±12V / ±15V Isolated Power Supply
Created: Jan 27, 2017
No description available.
This reference design is an evaluation circuit that is fully assembled and tested circuit board that demonstrates the performance of the MAX17681 high-efficiency, iso-buck DC-DC converter. It is designed to provide isolated power up to 3W, generates either (±15V, 100mA) or (±12V, 50mA) output voltages, and operates from a wide range of 17V to 32V input supply. The circuit also features a forced PWM control scheme that provides constant switching frequency of 200kHz operation at all load and line conditions.
The circuit includes an EN/UVLO pin on the device that serves as an ON/OFF control while also allowing the user to program the input Undervoltage-Lockout (UVLO) threshold. J1 configures the circuit’s output for ON/OFF control. Installing a shunt across J1 pins 1-2 enables VOUT OUTPUT. Installing a shunt on pins 2-3 disables VOUT, while leaving it open enables VIN ≥ 15.5V. The VPRI PCB pad helps measure the regulated non-isolated buck voltage. An additional RESET PCB pad is available for monitoring FB regulated voltage, the open-drain logic output. The programmable soft-start feature allows users to reduce input inrush current.
The iso-buck is a synchronous-buck-converter-based topology, useful for generating isolated outputs at low power level without using an optocoupler. This is useful for applications like floating power supply generation, isolated fieldbus interfaces, PLC I/O modules, smart meters, and other applications with related functions.