White LED
Charge Pump With 7 Drivers
FEATURES
- Powers Up to 7 LEDs for
BackLight Application.
- Up to 25mA/LED Drive
for Backlight
- Single-Wire 8-Step
Brightness Control
- Over temperature Over
Voltage, Output Short Protection
- Soft Start with Low
Input Ripple and EMI
- Maximized Efficiency
- 2.7V to 5.5V Supply
Voltage Range
- 3mmx3mm 16-Pin QFN
Package
DESCRIPTION
The BL107 is a low noise charge pump LED driver with regulated
constant current sink for uniform intensity. It is designed to drive seven LEDs (LED1-7) at up to 25mA per
LED for backlighting application. The
BL107 requires only four small ceramic capacitors and a current set resistor
for a complete LED power supply and current controller.
Built-in soft-start circuitry prevents excessive
inrush current during start-ups. The 1MHz fixed-frequency switching allows for
tiny external components, and the regulation scheme is optimized to ensure low
EMI and low input ripple. Backlight
full-scale current settings are set by an external resistors on RB pin.
Shutdown mode and current output levels are selected
via logic input ENB pin. ENB is toggled to adjust the LED currents via internal
counters and DACs. The part is shut down when ENB stays Low for >10µs.
The charge pump optimizes efficiency based on the voltage
across the LED current sources. The BL107 is available in a 3mm × 3mm 16-lead
QFN package.
