ML4830 Datasheet, PDF (1/15 Pages) Micro Linear Corporation – Electronic Ballast Controller

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
s Complete Power Factor Correction and Dimming
Ballast Control on one IC
s Low Distortion, High Efficiency Continuous Boost,
Average Current sensing PFC section
s Programmable Start Scenario for Rapid or Instant Start
Lamps
s Selectable Variable Frequency dimming and starting
s Programmable Restart for lamp out condition to
reduce ballast heating
s Over-Temperature Shutdown replaces external heat
sensor for safety
s PFC Over-Voltage comparator eliminates output
“runaway” due to load removal
s Large oscillator amplitude and gain modulator
improves noise immunity
*This Part Is End Of Life As Of August 1, 2000
BLOCK DIAGRAM
R(SET)
7
R(T)/C(T)
9
OSCILLATOR
R(X)/C(X)
12
INTERRUPT
10
PRE-HEAT
AND INTERRUPT
TIMERS
OVP/INHIBIT
11
IA OUT
2
IA–
1
IA+/I(LIM)
4
I(SINE)
3
EA OUT
20
EA–
19
POWER
FACTOR
CONTROLLER
PWM OR
FREQUENCY
MODULATOR
UNDER-VOLTAGE
AND THERMAL
SHUTDOWN
OUTPUT
DRIVERS
MODE
8
LAMP F.B.
5
LFB OUT
6
OUT A
15
OUT B
14
PFC OUT
16
VCC
17
V_REF
18
GND
13
1