Pin description (continued) – Rainbow Electronics MAX8709 User Manual
Page 9
MAX8709
High-Efficiency CCFL Backlight
Controller with SMBus Interface
_______________________________________________________________________________________
9
Pin Description (continued)
PIN
NAME
FUNCTION
26
CCV
Voltage-Loop Compensation Pin. CCV is the output of the voltage-loop transconductance amplifier (GMV)
that regulates the maximum average secondary transformer voltage. The CCV voltage controls the time
interval during which the full bridge applies the input voltage (BATT) to the transformer primary. The CCV
capacitor also sets the rise time and fall time of the lamp current in DPWM. Connect CCV to GND with a
6.8nF capacitor. CCV is internally discharged to GND in shutdown.
27
BATT
MAX8709 Supply Input. Input to the internal 5.3V linear regulator (V
CC
) that provides power to the device.
Bypass BATT to GND with a 0.1µF capacitor.
28
V
CC
5.3V Linear-Regulator Output. V
CC
is the supply voltage for the MAX8709. Bypass V
CC
to GND with a
0.47µF ceramic capacitor. V
CC
can also be connected to BATT if V
BATT
< 5.5V.
V
IN
7V TO 24V
C8
0.1µF
R4
100kΩ
C9
0.1µF
R5
100kΩ
C10
0.01µF
C11
0.1µF
SMBSUS
SMBDATA
SMBCLK
SCL
SDA
SUS
CCI
CCV
BATT
GND
LOT
REF
ILIM
V
CC
V
DD
BST2
BST1
GH1
LX1
LX2
GL1
PGND
GL2
GH2
VFB
ISEC
IFB
MAX8709
D1
C7
0.47µF
C5
0.1µF
C6
0.1µF
C1
4.7µF
25V
NH1
NL1
NH2
NL2
C2
1µF
T1
1:93
CCFL
C3
15pF
3kV
R3
40.2Ω
1%
C4
22nF
R2
2kΩ
R1
150Ω
1%
Figure 1. Typical Operating Circuit of the MAX8709