NCP1379_11 datasheet(11/22 Pages) ONSEMI

Part #	NCP1379

Description	Quasi-Resonant Current-Mode Controller for High-Power Universal Off-line Supplies

Download	22 Pages

Scroll/Zoom	100%

Manufacturer	ONSEMI [ON Semiconductor]

Direct Link	http://www.onsemi.com

Logo

11 / 22 page

NCP1379

http://onsemi.com

11

NCP1379 OPERATING MODES

NCP1379 has two operating mode: quasi−resonant

operation and VCO operation for the frequency foldback.

The operating mode is fixed by the FB voltage as

portrayed by Figure 22:

• Quasi−resonant operation occurs for FB voltage higher

than 0.8 V (FB decreasing) or higher than 1.4 V (FB

increasing) which correspond to high output power and

medium output power. The peak current is variable and

is set by the FB voltage divided by 4.

• Frequency foldback or VCO mode occurs for FB

voltage lower than 0.8 V (FB decreasing) or lower than

1.4 V (FB increasing). This corresponds to low output

power.

• During VCO mode, the peak current decreases down to

17.5% of its maximum value and is then frozen. The

switching frequency is variable and decreases as the

output load decreases.

• The switching frequency is set by the end of charge of

the capacitor connected to the CT pin. This capacitor is

charged with a constant current source and the

capacitor voltage is compared to an internal threshold

fixed by FB voltage. When this capacitor voltage

reaches the threshold the capacitor is rapidly discharged

down to 0 V and a new period start.

Figure 22. Operating Valley According to FB Voltage

VALLEY DETECTION AND SELECTION

The valley detection is done by monitoring the voltage of

the auxiliary winding of the transformer. A valley is detected

when the voltage on pin 1 crosses down the 55 mV internal

threshold. When a valley is detected, an internal counter is

incremented. The operating valley (1st, 2nd, 3rd or 4th) is

determined by the FB voltage as shown by Figure 22.

Similar Part No. - NCP1379_11

Manufacturer	Part #	Datasheet	Description
ON Semiconductor	NCP1379DR2G	346Kb / 22P	Quasi-Resonant Current-Mode Controller for High-Power Universal Off-line Supplies December, 2009 ??Rev. P0

More results

Similar Description - NCP1379_11

Manufacturer	Part #	Datasheet	Description
ON Semiconductor	NCP1380	388Kb / 26P	Quasi-Resonant Current-Mode Controller for High-Power Universal Off-Line Supplies June, 2012 ??Rev. 4
	NCP1380	417Kb / 26P	Quasi-Resonant Current-Mode Controller for High-Power Universal Off-Line Supplies December, 2009 ??Rev. 1
	NCP1336A	1,022Kb / 27P	Quasi-Resonant Current Mode Controller for High Power Universal Off-Line Supplies March, 2017 - Rev. 4
	NCP1379	346Kb / 22P	Quasi-Resonant Current-Mode Controller for High-Power Universal Off-line Supplies December, 2009 ??Rev. P0
	NCP1336A	1,004Kb / 26P	Quasi-Resonant Current Mode Controller for High Power Universal Off-Line Supplies July, 2012 ??Rev. 0
	NCP1380	424Kb / 28P	Quasi-Resonant Current-Mode Controller for High-Power Universal Off-Line Supplies February, 2018 - Rev. 6
	NCP1216P065	287Kb / 18P	PWM Current-Mode Controller for High-Power Universal Off-Line Supplies December, 2010 ??Rev. 13
	DAP011	827Kb / 24P	PWM Current−Mode Controller for High−Power Universal Off−Line Supplies November, 2005 - Rev. 2
	DAP018A	792Kb / 28P	PWM Current-Mode Controller for High-Power Universal Off-Line Supplies July, 2009 - Rev. 0
	NCP1216	182Kb / 18P	PWM Current-Mode Controller for High-Power Universal Off-Line Supplies September, 2004 ??Rev. 8

More results

NCP1379 Datasheet(PDF) 11 Page - ON Semiconductor

NCP1379 Datasheet(HTML) 11 Page - ON Semiconductor

Similar Part No. - NCP1379_11

Similar Description - NCP1379_11

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

Datasheet Download

Link URL