tea1752t NXP Semiconductors, tea1752t Datasheet - Page 20

• Manufacturer Part Number: tea1752t
• Description: Greenchip Iii Smps Control Ic
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TEA1752T_LT
Product data sheet
7.3.10 Overpower protection
7.3.9 Overcurrent protection (FBSENSE pin)
The output voltage V
demagnetization resistor, R
where N
transformer. The current I
The value of R
accurate OVP detection possible.
The primary peak current in the transformer is accurately measured cycle-by-cycle using
external sense resistor R
internal level (see
edge blanking period, t
During the primary stroke of the flyback converter its input voltage is measured by sensing
the current that is drawn from pin FBAUX.
This information is used to adjust the peak drain current of the flyback converter
measured via pin FBSENSE. The internal compensation is such that an almost input
voltage independent maximum output power can be realized.
The OPP curve is given in
V
Fig 16. OCP leading edge blanking
o OVP
(
)
s
=
is the number of secondary turns and N
----------- I
N
N s
aux
FBAUX
All information provided in this document is subject to legal disclaimers.
(
ovp FBAUX
Section
o(OVP)
can be adjusted to the turns ratio of the transformer, making an
(
leb
Rev. 02 — 24 June 2010
SENSE2
, to prevent false triggering caused by switch-on spikes.
ovp(FBAUX)
7.3.3). The OCP detection is suppressed during the leading
Figure
at which the OVP function trips, can be set by the
FBAUX
)
V
OCP level
FBSENSE
×
R
. The OCP circuit limits the voltage on pin FBSENSE to an
FBAUX
t
:
leb
17.
is internally trimmed.
+
TEA1752T; TEA1752LT
V
clamp FBAUX
(
aux
is the number of auxiliary turns of the
014aaa022
)
)
GreenChip III SMPS control IC
t
© NXP B.V. 2010. All rights reserved.
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