STMicroelectronics VIPER22-LED-EV

Overview

VIPER22-LED-EV from STMicroelectronics is a dedicated evaluation board for the VIPer22A-E, VIPer22ADIP-E, and VIPer22AS-E high-voltage PWM controllers with integrated 730 V MOSFET. It implements a flyback converter delivering up to 12 W (SO-8) or 20 W (DIP-8) across universal AC input (85–265 Vac), features fixed 60 kHz switching, current-mode control, and built-in overvoltage/overtemperature/overcurrent protection with auto-restart - optimized for LED driver and auxiliary supply reference designs.

For engineers reviewing the VIPER22-LED-EV datasheet, VIPER22-LED-EV pinout, VIPER22-LED-EV application, or VIPER22-LED-EV equivalent, this board enables rapid validation of constant-current LED driver topologies, low-power offline SMPS startup behavior, feedback loop stability under burst-mode operation, and thermal performance under sustained load in compact form factor designs.

Technical Context

The VIPER22-LED-EV implements a primary-side regulated flyback converter using the VIPer22A-E IC in SO-8 package, with DRAIN connected to high-voltage rectified AC input and SOURCE tied to primary ground. The FB pin receives optocoupler feedback from secondary-side current-sense circuitry, enabling precise constant-current regulation without secondary-side shunt regulator.

Startup relies on the internal 1 mA high-voltage current source charging the VDD capacitor from DRAIN until VDD reaches 14.5 V (VDDon), after which the controller begins switching and disables the start-up source. Protection functions include VDD overvoltage latch at 42 V, thermal shutdown at 170 °C with 40 °C hysteresis, and peak current limiting set by FB pin current (0.9 mA shutdown threshold).

Key Specifications

Availability

VIPER22-LED-EV is available at Aetrix Electronics and suitable for LED driver development, battery charger adapter prototyping, and standby power supply qualification requiring stable component supply and documented reference design validation.

Supply support for VIPER22-LED-EV 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 chips, and MEMS sensors for industrial, automotive, and consumer applications.

The VIPER™ family targets cost-sensitive, high-reliability offline SMPS designs - integrating controller and 730 V MOSFET to reduce bill-of-materials and simplify compliance with safety isolation standards.

FAQ

What is the purpose of the VIPER22-LED-EV evaluation board?

The VIPER22-LED-EV is a fully assembled, tested reference design board demonstrating constant-current LED driver implementation using the VIPer22A-E IC. It provides measurable waveforms at key nodes (DRAIN, VDD, FB), pre-characterized efficiency curves, and layout guidance for thermal management and EMI suppression in Class II isolated flyback topologies.

Does VIPER22-LED-EV support dimming functionality?

No - the VIPER22-LED-EV implements fixed-output constant-current regulation only. Dimming requires external circuitry: analog dimming via FB pin voltage scaling (within 0–1 V range) or PWM dimming applied to the LED string, both requiring modification of the feedback network and verification of stability per ST Application Note AN2362.

Can VIPER22-LED-EV be used with VIPer22ADIP-E instead of VIPer22A-E?

Yes - the board's SO-8 footprint matches VIPer22A-E and VIPer22AS-E; VIPer22ADIP-E uses DIP-8 and is not mechanically compatible. However, electrical characteristics (e.g., R_DS(on), thermal resistance) differ between packages, so power derating and thermal validation are required if substituting ICs beyond the intended SO-8 variant.

What safety certifications does VIPER22-LED-EV hold?

The VIPER22-LED-EV itself is not a certified end-product but is designed to meet IEC/EN 62368-1 creepage/clearance requirements for reinforced insulation (≥6.4 mm primary-secondary spacing) and includes Y-capacitor placement compliant with EN 55032 Class B conducted emissions. Final system certification remains the responsibility of the end-equipment designer.