May 2010

Doc ID 15073 Rev 1

1/21

AN2835

Application note

70 W HID lamp ballast

based on the L6569, L6385E and L6562A

Introduction

This application note describes the electronic lamp ballast for 70 W high intensity discharge

(HID) metal halide lamps (MHL) used for general indoor applications. The ballast is

composed of a boost converter and an inverter. The inverter is realized by a full bridge driver

with a power control circuit.

The booster converter for power factor correction (PFC) is controlled by the L6562A

controller (U1). The inverter is a full bridge topology driven by two pairs of half bridge buck

converters, L6385E (U3) and L6569 (U4), with the constant power control circuit L6562A

(U2).

In this note the dual-buck converter is introduced. One works in high frequency and the

other works in complementarity with necessary dead time at a lower frequency.

Figure 1.

The demonstration board

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