March 1997
ML4830*
Electronic Ballast Controller
GENERAL DESCRIPTION
The ML4830 is a complete solution for a dimmable, high
power factor, high efficiency electronic ballast.
Contained in the ML4830 are controllers for “boost” type
power factor correction as well as for a dimming ballast.
The Power factor circuit uses the average current sensing
method with a gain modulator and over-voltage
protection. This system produces power factors of better
than 0.99 with low input current THD at > 95%
efficiency. Special care has been taken in the design of
the ML4830 to increase system noise immunity by using a
high amplitude oscillator, and a gain modulator. An over-
voltage protection comparator stops the PFC section in
the event of sudden load decrease.
The ballast section provides for programmable starting
scenarios with programmable preheat and lamp out-of-
socket interrupt times. The IC controls lamp output
through either frequency or Pulse Width control using
lamp current feedback.
The ML4830 is designed using Micro Linear‘s Semi-
Standard tile array methodology. Customized versions of
this IC, optimized to specific ballast architectures can be
made available. Contact Micro Linear or an authorized
representative for more information.
FEATURES
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Complete Power Factor Correction and Dimming
Ballast Control on one IC
Low Distortion, High Efficiency Continuous Boost,
Average Current sensing PFC section
Programmable Start Scenario for Rapid or Instant Start
Lamps
Selectable Variable Frequency dimming and starting
Programmable Restart for lamp out condition to
reduce ballast heating
Over-Temperature Shutdown replaces external heat
sensor for safety
PFC Over-Voltage comparator eliminates output
“runaway” due to load removal
Large oscillator amplitude and gain modulator
improves noise immunity
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*This Part Is End Of Life As Of August 1, 2000
BLOCK DIAGRAM
MODE
7
9
R(SET)
R(T)/C(T)
OSCILLATOR
LAMP F.B.
LFB OUT
8
5
6
OUTPUT
DRIVERS
12
10
R(X)/C(X)
INTERRUPT
PRE-HEAT
AND INTERRUPT
TIMERS
PWM OR
FREQUENCY
MODULATOR
OUT B
OUT A
15
14
11
2
1
4
3
20
19
OVP/INHIBIT
IA OUT
IA–
IA+/I(LIM)
I(SINE)
EA OUT
EA–
POWER
FACTOR
CONTROLLER
UNDER-VOLTAGE
AND THERMAL
SHUTDOWN
PFC OUT
16
VCC
V
REF
GND
17
18
13
1
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
