STEVAL-ISA204V1 STMicroelectronics

STEVAL-ISA204V1 Data brief 100W 5V/20A active clamp forward converter based on PM8804 for telecom systems Features DC-DC forward converter based on PM8804 Input voltage range: 42 56 V DC Switching frequency: 250 kHz Output: Power: 100 W Voltage: 5 V DC Current: up to 20 A Peak efficiency > 94% Open circuit protection RoHS complaint WEEE compliant Description The STEVAL-ISA204V1 evaluation board is designed to demonstrate high efficiency DC-DC conversion, able to output 100 W (5 V/20 A) from 42 to 56 V DC input, which is especially suitable for telecom applications. The power conversion stage is based on an active clamp forward topology managed by a PM8804 PWM controller featuring all the integrated circuitry necessary for a compact and efficient 48 V converter. The highly configurable controller includes a programmable oscillator for switching frequency regulation up to 1 Mhz, adjustable slope compensation, dual complementary low-side drivers with programmable dead Product summary time, programmable soft start, soft turn off and a programmable current sense 100W 5V/20A forward blanking time. STEVAL- converter based on ISA204V1 PM8804 PWM controller PWM peak current mode controller for PoE PM8804 and telecom systems Server & Application Telecom Power DB3958 - Rev 1 - June 2019 www.st.com For further information contact your local STMicroelectronics sales office.STEVAL-ISA204V1 Application overview 1 Application overview The STEVAL-ISA204V1 represents a forward converter application with synchronous rectification for 48 V auxiliary power supplies destined for server and telecommunications equipment. The board can supply an output current up to 20 A. The PM8804 integrates two MOSFET drivers with up to 1 A peak sink current capability. The GAT1 signal drives the main switching MOSFET, while the GAT2 signal controls a P-channel MOSFET referred to PGND in active clamp forward topology. The synchronous rectification stage can be paralleled by mounting two further STL160N4F7 N-channel MOSFETs (Q2 and Q8), which can significantly reduce the operating temperatures of the mounted synchronous rectifier MOSFETs. Figure 1. STEVAL-ISA204V1 block diagram Forward Converter 48V Input Input Filter Active Clamp Synchronous Output Reset Rectification Filter GAT1 N-channel Mosfet Output PWM peak current Load mode controller for PM8804 5V 20A telecom systems GAT2 Adjustable shunt Voltage Reference VCC Feedback Feedback Circuit (TS431AILT) Optocoupler RELATED LINKS Visit the Server & Telecom application page for more information on relevant power supply and conversion strategies DB3958 - Rev 1 page 2/7