IRISMPS3

The IRISMPS3 reference design is a complete tested power supply circuit. It is designed for a universal AC line input and will provide a 15V, 4A full load DC output.

The design uses a flyback converter topology, with an IRISMPS3 as the main switch and control device. The initial start-up current for the IRISMPS3 is provided by a dropper resistor from the DC bus. Once the circuit is started the Vcc power for the IRISMPS3 comes from the bias winding of the main transformer. The primary current control circuit consists of a current sensing resistor which feeds a voltage proportional to the transformer primary current into the feedback (FB) pin of the  IRISMPS3. The secondary voltage control loop uses an LM431 precision shunt regulator as the reference and an optocoupler to feedback the information across the transformer galvanic isolation boundary back to the control circuit of the IRISMPS3.