ML4831
LFB OUT is ignored by the oscillator until C(X) reaches
6.8V threshold. The lamps are therefore driven to full
power and then dimmed. The C(X) pin is clamped to
about 7.5V.
0.625
R(SET)
R(X)/C(X)
10
+
–
A summary of the operating frequencies in the various
operating modes is shown below.
HEAT
C(X)
1.2/3.4
R(X)
6.8
Operating Mode
Operating Frequency
+
–
DIMMING
LOCKOUT
[F(MAX) to F(MIN)]
2
1.2/6.8
Preheat
R
S
INHIBIT
Dimming
Lock-out
INT
Q
–
9
F(MIN)
+
V
REF
Dimming
Control
F(MIN) to F(MAX)
Figure 7. Lamp Preheat and Interrupt Timers
6.8
3.4
R(X)/C(X)
1.2
.65
0
HEAT
DIMMING
LOCKOUT
7.5
INT
INHIBIT
Figure 8. Lamp Starting and Restart Timing
9
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
