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.
Reference Design 基於ST STM32F334C8 Cortex M4 MCU的數位AC-DC電源供應器方案
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
Go to ST Micro for more information