ML4836
FUNCTIONAL DESCRIPTION
The ML4836 consists of flexible ballast control section.
Start-up and lamp-out retry timing are controlled by the
selection of external timing components, allowing for
control of a wide variety of different lamp types. The
ballast section controls the lamp power using frequency
modulation (FM) with additional programmability
provided to adjust the VCO frequency range. This allows
for the IC to be used with a variety of different output
networks. Figure 1 depicts a detailed block diagram of
ML4836.
The ML4836 provides several safety features. See the
corresponding sections for more details:
• End-of-lamp life detection to detect EOL and shut-off
lamps; See End Of Life Section.
• Thermal shutdown for temperature sensing extremes;
See IC Bias, Under-Voltage Lockout and Thermal
Shutdown Section.
• Relamping starting with anti-flash for programmable
restart for lamp out conditions while minimizing
“flashing” when powering from full power to dimming
levels; See Starting, Re-Start, Preheat and Interrupt
Section
REF
1
6.75V
+
–
REF_OK
THERMAL SHUTDOWN
OUT A
13
OUT B
+
TEMP
140ºC/100ºC
PGND
12
11
14
VCC
–
REF
Q
Q
R
S
PWDET
+
–
+
–
9
1.05V
1.20V/1V
INTERRUPT
AGND
10
Q
Q
S
R
COMP
7
–
+
RX/CX
6.65V/1.25V
Q
T
–
RT2
Q
UVLO
+
5
14V
+
PREHEAT
RT/CT
LEAO
3
LAMP FB
–
+
4.65V/
1.75V
–
6
CLK
RX/CX
OSCILLATOR
8
2
2.5V
4
RSET
V
TO
I
V
TO
I
Figure 1. Detailed Block Diagram
5
MICRO-LINEAR [ MICRO LINEAR CORPORATION ]
