NCP1200A
MAX PEAK
CURRENT
300 M
200 M
100 M
0
SKIP CYCLE
CURRENT LIMIT
315.40
882.70
1.450 M
2.017 M
2.585 M
Figure 19. The Skip Cycle Takes Place at Low Peak Currents which Guaranties Noise−Free
Operation
We recommend a pin 1 operation between 400 mV and 1.3
V that will fix the skip peak current level between 120 mV
/ RSENSE and 390 mV / RSENSE.
disappeared. This option can easily be accomplished
through a single NPN bipolar transistor wired between FB
and ground. By pulling FB below the Adj pin 1 level, the
output pulses are disabled as long as FB is pulled below
pin 1. As soon as FB is relaxed, the IC resumes its operation.
Figure 20 depicts the application example:
Non−Latching Shutdown
In some cases, it might be desirable to shut off the part
temporarily and authorize its restart once the default has
1
2
3
4
8
7
6
5
Q1
ON/OFF
Figure 20. Another Way of Shutting Down the IC without a Definitive Latchoff State
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