May 2012
Doc ID 17220 Rev 2
1/14
UM0920
User manual
4 W non-isolated, wide input-voltage range SMPS demonstration
board based on the VIPer16
Introduction
The purpose of this document is to provide information for the STEVAL-ISA071V2 switched
mode power supply (SMPS) demonstration board. The STEVAL-ISA071V2 is a non-isolated
SMPS capable of delivering a 4 W output over a wide input voltage range, and is designed
for a mains application requiring -5 V and +7 V, referred to neutral. The basic concepts used
in this design can also be applied for higher power outputs or different voltage ranges.
The SMPS generates outputs of 5 V and 12 V, referred to the output marked -5 V. The 5 V is
dedicated to supplying an MCU. This configuration allows the use of the MCU to directly
drive a Triac (referred to neutral). The 12 V output is used to supply additional circuits
(relays, OA, etc.).
This document contains a fundamental technical description of the demonstration board
(schematic diagram, PCB details and bill of materials) and basic measurements (load
regulation, efficiency, standby behavior and EMI data).
Figure 1.
STEVAL-ISA071V2 board
www.st.com
Downloaded from
