HV831

*Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is not implied.Continuous operation of the device at the absolute rating level may affect device reliability. All voltages are referenced to device ground, Gnd

The Supertex HV831 is a high voltage driver designed for driving two EL lamps with a combined area of 3.5 square inches. The input supply voltage range is from 2.0V to 5.0V. The device is designed to reduce the amount of audible noise emitted by the lamp. This device uses a single inductor and minimum number of passive components to drive two EL lamps. The nominal regulated output voltage of ±80V is applied to the EL lamps. The two EL lamps can be turned on and off by the two logic input control pins, C₁ and C₂. The device is disabled when both C₁ and C₂ (pins 1 and 4) are at logic low.

The HV831 has an internal oscillator, a switching MOSFET, and two high voltage EL lamp drivers. An external resistor connected between the R_SW-OSC and the voltage supply pin V_DD sets the frequency for the switching MOSFET. The EL lamp driver frequency is set by dividing the MOSFET switching frequency by 128. An external inductor is connected between the LX and the VDD pins. Depending on the EL lamp size, a 1.0 to 10.0nF, 100V capacitor is connected between C_S and Ground. The two EL lamps are connected between EL1 to Com and EL2 to Com.

The HV831 switching MOSFET charges the external inductor and discharges it into the capacitor at C_S. The voltage at C_S increases. Once the voltage at C^S reaches a nominal value of 80V, the switching MOSFET is turned off to conserve power. The outputs EL₁ to Com and EL₂ to Com are confi gured as H bridges and switch in opposite states to achieve 160V across the EL lamp.