tea1750t-n1 NXP Semiconductors, tea1750t-n1 Datasheet - Page 5

• Manufacturer Part Number: tea1750t-n1
• Description: Tea1750 Greenchip Iii Smps Control Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
7. Functional description
TEA1750_1
Product data sheet
7.1.1 Start-up and undervoltage lock-out
7.1 General control
The TEA1750 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 charge current when
the voltage on pin V
and the soft-start capacitors on the PFCSENSE and FBSENSE pins are charged. When
the LATCH pin voltage exceeds the V
PFCSENSE pin is charged, the PFC circuit is activated. The supply current from the
HV pin is then switched on again and the PFC circuit charges the C
the voltage on pin VOSENSE reaches the V
and 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
Fig 3. Typical configuration of TEA1750
CC
pin is shorted to ground. For a short start-up time the charge current above V
CC
Figure
is below V
CC
reaches V
CC
4.
passes the V
Rev. 01 — 6 April 2007
trip
, the charge current is low. This protects the IC in case the
CC
th(UVLO)
pin is charged from the high voltage mains via the HV pin.
8
6
7
3
12
startup
. If V
en(LATCH)
11
TEA1750T
CC
level. First, the LATCH pin output is activated
start(fb)
2
9
is between V
voltage and the soft-start capacitor on the
level, the charge current is switched off
16 13
10
4
1
GreenChip III SMPS control IC
th(UVLO)
Figure
and V
bus
TEA1750
capacitor. When
© NXP B.V. 2007. All rights reserved.
3.
startup
, the charge
014aaa016
trip
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is