DC-DC converter

Abstract

The invention discloses a DC-DC converter, which comprises an oscillator, an error amplifier, an auxiliary soft starting circuit, a drive circuit and a reference circuit, wherein the reference circuitoutputs first reference voltage to the error amplifier and outputs second reference voltage to the oscillator; the oscillator receives feedback voltage after dividing of output voltage and the secondreference voltage and generates a square wave and a triangular wave, the square wave is output to the error amplifier and the triangular wave is output to the comparator; the error amplifier receivesthe square wave, the feedback voltage and the first reference voltage; the voltage output by the error amplifier is input into the comparator under the control of the auxiliary soft starting circuit;and the comparator outputs the compared level to the drive circuit, input voltage is driven and then the output voltage is output through a BUCK circuit. According to the DC-DC converter, the frequency of the oscillator during power on is controlled to slowly increase through the oscillator, the error amplifier and the auxiliary soft starting circuit, and stable voltage is output to reduce power-on surge current, thereby protecting a load circuit.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a DC-DC converter. Background technique [0002] With the development of portable electronic devices, high-efficiency and high-quality power management in integrated circuits has become more and more important. Therefore, DC-DC (DC-DC converter, refers to the conversion of electrical energy of one voltage value into another in a DC circuit. A device with a voltage value of electric energy) plays an irreplaceable role in improving chip power efficiency. However, during the power-on process of DC-DC, the fast charging of the off-chip capacitor will generate a large surge current in the off-chip inductor. This current may cause the output voltage to decrease or increase instantaneously, thus causing the load circuit to work abnormally or even be damaged. In order to solve this problem, a soft-start circuit is needed to reduce the power-on surge current. [0003] At present, the...

AI Technical Summary

Problems solved by technology

The first two soft start methods have the problems of unstable inductor current and low output voltage linearity during the start-up phase; the third method uses a large number of digital circuits and digital-to-analog converters such as D flip-flops, edge detection circuits, and T flip-flops. The DAC converts the digital signal into a reference voltage. In this way, a stable power-on current can be obtained. However, if you want to obtain a smoother reference voltage, the number of digits required for the digital circuit will increase, and the corresponding chip area will also increase. Big

The on-chip integrated DC-DC is only one of the small auxiliary circuits that supply power to the chip, and the load current is not large, so it is not cost-effective to occupy too much area

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