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TEA1532BT View Datasheet(PDF) - NXP Semiconductors.

Part Name
Description
Manufacturer
TEA1532BT
NXP
NXP Semiconductors. NXP
TEA1532BT Datasheet PDF : 23 Pages
1 2 3 4 5 6 7 8 9 10 Next Last
NXP Semiconductors
TEA1532BT; TEA1532CT
GreenChip II SMPS control IC
value of Rslopecomp. Slope compensation prevents modulation of the on-time (duty cycle)
while operating in FF CCM. A possible drawback of sub-harmonic oscillation can be
output voltage ripple.
RCTRL
slope compensation
current
Rsc
CTRL 4
1
5.6 V
control
detect
0.63 V
Fig 7. Slope compensation
001aaa830
7.11 Minimum and maximum on-time
The minimum on-time of the SMPS is determined by the Leading Edge Blinking (LEB)
time (typically 400 ns). The IC limits the on-time to a maximum time, which is dependent
on the mode of operation:
QR mode: When the system requires an ‘on-time’ of more than 25 µs, a fault condition is
assumed (e.g. CVCC removed). The IC stops switching and enters the safe restart mode.
CCM: The driver duty cycle is limited to 70 %. So the maximum on-time is correlated to
the oscillator time, which results in an accurate limit of the minimum input voltage of the
flyback converter.
7.12 Soft start-up (pin SENSE)
To prevent transformer rattle at start-up or during hiccup, the transformer peak current is
slowly increased by the soft start function. This can be achieved by inserting a resistor
and a capacitor between pin SENSE (pin 6) and sense resistor Rsense. An internal current
source charges the capacitor to VSENSE = Istartup(soft) × Rss (about 0.5 V maximum).
The start level and the time constant of the increasing primary current level can be
adjusted externally by changing the values of Rss and Css.
I DM = V-----s--e---n--s---e--(--m----a---x---)--------R(--I-s--s-e-t-n-a--sr--e-t-u---p---(--s--o---f--t--)---×-----R----s--s---)
τ = Rss × Css
TEA1532BT_TEA1532CT_1
Product data sheet
Rev. 01 — 18 January 2007
© NXP B.V. 2007. All rights reserved.
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