ML4835CP MICRO-LINEAR [Micro Linear Corporation], ML4835CP Datasheet - Page 6

• Manufacturer Part Number: ML4835CP
• Description: Compact Fluorescent Electronic Dimming Ballast Controller
• Manufacturer: MICRO-LINEAR [Micro Linear Corporation]

ML4835
FUNCTIONAL DESCRIPTION
The ML4835 consists of peak or average current
controlled continuous boost power factor front end section
with a 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 ML4835.
The ML4835 provides several safety features. See the
corresponding sections for more details:
6
20
19
14
13
18
11
1
2
4
3
7
2.75V
PVFB
REF
V CC
AGND
C RAMP
PVFB/OVP
PEAO
PIFBO
PIFB
PFC OUT
R X /C X
R SET
14V
2.5V
–1V
+
–
REF
+
–
–
+
OVP
+
–
UVLO
ILIM
6.75V
TO
V
I
+
–
REF_OK
+
–
R
S
Q
Q
PFC CONTROLLER
R
S
Q
Q
Figure 1. Detailed Block Diagram
THERMAL SHUTDOWN
4.75V/
1.75V
CLK1
+
–
• End-of-lamp life detection to detect EOL and shut-off
• Thermal shutdown for temperature sensing extremes;
• Relamping starting with anti-flash for programmable
PREHEAT
+
–
V
÷2
lamps; See End Of Life Section.
See IC Bias, Under-Voltage Lockout and Thermal
Shutdown Section.
restart for lamp out conditions while minimizing
“flashing” when powering from full power to dimming
levels; See Starting, Re-Start, Preheat and Interrupt
Section
TO
I
TEMP
130ºC/100ºC
Q
Q
Q
Q
Q
Q
OSCILLATOR
R
R
S
S
T
CLK
V
TO
I
COMP
+
–
–
+
1.25V/1V
R X /C X
6.75V/1.25V
+
–
INTERRUPT
+
–
LAMP FB
PWDET
OUT A
2.5V
OUT B
PGND
R T /C T
LEAO
1.0V
RT 2
17
16
15
12
10
8
9
6
5