The MP4603 is an integrated white LED driver. It uses MPS’s patent-pending technology to drive the backlights for LCD TVs measuring 60-inches or larger, for LED string voltages up to 350V. This novel technology can leverage the LED drive power by regulating only a small portion of the LED drive voltage—together with a fixed high-voltage source, a low-voltage LED driver can drive high voltage LED strings. This method allows for a super-high power density, higher efficiency and lower cost due to the low voltage stress, higher switching frequencies, and smaller passive components.  The MP4603 is a current-mode–controlled buck-boost regulator. With a 12V input VINL and a high voltage source VINH, it can deliver a regulated voltage (VINH to VINH+68V) to drive a LED string with up to 100 LEDs. It can drive an external switch in series with the LED string to achieve over 1:1000 dimming ratio. Analog dimming can be applied at the same time to further improve the dimming ratio. Fault protections include LED open-string protection, output short-circuit protection, cycle­by­cycle peak current limiting, and thermal shutdown.  The MP4603 is available in SOIC16 package.