High Performance Constant Voltage Primary Side PWM Controller with Power Factor Correction
The LD7841 is a controller targeting for isolated and non-isolated constant voltage LED drivers.
Designed to support flyback, buck/boost topologies, its proprietary voltage mode control algorithm provides
near-unity power factor and tightly regulates a constant output voltage from the primary side, thus eleminates
the need for a secondary side feedback circuit or an optocoupler.
The device is higly integrated with a minimum number of external components. A robust suite of safety protections
is built in to simply the design. The IC is specifically intended for very compact space efficient designs and also
provides a constant voltage regulation of the output if no load is connected to the LED driver.
The IC is available in SMD. LD7841 GR in SOP-7 and LD7841 GS in SOP-8 package.
FEATURES
▲ Wide input voltage range: 85VAC to 305VAC
▲ High voltage start up: Start up time (< 0.5sec)
▲ Low standby power
- No load power saving: < 0.2W
- Standby power consumption: < 0.4W at 150mW output
▲ Precise CV regulation in the steady state: < ± 5%
▲ CV regulation in the load transient: < ± 15%
▲ Total harmonic current optimization: THDi < 10%
▲ High power factor: PF > 0.92
▲ Robust protection features
- Brown-in/out detection on HV pin
- AC input over voltage protection on HV pin
- Programable output OVP on FB pin
- Cycle by cycle peak current limit on CS pin
- Over load protection
- Secondary diode short protection
- Pin short/open circuit protection on CS and FB pin
- Winding short circuit protection on FB pin
- Output short circuit protection
▲ 250mA / -700mA totem pole driving capability
APPLICATIONS
▲ LED power supply
▲ Off line appliances requiring power factor correction (PFC)
Datasheet 
