Patent ID: 8957710
Filing Date: 2015-02-17
Classification: G06F,G09G,Y10S

Abstract:
1. A start-up circuit, used for starting up a variable power supply circuit, and comprising: a detection circuit, used for detecting an output voltage of said variable power supply circuit, and producing a detection signal; a transition circuit, coupled to said detection circuit, transiting the level of said detection signal, and producing a control signal for starting up or cutting off said variable power supply circuit; a latch circuit coupled between said detection circuit and said transition circuit for latching said detection signal; and wherein the latch circuit comprises a first transistor coupled between a power supply and said detection circuit, and the gate thereof coupled to an output of said latch circuit; a second transistor coupled between said detection circuit and a reference voltage, and the gate thereof coupled to the gate of said first transistor; a third transistor coupled to said power supply and said second transistor, and the gate thereof coupled between said first transistor and said second transistor; and a fourth transistor coupled between said third transistor and said reference voltage, and the gate thereof coupled to the gate of said third transistor.