LD7839GJ

The LD7839 is an excellent single-stage flyback PFC controller with dimmable constant current and primary side regulation (PSR) control algorithm for LED lighting applications. It drives converter operating in quasiresonant mode to achieve high efficiency. By PSR, The LD7839 is feedback accurately with primary side current without the shunt regulator and opto-coupler at secondary side. LD7839 is a QR/DCM mode and voltage-mode PFC controller. The turn-on time of the switch is fixed while the turn-off time is varied in steady state. Therefore, the switching frequency varies in accordance with the input voltage or output power variation. The maximum switching frequency is limited about 90kHz and minimum switching frequency is limited about 20kHz. The LD7839 can support analog dimming by adjusting the voltage of DIM pin. LD7839 provides robust protections as over load protection, over voltage protection, over current protection, under voltage lockout and LEB of the current sensing. Specially, LD7839 also provide thermal foldback function by programmable NTC.

Applications

• AC-DC LED Lighting Driver

Key features

• Wide Input Voltage Range: 85~277Vac
• Fast Start up Controller by ST pin (<0.55ec)
• Primary Side Feedback Controller
• Line Feed forward for Enhanced Accuracy
• Tight Constant Current Regulation (+/-2%, typ.)
• Power Factor Correction (> 0.9, typ)
• Optimization Total Harmonic (x10%, typ)
• Dimming function by DIM pin - DC dimming input range : 0.5V~2.5V - PWM dimming input range : 800Hz~2KHz
• Robust Protection Features - Brown−In/Out Detections by VS pin - AC input Over Voltage Protection by VS pin - Over Voltage Protection on VCC pin - Programmable Open LED (OVP) Protection on ZCD or SD pin - Cycle−by−cycle Peak Current Limit - 2rd Current Limited Protection (CSP) - Current Sense Short Circuit Protection (CSCP) - Output Short Circuit Protection - Thermal Fold-back on SD pin by External NTC - Internal Over Temperature Protection