Datasheet

20
LT1182/LT1183/LT1184/LT1184F
TYPICAL APPLICATIONS N
U
90% Efficient Grounded CCFL Configuration with Negative Polarity LCD Contrast
BAT
8V TO 28V
NEGCON
1182 TA02
VARYING THE V(CONTRAST)
VOLTAGE FROM 0V TO 5V GIVES
VARIABLE NEGATIVE CONTRAST
FROM –10V TO –30V
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
I
CCFL

DIO
CCFL V
C

AGND
SHDN
LCD V
C
CCFL V
SW

BULB
BAT
ROYER
V
IN

REF
FB
LCD V
SW
CCFL
PGND
LCD
PGND
LT1183
LAMP
UP TO 6mA
10
6
L1
L3
R1
750Ω
L2
100µH
3214
5
+
C12
2.2µF
35V
+
+
C7, 1µF
C1*
0.068µF
D1
1N5818
D5
BAT85
D2
1N914
D4
1N914
V (PWM)
0V TO 5V
1kHz PWM
SHUTDOWN
C8,0.68µF
R7, 10k
R4
38.3k
1%
C5
1000pF
R2
220k
R3
100k
C3A
2.2µF
35V
C11
22µF
35V
V (CONTRAST)
0V TO 5V
R11
40.2k
1%R10, 10k, 1%
C4
2.2µF
V
IN
≥ 3V
D3
1N5934A
24V
C3B
2.2µF
35V
C2
27pF
3kV
+
C1 MUST BE A LOW LOSS CAPACITOR,
C1 = WIMA MKP-20
Q1, Q2 = ZETEX ZTX849 OR ROHM 2SC5001
L1 = COILTRONICS CTX210605
L2 = COILTRONICS CTX100-4
L3 = COILTRONICS CTX02-12403
*DO NOT SUBSTITUTE COMPONENTS
COILTRONICS [phone]

THE I
CCFL
CURRENT REQUIRED FOR AN
RMS BULB CURRENT IS:
I
CCFL
(9 × 10
–3
) (I
BULB
).
0% TO 90% DUTY CYCLE FOR THE PWM
SIGNAL CORRESPONDS TO 0 TO 6mA.


Q2* Q1*
N = 1:2

C6
2.2µF
R5,38.3k, 1%
R9, 4.99k, 1%
D5
1N4148
C10
0.1µF
64
29
C9
0.01µF
+
+