Siemens TDA 4601 Technical data

查询TDA 4601供应商

Control ICs for Switched-Mode Power Supplies

Features

● Direct control of the switching transistor

● Low start-up current

● Reversing linear overload characteristic

● Base current drive proportional to collector current

● Protective circuit in case of disturbance

TDA 4601

Bipolar IC

P-SIP-9-1

Type Ordering Code Package

TDA 4601 Q67000-A2379 P-SIP-9-1

The integrated circuit TDA 4601/D is designed for driving, controlling and protecting the switching
transistor in self-oscillating flyback converter power supplies as well as for protecting the overall
power supply unit. In case of disturbance, the rise of the secondary voltage is prevented. In addition
to the ICs application range including TV-receivers video tape recorders, hifi devices and active
loudspeakers, it can also be used in power supply units for professional applications due to its wide
control range and high voltage stability during increased load changes.

Semiconductor Group 7 06.94

Pin Definitions and Functions
Pin No. Function

TDA 4601

1
2 Zero passage identification
3 Input control amplifier, overload amplifier
4 Collector current simulation
5 Connection for additional protective circuit
6 Ground (rigidly connected to substrate mounting plate)
7 DC-output for charging coupling capacitor
8 Pulse output - driving of switching transistor
9 Supply voltage

V

REF

output

Block Diagram

Semiconductor Group 8

TDA 4601

Circuit Description

The TDA 4601 is designed for driving, controlling and protecting the switching transistor in flyback
converter power supplies during start-up, normal and overload operations as well as during
disturbed operation. In case of disturbance the drive of the switching transistor is inhibited and a
secondary voltage rise is prevented.

Start-Up

The start-up procedures (on-mode) include three consecutive operating phases as follows:

1. Build-Up of Internal Reference Voltage
The internal reference voltage supplies the voltage regulator and effects charging of the coupling
electrolytic capacitor connected to the switching transistor. Current consumption will remain at

I

< 3.2 mA with a supply voltage up to V9 approx. 12 V.

9

2. Enabling of Internal Voltage - Reference Voltage V1 = 4 V
Simultaneously with V9 reaching approx. 12 V, an internal voltage becomes available, providing
all component elements, with the exception of the control logic, with a thermally stable and
overload-resistant current supply.

3. Enabling of Control Logic
In conjunction with the generation of the reference voltage, the current supply for the control logic
is activated by means of an additional stabilization circuit. The integrated circuit is then ready for
operation.

The start-up phase above described are necessary for ensuring the charging of the coupling
electrolytic capacitor, which in turn supplies the switching transistor. Only then is it possible to
ensure that the transistor switches accurately.

Normal Operating Mode / Control Operating Mode

At the input of pin 2 the zero passages of the frequency provided by the feedback coil are registered
and forwarded to the control logic. Pin 3 (control input, overload and standby identification) receives
the rectified amplitude fluctuations of the feedback coil. The control amplifier operates with an input
voltage of approx. 2 V and a current of approx. 1.4 mA. Depending on the internal voltage reference,
the overload identification limits inconjunction with collector current simulator pin 4 the operating
range of the control amplifier. The collector current is simulated by an external RC-combination
present at pin 4 and internally set threshold voltages. The largest possible collector current
applicable to the switching transistor (point of return) increases in proportion to the increased
capacitance (10 nF). Thus the required operating range of the control amplifier is established. The
range of control lies between a DC-voltage clamped at 2 V and a sawtooth - shaped rising AC­voltage, which can vary up to a max. amplitude of 4 V (reference voltage). During secondary load
reduction to approx. 20 W, the switching frequency is increased (approx. 50 kHz) at an almost
constant pulse duty factor (1:3). During additional secondary load decreases to approx. 1 W, the
switching frequency increases to approx. 70 kHz and pulse duty factor to approx. 1:11. At the same
time collector peak current is reduced to < 1 A.

Semiconductor Group 9

TDA 4601

The output levels of the control amplifier as well as those of the overload identification and collector
current simulator are compared in the trigger and forwarded to the control logic. Via pin 5 it is
possible to externally inhibit the operations of the IC. The output at pin

V

REF

pin 8 will be inhibited when voltages of ≤ – 0.1 are present at pin 5.

Flipflops for controlling the base current amplifier and the base current shut-down are set in the
control logic depending on the start-up circuit, the zero passage identification as well as on the
enabling by the trigger. The base current amplifier forwards the sawtoothspahed
output of pin 8. A current feedback with an external resistor (R = 0.68 Ω) is present between pin 8
and pin 7. The applied value of the resistor determines the max. amplitude of the base driving
current for the switching transistor.

Protective Operating Mode

The base current shut-down activated by the control logic clamps the output of pin 7 to 1.6 V. As a
result, the drive of the switching transistor is inhibited. This protective measure is enabled if the
supply voltage at pin 9 reaches a value ≤ 6.7 V or if voltages of

------------

2

V

voltage to the

4

V

REF

------------

≤ – 0.1 are present at pin 5.

2

In case of short-circuits occurring in the secondary windings of the switched-mode power supply,
the integrated circuit continuously monitors the fault conditions. During secondary, completely load­free operation only a small pulse duty factor is set. As a result the total power consumption of the
power supply is held at
inhibited for a voltage supply of ≤ 6.7 V, the reference voltage (4 V) is switched off if the voltage
supply is further reduced by ∆V9= 0.6 V.

