PAM2846 Datasheet | Power Analog Micoelectronics

Features n Six Constant-Current Output Channels n Parallel Channels Allow Higher Current per LED String n Maximum 40V Continuous Voltage Output Limit for Each Channel n Self-adaptive Vout to Fit Different LED Number n Adjustable Constant LED Current n Drives 10 or more LEDs Each String as Long as the String Voltage Less Than 40V n Internal 2.5A Power MOSFET n Low 400m V Feedback Voltage at Full Current Improves Efficiency n Allows Digital PWM and Analog Dimming n Wide (100:1) PWM Dimming Range without Color Shift n Independent Dimming and Shutdown Control of the LED Driver n ±1% Typical Current Matching between Strings n Open LED Protection: Adjustable Clamp Voltage n Short LED Protection n 3 Frequencies Selection: 1.6MHz/1MHz/500k Hz n Wide Input Voltage Range: 4.8V to 28V n Over Temperature Protection n Available in 24-pin 4mmx4mm QFN Package n Pb-free Package Description The PAM2846 is a high-efficiency boost type LED driver. It is designed for large LCD panel that employs an array of LEDs as back light source. The PAM2846 employs a current-mode step-up converter that drives six parallel strings of LEDs connected in multiple series. This built-in stringcurrent-control circuit achieves ±1% typical current matching between strings, which ensures even brightness for all LEDs. The device is able to adapt to different numbers of LEDs in each string or different forward voltage for different types of LEDs and keep the string current constant. Separate feedback loops limit the output voltage if one or more LEDs open or short. The limit voltage of over voltage protection is adjustable by changing the feedback resistor ratio. The PAM2846 has Features cycle-by-cycle current limit to provide consistent operation and soft-start capability. A thermal-shutdown circuit provides another level of protection. The PAM2846 has a wide +4.8V to +28V inputvoltage range and provides adjustable full-scale LED current. The switching frequency of this device can be selected among 500k Hz,...