LX1689

LX1689 I N T E G R A T E D P R O D U C T S Third Generation CCFL Controller P RODUCTION D ATA S HEET DESCRIPTION KEY FEATURES WWW . Microsemi . C OM The LX1689 is the latest generation Direct Drive CCFL (Cold Cathode Fluorescent Lamp) Controller. It uses new circuit design techniques (patents pending) and combines digital and linear circuits with an advanced BiCMOS process to create a more complete controller in a small package. When compared to the original LX1686 design, identical module applications use from 12 to 30 less components. New functions and enhancements have been added to make the LX1689 even easier to use. The on-chip PLL circuit used to synchronize the digital dimming burst frequency to the video frame rate, as used in the LX1686, is replaced with a programmable counter. This counter can divide the video controller horizontal sync pulse, other external clock source or the internal chip clock source to generate the burst frequency. The brightness control input allows the use of either a DC voltage or a PWM input to simplify design. Programmable polarity brightness control is retained, except in the case of externally clocked digital dimming. Two onboard LDO regulators extend the input voltage range of the IC up to 28 Volts without using external circuitry as was required with our previous controllers. The LX1689 includes a new lamp strike detection scheme that saves a package pin and three external components. Internal circuits monitor lamp current pulses...