The TPS40200 is a flexible nonsynchronous controller with a built-in 200-mA driver for P-channel FETs. The circuit operates with inputs up to 52 V, with a power-saving feature that turns off driver current once the external FET has been fully turned on. This feature extends the flexibility of the device, allowing it to operate with an input voltage up to 52 V, without dissipating excessive power. The circuit operates with voltage-mode feedback and has feed-forward input-voltage compensation that responds instantly to input-voltage change. The integral 700-mV reference is trimmed to 2%, providing the means to accurately control low voltages. Clock frequency, soft start, and overcurrent limit each are easily programmed by a single, external component. The part has undervoltage lockout, and can be easily synchronized to other controllers or a system clock to satisfy sequencing and/or noise-reduction requirements.