tea1612t NXP Semiconductors, tea1612t Datasheet - Page 6

• Manufacturer Part Number: tea1612t
• Description: Zero Voltage Switching Resonant Converter Controller
• Manufacturer: NXP Semiconductors

NXP Semiconductors
TEA1612T_1
Product data sheet
7.2 Oscillator
7.3 Non-overlap time resistor
7.4 Minimum frequency resistor
The internal oscillator is a current-controlled oscillator that generates a sawtooth output.
The frequency of the sawtooth is determined by the external capacitor C
flowing into the IFS and IRS pins.
The minimum frequency and the non-overlap time are set by the capacitor C
resistors R
The oscillator frequency is exactly twice the bridge frequency to achieve an accurate 50 %
duty factor. An overview of the oscillator and driver signals is given in
The non-overlap time resistor R
the IFS current input pin (see
temperature independent value of 0.6 V. The current that flows into the IFS pin is
determined by resistor's R
equals 1/16 of the discharge current of capacitor C
oscillator.
The falling slope time is used to create a non-overlap time (t
switching actions of the half-bridge switches:
The R
IRS current input pin (held at a temperature independent voltage level of 0.6 V). The
charge current of the capacitor C
I
t
t
no
IFS
IFS
Fig 5.
=
=
=
f(min)
C
--------------------------
16
t
2.4V
-----------
no
R
f
Oscillator and driver signals
no
f(min)
resistor is connected between the VREF pin (3 V reference voltage) and the
I
V
IFS
Cf
and R
GH-SH
CF
GL
Rev. 01 — 24 September 2009
no
0
0
. The maximum frequency is set by resistor R
non-overlap time (high to low)
no
2.4 V voltage drop divided by its value. The IFS input current
Figure
no
Zero voltage switching resonant converter controller
f
is connected between the 3 V reference pin VREF, and
is twice the current flowing into the IRS pin.
7). The voltage on the IFS pin is kept constant at a
f
non-overlap time (low to high)
and determines the falling slope of the
no
t
) between two successive
014aaa685
TEA1612T
Figure
f
© NXP B.V. 2009. All rights reserved.
(see
f
and the currents
Figure
f
5.
and
7).
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