HV825

The Supertex HV825 is a high voltage driver designed for driving EL lamps typically up to 6nF. The input supply voltage range is from 1.0V to 1.6V. The device uses a single inductor and a minimum number of passive components. Typical output voltage that can be applied to the EL lamp is ±56V.

The HV825 can be enabled/disabled by connecting the RSW-osc resistor to VDD/ground.

The HV825 has two internal oscillators, a switching bipolar junction transistor (BJT), and a high voltage EL lamp driver. The frequency for the switching BJT is set by an external resistor connected between the RSW-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 V_DD pins. A 0.01 to 0.1F, 100V capacitor is connected between C_S and ground. The EL lamp is connected between V_A and V_B.

The HV825 switching BJT charges the external inductor and discharges it into the 0.01 to 0.1F, 100V capacitor at C_S. The voltage at C_S will start to increase. The outputs V_A and V_B are configured as an H-bridge and are switching in opposite states to achieve a peak-to-peak voltage of two times the V_CS voltage across the EL lamp.