HV832

The Supertex HV832 is a high voltage driver designed for driving two EL lamps with a combined area of 3.5 square inches. The input supply voltage range is from 2.0V to 5.0V. The device is designed to reduce the amount of audible noise emitted by the lamp. The device uses a single inductor and a minimum number of passive components. The nominal regulated output voltage that is applied to the EL lamp is ±90V.

The HV832 has an internal oscillator, a switching MOSFET, and two high voltage EL lamp drivers. The frequency for the switching MOSFET is set at 51KHz nominal. The EL lamp driver frequency is set by dividing the MOSFET switching frequency by 128. An external inductor is connected between the LX and VDD pins or VIN for split supply applications. A 0.001 to 0.01F, 100V capacitor is connected between CS and Ground. The EL lamps are connected between EL1 to Com and EL2 to Com.

An input control pin is available to select various modes of the device. Each logic pulse applied to the control pin will cause the device to change to the next mode. The sequence for the modes is: (1) EL1 on only, (2) EL2 on only, (3) both EL1 and EL2 on, and (4) device shuts down. During power up of the device HV832, the mode will default to shut down.

The HV832 switching MOSFET charges the external inductor and discharges it into the capacitor at Cs. The voltage at CS will start to increase. Once the voltage at Cs reaches a nominal value of 90V, the switching MOSFET is turned off to conserve power. The outputs EL1 to Com and EL2 to Com are configured as H bridges EL1/EL2 and Com are switching in opposite states to achieve 180V across the EL lamp.