VOLTAGE SUPPLY CIRCUIT

PROBLEM TO BE SOLVED: To provide a voltage supply circuit which can reduce noise, simplify the circuit configuration, and reduce a cost by suppressing the occurrence of spike currents in a power supply current in the operation state thereof. SOLUTION: Clock signals CLK of a prescribed frequency are supplied to a charge pump drive circuit 10. Current sources IS1, IS2,..., IS6 operate at timings set by the clock signals CLK and output drive currents, capacitors C1, C2, etc., are charged or discharged alternately, the charge stored in the preceding capacitor is transferred to the capacitors on past stages successively, and a step-up voltage higher than a power supply voltage Vcc is obtained. In a charge pump type step-up circuit, by driving the capacitors with the current sources, spike noise, produced in the step-up operations, can be reduced and influences upon other analog circuits can be suppressed.