Patent ID: 7368899
Filing Date: 2008-05-06
Classification: H02M,Y10S

Abstract:
1. A boost circuit, comprising: a DC/DC converter having a switch, receiving an input voltage and outputting an input voltage feedback signal, an output voltage feedback signal, an input current feedback signal and an output voltage after a boost of said input voltage; and a feedback control circuit coupled to said converter and comprising: a pulse-width modulation limiting controller (PWMLC) outputting a first, a second and a third control signals; a voltage/current detector coupled to said converter and said PWMLC, receiving said input voltage feedback signal, said output voltage feedback signal, said first control signal and said input current feedback signal, and generating a voltage output signal; a modulator coupled to said voltage/current detector and said PWMLC, receiving said voltage output signal and said second control signal and generating a modulated signal; an oscillator generating and outputting a saw-tooth wave to said modulator; a soft starting unit receiving said third control signal and generating a soft starting control signal; and a feedback controller coupled to said oscillator, said modulator and said soft starting unit, receiving said saw-tooth wave, said modulated signal and said soft starting control signal and generating an output signal; wherein said feedback controller generates said output signal with a fixed time period through a control of said PWMLC to control at least one of said voltage/current detector, said modulator and said soft starting unit for controlling a turn on and a turn off of said switch so as to generate said boost.