Topics Covered

Overview

Features

Electrical Characteristics

IR2520D Ballast Control IC

Circuit Description

Miniballast Circuit Diagram

Functional Description

Fault Conditions

Miniballast Layout

Design Tip: AUto-restart Option

Design Procedure to adapt the

design to different lamp types

1. Overview

Small sizes ballasts (often called Matchbox ballasts) are becoming very common in Europe to drive a wide

range of lamps with power between 18W and 26W like PLC 18W, PLT 18W, TC-L 18W, TC-L 24W, TC-F 18W,

TC-F 24W, TC-DEL/TEL 26W, T5 24W, T8 18W, T5C 22W and TR 22W. Limiting the maximum power to 25W

the design does not need to conform to THD and PF requirements and this allows saving the PFC stage

reducing the components count and maintaining a very small size.

The MINIBALLAST1 is an electronic ballast for driving 26W compact fluorescent lamps from 220VAC. The

circuit provides all of the necessary functions for preheat, ignition and on-state operation of the lamp and

also includes the EMI filter and the rectification stage. The ballast size is 36mmx55mm.

The circuit is built around the IR2520D Ballast Control IC. The IR2520D provides adjustable preheat time,

adjustable run frequency to set the lamp power, high starting frequency for soft start and to avoid lamp flash,

fault protection for open filament condition and failure to strike, low AC line protection and auto-restart after

line brownout conditions. The IR2520D is a low-cost solution with only 8 pins and allows the component

count for the complete solution to be reduced down to 19 components.

www.irf.com

1

By

Cecilia Contenti

IRPLMB1E

International Rectifier

• 233 Kansas Street, El Segundo, CA 90245 USA