The TSM111 from STMicroelectronics Inc. (Lexington, MA) is a new multi-function analog IC that integrates all the functions needed to provide efficient and secure protection against overvoltage and overcurrent for all three output rails (3.3V, 5V and 12V) in PC switchmode power supplies. The IC is a secondary-side housekeeping circuit that integrates more than 25 discrete components in a small 20-pin package.Specifically designed for triple rail PC power supplies, the TSM111 requires no external components for threshold adjustments and the over-voltage and over-current protection circuits are preset for each power line. Timing adjustments are supported to allow optimal sequencing of the power rails at turn-on. The device includes all of the necessary logic interfaces for communication with the motherboard, including power good and fault status signals and remote control input pin. The TSM111 operates from a wide supply voltage range up to 44V and draws a low supply current of 10mA. It is priced at $1.10 in quantities of 10,000.