DAP011 datasheet(21/24 Pages) ONSEMI

Part #	DAP011

Description	PWM Current−Mode Controller for High−Power Universal Off−Line Supplies

PDF	24 Pages

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Manufacturer	ONSEMI [ON Semiconductor]

Direct Link	http://www.onsemi.com

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21 / 24 page

DAP011/DAP011C

http://onsemi.com

@ Lp @ Ip2Fsw + 4W

(eq. 4)

If this IC enters skip cycle mode with a bunch length of

10 ms over a recurrent period of 100 ms, then the total power

transfer is: 4.

0.1 = 400 mW.

To better understand how this skip cycle mode takes place,

a look at the operation mode versus the FB level

immediately gives the necessary insight:

5.0 V, FB Pin open

3.0 V upper dynamic range

Normal Current Mode Operation

1.0 V

Skip−cycle Operation

Ip min = 350 mV/Rsense

FB Pin Voltage

Figure 36.

When FB is above the skip cycle threshold (1.0 V by

default), the peak current cannot exceed 1.0 V / Rsense.

When the IC enters the skip cycle mode, the peak current

cannot go below 1.0 V / 3 or around 350 mV / Rsense.

Figure 38 shows different values of pulse widths when the

SMPS starts−to−skip cycles at different power levels:

Figure 37. Output Pulses at Various Power Levels (X = 5

ms/div) P1 < P2 < P3

Power P1

Power P2

Power P3

DAP011 Datasheet(PDF) 21 Page - ON Semiconductor