Buck boost converts any input voltage into fixed output voltage
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Said to offer efficiencies up to 98%, Linear Technology's new synchronous buck boost dc/dc controller, the LT8705, is designed to convert any input voltage from 2.8 to 80V into 1.3 to 80V at up to 250W.
The device has four feedback loops to regulate the input current/voltage, along with the output current/voltage.
Linear says output power up to 250W can be delivered with a single device, although higher output power can be achieved when multiple circuits are paralleled.
The operating frequency is selectable between 100 and 400kHz and can be synchronised to an external clock.
In addition, the LT8705 employs a proprietary current mode control architecture for constant frequency operation in buck or boost mode and has on board quad N channel mosfet gate drivers.
Users can select among forced continuous, discontinuous and burst mode operation to maximise light load efficiency.
Additional features include servo pins to indicate which feedback loops are active, a 3.3V/12mA ldo, adjustable soft start, on board die temperature monitor and ±1% reference voltage accuracy over an operating junction temperature range of -40 to 125°C.
