IR21571: Dual Lamp Series Configuration - International Rectifier - #1

International iôr Rectifier

By T. Ribarich, E. Thompson, A. Mathur Table of Contents

Functional Description..........................................................................1

Measurements.....................................................................................4

Schematic Diagram..............................................................................7

Bill of Materials.....................................................................................8

Dual lamps connected in series is the popular conventional magnetic ballast retrofit configuration for the U.S. lighting market. The center lamp filaments are connected in parallel which results in six connections to the lamps from the output of the ballast. This retrofit configuration is accomplished using the IR21571 and some modifications to the ballast output stage. Through externally programmable components, the IR21571 affords flexibility of various features such as preheat time and frequency, ignition ramp characteristics, and running mode operating frequency. Comprehensive protection features protect the circuit against conditions such as lamp strike failures, filament failures, low DC bus, thermal overload, or ramp failure during normal operation. This circuit switches off both lamps when one is taken out, and automatically restarts when both lamps are in place.

AN-1013

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