HV829B

The Supertex HV829A/HV829B are high voltage EL lamp driver integrated circuits designed for driving EL lamps of up to 70nF at 1000Hz. The input supply voltage range is from 2.7V to 5.5V.

These devices HV829B use a single inductor, a high voltage switching FET and a minimum number of passive components. The HV829A/B will supply the EL lamp with an AC square wave with a peak-to-peak voltage of two times the set regulated DC voltage.

The HV829A/HV829B has one internal oscillator and a high voltage EL lamp driver. The frequency for the external switching MOSFET is set by an external resistor connected between the R _SW-osc pin and GND. The EL frequency for the HV829A is equal to the switching frequency divided by 64 where the EL frequency for the HV829B is equal to the switching frequency divided by 128. Gate of the external MOSFET is connected to the Gate pin. An external inductor is connected between the Drain of external MOSFET and VDD pin. A 0.01-2.5F capacitor is connected between Cs and ground. The EL lamp is connected between V_A and V_B. The output voltage regulation level is controlled via the VREG pin for dimming and/or conservation of power. The output voltage regulation can be controlled continuously between 50V and 200V depending on the voltage applied to V_REG pin (0.75V to 3V).

The HV829B 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 CS reaches a nominal value chosen by the user, 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 the AC voltage of +/- VREG voltage across the EL lamp.