Microchip HV980550W离线LED驱动方案

Microchip公司的HV9805是用于通用LED照明的LED驱动器,最大功率120VAC时为25W,230VAC时为50W,功率因素典礼为98%,典型效率为90%,对LED有过压保护.本文介绍了HV9805主要特性,框图,典型应用电路以及230VAC离线LED驱动器评估板主要特性,电路图,材料清单和PCB设计图.
The HV9805 driver integrated circuit (IC) is targeted atgeneral LED lighting products, such as LED lamps andLED lighting fixtures with a maximum power rating ofabout 25W at 120VAC and about 50W at 230VAC.
A two-stage topology provides true constant currentdrive for the LED load while drawing mains power withhigh power factor. The first stage, a boundaryconduction mode boost converter, transfers powerfrom the AC line to a second stage with high powerfactor and high efficiency. The second stage,a linearregulator arranged for operation with low overheadvoltage, transfers power from the first stage to the LEDload with true constant current and protects the LEDload from overvoltage that may pass from mains to theoutput of the first stage.
The IC is particularly geared to drive a high voltageLED load. An LED load arranged as a high-voltage loadis capable of offering cost advantages in terms of heatmanagement and optics.
The boost converter employs a cascode switch forhigh-speed switching and convenient generation of theVDD supply. The control device of the cascode switch isan integral part of the HV9805 and is rated at 700 mApeak. Current for powering the VDD supply is derivedby way of an internal connection to the cascode switch.Applications with low output voltage can beaccommodated using the SEPIC topology.
HV9805主要特性:
• Provides True DC Light and protects load fromline voltage transients
• Driver topology includes:
- Boundary Conduction Mode (BCM) BoostConverter with Power Factor Correction
a) High Power Factor (98% typical)
b) High Efficiency (90% typical)
- Linear Post-Regulator with Low OverheadVoltage
a) Zero LED Current/Brightness Ripple
b) Overvoltage...