Patent ID: 8427804

Claim:
A power amplifier for driving a load connected to an output terminal, comprising: an output transistor connected between said output terminal and a power supply, said output transistor supplying a driving signal to said load; an amplifier driver for driving said output transistor; a current detection path comprising a switching device and a resistor connected in series and said path disposed in parallel with said output transistor between said power supply and said output terminal; and an over-current detector for controlling said switching device so as to turn on during an on-state operating period of said output transistor and detecting over-current flowing to said output transistor on the basis of a sensing signal obtained from a point connecting said switching device and said resistor of said current detection path; wherein the sensing signal and a signal for turning on or off the switching device are input to a first AND gate; the over-current detector is configured to control said output transistor on the basis of the output signal of the AND gate; wherein the power amplifier further comprises a second AND gate configured to output the signal for turning on or off the switching device to the first AND gate; and wherein inputs to the second AND gate comprise: a first signal provided from a pre-drive; a gate signal obtained by delaying the first signal with a first delay circuit; and a delayed gate signal obtained by delaying the gate signal by a second delay circuit.