36V High Efficiency Boost Converter with I²C Controlled 6-CH LED Driver

RT8555

The RT8555 is a high efficiency driver for white LEDs. It is suitable for single/two cell battery input to drive LED light bars which contains six strings in parallel and up to 10 WLEDs per string. The internal current sinks support a maximum of ±2% current mismatching for excellent brightness uniformity in each string of LEDs. To provide enough headroom for current sink operation, the Boost controller monitors the minimum voltage of the feedback pins and regulates an optimized output voltage for power efficiency. The RT8555 has a wide input voltage operating range from 2.7V to 24V and contains I²C interface for controlling the dimming mode, operating frequency and the LED current. The internal 100mΩ, 36V power switch with current-mode control provides over-current protection. The switching frequency of the RT8555 is adjustable from 300kHz to 2MHz, which allows flexibility between efficiency and component size.

The RT8555 is available in the WL-CSP-20B 1.65 x 2.05 (BSC), with pitch 0.4mm package.

Applications

Tablet and Notebook Backlight

Key Spec.

	RT8555
Status	Active
Vin (min) (V)	2.7
Vin (max) (V)	24
SW Freq (typ) (kHz)	900
Number of LEDs (max) (pcs)	11
Iout (max)/channel (mA)	35
Iq (typ) (mA)	2.7
Dimming Control	I2C;PWM
Topology	Boost + Current Source
Features	Adjustable Frequency;Adjustable Soft-Start;Current Mode Control;Cycle-by-Cycle Current Limit;Enable Input;OCP;OVP
Package Type	WL-CSP1.65x2.05-20(BSC)

Features

Wide Operating Input Voltage : 2.7V to 24V
High Output Voltage : Up to 36V
Programmable Channel Current : 10mA to 35mA
Channel Current Regulation with Accuracy ±3% and Matching ±2%
Dimming Controls
► Direct PWM Dimming up to 20kHz and Minimum On-Time to 400ns
► PWM to Analog Dimming up to 20kHz with 8-bit Resolution
I²C Programs LED Current, Switching Frequency, Dimming Mode
Embedded Memory by OTP
Switching Frequency : 300kHz to 2MHz
Protections
► LED Strings Open Detection
► Current Limit
► Programmable Over Voltage Protection
► Over-Temperature Protection
20-Ball WL-CSP, with pitch 0.4mm Package
RoHS Compliant and Halogen Free