Abstract: A low loss recirculation apparatus for recirculating current through an inductive load (101) includes an active recirculation circuit. The low loss recirculation apparatus includes a control device (201) with a drive output (203) that provides a drive signal (205), and a recirculate output (207) that provides a recirculation signal (209). A device (103) provides drive current, along a path (109), to the inductive load (101) responsive to the drive signal (205). A gated recirculation circuit (202), recirculates current, along a path (115), through the inductive load (101) responsive to the recirculation signal (209).

Abstract: A lamp driver circuit for supplying and controlling power to a lamp from a power supply subject to voltage variations. A semiconductor switch is disposed in series with the lamp and a current sensing resistor. A capacitor integrates the lamp current during ON time of the switch and power supply voltage during OFF time. A voltage comparator with hysteresis responds to the capacitor voltage to control the conductive state of the switch. Above a nominal supply voltage, the driver circuit begins to pulse width modulate the power supplied to the lamp with a duty cycle inversely proportional to the square of the supply voltage to maintain constant power to the lamp. As the supply voltage rises above a second predetermined level, the driver circuit ceases to supply power.