FEATURES
►► No external components required when using an external EL clock frequency ►► EL frequency can be set by an external resistor ►► Low noise ►► DC to AC converter ►► Drives up to 5.0nF load (approx. 1.5in2 lamp) ►► Output voltage regulation ►► Enable function ►► EL Lamp dimming APPLICATIONS
►► Cell phone keypads and displays ►► Transceivers ►► MP3 players ►► Watches ►► Pagers ►► Measuring instruments/gauges GENERAL DESCRIPTION
The Supertex It uses a charge pump scheme to boost the input voltage, eliminating the need for external inductors, diodes, and high voltage capacitors, components commonly found in conventional topologies. The charge pump circuit discharges its energy into an EL lamp through a high voltage H-bridge. Once the voltage reaches its regulated limit, it is turned off to conserve power. The EL lamp is then discharged to ground and the H-bridge changes state to allow the charge pump to charge the EL lamp in the opposite direction. The EL lamp frequency can be set either by an external resistor, REL, or by applying an external clock, where the clock frequency is divided by 128 to set the EL lamp frequency.
Supertex
