ST公司的VIPER17是离线高压转换器,集成了高压800V的功率部分,PWM控制,两级过流保护,过压保护和过负载保护,以及滞后热保护,软起动和故障条件消除后自动重起等功能. VIPER17采用突发模式工作,消耗非常低电流,有助于满足待机时节能指标.本文介绍了VIPER17的主要特性,方框图, 简单特性和全特性的反激应用方框图,以及6W单输出VIPer17演示板电路图和所用材料清单与变压器特性参数.
VIPer17: Off-line high voltage converters
The device is an off-line converter with an 800 V rugged power section, a PWM control, two levels of over current protection, over voltage and overload protections, hysteretic thermal protection, soft-start and safe auto-restart after any fault condition removal. Burst mode operation and device very low consumption help to meet the standby energy saving regulations.
Advance frequency jittering reduces EMI filter cost. 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. The high voltage start-up circuit is embedded in the device.
VIPER17主要特性:
800 V avalanche rugged power section
PWM operation with frequency jittering for low EMI
Operating frequency:
– 60 kHz for L type
– 115 kHz for H type
Standby power < 50 mW at 265 Vac
Limiting current with adjustable set point
Adjustable and accurate over voltage protection
On-board soft-start
Safe auto-restart after a fault condition
Hysteretic thermal shutdown
VIPER17应用:
Adapters for PDA, camcorders, shavers, cellular phones, video games
Auxiliary power supply for LCD/PDP TV, monitors, audio systems, computer, industrial systems
SMPS for set-top boxes, DVD players and recorders, white goods
图1.VIPER17方框图
图2.简单特性反激应用方框图
图3.全特性反激应用方框图
6W单输出VIPer17演示板
6 W single-output VIPer17 demonstration board
The new VIPer17 device integrates in the same package two components: an advanced PWM controller with built-in BCD6 technology and an 800 V avalanche rugged vertical power MOSFET. The device is suitable for offline power conversion operating either with wide range input voltage (85 VAC - 270 VAC) up to 6 W or with single range input voltage (85 VAC - 132 VAC or 175 VAC - 265 VAC). With European range input voltage (175 VAC–265 VAC) the device can handle up to 10 W of output power. The proposed solution has the advantage of using few external components compared to a discrete solution, providing several switch mode power supply protections and very low standby consumption in no-load condition. The device operates at fixed frequency that can be 115 kHz or 60 kHz.
Frequency jittering is implemented which helps to meet the standards regarding electromagnetic disturbance. The protections present on the device such as overload and output overvoltage protections, secondary winding short-circuit protection, hard transformer saturation and brownout protections improve the reliability and safety of the design.
Moreover internal thermal shutdown and an 800 V avalanche rugged power MOSFET improve the robustness of the system. The VIPer17 demonstration board is a standard single-output isolated flyback converter that uses all the protections mentioned above. If brownout and overvoltage protection are not necessary, the number of external components is further reduced.
图4.VIPer17演示板外形图
图5. VIPer17演示板电路图
VIPer17演示板材料清单(BOM):
变压器特性参数:
