Synchronous four-switch buck-boost controller operates over a wide input voltage range

The LM34936, from Texas Instruments, is a synchronous four-switch buck-boost DC-DC controller able to regulate the output voltage at, above, or below the input voltage. The device operates over a broad input voltage range of 4.2V to 30V (42V absolute maximum) to support a variety of applications. The device uses current-mode control both in buck and boost modes of operation for excellent load and line regulation. The switching frequency is programmed by an external resistor and can be synchronised to an external clock signal. The device also offers a programmable soft-start function and provides protection features including cycle-by-cycle current limiting, input UVLO, OVP, and thermal shutdown. Also, the device provides optional average input or output current limiting, optional spread spectrum to decrease peak EMI, and optional hiccup mode protection in sustained overload conditions.