LD7841High Performance Constant-Voltage Primary-Side-Regulation 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 eliminating the need for a secondary side feedback circuitry or an optocoupler.
The device is highly integrated with a minimum number of external components. A robust suite of safety protection is built in to simplify the design. This device 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.
Features
- Wide universal input range (85VAC ~ 305 VAC)
- High Voltage Startup: Start-up time : < 0.5 sec.
- 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 Over Voltage Protection on HV pin
- Programmable 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
- 250 mA / -700 mA Totem Pole Driving capability
Applications
- LED Driver Power Supplies
- Off Line Appliances Requiring Power Factor Correction
