Soft starting circuit applied in buck type direct current (DC)-DC switch power supply

Abstract

The invention discloses a soft starting circuit applied in a buck type direct current (DC)-DC switch power supply. The soft starting circuit mainly resolves the problem that overshoot voltage and surge current exist in the existing starting circuit, and static power consumption is too large. The starting circuit comprises a frequency converter circuit, a control circuit and a current-voltage conversion circuit. The first output end of the frequency converter circuit is connected with the control circuit to output a soft starting ending signal OVER, and the second output end of the frequency converter circuit si connected with a current-voltage conversion circuit to output digital signals F1-F7. The first output end of the control circuit is connected with the frequency converter circuit to output a clearing signal clr, the second output end and the third output end of the control circuit are connected with the current-voltage conversion circuit to respectively output a digital signal F8 and a digital signal XF8, and the current-voltage conversion circuit outputs voltage signals VSS. The soft starting circuit adopts the current-voltage conversion circuit, improves output voltage stability, reduces static power consumption, shortens domain area, reduces cost and can be used for simulating an integrated circuit.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, in particular to a soft start circuit applied to a step-down DC-DC switching power supply, which can be used for analog integrated circuits. Background technique [0002] In the field of switching power supplies, step-down DC-DC is especially suitable for switching power supplies due to its simplicity, high efficiency, and low power consumption. However, there are surge currents and overshoot voltages during the circuit start-up phase, which will damage the internal structure of the chip where it is located. its external circuit. [0003] refer to figure 1 , the soft start circuit includes a frequency divider circuit and a digital-to-analog conversion circuit. The first input terminal of the frequency divider circuit is connected to the clear signal clr of the chip where it is located, and the second input terminal of the frequency divider circuit is connected to the clock of the chi...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a soft start circuit applied in step-down DC-DC switching power supply, to solve the problems of large static current, large power consumption, large layout area and high cost in the prior art, and reduce the chip where it is located the complexity of

Images