FEATURES

• Controls Different Types of Lamps:

Cold Cathode Fluorescent, Neon, and

Gas Discharge

• Zero Voltage Switching (ZVS) of

Push-Pull Drivers

• Accurate Control of Lamp Current

• Variable Lamp Intensity Control

• 1μA Disable Current

• 4.5V to 24V Operation

• Open Lamp Detection Circuitry

DESCRIPTION

The UC3872 is a resonant lamp ballast controller optimized for driving

cold cathode fluorescent, neon, and other gas discharge lamps. The resonant

power stage develops a sinusoidal lamp drive voltage, and minimizes

switching loss and EMI generation. Lamp intensity adjustment is

accomplished with a buck regulator, which is synchronized to the external

power stage’s resonant frequency. Suitable for automotive and battery

powered applications, the UC3872 draws only 1μA when disabled.

Soft start and open lamp detect circuitry have been incorporated to minimize

component stresses. Open lamp detection is enabled at the completion

of a soft start cycle. The chip is optimized for smooth duty cycle

control to 100%.

Other features include a precision 1.2% reference, undervoltage lockout,

and accurate minimum and maximum frequency control.