Abstract: A half-bridge driver provides a current limit on the low-side driver (20) and a current limit on the high-side driver (16). The current limits are initially set equal. If the low-side driver current limits, then a modulation current from the low-side driver increases the high-side driver current limit threshold to maintain stable operation of the control circuits. In addition, the present invention provides dual conduction paths to charge the main conduction transistor of the low-side driver, while detecting current limit. When current limit is detected, the charging current to the main conduction transistor is switched to current limit mode.

Abstract: A clamp circuit (10) for protecting a MOSFET (12) from destructive voltages and currents includes a clamping element (30), a current switch (27), a bond pad (23), a probe pad (25), and a resistor (21). When no external signal is applied to the probe pad (25), a FET (18) in the clamping element (30) is conductive. When the drain voltage of the MOSFET (12) rises above a clamping voltage of the clamping element (30), a current flows through the clamping element (30) and switches on the MOSFET (12). To ensure a safe operating area of the MOSFET (12), a voltage is applied to the probe pad (25) to turn off the FET (18), a breakdown voltage of the MOSFET (12) measured from the bond pad (23) is compared with the clamp voltage, and circuit die with the breakdown voltage less than the clamp voltage are discarded.

Abstract: An actuator movement detector (10) indicates proper engagement of a solenoid (12). The current flowing through a field coil (16) is converted to a sense voltage that exponentially increases and then follows a dip before increases again to a steady state value greater than the first peak value. The exponentially increasing sense voltage is stored across a capacitor (24). Any AC variation about the stored sense voltage sets the output state of comparators (30, 32) and determines a first peak value of the sense voltage. After the first peak, a counter (44) must count to a predetermined value during the low peak before the sense voltage returns to its first peak value. If the counter reaches at least the predetermined count value before returning to its first peak value and count back down to zero before reaching steady state, then the solenoid is considered engaged.