HV833

The Supertex HV833 is a high voltage driver designed for driving EL lamps of up to 35nF (10-12in2). The input supply voltage range is from 1.8V to 6.5V. 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 chip can be enabled/disabled by connecting the resistor on R _SW-OSC to V_DD/ground.

The HV833 has two internal oscillators, a switching MOSFET, and a high voltage EL lamp driver. The frequency for the switching MOSFET is set by an external resistor connected between the R _SW-osc pin and the supply pin V_DD. The EL lamp driver frequency is set by an external resistor connected between R _EL-osc pin and the V_DD pin. An external inductor is connected between the LX and V_DD or VIN pins. A 0.003-0.1F capacitor is connected between CS and ground. The EL lamp is connected between VA and VB.

The HV833 switching MOSFET charges the external inductor and discharges it into the capacitor at C_S. The voltage at C_S will start to increase. Once the voltage at C_S reaches a nominal value of 90V, the switching MOSFET is turned OFF to conserve power. The outputs V_A and V_B are configured as an H bridge and are switching in opposite states to achieve 180V peak-to-peak across the EL lamp.