STMicroelectronics EVLHV101PSR50W

Overview

EVLHV101PSR50W from STMicroelectronics is a 50 W, 60 V / 833 mA isolated AC-DC evaluation board based on the HVLED101 quasi-resonant high-power-factor flyback controller with primary-side regulation. It delivers >91% average efficiency across 25–100% load, supports universal 90–265 V_rms input, and implements valley-locking frequency foldback for low acoustic noise-designed for LED driver front-end or standalone constant-voltage power supply applications.

For engineers reviewing the EVLHV101PSR50W datasheet, EVLHV101PSR50W pinout, EVLHV101PSR50W application, or EVLHV101PSR50W equivalent, this board enables rapid validation of HVLED101-based PSR flyback designs requiring high PF (>0.9), low THD (<10%), <65 V open-load voltage limiting, short-circuit auto-restart, and NTC-based MOSFET overtemperature protection under EN60065 safety compliance.

Technical Context

The board implements a quasi-resonant flyback topology using the HVLED101 controller in primary-side regulation mode, eliminating optocoupler and secondary-side feedback components. Valley locking ensures switching occurs at minimum drain voltage, reducing switching losses and EMI while enabling stable operation across wide input voltage (45–66 Hz) and load ranges.

Protections include overvoltage limiting (<65 V), short-circuit with auto-restart, open-load detection, NTC-monitored MOSFET overtemperature shutdown, and surge/overvoltage handling via dual VDRs (V320LA7P). Input stage uses GBU406 bridge rectifier and PQ26-320 µH custom transformer with 27 mH common-mode choke (B82732F2901B001).

Key Specifications

Availability

EVLHV101PSR50W is available at Aetrix Electronics and suitable for LED driver development, industrial control power supplies, and smart lighting system prototyping requiring stable component supply, fast design iteration, and regulatory-compliant reference implementation.

Supply support for EVLHV101PSR50W 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, Switzerland, designing and manufacturing microcontrollers, power ICs, analog devices, and silicon solutions for automotive, industrial, and consumer markets.

This board belongs to ST's HVLED evaluation platform family, engineered to accelerate adoption of their high-voltage LED driver controllers-specifically targeting cost-sensitive, high-efficiency, dimmable/non-dimmable offline LED lighting systems with integrated safety and EMI performance.

FAQ

Is EVLHV101PSR50W a production-ready power supply or only for evaluation?

EVLHV101PSR50W is an evaluation board-not a certified end-product power supply. It provides a fully assembled, tested reference design to validate HVLED101 controller performance, layout, thermal behavior, and protection schemes. Final product certification (e.g., UL, CE) requires full system-level testing per applicable standards.

What is the role of the NTC thermistor (NTC1) on this board?

NTC1 (100 kΩ, 1%) monitors the heatsink temperature near Q1 (STF14N80K5 MOSFET) and feeds analog voltage to the HVLED101's THD pin. When temperature exceeds threshold, the controller reduces switching frequency and eventually shuts down to prevent MOSFET thermal runaway-enabling precise, self-regulating overtemperature protection.

Can this board be used with leading-edge TRIAC dimmers?

Yes-EVLHV101PSR50W supports both dimmable and non-dimmable configurations. Its HVLED101 controller includes active valley detection and frequency foldback that maintain stable regulation and low THD even under phase-cut dimmer waveforms, provided the front-end circuitry (e.g., bleeder network) is adapted per ST Application Note AN4525.

How is output voltage regulated without an optocoupler?

Regulation is achieved via primary-side sensing: the HVLED101 samples reflected auxiliary winding voltage during demagnetization, calculates output voltage using internal compensation algorithms, and adjusts switching frequency in real time. This eliminates optocoupler drift, improves reliability, and reduces BOM cost while maintaining ±5% output accuracy across line/load/temperature.