altThe HV9957 from Supertex (Sunnyvale, CA) combines a switch-mode boost converter and six low-dropout, linear current regulators to deliver high efficiency and precise current control in an LED driver. The IC can drive up to six strings of LEDs at 30 mA each, which is well-suited for battery-powered LED backlighting applications. Temperature-triggered fault protection combined with an outlier approach to identify faulty strings overcomes problems inherent with ordinary fault protection. Faulty strings are turned off only when absolutely necessary. HV9957 provides protection from fault conditions such as over- and under-voltage supply, over-current, and over-temperature.