Patent ID: 7477025
Filing Date: 2009-01-13
Classification: H05B

Abstract:
1. A power control circuit for adjusting light of a lamp set, which is applied for correcting a duty cycle of an inverter and the inverter comprises a pulse controller for providing a duty cycle, a power source provided for the inverter to adjust the light and power, a switch for determining the connection of the power source by the duty cycle, and a transformer for converting the power source according to the duty cycle to output power to drive a rear-end load, wherein the duty cycle is corrected according to the using status of the transformer or a load feedback power, and a feedback circuit is connected to a control circuit, and the control circuit comprises: a sampling unit, for obtaining a feedback signal; a frequency modulation circuit, coupled to the pulse controller, for determining a duty cycle, and the frequency modulation circuit comprising a frequency limiter and a frequency generator, and the frequency generator generates a frequency reference signal to form an operating frequency of a first duty cycle, and the frequency limiter is used for setting a frequency range of the frequency reference signal of the frequency generator; an adjusting unit, having a standard voltage to be compared with the feedback signal to output a frequency modulation signal to the frequency modulation circuit and determine the frequency range of the frequency reference signal set by the frequency limiter to form a feedback correction, and the pulse controller generates a second duty cycle to adjust the brightness of the lamp set.