AN1902 Datasheet, PDF (1/32 Pages) STMicroelectronics – DEVICES TO DRIVE 58W TL TUBES

AN1902
®
- APPLICATION NOTE
VIPower: HF CONVERTER BASED ON VK06TL
DEVICES TO DRIVE 58W TL TUBES
N. AIELLO - S. MESSINA
This document describes a reference design for Lighting Ballast dedicated to drive 58W T8 tubes. The
board accepts DC input voltage (up to 430V) realizing the cathodes preheating, the EoL protection and
the maximum current limitation. It is based on the new VK06 device that integrates the controller and the
Power stage on the same chip. It is housed in SO-16 and SIP-9 packages.
INTRODUCTION
The European Community has agreed on a new directive for banning electromagnetic control gear for
) ^{fluorescent lamps. The aim is to improve the system efficiency (EEI-Energy Efficiency Index) reducing}
t(s ^{the environmental impact. This new directive divides the ballast in different classes from A1 to D. A1 is}
the most efficient system, D the least efficient.
duc _{s A1 → Dimmable electronic}
ro _{s A2 → Low-loss electronic}
P _{s A3 → Standard electronic}
te _{s B1 → Extra low-loss magnetic}
le _{s B2 → Low-loss magnetic}
so ^{s C → Normal-loss magnetic}
b _{s D → High-loss magnetic}
) ^{- O Since 1998, the energy classification has become compulsory and it has been inserted in a Cenelec}
t(s ^{standard. It means:}
- since April 2002, all ballasts with an EEI of D are banned;
uc _{- starting from October 2005, all ballasts with an EEI of C will be banned.}
d _{Thus the market is asking for cost effectiveness, good performance, low noise and compact ballasts to}
ro _{feed this kind of applications. The VK06 is a very suitable device, satisfying all the requirements with few}
P _{external components.}
te ^{The proposed reference design can supply 58W T8 FL tube with preheating function and EoL}
le ^{protection. Being the design reference focused on the converter realization (we don’t cover the PFC}
o stage) it has been set to give out the right output power when 400V dc voltage is applied.
Obs^{1. VK06 DESCRIPTION}
The VK06 is a monolithic device made by using the VIPower^® M3-3 STMicroelectronics proprietary
technology that integrates in the same chip a vertical flow Power stage and a BCD based control circuit.
The Power stage is made by a high voltage Bipolar transistor together with a low voltage n-channel
MOS transistor in emitter switching configuration Its performances are a good trade-off between the
Bipolar transistor low drop/high breakdown voltages and the MOS transistor high switching speed. The
block diagram is shown in figure 1.
March 2004
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