A CMOS integrated driver for incandescent lamps with output power control

An integrated protection circuit to be used as a part of an intelligent power switch is presented in this paper. The circuit is designed to address the overcurrent solicitation due to incandescent lamp loads, typical in industrial and automotive environment. The circuit realizes, with a nonlinear feedback loop, an on-off switching of the load voltage as a function of the value of the load current, with the aim of keeping its mean value constant. This mechanism allows an efficient power transfer to the load, by minimizing the power dissipated on the MOS switch. Simulations and experimental measurements, carried out on a prototype chip fabricated with a 2-μm CMOS high-voltage (50 V) process, are also shown.