NCV7680 ON Semiconductor, NCV7680 Datasheet - Page 19

• Manufacturer Part Number: NCV7680
• Description: Linear Current Regulator and Controller
• Manufacturer: ON Semiconductor

Latch−Off on Open String Detection
system to shut down when the output intensity has
diminished. This eliminates a slow degradation of output
illumination. Figure 28 provides one solution for this
requirement. The open circuit fault information provided on
STOP Input
TAIL Input
Some LED lighting systems require the complete lighting
C4
10nF
R1
10k
MRA4003T3G
MRA4003T3G
MRA4003T3G
R10
10k
MUN2211
0.1uF
C1
R11
10k
Note: Latch−off will be implemented under all conditions which cause DIAG to go high.
Reference the pin function description table for a summary of DIAG performance.
R3
1k
NTD2955
R2
4.99k
R9
499
0.22uF
C2
C6
0.1uF
Figure 28. Latch−Off Circuit
R4, 3.09k
R5, 2.21k
C3
100nF
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19
OUT1
VP
Ballast Drive
FB
STOP
DIAG
RSTOP
RTAIL
the DIAG pin coupled with external discrete transistors
provides the feedback needed to the FB pin to turn off the
ballast transistor drive removing the LED anode string from
any power source. This condition is held until the input
signal is toggled.
NCV7680
OUT2
OUT3
OUT4
OUT5
OUT6
OUT7
OUT8
GND
V
STRING
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8.87K
V
R6
R7
1K
ref