High Power CCFL Controller for Wide Dimming Range and Maximum Lamp Lifetime

The LT1768 is designed to control single or multiple cold cathode fluorescent lamp (CCFL) displays. A unique Multimode Dimming scheme* combines both linear and PWM control functions to maximize lamp life, efficiency, and dimming range. Accurate maximum and minimum lamp currents can be easily set. The LT1768 can detect and protect against lamp failures and overvoltage start-up conditions. It is designed to provide maximum flexibility with a minimum number of external components.

The LT1768 is a current mode PWM controller with a 1.5A MOSFET driver for high power applications. It contains a 350kHz oscillator, 5V reference, and a current sense comparator with a 100mV threshold. It operates from an 8V to 24V input voltage. The LT1768 also has undervoltage lockout, thermal limit, and a shutdown pin that reduces supply current to 65µA. It is available in a small 16-lead SSOP package.

Applications

* Desktop Flat Panel Displays

* Multiple Lamp Displays

* Notebook LCD Displays

* Point of Sale Terminal Displays

* Ultrawide Multimode Dimming™ Range

* Multiple Lamp Capability

* Programmable PWM Dimming Range and Frequency

* Precision Maximum and Minimum Lamp Currents Maximize Lamp Lifetime

* No Lamp Flicker Under All Supply and Load Conditions

* Open Lamp Detection and Protection

* 350kHz Switching Frequency

* 1.5A MOSFET Gate Driver

* 100mV Current Sense Threshold

* 5V Reference Voltage Output

* The 16-Lead SSOP Package