HV823

Supply Voltage, V_DD                            -0.5V to +10V
Output Voltage, V_Cs                          -0.5V to +120V
Operating Temperature Range       -25°C to +85°C
Storage Temperature Range       -65°C to +150°C
Power Dissipation                                        400mW

Note:
*All voltages are referenced to GND.

The Supertex HV823 is a high-voltage driver designed for driving EL lamps of up to 50nF. EL lamps greater than 50nF can be driven for applications not requiring high brightness. The input supply voltage range is from 2.0 to 9.5V. 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 ±90V. The chip can be enabled by connecting the resistors on R _SW-osc and R _EL-osc to VDD and disabled when connected to GND.

The HV823 has two internal oscillators, a switching MOSFET, and a high-voltage EL lamp driver. The frequency for the switching converter MOSFET is set by an external resistor connected between the RSW-osc pin and the supply pin VDD. The EL lamp driver frequency is set by an external resistor connected between R _EL-osc pin and the V_DD pin. An external inductor is connected between the Lx and V_DD pins. A 0.01F to 0.1F capacitor is connected between CS and GND. The EL lamp is connected between V_A and V_B.

The switching MOSFET HV823 charges the external inductor and discharges it into the Cs capacitor. The voltage at Cs will start to increase. Once the voltage at Cs reaches a nominal value of 90V, the switching MOSFET is turned OFF to conserve power. The outputs VA and VB are configured as an H-bridge and are switched in opposite states to achieve 180V peak-to-peak across the EL lamp.