VIPER27LD

Overview

The VIPER27LD is a fixed frequency, high-performance off-line high voltage converter from the VIPerPlus family. It integrates an 800 V avalanche-rugged power MOSFET with PWM current mode control and operates at a switching frequency of 60 kHz. The device supports flyback, buck, and buck-boost topologies for AC/DC conversion. Key electrical parameters include a maximum input voltage of 23.5 V (rectified), an output capability up to 800 V, and a limiting current of 0.74 A. It features adjustable over-current protection, hysteretic thermal shutdown, and safe auto-restart mechanisms.

Feature Summary

• Integrates an 800 V avalanche-rugged power section for extended input voltage range coverage.
• Features PWM operation with frequency jittering to reduce EMI filter costs.
• Includes embedded high-voltage startup circuitry and sense-FET for minimal component count.
• Provides hysteretic thermal shutdown and safe auto-restart after fault conditions.

Applications

• Auxiliary power supplies for LCD or plasma TVs
• Desktop computer auxiliary power modules
• USB port power supplies
• Remote receiver power circuits
• Modem power supplies

Procurement Notes

Verify the specific suffix 'LD' corresponds to the 60 kHz operating frequency variant when sourcing. Confirm package type requirements, as this model is available in surface mount configurations such as SOIC. Ensure design compatibility with the 800 V breakdown rating and 60 kHz switching frequency against system constraints. Cross-reference official STMicroelectronics documentation for exact pinout and thermal characteristics before finalizing procurement specifications.

Selection Notes

Select the VIPER27LD for designs requiring a fixed 60 kHz switching frequency, distinguishing it from the 115 kHz H-type variants within the VIPerPlus family. This component is suitable for applications needing integrated high-voltage startup and low standby power consumption. Consider the 800 V avalanche ruggedness for robustness against input transients. Evaluate the need for adjustable current limiting and soft-start features inherent to this controller architecture.

Part Context

The VIPER27LD belongs to the VIPerPlus family of high-voltage converters by STMicroelectronics. This family integrates power MOSFETs with PWM controllers to simplify offline power supply design. The LD suffix specifically denotes the 60 kHz operating frequency version, contrasting with other frequency options in the series. These devices are engineered to meet stringent energy-saving regulations through burst mode operation and low no-load consumption.

Replacement Considerations

Public confirmed substitute part numbers are not provided in the source material.