DC1899A-B: 12 V, 9 A OR'ing Controller

Demonstration circuit 1899A controls two independent power rail circuits each with Hot Swap™ and ideal diode functionality provided by the LTC4228-1/LTC4228-2 dual ideal diode and Hot Swap controller.

DC1899A facilitates evaluation of LTC4228 performance in different operation modes such as supply ramp-up, power supply switchover, steady state, and overcurrent faults. Power supply switchover mode can be realized as either an ideal diode or as a prioritizer.

Each DC1899A circuit is assembled to operate with a 12V supply and 9A maximum current load. The main components of the board are the LTC4228 controller, two MOSFETs operating as ideal diodes, two MOSFETs operating as Hot Swap devices, two current sense resistors, two jumpers for independently enabling each rail, six LEDs to indicate status, power good and fault conditions separately for each channel, and input voltage snubbers. There are pads for optional RC circuits for each Hot Swap MOSFET gate in order to adjust output voltage slew rate. In addition to this there are jumpers allowing monitoring of supply undervoltage conditions at either IN or SENSE+ pins.

The standard configuration (as DC1899A populated by default) places the ideal diode MOSFET ahead of the Hot Swap MOSFET. The board also has pads for an alternative configuration with the Hot Swap MOSFET located ahead of the ideal diode MOSFET.