TDA4605-2 Infineon Technologies, TDA4605-2 Datasheet - Page 10

• 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

If the voltage level of the rectified mains voltage is reduced strongly under the influence of the
applied load it can happen that
diagram. This is because if an attempt is made to start the SMPS with a too low mains voltage. The
internal primary voltage monitor circuit then clamps the voltage
IC switches off (
diagram.
Control Range, Overload and No-Load Behaviour
After the IC has started, it is operating in the control range. The voltage level at pin 1 is typically
400 mV. The gain of the control circuit consist of two parts: at first a fixed proportional part which is
internally fixed and an integrating part which can be set by means of the external capacitor at pin 7.
If the load is applied to the output of the SMPS, the control and overload amplifier allows wider
pulses (
increased further the overload amplifier begins to reduce the pulse width of the output pulse. This
point is referred to as the fold-back point of the power supply. Because of the fact that the IC supply
voltage is directly proportional to the secondary voltage, the supply voltage
according to the behaviour of the control circuit under the overload condition. If
value
up circuit which is operating with half-wave rectification, only a small output power is transferred into
the load during the secondary short-circuit of the SMPS. The overload amplifier reduces the output
pulse width down to the pulse width
IC to start up without problems from the virtual short-circuit, which every switching on with
representing.
If no load is applied to the secondary side, the output pulses (
If the pulse width is reduced be low a certain internal limit the IC will suppress some of the output
pulses. If the load is reduced further because of the decreasing duty cycle the measurement error
of the rectifier network (
secondary output voltage will increase, too. If the IC is operating with small pulse width of the output
pulse the control amplifier applies an additional current to the control amplifier in order to reduce the
output voltage. The value of the additional current depends on the size of the resistors
This can be used to compensate the increase of the secondary voltages.
Behaviour if the Chip Temperature Exceeds Predefined Limits
An integrated protection circuit against over temperature disables the internal logic if the chip
temperature is too high. The internal logic automatically checks the chip temperature and restart the
SMPS as soon as the temperature decreases to a permissible level.
Version 2.0
V
6 min
V
5
= "H") .The peak voltage value at pin 2 increases up to
, the IC will operate in the burst mode. Because of the large time constant of the start-
V
6
<
V
6A
). After this a new attempt to start the SMPS will begin at the time
R
8
, D3, C
V
3
is below the voltage level
t
pk
6
. This pulse width must remain possible in order to permit the
of the application circuit) is increasing and therefore the
10
V
V
3A
5
V
3
= H) become shorter.
- please refer to the time
V
to the voltage level
2S max
. If the secondary load is
V
6
V
6
will be reduced
TDA 4605-2
falls below the
R
V
5
3S
,
R
V
t
until the
t
1 Jul 2002
3
1
1
8
in the
in the
= 0 is
,
R
7
.