公开(公告)号：US09106151B2

公开(公告)日：2015-08-11

申请号：US13659431

申请日：2012-10-24

Applicant: Richtek Technology Corp.

Inventor： Roland Van Roy ,  Leng-Nien Hsiu ,  Pei-Yuan Chen

IPC: G05F5/00 ,  H02M1/42 ,  H02M1/00

CPC classification number: H02M1/4258 ,  H02M2001/0025 ,  Y02B70/126

Abstract: A power-factor-improving circuit and method for an offline converter block the DC component and obtain the AC component of an input voltage of the offline converter. The AC component is superpositioned onto a DC bias signal to generate a dimming signal for the offline converter to adjust an output current of the offline converter. The offline converter has a high power factor due to the dimming signal with the AC component of the input voltage. In addition, the average of the dimming signal is determined by the DC bias signal, hence the output current can be precisely controlled according to the DC bias signal.

Abstract translation: 用于离线转换器的功率因数改善电路和方法阻断DC分量并获得离线转换器的输入电压的AC分量。 AC分量叠加到DC偏置信号上，以产生离线转换器的调光信号，以调整离线转换器的输出电流。 离线转换器由于具有输入电压的AC分量的调光信号而具有高功率因数。 此外，调光信号的平均值由直流偏置信号确定，因此可以根据直流偏置信号精确控制输出电流。