20

LT1182/LT1183/LT1184/LT1184F

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

DIO

AGND

SHDN

BULB

BAT

ROYER

REF

FB

CCFL

PGND

LCD

PGND

LT1183

LAMP

UP TO 6mA

10

6

L1

L3

R1

750

Ω

L2

100

µH

3

2

1

4

5

+

C12

2.2

µF

35V

+

+

C7, 1

µF

C1*

0.068

µF

D1

1N5818

D5

BAT85

D2

1N914

D4

1N914

V (PWM)

0V TO 5V

1kHz PWM

SHUTDOWN

C8,0.68

µF

R7, 10k

R4

38.3k

1%

C5

1000pF

R2

220k

R3

100k

C3A

2.2

µF

35V

C11

22

µF

35V

V (CONTRAST)

0V TO 5V

R11

40.2k

1%

R10, 10k, 1%

C4

2.2

µF

≥ 3V

D3

1N5934A

24V

C3B

2.2

µF

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 (407) 241-7876

RMS BULB CURRENT IS:

0% TO 90% DUTY CYCLE FOR THE PWM

SIGNAL CORRESPONDS TO 0 TO 6mA.

Q2*

Q1*

N = 1:2

C6

2.2

µF

R5,38.3k, 1%

R9, 4.99k, 1%

D5

1N4148

C10

0.1

µF

6

4

29

C9

0.01

µF

+

+