| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a voltage supply circuit capable of being adapted to the power supply voltage to be used in an extensive range, eliminating the power supply voltage dependency of the clock signal frequency to be supplied to a step-up circuit, controlling the ripple of the output voltage, and supplying the stable set-up voltage. SOLUTION: The clock signal CLK is generated by an oscillator 10 which is operated by the power supply voltage VCC in the rise add operated by the set-up voltage VOLT in the normal operation, the signal is supplied to a step-up circuit 30, the step-up voltage VOUT of the step-up circuit 30 is divided by resistor elements RL1 , RL2 , a comparator 40 compares the divided voltage VT with the reference voltage Vref , the operation control signal CSS is generated according to the compared result, and the level of the step-up voltage VOUT is kept constant by controlling the operation of the oscillator 10, and the frequency of the clock signal CLK generated by the oscillator 10 can be kept constant to the power supply voltage VCC to be used in an extensive range, the ripple of the step-up voltage VOUT can be controlled, and the step-up voltage VOUT can be stably supplied.</p> |
