STMicroelectronics VIPER15HN

Overview

VIPER15HN from STMicroelectronics is an off-line high-voltage PWM controller IC with integrated 800 V avalanche-rugged N-channel power MOSFET, quasi-resonant (QR) valley-switching control, adjustable current limiting via ZCD pin, hysteretic thermal shutdown at 150 °C, and <50 mW standby power at 265 Vac - used in compact AC/DC flyback converters for adapters and auxiliary supplies.

For engineers reviewing the VIPER15HN datasheet, VIPER15HN pinout, VIPER15HN application, or VIPER15HN equivalent, this page delivers verified technical context, validated pin functions, confirmed QR flyback design parameters, and real-world alternative selection guidance for energy-efficient low-power SMPS designs.

Technical Context

The VIPER15HN integrates a high-voltage startup generator drawing current directly from the DRAIN pin (60–100 V start threshold), enabling self-biasing without external high-voltage resistors. Its ZCD pin performs zero-current detection for QR operation, sets drain current limit via RLIM resistor, enables voltage feed-forward, and implements strobed overvoltage protection with 2.2 μs digital filtering.

It features dual overcurrent protection: primary cycle-by-cycle limiting (0.4 A typ.) and secondary hiccup-mode OCP at 0.6 A; burst-mode operation below 0.5 V FB input reduces no-load consumption; brown-out detection (0.45 V threshold ±50 mV hysteresis) disables switching during low-line conditions.

Key Specifications

Pinout & Package

DIP-7 package with exposed DRAIN pins (7 & 8) connected to internal metal frame for enhanced thermal dissipation; GND (pins 1–2) serves as both control ground and power section source reference.

Key Features

Applications

Equivalent & Alternatives

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

Compared with VIPER15HN, ICE2QS03G offers higher power scalability but adds component count and layout complexity, while LNK306P simplifies sourcing and certification at the expense of QR efficiency and adaptive current limiting.

Availability

VIPER15HN is available at Aetrix Electronics and suitable for adapter power supplies, auxiliary SMPS, and no-electrolytic LED drivers requiring stable component supply and long-term industrial availability.

Supply support for VIPER15HN 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

VIPER15HN belongs to ST's VIPer™ family of high-voltage offline controllers - engineered specifically for cost-sensitive, space-constrained AC/DC converters demanding integrated safety, low no-load power, and robust protection.

FAQ

What is the maximum continuous output power achievable with VIPER15HN in a DIP-7 package?

In a non-ventilated enclosed adapter at 50 °C ambient, VIPER15HN delivers up to 9 W continuous output power. In open-frame configurations with adequate heatsinking, it supports 10 W. Derating is required above 50 °C due to DIP-7's 110 °C/W junction-to-ambient thermal resistance - actual power depends on PCB copper area and airflow.

How does the ZCD pin enable both zero-current detection and adjustable current limiting?

The ZCD pin senses auxiliary winding voltage to detect transformer demagnetization (zero-current point) for QR timing. Simultaneously, a resistor (RLIM) from ZCD to GND sets I_ZCD, which linearly adjusts the internal current limit threshold - 10 μA corresponds to ~0.4 A peak drain current. No separate current-sense resistor is needed.

Can VIPER15HN operate without an auxiliary winding?

No - the VIPER15HN requires an auxiliary winding to sustain VDD after startup. The internal HV start-up circuit only charges VDD initially; once VDD exceeds 15 V, the HV generator disables and the IC relies entirely on auxiliary-derived supply. Omitting the winding causes immediate shutdown after startup.

What protection features activate during brown-out conditions?

When the BR pin voltage falls below 0.45 V (with 50 mV hysteresis), VIPER15HN immediately halts switching and enters ultra-low-power state (IDD_OFF ≈ 270 μA). It remains disabled until BR voltage rises above 0.5 V, preventing unstable operation, audible noise, and output droop during low-line events like grid sags.