STMicroelectronics VIPER12-LED-EV

Overview

VIPER12-LED-EV from STMicroelectronics is a dedicated evaluation board for the VIPER12A primary-switcher IC, designed to demonstrate low-power offline SMPS operation in LED driver applications. It integrates the VIPER12A (730 V MOSFET + current-mode PWM controller), supports 85–265 Vac input, delivers up to 8 W output in DIP-8 configuration, features fixed 60 kHz switching, and includes overtemperature, overcurrent, and overvoltage protection with auto-restart.

For engineers reviewing the VIPER12-LED-EV datasheet, VIPER12-LED-EV pinout, VIPER12-LED-EV application, or VIPER12-LED-EV equivalent, this board enables rapid validation of constant-current LED driver topologies using auxiliary-winding feedback, burst-mode light-load management, and HICCUP-mode overvoltage recovery - critical for cost-sensitive, isolated AC/DC LED lighting designs.

Technical Context

The VIPER12-LED-EV implements a flyback converter topology with primary-side regulation via the VIPER12A's current-mode control and FB pin current-sensing architecture. It uses an optocoupler-coupled secondary feedback loop with TSM101 dual op-amp reference to achieve rectangular U-I output characteristics - enabling precise constant-current (CC) and constant-voltage (CV) boundary control essential for Li-ion-compatible and multi-stage LED charging.

Startup relies on the VIPER12A's internal high-voltage current source (–1 mA at 100–400 V_DS) charging the VDD capacitor from the drain pin; regulation engages once VDD exceeds 14.5 V, with hysteresis (6.5 V) ensuring clean undervoltage lockout. Thermal shutdown activates at 170 °C with 40 °C hysteresis, and overvoltage protection triggers at 42 V_VDD, latching only until VDD falls below 8 V before auto-restart.

Key Specifications

Availability

VIPER12-LED-EV is available at Aetrix Electronics and suitable for LED streetlight drivers, architectural accent lighting, industrial status indicators, and smart home lighting controls requiring stable component supply and validated reference design reuse.

Supply support for VIPER12-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, delivering silicon solutions for automotive, industrial, power, and analog applications with emphasis on energy efficiency and system integration.

The VIPER12-LED-EV belongs to ST's VIPer™ AC-DC primary switcher evaluation platform family, engineered specifically to accelerate development of cost-optimized, isolated LED drivers meeting IEC 61347-1/2-13 safety and EMC requirements.

FAQ

What is the maximum output current achievable with VIPER12-LED-EV in constant-current LED mode?

The board supports up to 330 mA output current at 24 V (8 W), limited by the VIPER12A's 0.4 A peak drain current and thermal derating of the DIP-8 package. Actual current depends on transformer turns ratio, feedback resistor (R_FB), and optocoupler CTR - typical design achieves ±3% CC accuracy across line and temperature per ST Application Note AN2369.

Can VIPER12-LED-EV be modified for non-isolated buck-derived LED drivers?

No - the board is strictly configured as an isolated flyback converter with transformer-coupled output and primary-side sensing. Its layout, transformer, and VIPER12A's internal start-up architecture assume high-voltage isolation; removing isolation violates safety certification and risks latch-up due to missing VDD auxiliary winding supply.

Does VIPER12-LED-EV support dimming interfaces such as PWM or 0–10 V?

The base board does not include native dimming circuitry, but its FB node is accessible for external injection: applying a variable current (0–0.9 mA) into the FB pin modulates peak drain current linearly, enabling analog dimming. For PWM dimming, users must add external MOSFET gating on the LED string - ST recommends synchronizing PWM frequency above 1 kHz to avoid audible noise.

What safety certifications has VIPER12-LED-EV been tested against?

The board itself is not certified, but it implements a design compliant with EN 61347-1 (general lamp controlgear) and EN 61347-2-13 (LED controlgear), including reinforced insulation (≥4 mm creepage/clearance), Class II construction, and 3 kV AC hi-pot test margin. Full certification requires end-product-level testing per regional regulatory bodies (UL, CE, CCC).