LED Backlight with I2C Programmable Brightness Controller and LCD Bias Voltage Supply

Controller operates from a 12VDC supply and provides brightness and contrast control for an LCD display with LED backlight.


The Ringdale 05-15860000 controller operates from a 12VDC supply and provides brightness and contrast control for an LCD display with LED backlight. An SPI interface accepts microcontroller signals to adjust the brightness and contrast levels.

Applications
Retrofitting LCD display with LED backlighting
Other LED lighting applications

DEVICE OPERATION
The Ringdale 05-15860000 controller operates from a 12VDC supply. A 3-24mA adjustable output drives a string of LEDs. A 26-33V adjustable output provides a contrast control signal for an LCD display. The outputs are controlled by a 3.3V/5V SPI interface.

11 to 15VDC is supplied to terminal J4. The input is reverse-voltage protected. The controller will power up with a default 13.5mA supplied to the LED string and 29.2V supplied to the contrast control output. The two outputs may be adjusted through the SPI interface by communicating with a dual digital pot internal to the controller. The LED output will interface directly with the Ringdale 05-15880000 LED backlighting strip. The SPI can operate at either 3.3V or 5.0V (jumper selectable). The SPI interface is 4-pin connector J3.

TERMINATIONS
The 05-15860000 controller has 4 connectors for connecting the supply, SPI interface, and the two outputs.

Power Supply J4
11 to 15VDC is connected to J4. J4 accepts a plug-in 2-terminal strip, Kobiconn P025ESDVP-E. Pin 1 is +V and Pin 2 is V. The screw terminals accommodate 28 to 12 AWG stranded conductors. The power input is reverse-voltage protected.

SPI Interface J3
J3 is a 4-pin 2mm pitch connector that accepts a Molex 35507-0400 plug with Molex 50210-8100 pins.

Pin 1: chip select
Pin 2: clock
Pin 3: signal in
Pin 4: signal out.

Either 3.3V or 5.0V signals may be used with the appropriate setting of jumper JP1.

LED output J1
J1 is a 3-pin connector for connecting an LED string. The connector is a .100 pitch polarizing type with latch and mates with Molex 50-57-9403 using Molex 16-02-1125 pins. Pin 1 is the positive output from the controller board and Pin 3 is the negative return. Pin 2 is unconnected.

Contrast output J2
J2 is a 2-pin connector for connecting the contrast voltage output. The connector is a .100 pitch polarizing type with latch and mates with Molex 50-57-9402 using Molex 16-02-1125 pins. Pin 1 is ground and Pin 2 is the positive output voltage.

SPI INTERFACE
The 4-wire SPI interface at J3 permits adjustment of the LED current and contrast voltage outputs from an external microcontroller. See the pinout in section 3.2. A 3.3V or 5.0V interface is selectable by Jumper JP1.

A command byte 0x11 causes the data byte to be written to potentiometer 0. A command byte 0x12 causes the data byte to be written to potentiometer 1. The data is loaded when CS returns high. The signal out line from the dual digital pot is included in the SPI interface but is not required for normal operation.

DIMENSIONS
The 3.625 X 1.5 PCB requires a minimum vertical clearance of 0.6. Two 0.162 diameter mounting holes are provided.

Caution! All specifications published herein are subject to change without notice. See website for Terms and Conditions of use of the website and the information provided herein. See Ringdale website on www.ringdale.com for Terms and Condtions of Sale and Service.

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