AMG-LM302
Ballast Controller for Metal Halide Lamps
1. Functional Description of the AMG-LM302
The AMG-LM302 is a Ballast Controller IC for Metal Halide Lamps (HID, CDM, HQI…).
The AMG-LM302 integrates all functions necessary for control off Metal Halide lamps
including power factor correction (PFC), ignition voltage generation and overdrive, current
supply and power management. The ballast controller specifically supports high stability of
color temperature.
2. Features
PFC
HID
PFC operates in current controlled transition mode (TM) with overvoltage protection
Separate undervoltage lockout for PFC and HID part
Zero current detection for TM operation
Real multiplier for excellent THD
High pulse current driver output for HV Power MOS
Internal reference voltage
Current mode controlled buck converter
Buck converter with Driver for external transistor
Power drive mode for HV MOSFETS
Safe ignition through burst oscillation
30kHz PWM in capture compare mode with maximum duty cycle of 50%
Regulation of lamp power
Slope compensation
Open load and short-circuit detection
Completely adjustable current and power ramp during lamp warm-up period
Full bridge drive for acoustic control
Automatic time control for all function
Monitoring of lamp state
Wide supply range of 14.5V to 35V
Low power startup current
Disable function to shut down the ballast and reduce power consumption
Over temperature protection
Short-circuit protected
Ambient temperature range: -25°C to +125°C
General
Package: TQFP48
3. Application
The AMG-LM302 is suitable for all application where the light spectrum and color temperature
of the sun, which is given by Metal Halide lamps, are needed. The AMG-LM302 controls the
whole lamp ballast and thus not only provides for a low cost solution, but also one, which is
high quality and easy to design.
AMG-LM302
Revision: A
29. Jul. 2010
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AMG-LM302
Ballast Controller for Metal Halide Lamps
3.1. Example Application Drawing
230VAC
AMG-DF102
Buck
HSD
CDM Lamp
HSD
LSD
LSD
Control
OTh
PWM
PWM
Vc Supply
OVLO
Digital
Control
UVLO
AMG-LM302
PFC
CDM
Figure 1: Simplified application drawing.
3.2. Application Notes
Please see AMG-AN-LM302.
AMG-LM302
Revision: A
29. Jul. 2010
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AMG-LM302
Ballast Controller for Metal Halide Lamps
Table of Contents
1.Functional Description of the AMG-LM302............................................................................. 1
2.Features................................................................................................................................. 1
3.Application............................................................................................................................. 1
3.1.Example Application Drawing................................................................................................... 2
3.2.Application Notes..................................................................................................................... 2
4.Block Diagram....................................................................................................................... 4
5.Block Descriptions (optional).................................................................................................. 5
6.Pinning / Pad Coordinates..................................................................................................... 6
7.Pin description (optional)....................................................................................................... 8
8.Absolute Maximum Ratings................................................................................................... 8
9.Electrical Characteristics...................................................................................................... 10
9.1.Operational Range................................................................................................................. 10
9.2.DC Characteristics................................................................................................................. 10
9.3.AC Characteristics.................................................................................................................. 14
10.Flow Chart ........................................................................................................................ 16
11.Timing Diagrams................................................................................................................ 17
12.Application......................................................................................................................... 18
12.1.Example Application Circuit(s)............................................................................................. 18
12.2.Calculating PFC Parameters................................................................................................18
12.3.Calculating HID Parameters.................................................................................................19
12.4.Application Notes................................................................................................................. 20
13.IC-Package........................................................................................................................ 20
14.IC-Marking......................................................................................................................... 20
15.Ordering Information.......................................................................................................... 21
16.Notes and Cautions........................................................................................................... 21
16.1.ESD Protection..................................................................................................................... 21
16.2.Storage conditions................................................................................................................ 21
17.Disclaimer.......................................................................................................................... 21
18.Contact Information............................................................................................................ 22
AMG-LM302
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29. Jul. 2010
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AMG-LM302
Ballast Controller for Metal Halide Lamps
4. Block Diagram
AMG-LM302
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AMG-LM302
Ballast Controller for Metal Halide Lamps
5. Block Descriptions
The whole application for a metal halide lamp needs the following major function blocks:
•
•
•
•
•
•
mains rectification
PFC
lamp power regulation
lamp ignition control
high voltage bridge
bridge drivers
The mains rectification and the high voltage bridge are completely built using discrete
components.
There are two basic options to do the bridge drivers, either discrete or integrated. Alpha
recommends the use of a fully integrated full bridge gate driver AMG-DF102.
The AMG-LM302 does have the PFC, lamp power regulation, ignition control and other
subfunctions integrated.
The PFC part of the AMG-LM302 is a standard power factor correction regulator.
The CDM part contains the power and ignition control of the lamp. For power control the lamp
current I
outi
and the lamp voltage V
outi
get measured and then multiplied to receive the actual
lamp power. The power is then outputed via the CTRLo pin. It can be manipulated and filtered
by external devices and will then get fed (as the actual value) into an error amplifier via the FB
pin. The error amplifier uses an internal 2.5V reference voltage as the set value. The output of
the error amplifier is fed into a current limiter stage and finally outputed via the PWMo pin. The
signal from the PWMo pin eventually drives the buck converter, thus impacting the bridge
voltage and in turn the lamp power.
A capacitor connected to the COP pin sets the frequency of the internal oscillator. The
oscillator frequency eventually determines the switching frequency of the bridge. The oscillator
frequency needs to be double the resonant frequency of the LC low pass filter for the CDM-
lamp. The output BR drives a low and it's corresponding high side transistor. The output nBR
is inverted to BR and drives the other low and high side transistors. A dead time is
automatically inserted before the rising edges of BR and nBR so to avoid shoot through. This
dead time can externally be influenced with a capacitor connected to the CDT pin. The
switching frequency of the oscillator should not be high enough, to avoid audible noise from
the plasma in the lamp. It should not be too high either, cause this will increase power
consumption.
There is a control logic, which senses the state of the lamp. For ignition, it will generate a high
AMG-LM302
Revision: A
29. Jul. 2010
© All rights reserved
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