Patent Number: 6,166,562

Title: Semiconductor integrated circuit device

Abstract: A driving voltage supplied to a semiconductor integrated circuit can be controlled. The semiconductor integrated circuit device provided with a voltage converter circuit comprises: a buffer circuit having: a P-channel MOS transistor having a source connected to a first supply voltage; and an N-channel MOS transistor having a source connected to a second supply voltage and a drain connected to a drain of the P-channel MOS transistor, an output voltage being outputted from a common-connected drain terminals of the two MOS transistors; a duty ratio control circuit having: a counter for outputting a first n-bit signal by repeatedly counting up numbers from 0 to (2.sup.n -1) one by one in synchronism with a first clock signal; and a comparator circuit for comparing the first n-bit signal with a second n-bit signal applied from the outside, and for outputting a first control signal to a gate of the P-channel MOS transistor and a second control signal to the N-channel MOS transistor; and a smoothing circuit for smoothing the output of the buffer circuit, a voltage smoothed by the smoothing circuit being outputted as an output of the voltage converter circuit.

Inventors: Mita; Shinji (Kawasaki, JP), Suzuki; Kojiro (Kawasaki, JP), Kuroda; Tadahiro (Yokohama, JP)

Assignee: Kabushiki Kaisha Toshiba

International Classification: H02M 3/157 (20060101); H02M 3/04 (20060101); H02M 3/158 (20060101); H03K 019/0185 ()

Expiration Date: 12/26/2013