STMicroelectronics VIPER50A-22-E

Overview

VIPER50A-22-E from STMicroelectronics is a high-voltage, current-mode PWM controller with integrated 700 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 consumption per Blue Angel norm.

For engineers reviewing the VIPER50A-22-E datasheet, VIPER50A-22-E pinout, VIPER50A-22-E application, or VIPER50A-22-E equivalent, key selection considerations include its integrated HV start-up current source, 250 ns current-sense blanking time, 1.5–2.7 A peak current limit, and PENTAWATT HV (022Y) package thermal resistance of 1.9 °C/W junction-to-case.

Technical Context

The device implements a current-mode control topology with inner current-loop sensing via SenseFET technique and outer voltage-loop regulation through a transconductance error amplifier (Gm = 1.5 mA/V typ.). It uses an internally trimmed 13 V reference for VDD regulation and supports both primary and secondary feedback configurations via the COMP pin.

Burst-mode stand-by operation is triggered when VCOMP falls below 0.5 V, forcing zero-duty-cycle shutdown until VDD recovers to 11 V (UVLO reset). Thermal protection activates at 140–170 °C with 40 °C hysteresis, and oscillator frequency is set externally via RT–CT network with ±1% RT and ±5% CT yielding 90–110 kHz variation.

Key Specifications

Pinout & Package

Packaged in PENTAWATT HV (022Y), a 5-pin, high-voltage, thermally enhanced through-hole package with isolated drain pad and 1.9 °C/W R_thJC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with VIPER50A-22-E, VIPER22ADIP offers lower BOM cost at reduced voltage/current capability, while ICE2QS03G trades integration for thermal headroom and layout control-making VIPER50A-22-E optimal for compact, self-contained 25–50 W offline supplies needing minimal external components.

Availability

VIPER50A-22-E is available at Aetrix Electronics and suitable for AC-DC adapters, LED driver power supplies, industrial control power modules, and white goods auxiliary supplies requiring stable component supply, long-term lifecycle support, and compliance with Blue Angel and Energy Star standby standards.

Supply support for VIPER50A-22-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, analog ICs, and embedded processing solutions for industrial, automotive, and consumer markets.

VIPER50A-22-E belongs to the VIPer™ family of high-voltage SMPS primary controllers, engineered specifically for compact, low-component-count offline power supplies targeting efficiency, safety, and regulatory compliance in universal-input applications.

FAQ

What is the minimum recommended value for the VDD bypass capacitor?

The minimum VDD capacitor must satisfy C_VDD > (I_DD × t_SS) / V_DDhyst, where I_DD = 16 mA (max operating current), t_SS is worst-case startup time (typically 50–100 ms), and V_DDhyst = 2.4 V (min). For t_SS = 80 ms, C_VDD > 530 µF. A 1000 µF/25 V low-ESR electrolytic capacitor is standard practice to ensure reliable startup under full-load conditions.

Can VIPER50A-22-E operate without an external compensation network on the COMP pin?

No. The COMP pin is the output of a transconductance amplifier requiring external RC or R-C-C network for loop stability. Leaving it unconnected causes oscillation or latch-up. A minimum 1 nF capacitor to ground is mandatory for noise filtering; typical designs use 1–10 nF in series with 1–10 kΩ for dominant-pole compensation and phase margin control.

How does the internal blanking time affect transformer design?

The fixed 250–360 ns blanking window suppresses false current-sense triggering from primary-side ringing. This allows use of transformers with higher leakage inductance (up to 2% of magnetizing inductance) without snubber circuits-reducing component count and improving efficiency in 25–50 W designs where precise timing margins are critical.

Is external synchronization of the OSC pin compatible with burst-mode operation?

Yes. External clock synchronization remains active during normal switching but is automatically disabled during burst-mode intervals when the power MOSFET is held off. Upon resuming normal operation, the OSC pin re-engages with the external clock source, ensuring deterministic timing alignment without disrupting low-power standby behavior.