
AP8802H
60V 1A LED STEP-DOWN CONVERTER
Applications Information (cont.)
Soft-Start
An external capacitor from the CTRL pin to ground will provide a soft-start delay, by increasing the time taken for the voltage on this pin to
rise to the turn-on threshold and by slowing down the rate of rise of the control voltage at the input of the comparator. Adding capacitance
increases this delay by approximately 200μs/nF. The graph below shows the variation of soft-start time for different values of capacitor.
16
14
12
10
8
6
4
2
0
-2
0
20
40
60
80
100
120
CAPACITANCE (nF)
Soft Start Time vs. Capacitance from ADJ Pint to Ground
Thermal Considerations
The graph below in Figure 19, gives details for power derating. This assumes the device to be mounted on a 25x25mm PCB with 1oz
copper standing in still air.
2.5
2
1.5
1
0.5
0
-40
-25
-10
5
20 35 50
65
80
95
110
125
AMBIENT TEMPERATURE (°C)
Maximum Power Dissipation
Figure. 19 AP880H Derating Curve
AP8802H
Document number: DS32227 Rev. 6 - 2
10 of 14
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May 2012
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