tea1753lt NXP Semiconductors, tea1753lt Datasheet - Page 17

• Manufacturer Part Number: tea1753lt
• Description: Tea1753lt Greenchip Iii Smps Control Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TEA1753LT
Objective data sheet
7.3.6 Soft start-up (pin FBSENSE)
To prevent audible transformer noise during start-up, the transformer peak current, I
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:
with a maximum of approximately 0.63 V.
The start level and the time constant of the increasing primary current level can be
adjusted externally by changing the values of R
The soft start current I
voltage on pin FBSENSE has reached 0.63 V the flyback converter starts switching.
V
softstart
Fig 12. Time-out protection circuit
Fig 13. Latched time-out protection (signals) in the TEA1753LT
=
I
start soft

=
V
fb
3
FBCTRL
time-out
voltage
output

All information provided in this document is subject to legal disclaimers.

R
R
SS2
SS2

start(soft)fb
Rev. 01 — 4 March 2011
C
SS2
4.5 V
intended output
reached within
time−out time.
voltage not
2.5 V
is switched on as soon as V
3.5 V
3 kΩ
latched
SS2
30 μA
and C
FBCTRL
GreenChip III SMPS control IC
SS2
CC
.
reaches V
TEA1753LT
4.5 V
2.5 V
014aaa049
014aaa298
© NXP B.V. 2011. All rights reserved.
startup
. When the
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