Demonstration circuit 2519A is a high voltage, high efficiency synchronous buck-boost DC/DC converter with a 16V to 120V input voltage range. It can supply a 10A maximum load current with a 48V output. The demo board features the LTC®3777EFE controller. The constant frequency current mode architecture allows a phase-lockable frequency of up to 600kHz, while an optional output current feedback loop provides support for applications such as battery charging. The 150V integrated switching bias supply is a high efficiency step-down regulator that draws only 12μA typical DC supply current with a regulated output voltage at no load. With a wide input range, wide output range and seamless transfers between operation modes, the LTC3777 is ideal for Industrial, Automotive, Medical, Military and Avionics applications.
The light load operation mode of the converter is determined with the MODE pin. Use JP2 jumper to select pulseskipping mode or forced continuous mode (CCM) operation. The switching frequency is pre-set at about 200kHz. The converter can also be externally synchronized to an external clock through the PLLIN pin (PLLIN terminal on the board). To shut down the converter, force the RUN pin below 1.2V (SW1: OFF). The power good output (PGOOD terminal) is low when the output voltage is outside of the ±10% regulation window.