Patent ID: 7514956

Claim:
A semiconductor device, comprising: an output terminal; an output buffer for outputting a signal via said output terminal; a power supply for supplying a voltage to, and operating, an electronic circuit that includes said output buffer; a first circuit which is connected to said output buffer and in which an overshoot whose output voltage exceeds the power supply voltage during the transition of the output signal level is recovered as energy and charged; a second circuit which is connected to said output buffer and in which an undershoot whose output voltage falls below the ground voltage during the transition of the output signal level is recovered as energy and charged; a charging circuit which is connected to said first or second circuit and which collects the charge charged by the first or second circuit; a switch for switching the connection between said first and second circuit and said charging circuit; a capacitor which is connected to said charging circuit and which stores the charge collected by the charging circuit; and a supply circuit which is connected to said capacitor and which converts the charge stored in the capacitor into a power supply voltage of an internal power supply, and supplies the power supply voltage as an internal power supply.