STMicroelectronics VIPER15HD

Overview

VIPER15HD from STMicroelectronics is an off-line high-voltage quasi-resonant (QR) PWM controller IC with integrated 800 V avalanche-rugged N-channel power MOSFET, adjustable current limiting via ZCD pin, hysteretic thermal shutdown at 150–160 °C, and <50 mW standby power at 265 Vac. It enables compact, low-EMI flyback converters for auxiliary power supplies in LCD TVs, LED drivers, and utility meters.

For engineers reviewing the VIPER15HD datasheet, VIPER15HD pinout, VIPER15HD application, or VIPER15HD equivalent, this device supports valley-switching QR operation, brown-in/brown-out protection, burst-mode no-load regulation, dual overcurrent protection (0.4 A primary + 0.6 A hiccup), and on-board soft-start with 4.2 ms timing - critical for energy-compliant SMPS design.

Technical Context

The VIPER15HD integrates a high-voltage startup generator drawing current directly from the DRAIN pin (60–100 V start threshold), eliminating external bias windings. Its ZCD pin performs zero-current detection for QR timing, sets drain current limit via external resistor (IZCD = −10 µA → IDlim = 0.4 A), and implements strobed digital overvoltage protection (VOVP = 4.2 V ±0.4 V).

Control logic includes frequency foldback (down to 1/64 × FOSClim), leading-edge blanking (300 ns), minimum ON-time enforcement (220–480 ns), and auto-restart with low repetition rate after fault clearance. The FB pin provides linear regulation (VFBlin = 3.3 V), overload shutdown (VFBolp = 4.8 V), and burst-mode activation (VFBbm = 0.45 V falling).

Key Specifications

Pinout & Package

VIPER15HD is housed in SO-16 narrow (SO16N) package with exposed drain pads (pins 7–8 and 13–16) connected to internal metal frame for enhanced thermal dissipation. Pin 4 (N.A.) is not user-accessible.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar off-line QR flyback controller applications.

Compared with ICE2QS03G and LNK306P, VIPER15HD offers superior voltage ruggedness (800 V), true valley-switching control, and flexible current limit setting - making it optimal for industrial auxiliary supplies requiring robustness across wide input ranges and variable loads.

Availability

VIPER15HD is available at Aetrix Electronics and suitable for auxiliary power supplies in LCD/PDP TVs, smart utility meters, no-el-cap LED drivers, and universal-input adapters requiring stable component supply and long lifecycle support.

Supply support for VIPER15HD 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, delivering silicon solutions for automotive, industrial, and consumer markets since 1987.

The VIPER™ family targets highly integrated, low-system-cost off-line SMPS controllers - designed specifically for energy-efficient auxiliary and main power supplies in cost-sensitive, space-constrained applications.

FAQ

What is the maximum continuous output power achievable with VIPER15HD in open-frame design?

VIPER15HD delivers up to 6 W continuous output power in open-frame configuration at 50 °C ambient with adequate heatsinking, per ST's typical power table. This assumes SO16N package mounted on standard FR4 with 100 mm² copper pour, and accounts for RthJA = 80 °C/W and 1 W total dissipation limit. Higher power requires forced air or enhanced thermal design.

Can VIPER15HD operate without an auxiliary winding for VDD supply?

Yes - VIPER15HD features an integrated high-voltage startup generator that draws current directly from the DRAIN pin (60–100 V threshold), enabling initial VDD charging without auxiliary winding. However, once switching begins, the auxiliary winding must sustain VDD above 8.5 V; otherwise, UVLO triggers shutdown. The CVDD capacitor must be sized per Equation 1 in the datasheet to bridge startup delay.

How does the ZCD pin implement both zero-current detection and overvoltage protection?

The ZCD pin combines three functions via internal circuitry: (1) analog comparator detects transformer demagnetization via reflected auxiliary voltage; (2) current sink adjusts peak drain current based on external RLIM resistor value; (3) digital strobe circuit monitors ZCD voltage and triggers shutdown if VOVP threshold (4.2 V) is exceeded for ≥2.2 µs - providing noise-immune OVP independent of feedback loop.

Is VIPER15HD pin-compatible with VIPER12 or VIPER22A?

No - VIPER15HD uses SO16 narrow package with 16 pins including dedicated DRAIN pins (7,8,13–16), whereas VIPER12 (DIP-8) and VIPER22A (DIP-8/SO-8) have different pin counts, layouts, and internal architectures. Key differences include absence of ZCD pin in VIPER12 and lack of QR control in VIPER22A. Migration requires PCB redesign and firmware adaptation.