TDA4605-2 Infineon Technologies, TDA4605-2 Datasheet - Page 7

• Manufacturer Part Number: TDA4605-2
• Description: IC POWER SUPPLY CONTROLLER 8DIP
• Manufacturer: Infineon Technologies

Specifications of TDA4605-2

• Applications: Power Supply Controller
• Voltage - Supply: 7.5 V ~ 15.5 V
• Current - Supply: 11mA
• Operating Temperature: -20°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 8-DIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Input: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: SP000011728; TDA46052X; TDA46052XK

Circuit Description
Application Circuit
The application circuit shows a flyback converter for video recorders with an output power rating of
70 W. The circuit is designed as a wide-range power supply for AC-line voltages of 180 to 264 V.
The AC-input voltage is rectified by the bridge rectifier GR1 and smoothed by
the rush-in current.
The IC includes an internal circuit to avoid the turn-on of the power transistor T1 because of static
charges applied to the transistors gate, during the turn-off state of the IC. The resistor
limit the spectrum of the radiated noise.
During the conductive phase of the power transistor T1 the current rise in the primary winding
depends on the winding inductance and the mains voltage.
The network consisting of
collector current. The resulting control voltage is fed into pin 2 of the IC. The RC-time constant given
by
The ratio of the voltage divider
switching power supply shall stop operation because of the low mains voltage. The control voltage
present at pin 3 also determines the correction current for the foldback point.
This current added to the current flowing through
order to reduce the turn-on phase of T1. This is done to stabilize the fold-back point even under
higher mains voltages.
The control of the switched-mode power supply is done by means of a control voltage applied to
pin 1. The control voltage of winding
and stepped down at an adjustable ratio by
by the IC so that the voltage applied across the control winding, and hence the output voltages, are
at the desired level.
When the energy stored in the transformer is transferred into the load the control voltage passes
through zero. The IC detects the zero crossing via the series R
crossings of the control voltage can also be produced by ringing of the transformer after the turn-off
of the power transistor for T1 or when a short-circuit is applied to the output of the SMPS.
The capacitor
a shorter duty cycle in order to keep the operating frequency outside the audible frequency range.
On the secondary side of the transformer 3 output voltages are produced using the windings
n
the resistors with implemented fuse
output circuits, which are designed to supply only small loads.
Version 2.0
5
, rectified by D4 to D6 and smoothed by
R
4
-
C
5
must be designed that way that driving the transistor core into saturation is avoided.
C
8
is connected to pin 7. During the start-up phase this capacitor assures pulses with
R
4
-
R
C
5
10
is used to create a model of the sawtooth shaped rise of the
/
R
n
R
1
11
15
during the off-period of T1 is rectified by D3 smoothed by
is fixing a voltage level threshold. Below this threshold the
and
C
R
9
to
5
7
R
,
C
16
R
11
R
6
protect the rectifies against short circuits in the
. The resistor
4
and
and represents an additional charge to
R
7
. The primary peak current, is adjusted
R
9
12
connected to pin 8. But zero
is used as a bleeder resistor,
C
1
. The NTC limits
TDA 4605-2
R
13
1 Jul 2002
helps to
n
C
2
5
C
to
in
6