STMicroelectronics STEVAL-ISA036V1

Overview

STEVAL-ISA036V1 from STMicroelectronics is a 5 W universal-input isolated flyback demonstration board for metering and motor control applications, based on the L6565 quasi-resonant PWM controller and STC04IE170HP ESBT® primary switch. It delivers three regulated outputs: isolated 15 V/66 mA, primary-grounded 5 V/0.6 A (for MCU supply), and primary-grounded 15 V/66 mA, operating across 200–1200 V_DC rectified input with >65% efficiency at 400 V_DC.

For engineers reviewing the STEVAL-ISA036V1 datasheet, STEVAL-ISA036V1 schematic, STEVAL-ISA036V1 application notes (AN2254, AN2528, AN2454), or STEVAL-ISA036V1 bill of materials, this board serves as a validated reference design for high-voltage, wide-range auxiliary SMPS in utility metering and industrial motor drive power stages.

Technical Context

This board implements a quasi-resonant flyback topology using the L6565 controller to enable zero-voltage switching across its 200–1200 V_DC input range, minimizing switching losses. The STC04IE170HP ESBT® device integrates a high-voltage transistor and fast diode in a single package, enabling robust primary-side switching at up to 1700 V blocking voltage.

The design incorporates an active start-up network for reliable operation at low input voltages and uses transformer TRASF5W to provide galvanic isolation for the 15 V/66 mA output. Output regulation relies on optocoupler feedback to the L6565 COMP pin, with secondary-side rectification via STPS3L60U (15 V) and STPS1H100A (5 V) Schottky diodes.

Key Specifications

Availability

STEVAL-ISA036V1 is available at Aetrix Electronics and suitable for utility metering, industrial motor drives, and high-voltage auxiliary power supply development requiring stable component supply, reference-grade validation, and documented design reuse.

Supply support for STEVAL-ISA036V1 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing microcontrollers, power devices, analog ICs, and MEMS sensors for industrial, automotive, and consumer markets.

This board belongs to ST's STEVAL evaluation platform family, engineered to accelerate power supply design validation and reduce time-to-market for high-reliability, high-voltage auxiliary SMPS in metering and motor control systems.

FAQ

What is the purpose of the active start-up network on STEVAL-ISA036V1?

The active start-up network ensures reliable controller (L6565) biasing at low input voltages (down to 200 V_DC), where passive RC start-up would be too slow or insufficient. It uses discrete transistors and resistors to deliver controlled current to the V_CC pin until the auxiliary winding takes over, preventing brown-out lockout during cold-start conditions.

Can STEVAL-ISA036V1 be modified for higher output power?

Yes - the reference design methodology described in AN2254 and AN2528 supports scaling to higher power by upgrading the transformer (TRASF5W), increasing output capacitor values (e.g., C10, C13), selecting higher-current secondary diodes (e.g., STPS1H100A → STPS2H100), and verifying thermal performance of the STC04IE170HP under extended duty cycles.

Which application notes are essential for understanding this board's design?

AN2254 covers ESBT®-based auxiliary SMPS in QR flyback topologies; AN2528 details L6565-based QR controller implementation and loop compensation; AN2454 explains base driving network design for ESBT® devices like the STC04IE170HP - all three are directly referenced in the board's data brief and schematic documentation.

Does STEVAL-ISA036V1 include protection features?

Yes - it includes overvoltage protection via Zener D13 (18 V clamp on V_CC), overcurrent sensing through the L6565 CS pin (R26/R22 current sense network), and thermal derating inherent to the ESBT®'s SO-16 package. No dedicated OTP or OVP IC is used; protection is implemented via controller internal thresholds and passive clamping.