Power supply circuit of semiconductor device, semiconductor device having the same, and method for adjusting operation voltage of device

A method for adjusting an operation voltage of a device including a voltage generation circuit configured to generate the operation voltage based on setting information, a first terminal configured to be at a reference voltage corresponding to an external power supply voltage that is supplied from an external source external to the device, a second terminal, and a switch circuit including a first switch element disposed in a first wiring through which the operation voltage is supplied toward the second terminal and a second switch element disposed in a second wiring through which the reference voltage is supplied toward the second terminal, the method comprising:

• switching on the first switch element and off the second switch element, to output the operation voltage to the second terminal;
• switching off the first switch element and on the second switch element, to output the reference voltage to the second terminal;
• measuring a difference of the operation voltage output from the second terminal and the reference voltage output from the second terminal with an external measuring device that is external to the device and connected to the second terminal;
• and
• modifying the setting information based on the measured difference.

A method for adjusting an operation voltage of a device including a voltage generation circuit configured to generate the operation voltage based on setting information, a first terminal configured to be at a reference voltage corresponding to an external power supply voltage that is supplied from an external source external to the device, and a second terminal, the method comprising:

• outputting a first oscillation signal oscillating at a first frequency corresponding to the operation voltage to the second terminal;
• outputting a second oscillation signal oscillating at a second frequency corresponding to the reference voltage to the second terminal;
• measuring a difference of the first frequency of the output first oscillation signal and the second frequency of the output second oscillation signal;
• and
• modifying the setting information based on the measured difference.

A power supply circuit of a semiconductor device comprising:

• a voltage generation circuit configured to generate an operation voltage of the semiconductor device;
• a first terminal configured to be at a reference voltage corresponding to an external power supply voltage that is supplied from an external source external to the semiconductor device;
• a second terminal connectable to a measuring device;
• a switch circuit configured to cause one of the operation voltage and the reference voltage to be output toward the second terminal and then the other of the operation voltage and the reference voltage to be output toward the second terminal;
• and
• an oscillator configured to generate a first oscillation signal oscillating at a first frequency corresponding to the operation voltage and a second oscillation signal oscillating at a second frequency corresponding to the reference voltage.