4.5-V to 25-V, synchronous buck controller with three operating modes

The TPS5103 is a synchronous buck dc/dc controller, designed for notebook PC system power. The controller has three user-selectable operation modes available: hysteretic mode, fixed-frequency PWM control, or SKIP control.

In high-current applications, where fast transient response is advantageous for reducing bulk capacitance, the hysteretic mode is selected by connecting the RT pin to VREF5. Selecting the PWM/SKIP modes for less demanding transient applications is ideal for conserving notebook battery life under light load conditions. The device includes high-side and low-side MOSFET drivers capable of driving low r ds(on) N-channel MOSFETs.

The user-selectable overcurrent protection (OCP) threshold is set by an external TRIP-pin resistor in order to protect the system. The TPS5103 is configured so that a current-sense resistor is not required, improving the operating efficiency.