Switching power supply

Abstract

The invention provides a switching power source having a stable negative voltage output. The switching power source is characterized by comprising a switching power source controller having a soft start circuit, an output stage including a coil, a switching element for controlling an electric current to flow through the coil by driving the coil with the switching power source controller, and a diode having its anode side connected with the output end and its cathode side connected with the node between the switching element and the coil, a voltage dividing circuit for dividing the output voltage of the soft start circuit and the voltage of the output end, and a soft start period adjusting circuit for adjusting the soft start period.

Description

technical field [0001] The present invention relates to switching power supplies. In particular, it relates to a switching power supply provided with a soft start circuit, which switches the current flowing to the coil and outputs a predetermined negative voltage to the output side. Background technique [0002] Conventionally, soft-start circuits have been used in switching power supplies to prevent damage or malfunction of ICs, which are loads of switching transistors and switching power supplies, due to inrush current for charging output capacitors at startup. [0003] Here, refer to FIG. 14 . FIG. 14 shows a circuit example of a positive voltage output switching power supply 1000 in step-down mode (a mode in which the relationship of power supply voltage (Vcc)>output voltage (Vo) is also called "Buck Mode"). A conventional switching power supply 1000 shown in FIG. 14 includes a soft start circuit 1001, a triangular wave generating circuit 1002, an error amplifier 10...

AI Technical Summary

Problems solved by technology

) switching power supply circuit, but there is no inversion mode that is improved to output negative voltage (also known as "Inverting Mode")

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