Patent ID: 7646181
Filing Date: 2010-01-12
Classification: H02M,Y02B

Abstract:
1. A control circuit of a direct current-direct current converter, comprising: a mode selection section for selecting an active clamp forward operating mode or a logic link control operating mode; a soft start section for generating a soft start signal in the active clamp forward operating mode and the logic link control operating mode; a pulse width modulation comparison section for comparing a current detection signal from a slope compensation section with a feedback signal, a feedback reference signal and the soft start signal when the active clamp forward operating mode is selected, and generating a pulse width modulation signal based on a comparison result; a selection section for selecting the pulse width modulation signal of the pulse width modulation comparison section when the active clamp forward operating mode is selected; a clock generation section for generating a clock signal having a preset fixed frequency when the active clamp forward operating mode is selected, and generating a clock signal having a frequency based on an operating current and the soft start signal when the logical link control operating mode is selected; and a latch section for maintaining the pulse width modulation signal through the selection section in response to the clock signal of the clock generation section when the active clamp forward operating mode is selected, and maintaining the clock signal of the clock generation section when the logical link control operating mode is selected.