The RT4537 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 RT4537 contains I2C interface for controlling the dimming mode, operating frequency and the LED current. The internal 250mΩ, 36V power switch with current-mode control provides over current protection.

The switching frequency of the RT4537 is also adjustable from 100 kHz to 1.6MHz, which allows flexibility between efficiency and component size.

The RT4537 is available in the WQFN-24L 3x3 with pitch 0.4mm package.

应用

Tablet and Notebook LED Backlight

关键特性

Wide Operating Input Voltage : 2.7V to 24V

High Output Voltage : Up to 36V

Channel Current Programmable : 3mA to 12.5mA

Channel Current Regulation with Accuracy ±3% and Matching ±2%

Dimming Controls

Direct PWM up to 25kHz with Minimum 1% Duty

PWM to Analog up to 2kHz with 12-Bit Resolution, Up to 4kHz with 11-Bit Resolution, Up to 8kHz with 10-Bit Resolution

PWM to Mixed Up to 2kHz with 12-Bit Resolution, Up to 4kHz with 11-Bit Resolution, Up to 8kHz with 10-Bit Resolution

PWM to Mixed-26KHZ up to 2kHz with 12-Bit Resolution, 4kHz with 11-Bit Resolution, Up to 8kHz with10-Bit Resolution

I2C Programs LED Current, Switching Frequency, Dimming Mode

Switching Frequency : 100kHz to 1.6 MHz

Embedded Memory with MTP.

Protections

LED Strings Open Protection

Current Limit Protection

Programmable Over Voltage Protection

Over Temperature Protection

Strings Short Detection