STMicroelectronics VIPER15LD

Overview

VIPER15LD from STMicroelectronics is an off-line high-voltage quasi-resonant (QR) flyback controller IC with integrated 800 V avalanche-rugged power MOSFET, adjustable current limiting via ZCD pin, <50 mW standby power at 265 Vac, and on-board soft-start. It delivers up to 6 W in open-frame designs and targets auxiliary power supplies for LCD/PDP TVs, LED drivers, and utility meters.

For engineers reviewing the VIPER15LD datasheet, VIPER15LD pinout, VIPER15LD application, or VIPER15LD equivalent, this device is selected for low-standby, high-reliability AC/DC conversion where integrated HV startup, valley-switching EMI reduction, and dual overcurrent protection are required - not for isolated gate driving, linear regulation, or synchronous rectification.

Technical Context

The VIPER15LD implements a current-mode PWM controller with zero-current detection (ZCD) for valley-switching QR operation, enabling reduced switching losses and lower EMI filter cost. Its internal 800 V power section eliminates external HV startup circuitry, while brown-in/brown-out protection ensures robust operation across 85–265 Vac input ranges.

It features dual-level overcurrent protection: primary cycle-by-cycle limiting set via ZCD pin resistor (typ. 0.4 A), and secondary hiccup-mode OCP at 0.6 A. Burst-mode operation below 0.5 V FB input enables <50 mW no-load consumption, meeting stringent energy-saving regulations.

Key Specifications

Pinout & Package

Package: SO16 narrow (SOIC-16, 300 mil width), thermally enhanced with DRAIN pins (13–16) connected to metal frame for heat dissipation.

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, VIPER15LD provides higher integration (800 V MOSFET + HV startup + brown-out + ZCD OVP), superior light-load efficiency via QR+burst, and simpler layout - making it optimal for space-constrained, low-standby, high-reliability auxiliary supplies.

Availability

VIPER15LD is available at Aetrix Electronics and suitable for auxiliary power supplies in LCD/PDP TVs, utility power meters, and no-el-cap LED drivers requiring stable component supply, long-lifecycle support, and compliance with global energy regulations.

Supply support for VIPER15LD 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.

VIPER15LD belongs to ST's VIPer™ family of high-voltage offline converters, engineered specifically for compact, low-standby, cost-optimized AC/DC power supplies in consumer and industrial auxiliary applications.

FAQ

What is the maximum continuous output power achievable with VIPER15LD in an open-frame design?

VIPER15LD delivers up to 6 W continuous output power in open-frame configurations at 50 °C ambient with adequate heat sinking, as confirmed in Table 2 of the datasheet. This assumes proper PCB copper area under DRAIN pins and SO16N thermal resistance (RthJA = 90 °C/W on standard FR4). Higher outputs require derating above 50 °C or forced cooling.

How is the current limit adjusted, and what is its tolerance?

The current limit is set by a resistor (RLIM) between ZCD pin and GND, producing IZCD that scales the drain current threshold. At TJ = 25 °C, IDlim is 0.38–0.42 A (typ. 0.4 A) with ±5% variation across production units, per Table 8. Temperature drift is ±15% over −25 to 125 °C, shown in Figure 7.

Does VIPER15LD support both DIP-7 and SO16 packages interchangeably in the same design?

No - VIPER15LD is specified only for SO16 narrow package (Table 1), while VIPER15LN/HN use DIP-7. Pinouts differ significantly: DIP-7 has 7 pins with shared functions, whereas SO16 has dedicated DRAIN pins (13–16), separate GND (1–2), and distinct ZCD/FB/BR assignments. Layout and thermal design are not interchangeable.

What happens during brown-out, and how does recovery work?

When BR pin voltage falls below 0.45 V (VBRth), VIPER15LD disables switching and reduces consumption to 270 µA (IDD_OFF). Recovery occurs only when BR voltage rises above VBRth + VBRhyst = 0.50 V - the 50 mV hysteresis prevents oscillation during marginal input conditions, ensuring clean restart after grid recovery.