HV826

The Supertex HV826 is a high voltage driver designed for driving EL lamps. The input supply voltage range is from 1.8V to 3.5V. 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 ±80V. The chip can be enabled/ disabled by connecting the resistor on R _SW-OSC to V_DD/ground.

The HV826 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 REL-osc pin and the V_DD pin. An external inductor is connected between the LX and VDD pins. A 0.01-0.1F capacitor is connected between C_S and ground. The EL lamp is connected between V_A and V_B.

The HV826 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 80V, the switching MOSFET is turned OFF to conserve power. The outputs VA and VB are configured as an H bridge and are switching in opposite states to achieve 160V peak-to-peak across the EL lamp.