POWER CONVERTER CIRCUIT FOR LOW POWER ILLUMINATION DEVICE, CONTROL CIRCUIT THEREOF AND METHOD THEREOF

摘要

A power converter circuit for a low power illumination device includes a boost converter circuit, a buck converter circuit, and a control circuit. The control circuit configures the boost converter circuit to alternately operate in a current conducting mode and an off mode, to draw different values of the current from an electric transformer in different periods in the current conducting mode, and to stop drawing current from the electric transformer in the off mode. The control circuit further configures the buck converter circuit to generate the required output signals to the low power illumination device according to the output of the boost converter circuit so that the low power illumination device may function normally.

主权项

1. A power converter circuit of an illumination system, for coupling with an electric transformer through a rectifier circuit; wherein the rectifier circuit generates a rectified voltage signal according to a conversion voltage signal provided by the electric transformer, and the power converter circuit supplies power to a low power illumination device according to the rectified voltage signal; comprising:
a boost converter circuit, for coupling with the rectifier circuit, configured to operably generate a boost output signal according to the rectified voltage signal; a buck converter circuit, coupled with the boost converter circuit, configured to operably generate a buck output signal to supply power to the low power illumination device according to the boost output signal; and a control circuit, coupled with the boost converter circuit and the buck converter circuit, configured to operably configure the boost converter circuit to alternately operate in a current conducting mode and an off mode so that the boost converter circuit draws current from the electric transformer in the current conducting mode and stops drawing current from the electric transformer in the off mode; wherein a signal value of the boost output signal is greater than a signal value of the rectified voltage signal; a signal value of the buck output signal is less than the signal value of the boost output signal; the control circuit configures the boost converter circuit to draw a first current in a first period in the current conducting mode before drawing a second current in a second period in the current conducting mode; and the first current drawn in the first period is greater than the second current drawn in the second period.