| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of external terminals (pins) of a PFC control IC that is used in a PFC-type power unit, to reduce a chip size and a package size, to reduce the number of external elements connected to the external terminals of the PFC control IC, to reduce the number of part items that constitute a system, and to reduce power losses induced to the external elements. SOLUTION: In the PFC control IC that constitutes the PFC-type power unit, a terminal for monitoring an input waveform and a terminal for detecting the DC level of an input voltage are integrated in one piece, a voltage that varies in proportion to the input voltage generated by resistance-dividing is inputted to the integrated terminal, an effective value detecting circuit that contains a comparator and a counter is provided and the waveform of the input voltage is formed by the comparator, the number of wave crests is counted by the counter, and the effective value of the input voltage is discriminated based on the counted value. COPYRIGHT: (C)2003,JPO
|
