Omron Corporation

Hiroki Ishibashi

Takeshi Uematsu

Hiroyuki Onishi

Toshiyuki Zaitsu

Shingo Nagaoka

In a power converter apparatus including a PFC circuit operating in a current-critical mode, a zero point of an inductor current is accurately detected. The control circuit includes a current detector unit including a first detection circuit that detects an inductor current, amplifies a voltage corresponding to the detected current with a gain, and outputs it as a detection voltage and a comparison circuit that compares the detected voltage with a predetermined reference voltage and outputs a comparison result signal. The control circuit calculates the reference voltage for making a delay when detecting the zero value of the inductor current substantially zero, based on the detected input voltage, the detected output voltage, the preset delay time, the inductance value of the inductor, the conversion factor in current/voltage converting, the power supply voltage, and the gain, and then, outputs it to the comparison circuit.

Control circuit for power converter apparatus provided with PFC circuit operating in current-critical mode

A control circuit is provided for a power converter apparatus including a PFC circuit with an inductor and operating in a current critical mode. The control circuit includes: a first detector circuit that detects an inductor current, amplifies a voltage corresponding to a detected current with a gain, and outputs the voltage as a detected voltage; a comparator that compares the detected voltage with a reference voltage, and outputs a comparison result signal; a second detector circuit that detects an input voltage; and a third detector circuit that detects an output voltage. The control circuit calculates a reference voltage for making a delay on detecting zero value of the inductor current be substantially zero, based on the input voltage, the detected output voltage, a preset delay time, an inductance, a conversion coefficient on current-to-voltage converting, a power supply voltage, and the gain, and outputs the reference voltage to the comparator.

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Kyoto, Japan

Hiroki Ishibashi