Low-Audible-Noise Inverter Suits EL Lamps

Oct 31, 2007 11:21 AM

Maxim Integrated Products’ MAX4990E is a high-voltage, dc-ac converter designed for driving electroluminescent (EL) lamps that also features a resistor-adjustable slew-rate control for audible-noise reduction. The device is ESD-protected to ±15 kV, and uses an inductor-based boost converter to generate a maximum drive voltage of 250 V_PK-PK. A high-voltage, full-bridge output converts this high voltage to the ac waveform required to drive an EL lamp. To maximize design flexibility, the MAX4990E provides capacitor-adjustable switching frequencies, and multiple options for controlling the output voltage.

Additionally, the MAX4990E implements flexible EL lamp-dimming control by letting users set the output voltage through a dc analog voltage, PWM signal, or an external resistor connected to ground. Featuring a +2.4-V to +5.5-V supply-voltage range, the device accepts a variety of voltage sources, such as Li-ion batteries and battery chargers. It also features a 100-nA shutdown current. It is available in a 3-mm x 3-mm, 14-pin TDFN package. Prices start at $0.99 for 1000 pieces.