Patent ID: 7075373

Claim:
An overcurrent protection circuit for a power transistor supplying a load current to a load, the power transistor and the load being connected in series between a first supply voltage and a second supply voltage, the overcurrent protection circuit comprising: a transconductance amplifier having a first input terminal coupled to receive a first signal indicative of the magnitude of the load current conducted by the power transistor, a second input terminal coupled to receive a reference voltage, a first output terminal providing a second signal for driving the control terminal of the power transistor for controlling the load current conducted by the power transistor, and a second output terminal providing a third signal, the third signal having a first logical state when the first signal is less than the reference voltage and a second logical state when the first signal is equal to or greater than the reference voltage, the second logical state of the third signal indicating an overcurrent condition at the power transistor; and a bias current circuit receiving an input bias current and providing an output bias current to the transconductance amplifier in response to the third signal, the output bias current having a first current value when the third signal has the first logical state and having a second current value when the third signal has the second logical state, the second current value being larger than the first current value.