is connected across the eleventh resistor and the fifteenth resistor connected in series through the switch, and the fourteenth resistor is connected with the gate of the second MOS tube.

[0006] The second MOS tube and the primary-side MOS tube are N-type field effect tubes, the third MOS tube is a P-type field effect tube, the drain of the second MOS tube is connected with the fifteenth resistor, the source is connected with the negative pole of the power supply, the source of the third MOS tube is connected with the fifth resistor, and the drain is connected with the PWM controller.

[0007] The secondary side of the transformer is further connected in series with a rectifier diode and a shielded magnetic ring.

[0008] The beneficial effects of the utility model are as follows: in the utility model, after the high-voltage-to-low-voltage module is connected with the high-voltage power supply, the flyback converter does not work, at this time, the high-voltage-to-low-voltage module is used to divide the high voltage into low voltage that can be touched by human body, that is, the 1KVdc high voltage of the high-voltage power supply is converted into safe low voltage, then the high-voltage power supply waits for the arrival of the wake-up signal; when the switch in the high-voltage-to-low-voltage module is pressed by human, the low voltage after voltage division drives the third MOS tube to be turned on, the PWM controller (flyback power supply chip) is powered on, and the PWM controller (flyback power supply chip) starts to work after being powered on; the PWM controller enables the primary-side MOS tube to be turned on and turned off, so that the voltage required by the load is converted on the secondary side of the transformer, therefore, the utility model has the advantages of simple structure, low cost, no external insulation and the like, and the flyback power supply can be powered on by manual key control, and the voltage required by the load can be output. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is the principle diagram of the utility model;

[0010] Figure 2 is the circuit principle diagram of the high-voltage-to-low-voltage module. DETAILED DESCRIPTION

[0011] As Figure 1 and Figure 2As shown, the utility model ofteel including setting between the positive and negative pole of high voltage power supply 1, still have transformer 2 and primary MOS tube Q4 in series between the positive and negative pole of high voltage power supply 1, the secondary side of transformer 2 has load Rload, still have rectifier diode D1 and shielded magnetic ring L in series on the secondary side of transformer 2.

[0012] The low-cost high-voltage flyback conversion circuit includes a fourth resistor R4, a fifth resistor R5, a high-voltage-to-low-voltage module 3, a third MOS tube Q3, and a PWM controller 4. The fourth resistor R4, the fifth resistor R5, and the high-voltage-to-low-voltage module 3 are connected in series between the positive and negative poles of the high-voltage power supply 1. The third MOS tube Q3 and the PWM controller 4 are connected in series between the connection point of the fifth resistor R5 and the high-voltage-to-low-voltage module 3 and the connection point of the high-voltage-to-low-voltage module 3 and the primary MOS tube Q4. The high-voltage-to-low-voltage module 3 outputs a control signal to the gate of the third MOS tube Q3. The PWM controller 4 is connected to the gate of the primary MOS tube Q4.

[0013] The high-voltage-to-low-voltage module 3 includes a power supply HV, an eighth resistor R8, a ninth resistor R9, an eleventh resistor R11, a fourteenth resistor R14, a fifteenth resistor R15, a zener diode, a second MOS tube Q2, and a switch K1. The eighth resistor R8 and the ninth resistor R9 are connected in series across the power supply HV. The zener diode is connected across the eighth resistor R8. The eleventh resistor R11 and the fifteenth resistor R15 are connected in series across the zener diode through the second MOS tube Q2. The fourteenth resistor R14 is connected across the series connection of the eleventh resistor R11 and the fifteenth resistor R15 through the switch K1. The fourteenth resistor R14 is connected to the gate of the second MOS tube Q2.

[0014] The second MOS tube Q2 and the primary MOS tube Q4 are both N-type field effect tubes. The third MOS tube Q3 is a P-type field effect tube. The drain of the second MOS tube Q2 is connected to the fifteenth resistor R15. The source is connected to the negative pole of the power supply HV. The source of the third MOS tube Q3 is connected to the fifth resistor R5. The drain is connected to the PWM controller 4. The drain of the primary MOS tube Q4 is connected to the primary side of the transformer 2. The source is connected to the negative pole of the high-voltage power supply 1.

