FUEL PUMP DRIVER CIRCUIT

A fuel pump driver circuit for an internal combustion engine includes a voltage supply which energizes the fuel pump through an output or switch transistor. The output transistor is turned off to stop the pump by a control transistor, which is controlled by a differential amplifier or switch. The voltage supply is coupled through the ignition switch of the engine to the circuit, and the differential switch is in the on condition and causes the output transistor to conduct to energize the fuel pump. A capacitor is coupled to the differential switch and is charged thereby to actuate the differential switch to the off condition to turn off the current to the fuel pump. When a signal responsive to the engine turning over is received, an input transistor discharges the capacitor and the differential switch is maintained in the on condition with one transistor thereof conducting and the current supply coupled to the fuel pump. Should the engine signal cease, the capacitor charges so that the differential switch actuates the control transistor to shunt the bias potential from the control electrode of the output transistor which applies the current to the fuel pump.