Patent ID: 8299830

Claim:
A semiconductor device having a nonvolatile variable resistor, the device comprising: a resistance value conversion circuit unit that is configured to convert a resistance value of the nonvolatile variable resistor into a potential or a current and that outputs the converted potential or current; a comparison circuit unit configured to compare the output from the resistance value conversion circuit unit with a potential or a current at some nodes within the semiconductor device; a resistance value changing circuit unit that is configured to change the resistance value of the nonvolatile variable resistor based on the comparison results from the comparison circuit unit, wherein the semiconductor device is implemented as a phase-locked loop (PLL) device, and wherein the resistance value conversion circuit unit comprises: a current source circuit; a first transistor having a source directly connected to the current source circuit, a gate invertedly connected to a voltage input, and a drain directly connected to a first end of the nonvolatile variable resistor; and a second transistor having a source directly connected to a second end of the nonvolatile variable resistor, a gate non-invertedly connected to the voltage input, and a drain directly connected to ground.