[0015] The working process of the utility model is as follows:

[0016] In the high-voltage-to-low-voltage module 3, 1Kv high voltage is divided by the ninth resistor R9 and the eighth resistor R8, and the voltage across the eighth resistor R8 is clamped to a safe low voltage, such as 15V or 20V, by the zener tube Zener, which sets the voltage. When the switch K1 is pressed, the voltage of the fourteenth resistor R14 is pulled up to the upper end of the zener voltage of the zener tube Zener, at this time, the second MOS tube Q2 is turned on, at this time, the eleventh resistor R11 and the fifteenth resistor R15 are connected in series and grounded, then an enabling signal CTRL is output in the form of voltage division between the eleventh resistor R11 and the fifteenth resistor R15, the signal is output to the gate of the third MOS tube Q3, and then the Q3 is enabled to be turned on, so that the PWM controller (flyback power supply chip) is powered on, and after the PWM controller (flyback power supply chip) is powered on, it starts to work, at this time, the primary side MOS tube Q4 is continuously turned on and turned off, so that the required voltage of the load is converted on the secondary side of the transformer 2.

[0017] Compared with the prior art, the utility model can use the key switch instead of the air switch in the application scene of high voltage, thereby achieving the purpose of reducing the cost; in the application scene of energy storage, whether the DCDC converter works or not can be dominated by the master control, thereby making the whole energy storage system more stable.

[0018] The above description is only the optimal solution embodiment of the utility model, and is not used to limit the utility model, and various modifications or replacements of the utility model can be made by the person skilled in the art without departing from the essence and protection scope of the utility model, and the modifications or replacements should be within the protection scope of the utility model.

Claims

1. A low-cost high-voltage flyback conversion circuit, arranged between the positive and negative poles of a high-voltage power supply (1), and further having a transformer (2) and a primary MOS transistor (Q4) connected in series between the positive and negative poles of the high-voltage power supply (1), the secondary side of the transformer (2) having a load (Rload) connected thereto, characterized in that: The low-cost high-voltage flyback conversion circuit comprises a fourth resistor (R4), a fifth resistor (R5), a high-voltage-to-low-voltage module (3), a third MOS tube (Q3) and a PWM controller (4), the fourth resistor (R4), the fifth resistor (R5) and the high-voltage-to-low-voltage module (3) are connected in series between the positive and negative poles of the high-voltage power supply (1), the third MOS tube (Q3) and the PWM controller (4) are connected in series and then connected between the connection point of the fifth resistor (R5) and the high-voltage-to-low-voltage module (3) and the connection point of the high-voltage-to-low-voltage module (3) and the primary MOS tube (Q4), the high-voltage-to-low-voltage module (3) outputs a control signal to the gate of the third MOS tube (Q3), and the PWM controller (4) is connected with the gate of the primary MOS tube (Q4). ​ 2. A low cost high voltage flyback converter circuit as claimed in claim 1, wherein: The high-voltage-to-low-voltage module (3) comprises a power supply (HV), an eighth resistor (R8), a ninth resistor (R9), an eleventh resistor (R11), a fourteenth resistor (R14), a fifteenth resistor (R15), a Zener diode, a second MOS tube (Q2) and a switch (K1), the eighth resistor (R8) and the ninth resistor (R9) are connected in series across the power supply (HV), the Zener diode is connected in parallel across the eighth resistor (R8), the eleventh resistor (R11) and the fifteenth resistor (R15) are connected in series and then connected in parallel across the Zener diode through the second MOS tube (Q2), the fourteenth resistor (R14) is connected in parallel across the series connection of the eleventh resistor (R11) and the fifteenth resistor (R15) through the switch (K1), and the fourteenth resistor (R14) is connected with the gate of the second MOS tube (Q2).

3. A low cost high voltage flyback converter circuit as claimed in claim 2, wherein: The second MOS tube (Q2) and the primary MOS tube (Q4) are both N-type field effect tubes, the third MOS tube (Q3) is a P-type field effect tube, the drain of the second MOS tube (Q2) is connected with the fifteenth resistor (R15), the source is connected with the negative pole of the power supply (HV), the source of the third MOS tube (Q3) is connected with the fifth resistor (R5), and the drain is connected with the PWM controller (4), the drain of the primary MOS tube (Q4) is connected with the primary side of the transformer (2), and the source is connected with the negative pole of the high-voltage power supply (1).

4. The low cost high voltage flyback converter circuit of claim 1, wherein: The secondary side of the transformer (2) further comprises a rectifier diode (D1) and a shielded magnetic ring (L).

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