Texas Instruments LM5175 4-Switch Synchronous Buck-Boost Controller is capable of regulating the output voltage at, above, or below the input voltage. The LM5175 operates over a wide input voltage range of 3.5V to 42V to support a variety of applications. The LM5175 employs current-mode control both in buck and boost modes of operation for superior load and line regulation. The switching frequency is programmed by an external resistor and can be synchronized to an external clock signal. Features include programmable soft-start function, and numerous protection features (cycle-by-cycle current limiting, input undervoltage lockout (UVLO), output overvoltage protection (OVP), and thermal shutdown). This device includes selectable Continuous Conduction Mode (CCM) or Discontinuous Conduction Mode (DCM) operations.