March 2016

DocID029092 Rev 1

1/10

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STEVAL-ISA147V3

500 W fully digital AC-DC power supply (D-SMPS) based on

STM32F334C8 microcontroller

Data brief

Features



Input AC voltage: 90 V to 264 V



Input AC frequency: 45 Hz to 65 Hz



Nominal power: 500 W



Output voltage: 12 V



Semi-Bridgeless PFC stage



DC-DC stage: resonant LLC with

synchronous rectification



Peak efficiency: 94%



PFC switching frequency: 60 kHz



DC-DC switching frequency: 80 kHz to 115

kHz (burst mode above)



HF transformer isolation voltage: 4 kV



Cooling: natural convection up to 300 W,

forced cooling above 300 W



PFC control: managed by STM32F051K8



LLC control: managed by STM32F334C8



Input short-circuit protection



Input under/overvoltage protection



Input under/overfrequency protection



DC Bus under/overvoltage protection



Output short-circuit protection



Output under/overvoltage protection



Overtemperature protection



RoHS compliant

Description

The STEVAL-ISA147V3 is a digital switch mode

AC-DC converter consisting of two power stages:

an input semi-bridgeless power factor corrector

(SBPFC) controlled by an STM32F051K8, and a

regulation stage implemented with an LLC half

bridge with synchronous rectification (SR),

controlled by an STM32F334C8 microcontroller.

This 500 W AC-DC converter uses the so-called

bridgeless PFC topology, with the advantage of

lower conduction losses and higher efficiency by

eliminating the need for a diode rectifier stage.

This choice also allows a reduced component

count compared to a standard PFC.

The input stage is typically controlled using an

outer voltage loop for bus voltage regulation and

an inner control loop to shape the current

according to a sinusoidal waveform. The outer

loop adjusts the current reference in order to

maintain a regulated bus voltage, independent of

load or input voltage variations. The output

isolation and regulation stage is implemented

using a half-bridge LLC topology, operating with

constant duty cycle and variable frequency

control.