HV824

The Supertex HV824 is a high voltage driver designed to drive EL lamps with capacitive loads of 2nF to 15nF. The input supply voltage range is 1.0V to1.6V.
The device uses a single inductor and a minimum number of passive components. Typical output voltage applied to the EL lamp is 120V to 150V peak-to-peak. The HV824 can be enabled/disabled by connecting the R_SW resistor to V_DD/ground. In die form, the device has an enable bar pad which enables the I_C when it is at logic low.

The HV824 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 V_DD pin. The EL lamp driver frequency is set by an external resistor connected between the R_EL-osc pin and the V_DD pin. An external inductor is connected between the Lx and V_DD pins.A 0.01mF to 0.1mF capacitor is connected between C_s and GND pins. The EL lamp is connected between V_A and V_B.

The switching MOSFET HV824 charges the external inductor and discharges it into the 0.01mF to 0.1mF capacitor at C_s. The voltage at C_S will start to increase. Once the voltage at Cs reaches a nominal value of 75V, 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 a maximum voltage of 180V peak-to-peak across the EL lamp.