Overview
The VIPER27LN, produced by STMicroelectronics, is an off-line converter IC designed for high-voltage applications. It features an 800 V rugged power section, PWM control, and multiple protection mechanisms including over-current, overvoltage, and hysteretic thermal shutdown. The device is optimized for low EMI through frequency jittering and includes a high voltage start-up circuit. It also supports burst mode operation to meet standby energy saving regulations and has a soft-start and safe auto-restart after fault conditions.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Drain-to-source (ground) voltage (VDRAIN) | 800 | V |
| Repetitive avalanche energy (EAV) | 5 | mJ |
| Repetitive avalanche current (IAR) | 1.5 | A |
| Pulse drain current (IDRAIN) | 3 | A |
| Operating frequency (VIPER27L) | 60 kHz | - |
| Operating frequency (VIPER27H) | 115 kHz | - |
| Standby power at 265 Vac | < 50 mW | - |
| Drain-source on state resistance (RDS(on)) at 25 °C | 7 Ω | - |
| Drain-source on state resistance (RDS(on)) at 125 °C | 14 Ω | - |
| Thermal resistance junction ambient (RthJA) for DIP-7 | 100 °C/W | - |
| Thermal resistance junction ambient (RthJA) for SO16N | 60 °C/W | - |
Key Features
- 800 V avalanche rugged power section
- PWM operation with frequency jittering for low EMI
- Operating frequencies: 60 kHz for L type and 115 kHz for H type
- Standby power < 50 mW at 265 Vac
- Limiting current with adjustable set point
- Adjustable and accurate overvoltage protection
- On-board soft-start
- Safe auto-restart after a fault condition
- Hysteretic thermal shutdown
- Brown-out function for input voltage protection
- Embedded high voltage start-up circuit
Applications
- Auxiliary power supply for consumer and home equipment
- ATX auxiliary power supply
- Low to medium power AC-DC adapters
- Switch Mode Power Supplies (SMPS) for set-top boxes, DVD players, and recorders
- SMPS for white goods
Q & A
- What is the maximum drain-to-source voltage of the VIPER27LN?
The maximum drain-to-source voltage is 800 V.
- What are the operating frequencies for the VIPER27L and VIPER27H types?
The VIPER27L operates at 60 kHz, and the VIPER27H operates at 115 kHz.
- What is the standby power consumption at 265 Vac?
The standby power consumption is less than 50 mW.
- Does the VIPER27LN have adjustable overvoltage protection?
- What is the purpose of the brown-out function in the VIPER27LN?
The brown-out function protects the switch mode power supply when the rectified input voltage level is below the normal minimum level specified for the system.
- How does the VIPER27LN manage thermal protection?
The device includes hysteretic thermal shutdown to protect against overheating.
- What is the role of the soft-start feature in the VIPER27LN?
The soft-start feature helps in gradually increasing the output voltage during startup to prevent inrush currents.
- Does the VIPER27LN support auto-restart after a fault condition?
- What are some common applications of the VIPER27LN?
Common applications include auxiliary power supplies for consumer and home equipment, ATX auxiliary power supplies, and SMPS for set-top boxes and white goods.
- How does the VIPER27LN reduce EMI?
The device reduces EMI through frequency jittering, which helps in lowering the EMI filter cost.
