ncv8881 ON Semiconductor, ncv8881 Datasheet - Page 24

• Manufacturer Part Number: ncv8881
• Description: Ncv8881 1.5a Automotive Buck Regulator With Watchdog
• Manufacturer: ON Semiconductor

SMPS CURRENT LIMIT AND SHORT CIRCUIT
PROTECTION
current exceeds the internal, fixed, current limit. After the
Soft−Start Timer has expired, an extreme overload is
prevented from producing switch current in excess of the
OUTPUT
ENABLE
ENABLE
Every cycle, the power switch will be shut off if switch
SMPS
5P0
SMPS
OUTPUT
8P5
VIN
8P5
5P0
VIN
SMPS OVERLOAD AFTER SUCCESSFUL STARTUP #2
0
0
Regulation Threshold
Short−Circuit Threshold
Regulation Threshold
Short−Circuit Threshold
1
1
2
2
Figure 47. SMPS Overload after Successful Startup #1
Figure 48. SMPS Overload after Successful Startup #2
SOFT−START TIMER
SOFT−START TIMER
3
3
4
4
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Current is Limited
5
5
24
current limit by detecting excessively low voltage at the FB
pin and latching the SMPS regulator off. Toggling the EN
input low then high, or cycling input voltage off and on is
required to restart the SMPS (see bubble 5 of Figure 41, and
Figures 49 − 51).
6
6
7
7
Current is Limited
8
8
9
9
10
10
11
11
12
12