| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to boost the operation voltage of a current load circuit even in a low power supply voltage state by constituting the switch circuit of a constant current source, a pair of switch circuits consisting of specific transistors (TRs) and allowed to be controlled by clocks and a pair of current mirrors provided with specific current I/O terminals. SOLUTION: One of P type MOS TRs M1, M2 is tuned on and the other is turned off by clock signals CLK, CLKB which are mutually complementary. Bipolar TRs Q1, Q3 and Q2, Q4 constitute a pair of current mirrors and the operation current of the TR Q1 is allowed to flow into a load circuit 5 through the TR Q3. On the other hand, a current is allowed to flow into either one of TR pairs Q1, Q3 and Q2, Q4 by a control clock and current supply to the load circuits 5, 6 is switched. Operation voltage applied to the load circuits 5, 6 can boost voltage required for the constant current soruce, increase the operation frequency of the load circuits and improve a dynamic range. |
