The LP8556 device is a white LED driver featuring an asynchronous boost converter and six high precision current sinks that can be controlled by a PWM signal or an I2C master.
The boost converter uses adaptive output voltage control for setting the optimal LED driver voltages as low as 7 V and as high as 43 V. This feature minimizes the power consumption by adjusting the output voltage to the lowest sufficient level under all conditions. The converter can operate at three switching frequencies: 312, 625 and 1250 kHz, which can be set with an external resistor or pre-configured via EPROM. Programmable slew rate control and spread spectrum scheme minimize switching noise and improve EMI performance.
LED current sinks can be set with the PWM dimming resolution of up to 15 bits. Proprietary adaptive dimming mode allows higher system power saving. In addition, phase shifted LED PWM dimming allows reduced audible noise and smaller boost output capacitors.
The LP8556 device has a full set of safety features that ensure robust operation of the device and external components. The set consists of input undervoltage lockout, thermal shutdown, over-current protection, up to 6 levels of overvoltage protection, LED open and short detection.
The LP8556 device operates over the ambient temperature range of –30°C to 85°C. It is available in space-saving 20-bump DSBGA and 24-pad WQFN packages.
High-Efficiency DC–DC Boost Converter with Integrated 0.19-Ω Power MOSFET and Three Switching Frequency Options: 312, 625, and 1250 kHz
2.7-V to 36-V Boost Switch Input Voltage Range Supports Multi-cell Li-Ion Batteries (2.7-V to 20-V VDD Input Range)
7-V to 43-V Boost Switch Output Voltage Range Supports as Few as 3 WLEDs in Series Per Channel and as Many as 12
Configurable Channel Count (1 to 6)
Up to 50 mA Per Channel
PWM and / or I2C Brightness Control
Phase-Shift PWM Mode Reduces Audible Noise
Adaptive Dimming for Higher LED Drive Optical Efficiency
Programmable Edge-Rate Control and Spread Spectrum Scheme Minimize Switching Noise and Improve EMI Performance
LED Fault (Short and Open) Detection, UVLO, TSD, OCP, and OVP (Up to 6 Threshold Options)
Available in Tiny 20-Bump, 0.4-mm Pitch DSBGA Package and 24-Pad 4-mm x 4-mm x 0.8-mm, 0.5-mm Pitch WQFN Package