STEVAL-ISA029V1: 12V @ 1A, 3.3V @ 100mA, -24V @ 40mA

The STEVAL-ISA029V1 evaluation board is an isolated triple-output flyback converter, suitable for wide-range input voltage operation. The converter is based on the smart power VIPer53-E, which integrates, in the same package, an enhanced current-mode PWM controller with a high-voltage MDmesh™ Power MOSFET.

The switching frequency is set to 60 kHz by means of an external RC network connected to a dedicated pin on the IC. The closed loop regulation is performed on the 12 V output using an optocoupler, which drives the COMP pin of the VIPer. The 3.3 V output is post regulated using a non-integrated low drop linear voltage regulator to achieve the required accuracy. The negative 24 V output is achieved by means of a discrete linear voltage regulator, made up of a Zener diode, a resistor and a PNP transistor.