A power supply circuit for a power drive chip

Abstract

The invention relates to a power supply circuit of a power drive chip, comprising a starting circuit, a voltage stabilizing circuit and a power supply circuit. , a diode and a second capacitor, the capacity of the first capacitor is greater than the capacity of the second capacitor. While the external load power supply charges the first capacitor through the first resistor, the first capacitor charges the second capacitor; because the first capacitor capacity is greater than the second capacitor capacity, the two capacitors have close charging speeds, and the first capacitor The charging current formed is very small, the voltage drop generated by the third resistor is very small, the voltage value formed on the first capacitor is almost equal to the voltage value formed on the second capacitor, and the reverse voltage formed by the base terminal and the emitter terminal of the triode Very small, thereby effectively avoiding the danger of reverse breakdown voltage breakdown of the triode, reducing circuit maintenance costs, and ensuring the normal operation of the power supply line.

Description

technical field [0001] The invention relates to the field of LED lighting, in particular to a power supply circuit for a power drive chip. Background technique [0002] In the structural design of the LED lamp, the LED lamp includes an LED chip and a power driver chip. When the power drive chip is powered by an external power supply, the chip controls the working state of the LED chip. Therefore, the design of the power supply circuit of the power driver chip has become one of the key issues in the manufacture of LED lamps. [0003] For the power supply problem of the power drive chip, the traditional power supply line is mainly in accordance with figure 1 The circuit shown is designed. The traditional power supply circuit includes a starting circuit 1, a voltage stabilizing circuit 2 and a power supply circuit 3. The starting circuit 1 includes a resistor R1 and a capacitor C1. The voltage stabilizing circuit 2 includes a triode Q, a voltage stabilizing tube D1 and a res...

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Problems solved by technology

[0004] However, the traditional power supply circuit still has fatal shortcomings: the external power supply voltage Vbus charges the capacitor C1 initially, the voltage on the voltage C2 is zero, and the voltage on the capacitor C1 will reach a larger voltage value, that is, the startup voltage of the chip IC , so that there is a large reverse voltage between the base and the emitter of the triode Q, which is greater than the reverse breakdown voltage between the base and the emitter of the general triode, so that the triode Q is struck dangerous to wear

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