Diodes AP431_A - Manual (Page 9)

AP431/AP431A
Document number: DS31002 Rev. 21 - 2
9 of 17
www.diodes.com
June 2013
© Diodes Incorporated
AP431/AP431A
Application Examples
V
IN
R1B
R2B
R1A
R2A
LED on when Low Limit < V < High Limit
Low Limit V (1 + R1B/R2B)
High
IN
REF

Limit V (1 + R1A/R2A)
Fig. 4 Voltage Monitor

REF
Fig 5. Delay Timer
N
OFF
R
+
V
IN
Delay = RC x ln
(
V - V
IN REF
)
V
IN
I = V /R
OUT REF CL
Fig 6. Current Limiter or Current Source
R
CL
I
OUT
V
IN
I = V / R
OUT REF S
Fig. 7 Constant-Current Sink
R
S
V
IN
I
OUT
V = (1 + R1/R2) x V
OUT REF
Fig. 8 Higher-Current Shunt Regulator
V
IN
V
OUT
R
1
R
2
V
OUT
V
IN
PULSE
R
1
R
2
Limit (1 + R1/R2) x V

REF
Fig. 9 Crow Bar
+
Low Limit V (1 + R1B/R2B) + V
High

REF BE
Limit V (1 + R1A/R2A)
Fig. 10 Over-Voltage/ Under-Voltage Protection Circuit

REF
Output ON when
Low Limit < V < High Limit
IN
V
IN
R1A
V
BE
R1B
R2A R2B
Note: 12. Online application note, “Design Consideration with AP431 when used as a Comparator”
URL: http://www.diodes.com/_files/products_appnote_pdfs/AN78.pdf