View tk6591x-series datasheet:

TK6591x SMALL EL LAMP DRIVER FEATURES APPLICATIONS High Ratio of Brightness / Input Power Battery Powered Systems Constant Brightness Versus Input Supply Changes Cellular Telephones Optimized for 3.5 nf to 12.5 nf Panel Capacitance Pagers Panel Voltage Slew Rates Controlled for Life LCD Modules Enhancement Wrist Watches Panel Peak to Peak Voltage Independent of Input Consumer Electronics Voltage and Temperature The oscillator circuits for the boost converter and lamp Panel Peak to Peak Frequency Independent of driver are both internally generated in the TK6591x, without Input Voltage and Temperature the need for external components. The clock frequency of Miniature Package (SOT23L-6) the boost converter is laser-trimmed to ensure good initial Operat