Electrifying startup circuit and electrifying startup method thereof

Abstract

The invention relates to an electrifying startup circuit and an electrifying startup method thereof. The electrifying startup circuit simultaneously realizes an electrifying time-delay control function and a current limiting protection function by using a multiplexing pin of a chip in which a power switching tube and a control circuit are integrated and using an external RC time-delay circuit, so the electrifying startup circuit starts to work after a certain time delay. A control chip is provided with at least three pins such as the multiplexing pin, an input pin and an output pin, wherein the multiplexing pin is connected with the RC time-delay circuit; the input pin is connected with an input voltage source; the output of the output pin is used for supplying power to lower level connected equipment; a first reference voltage source is arranged in the control chip; the output pin outputs a voltage signal; and the delay time is determined by first capacitance and a first reference voltage. As the electrifying time-delay control and the output current limiting protection share the same multiplexing pin of the integrated control chip, the number of pins of the chip is reduced, and the volume of the chip is reduced; and an output voltage of the electrifying startup circuit is slowly risen according to a certain rising slope, so that damage to subsequent circuits or influence on normal work of the subsequent circuits due to the overshoot of the output voltage in the electrifying process is avoided.

Description

technical field [0001] The invention relates to a power-on start-up circuit and a power-on start-up method of a power supply, belonging to an electronic circuit. Background technique [0002] With the continuous growth of portable electronic products in the fields of communications, computers and consumer electronics, the demand for power management ICs is also on the rise, such as typical DC / DC DC-DC switching power supplies, AC / DC switching power supplies, etc. more and more widely applied. As the electronic system tends to become more complex, the system puts forward higher requirements on the power-on sequence and power-on stability of the power supply voltage. [0003] In a complex electronic system, such as a notebook computer, there are multiple sets of power supplies. At the same time, the output voltage of each group of power supply may supply power to multiple loads at the same time. The load here is usually a digital chip in an electronic system. The power sup...

AI Technical Summary

Problems solved by technology

[0007] (1) The number of discrete components required is large; the area occupied by each discrete component is relatively large;

[0008] (2) The power-on delay is controlled by a delay circuit composed of a resistor and a capacitor. Due to the discreteness of the gate threshold voltage of the power switch tube M, the delay control is inaccurate;

[0009] (3) When the power is turned on, when the switching device is turned on instantaneously or the enabling start signal EN suddenly increases to a large value, this will cause a large surge current, which will give the components in the subsequent power supply chip cause damage, or the surge current may cause the input power voltage to drop enough to cause instantaneous power failure of other power equipment using the same input power

[0010] Visible, using figure 1 In the implementation scheme shown, the power-on delay control is not accurate enough, and because there is no current limiting protection function, it brings hidden dangers to the normal operation of the subsequent circuit

Images