Protective Operating Mode at Pin 5 in Case of Disturbance

The protection against disturbances such as primary undervoltages and/or secondary over­voltages (e.g. by changes in the component parameters for the switched-mode power supply) is
realized as follows:

Protective Operating Mode with Continuous Fault Condition Monitoring

In case of disturbance the output pulses at pin 8 are inhibited by falling below the protective
threshold V5, with a typical value of V1/2. As a result current consumption is reduced (I9≥ 14 mA
at V9=10V).

With a corresponding high-impedance start-up resistor *), supply voltage V9 will fall below the
minimum shut-down threshold (5.7 V) for reference voltage V1. V1 will be switched off and current
consumption is further reduced to I9≤ 3.2 mA at V9≤ 10 V.

N = 6 ... 10 W during both operating modes. After the output has been

Because of these reductions in current consumption, the supply voltage can rise again to reach the
switch-on threshold of V9≥ 12.3 V. The protective threshold at pin 5 is released and the power
supply is again ready for operation.

Semiconductor Group 10

TDA 4601

In case of continuing problems of disturbance (V5≤ V1/2 – 0.1 V) the switch-on mode is interrupted
by the periodic protective operating mode described above, i.e. pin 8 is inhibited and V9 is falling,
etc.

Switch-On in the Wide Range Power Supply (90 Vac to 270 Vac)

(application circuit 2)
Self-oscillating flyback-converters designed as wide range power supplies require a power source

independent of the rectified line voltage for TDA 4601. Therefore the winding polarity of winding
11/13 corresponds to the secondary side of the flyback converter transformer. Start-up is not as
smooth as with an immediately available supply voltage, because TDA 4601 has to be supplied by
the start-up circuit until the entire secondary load has been charged. This leads to long switch-on
times, especially if low line voltages are applied.

However, the switch-on time can be shortened by applying the special start-up circuit (dotted line).
The uncontrolled phase of feedback control winding 15/9 is used for activating purposes.
Subsequent to activation, the transistor T1 begins to block when winding 11/13 generates the
current supply for TDA 4601. Therefore, the control circuit cannot be influenced during operation.

Semiconductor Group 11

Absolute Maximum Ratings
Parameter Symbol Limit Values Unit

min. max.

TDA 4601

Supply voltage

Voltages

Reference output V
Zero passage identification
Control amplifier
Collector current simulation
Blocking input
Base current cut-off point
Base current amplifier output

Currents

Zero passage identification I
Control amplifier
Collector current simulation
Blocking input
Base current cut-off point
Base current amplifier output
Junction temperature
Storage temperature range
Thermal resistances:

system-air TDA 4601
system-case TDA 4601

system-air
system-case

1)

2)

TDA 4601-D
TDA 4601-D

V

9

1

V

2

V

3

V

4

V

5

V

7

V

8

l i2

I

l 3

I

l 4

I

l 5

I

Q 7

I

Q 8

T

j

T

stg

R

th SA

R

th SC

R

th SA

R

th SA1

020V

06V
– 0.6 0.6 V
03V
08V
08V
0 V
0 V

9
9

V
V

–5 5 mA
– 3 3 mA
05mA
05mA
– 1 1.5 A
– 1.5 0 A

125 ˚C

– 40 125 ˚C

70
15

60
44

K/W
K/W

K/W
K/W

Semiconductor Group 12

Absolute Maximum Ratings (cont’d)
Parameter Symbol Limit Values Unit

min. max.

Operating Range

TDA 4601

Supply voltage
Case temperature TDA 4601
Ambient temperature range

1) Case soldered on PC-board without cooling surface

2) Case soldered on PC-board with copper-clad 35 µm layer, cooling surface 25 cm

3) R

= 44 K/W and PV = 1 W

th SA1

3)

TDA 4601-D T

V

9

T

C
A

7.8 18 V
085˚C
070˚C

2

Semiconductor Group 13

TDA 4601

Characteristics

T

= 25 ˚C

A

according to measurement circuit 1 and diagram

Parameter Symbol Limit Values Unit

min. typ. max.

Start Operation

Current consumption (V1 not yet
switched on)

V

= 2 V

9

V

= 5 V

9

V

= 10 V

9

Switching point for

V

1

I

9

I

9

I

9

V

9

11.0 11.8 12.3 V

1.5

2.4

0.5

2.0

3.2

mA
mA
mA

Normal Operation

V

= 10 V; V

9

= – 10 V; V

cont

= ± 0.5 V; f = 20 kHz

clock

duty cycle 1:2 after switch-on
Current consumtion

V

= – 10 V

cont

V

= 0 V

cont

Reference voltage

I

< 0.1 mA

1

I

< 5 mA

1

Temperature coeffiecient of
reference voltage

Control voltage

V

= 0 V V

cont

Collector current simulation voltage

V

= 0 V

cont

V

= 0 V/– 10 V

cont

Clamping voltage
Output voltages

V

= 0 V

cont

V

= 0 V

cont

V

= 0 V/– 10 V

cont

Feedback voltage

I

9

I

9

V

1

V

1

TC

1

3

)

V

*

4

∆V4*

V

5

V

Q7

V

Q8

∆V

Q8

V

*

2

110
50

4.0

4.0
–10

135
75

4.2

4.2

– 3

160
100

4.5

4.5

mA
mA

V
V

1/K

2.3 2.6 2.9 V

1.8

)

0.3

2.2

0.4

2.5

0.5

V
V

6.0 7.0 8.0 V

)

*
*

)

2.7

)

2.7

1.6

3.3

3.4

2.0

4.0

4.0

2.4

V
V
V

0.2 V

*) DC-component only

Semiconductor Group 14