ml4836 Microsemi Corporation, ml4836 Datasheet - Page 11

• Manufacturer Part Number: ml4836
• Description: Compact Fluorescent Electronic Dimming Ballast Controller
• Manufacturer: Microsemi Corporation

FUNCTIONAL DESCRIPTION
After cathode heating, the inverter frequency drops to
F
If lamp current is not detected when the lamp is supposed
to have ignited, the C
inverter is inhibited until C
1.25V threshold. Shutting off the inverter in this manner
prevents the inverter from generating excessive heat when
the lamp fails to strike or is out of socket. Typically this
time is set to be fairly long by choosing a large value of
R
LFB OUT is ignored by the oscillator until INTERRUPT is
above 1.20V The C
Care should also be taken not to turn on the VCCZ clamp
START
X
.
DIMMING LOCKOUT
R
INTERRUPT
X
causing a high voltage to appear to ignite the lamp.
/C
INHIBIT
X
HEAT
LEA_ENB OR
6.75
4.75
1.25
.7
0
X
pin is clamped to about 7.5V.
X
charging current is shut off and the
X
is discharged by R
Figure10. Lamp Starting and Restart Timing
(Continued)
X
to the
so as not to dissipate excessive power in the IC. This will
cause the temp sensor to become active at a lower
ambient temperature.
A summary of the operating frequencies in the various
operating modes is shown below.
OPERATING MODE
Dimming
Preheat
Preheat
Control
After
OPERATING FREQUENCY
7.5
[F(MAX) to F(MIN)]
F(MIN) to F(MAX)
F(START)
2
ML4836
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