A converter suitable for high-voltage electronic equipment

Abstract

The invention relates to a converter (200), which comprises a starting capacitor (C1), a control unit (66), a transformer and a starting control circuit (300), the starting control circuit (300) is used to regulate a To start the current of the control unit (66); the start control circuit (300) includes a current source module (310, 310b, 310c), which is electrically connected to the start capacitor (C1), the control unit (66) and the transformer A primary winding (Lpri); the current source module (310, 310b, 310c) includes a voltage regulator (V1), a first control element (312), and a source current sampling resistor (Rcs), the source current The sampling resistor (Rcs) is used to cooperate with the first regulating element (312) to adjust the conductivity of the voltage regulator (V1); the current source module (310, 310b, 310c) is based on the first regulating element (312 ), and the resistance value of the source current sampling resistor (Rcs) to generate a source current (Isc) to charge the startup capacitor (C1).

Description

technical field [0001] The invention relates to a converter of electronic equipment, in particular to a start-up of a converter used in high-voltage electronic equipment. Background technique [0002] In a general converter (converter), such as a flyback (Flyback) or a forward converter (forward converter) circuit design, the converter includes a controller and a start-up circuit, and the start-up circuit is regulated to start the An initial current for the controller of the converter, and in the prior art, the start-up circuit usually includes a resistor with a high resistance value, such as figure 1 shown. [0003] figure 1 is a schematic diagram of a part of the circuit in a flyback converter 10a in the prior art. The flyback converter 10a is installed in an electronic device, which can be a high-voltage electronic device, such as a car charger. The flyback converter 10a includes a converter switch V0, a ​​control unit 66, a start-up resistor Rst, a start-up capacitor...

AI Technical Summary

Problems solved by technology

[0012] However, although the use of the source resistor Rc and the voltage regulator Va can avoid the above-mentioned problem of using a high-value start-up resistor Rst and a low-voltage current input, the time required for the start-up of the converter is too long. problem, however, it leads to the following three disadvantages

The first is the high-voltage N-channel depletion MOSFET used as the voltage regulator Va, which is a rare and expensive component, and it may not be able to maintain stable operation for a long time

Furthermore, if the input power supply is a high-voltage current, it will still cause high power loss, resulting in low working efficiency of the converter, and it is necessary to add a corresponding heat dissipation design for the converter

In addition, when using different types of MOSFET transistors as the voltage regulator Va, the gate threshold voltage Vgth varies and depends on the temperature, which may cause the output current Ic to no longer have a constant value as mentioned above, That said, the output current Ic has potential stability issues

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