| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a semiconductor device with a step-up circuit in charge pump method which can use supplied power efficiently and operate even if a communication range with a transmission device becomes large. <P>SOLUTION: An antenna, a step-up circuit, which includes two or more charge pumps made up of each diode and each capacitive element and a switch formed between the charge pumps, a reference voltage power supply circuit, which generates a reference voltage, a voltage comparison circuit, which has a comparator, are provided. Each output voltage of each stage of the charge pump in the step-up circuit is compared with the reference voltage by using a comparator. From magnitude relation between the reference voltage and the output voltage at each stage of the charge pump in the step-up circuit, the output is controlled by switching the on/off of the step-up circuit based on the output signal of the comparator. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
