APPLICATION INFORMATION

NOTE A : R3 and R4 are selected to provide the desired LED intensity and cathode current ≥1㎃

to the TL431 at the available VI(BATT).

Figure 24. Voltage Monitor

Figure 25. Delay Timer

Figure 26. Precision Current Limiter

TL431

VI(BATT)

OUT

R1A

R1B

R2B

650Ω

R2A

R3

(SEE NOTE A)

R4

(SEE NOTE A)

LOW LIMIT=

VREF

R1B

R2B

（1+

）

HIGH LIMIT=

VREF

R1A

R2A

（1+

）

LED ON WHEN LOW LIMIT＜<VI(BATT)＜HIGH LIMIT

12V

R

C

ON

OFF

2㏀

TL431

DELAY=RxCxIN

12V

12V-VREF

(

）

TL431

VI(BATT)

IO

RCL

0.1%

IOUT=

VREF

RCL

+ IKA

R1 =

VI(BATT)

IO

HFE

+ IKA

R1

TL431

SHENZHEN TUOFENG SEMICONDUCTOR TECHNOLOGY CO.,LTD

www.sztuofeng.com

Jan,2019 V1.0

11

$GMXVWDEOH5HIHUHQFH6RXUFH

TL431