Patent ID: 7663447

Claim:
A semiconductor device comprising: a voltage controlled oscillator circuit having a first voltage terminal, a second voltage terminal and an output terminal configured to output a clock signal; an antenna circuit configured to transmit and receive a signal; a rectifier circuit configured to generate a power supply voltage between the first voltage terminal and the second voltage terminal from the signal; a control circuit electrically connected between the first voltage terminal and the second voltage terminal, and configured so that a potential difference between the first voltage terminal and a control terminal of the control circuit remains constant; a first transistor having: a first gate electrode electrically connected to an input terminal of the voltage controlled oscillator circuit; a first source region electrically connected to the second voltage terminal; and a first drain region electrically connected to the first gate electrode; and a second transistor having: a second gate electrode electrically connected to the control terminal of the control circuit; a second source region electrically connected to the first voltage terminal; and a second drain region electrically connected to the first drain region.