General Description

The Supertex HV825 is a high voltage driver designed for driving EL lamps typically up to 6nF. The input supply voltage range is from 1.0V to 1.6V. The device uses a single inductor and a minimum number of passive components. Typical output voltage that can be applied to the EL lamp is ±56V.

The HV825 can be enabled/disabled by connecting the RSW-osc resistor to VDD/ground.

The HV825 has two internal oscillators, a switching bipolar junction transistor (BJT), and a high voltage EL lamp driver. The frequency for the switching BJT is set by an external resistor connected between the RSW-osc pin and the supply pin VDD. The EL lamp driver frequency is set by an external resistor connected between REL-osc pin and the VDD pin. An external inductor is connected between the LX and VDD pins. A 0.01 to 0.1μF, 100V capacitor is connected between CS and ground. The EL lamp is connected between VA and VB.

The switching BJT charges the external inductor and discharges it into the 0.01 to 0.1μF, 100V capacitor at CS. The voltage at CS will start to increase. The outputs VA and VB are configured as an H-bridge and are switching in opposite states to achieve a peak-to-peak voltage of two times the VCS voltage across the EL lamp.

Features

? Processed with HVCMOS? technology

? 1.0V to 1.6V operating supply voltage

? DC to AC conversion

? Output load of typically up to 6nF

? Adjustable output lamp frequency

? Adjustable converter frequency

? Enable function

Applications

? Pagers

? Portable Transceiver

? Cellular phones

? Remote control units

? Calculators