SSL4101T View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'SSL4101T' PDF : 29 Pages View PDF
NXP Semiconductors
SSL4101T
GreenChip III+ SMPS control IC
time-out
2.5 V
4.5 V
3.5 V
30 μA
3 kΩ
FBCTRL
Fig 10. Time-out protection circuit
014aaa049
VFBCTRL
4.5 V
2.5 V
output
voltage
intended output
voltage not
reached within
time-out time.
restart
intended output voltage
reached within time-out
time.
014aaa050
Fig 11. Time-out protection (signals), safe restart in the SSL4101T
7.3.6 Soft start-up (FBSENSE pin)
To prevent audible transformer noise during start-up, the transformer peak current, IDM is
slowly increased by the soft start function. This can be achieved by inserting a resistor and
a capacitor between pin 10, FBSENSE, and the current sense resistor.
An internal current source charges the capacitor to V = Istart(soft)fb × RSS2, with a maximum
of approximately 0.5 V.
The start level and the time constant of the increasing primary current level can be
adjusted externally by changing the values of RSS2 and CSS2.
τsoftstart = 3 × RSS2 × CSS2
The soft start current Istart(soft)fb is switched on as soon as VCC reaches Vstartup. When the
voltage on pin FBSENSE has reached 0.5 V, the flyback converter starts switching.
The charging current Istart(soft)(PFC) flows as long as the voltage on pin FBSENSE is below
approximately 0.5 V. If the voltage on pin FBSENSE exceeds 0.5 V, the soft start current
source starts limiting the current. After the flyback converter has started, the soft start
current source is switched off.
SSL4101T
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 21 April 2011
© NXP B.V. 2011. All rights reserved.
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