STMicroelectronics VIPER50-E

Overview

VIPER50-E from STMicroelectronics is a high-voltage, current-mode PWM controller with integrated 620 V/1.5 A vertical power MOSFET, designed for primary-side regulation in offline SMPS. It delivers up to 50 W in single-range AC input configurations, features adjustable switching frequency up to 100 kHz (typ.), internal 13 V VDD regulation, and burst-mode operation enabling <1 W standby power per Blue Angel norm.

For engineers reviewing the VIPER50-E datasheet, VIPER50-E pinout, VIPER50-E application, or VIPER50-E equivalent, key selection considerations include its integrated HV start-up current source, transconductance error amplifier (1.5 mA/V), 250 ns current-sense blanking, thermal shutdown at 140–170 °C, and PENTAWATT HV (022Y) package compatibility with snubberless flyback designs.

Technical Context

The VIPER50-E implements a fixed-frequency current-mode control architecture with inner peak-current sensing and outer voltage regulation via a transconductance error amplifier. Its PWM latch responds to COMP voltage crossing 0.5 V, with 250 ns blanking and 350–1200 ns minimum on-time to suppress noise-induced false triggering.

Burst-mode stand-by is autonomously triggered when secondary load drops below ~0.5–1 W, causing VCOMP to fall below 0.5 V and forcing zero-duty-cycle shutdown until VDD recovers to 11 V. The integrated 620 V MOSFET supports unclamped inductive switching and eliminates external HV start-up circuitry.

Key Specifications

Pinout & Package

PENTAWATT HV (022Y) package: 5-pin, high-voltage insulated plastic body with exposed drain tab for thermal dissipation (R_thJC = 1.9 °C/W). Pin 1 = Drain (HV MOSFET drain + internal start-up current source); Pin 2 = Source (MOSFET source, primary ground reference); Pin 3 = VDD (13 V regulated supply input/output); Pin 4 = COMP (transconductance amplifier output, loop compensation & shutdown control); Pin 5 = OSC (RC oscillator timing input, supports sync).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar SMPS primary controller applications.

Compared with VIPER50-E, VIPer06XS offers lower conduction loss at light load but sacrifices frequency adjustability and autonomous burst-mode entry; NCP1014 provides greater flexibility in sensing and protection implementation but increases design complexity and component count for equivalent performance.

Availability

VIPER50-E is available at Aetrix Electronics and suitable for AC-DC wall adapters, set-top box power supplies, smart home IoT power modules, and industrial control auxiliary supplies requiring stable component supply, long-lifecycle support, and compliance with Blue Angel energy standards.

Supply support for VIPER50-E 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, specializing in power management, microcontrollers, and analog ICs for industrial, automotive, and consumer markets.

The VIPer™ product line targets highly integrated, cost-optimized AC-DC conversion for sub-75 W applications, emphasizing reduced external component count, regulatory compliance (Blue Angel, Energy Star), and robustness in universal-input offline power supplies.

FAQ

What is the purpose of the COMP pin on VIPER50-E?

The COMP pin serves as the output of the transconductance error amplifier (1.5 mA/V typical), providing loop compensation via external RC networks and acting as the primary control interface for peak current limiting. When COMP voltage drops below 0.5 V, the device enters burst-mode shutdown-enabling <1 W standby operation without external circuitry. It also supports primary-side regulation by connecting directly to transformer auxiliary winding feedback.

Can VIPER50-E operate without an optocoupler?

Yes-VIPER50-E supports primary-side regulation using its internal 13 V VDD reference and transformer auxiliary winding feedback to the VDD pin. This eliminates the optocoupler in low-to-mid power applications (≤25 W), reducing cost and improving reliability. Secondary-side regulation remains possible via optocoupler-connected COMP pin, maintaining design flexibility.

How does the integrated start-up current source function?

The integrated HV start-up current source draws bias current directly from the Drain pin during initial power-up, charging the external VDD capacitor until it reaches 11 V (UVLO reset threshold). Once active, the source disables and the auxiliary winding sustains VDD. During fault conditions (e.g., output short), VDD discharges to 7.5–9 V (UVLO off threshold), reactivating the start-up source-creating a safe, low-duty-cycle restart cycle (~12%) that limits stress on rectifiers and transformer.

What thermal derating guidance applies to VIPER50-E in PENTAWATT HV package?

With R_thJC = 1.9 °C/W and R_thJA = 60 °C/W, the VIPER50-E requires copper pour under the exposed Drain tab for effective heat transfer. At T_A = 50 °C and no heatsink, maximum continuous power is ~12 W before reaching 125 °C junction limit. For 25–50 W designs, forced air or minimal heatsinking is recommended. Thermal shutdown activates at 140–170 °C with 40 °C hysteresis to prevent oscillation.