tea1753lt NXP Semiconductors, tea1753lt Datasheet - Page 6

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

NXP Semiconductors
7. Functional description
TEA1753LT
Objective data sheet
7.1.1 Start-up and UnderVoltage LockOut (UVLO)
7.1 General control
The TEA1753LT contains a controller for a power factor correction circuit as well as a
controller for a flyback circuit. A typical configuration is shown in
Initially the capacitor on the V
As long as V
V
increased until V
current is low again, ensuring a low duty cycle during fault conditions.
The control logic activates the internal circuitry and switches off the HV charge current
when the voltage on pin V
is activated and the soft start capacitors on the PFCSENSE and FBSENSE pins are
charged. Also the clamp circuit on the PFCCOMP pin is activated. When the LATCH pin
voltage exceeds the V
V
PFC circuit is activated. Also the flyback converter is activated (providing the soft start
capacitor on the FBSENSE pin is charged). The output voltage of the flyback converter is
then regulated to its nominal output voltage. The IC supply is taken over by the auxiliary
winding of the flyback converter. See
If during start-up the LATCH pin does not reach the V
V
again.
Fig 3.
CC
en(PFCCOMP)
th(UVLO)
pin is shorted to ground. For a short start-up time the charge current above V
, the LATCH pin output is deactivated and the charge current is switched on
A typical configuration of the TEA1753LT IC
CC
voltage and the soft start capacitor on the PFCSENSE pin is charged, the
All information provided in this document is subject to legal disclaimers.
is below V
CC
reaches V
en(LATCH)
Rev. 01 — 4 March 2011
CC
trip
, the charge current is low. This protects the IC in case the
passes the V
CC
th(UVLO)
voltage, the PFCCOMP pin voltage reaches the
pin is charged from the high voltage mains via the HV pin.
8
6
7
3
12
. If V
Figure
11
TEA1753LT
CC
startup
2
4.
is between V
9
level. First, the LATCH pin current source
16 13
en(LATCH)
10
4
1
5
GreenChip III SMPS control IC
th(UVLO)
level before V
Figure
TEA1753LT
and V
© NXP B.V. 2011. All rights reserved.
3.
startup
CC
, the charge
reaches
001aan786
trip
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is