The SC1652 is a high performance inverting DC-DC converter, designed to drive an external power switch to generate programmable negative voltages. In the particularly suitable LCD bias contrast application, efficiency of 87% can be achieved with low cost PNP bipolar transistor drivers. The output voltage can be scaled to -40V by two external resistors. A pulse frequency modulation scheme is employed to maintain high efficiency conversion under wide input voltage ranges. Quiescent current is about 80A and can be reduced to 0.7A in shutdown mode. With a switching frequency range of 70kHz to 160kHz, small size switching components may be used, which is ideal for battery powered portable equipment such as notebook and palmtop computers.