TDA4601.PDF

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SWITCH-MODE POWER SUPPLY CONTROLLER
TDA4601
SWITCH-MODE POWER SUPPLY CONTROLLER
. LOW START-UP CURRENT
. COLLECTOR CURRENT PROPORTIONAL
TO BASE-CURRENT INPUT
. REVERSE-GOING LINEAR OVERLOAD
CHARACTERISTIC CURVE
SIP9
(Plastic Package)
ORDER CODE : TDA4601
DESCRIPTION
The TDA4601 is a monolithic integrated circuit
desi-gned to regulate and control the switching
transistor in a switching power supply.
Because of its wide operational range and high
vol-tage stability even at high load changes, this IC
can be used not only in TV receivers and video
recorders but also in power supplies in Hi-Fi sets
and active speakers.
DIP 9+9
(Plastic Package)
ORDER CODE : TDA4601B
PIN CONNECTIONS
SIP9
DIP 9+9
9
8
7
6
5
4
3
2
1
V
IN
V REF
1
18
GROUND
PULSE OUTPUT
DC OUTPUT
GROUND
EXTERNAL FUNCTION
I SIMULATION
INPUT CONTROL
ZERO CROSSING
ZERO CROSSING
2
17
GROUND
INPUT CONTROL
3
16
GROUND
I C
SIMULATION
4
15
GROUND
C
EXTERNAL FUNCTION
5
14
GROUND
GROUND
6
13
GROUND
V
REF
DC OUTPUT
7
12
GROUND
PULSE OUTPUT
8
11
GROUND
V IN
9
10
GROUND
September 1993
1/8
. DIRECT CONTROL OF SWITCHING TRAN-
SISTOR
11043618.002.png
TDA4601
BLOCK DIAGRAM
9
7
8
START-UP
CIRCUIT
CONTROL
AMPLIFIER
BASE
CURRENT
AMPLIFIER
TRIGGER
START
HOLD
STANDBY
OPERATION
COUPLING -C-
CHARGING
CIRCUIT
VOLTAGE
CONTROL
OVERLOAD
IDENTIFICATION
CONTROL
LOGIC
BASE
CURRENT
SWITCH-OFF
REFERENCE
VOLTAGE
ZERO PASSAGE
IDENTIFICATION
COLLECTOR
CURRENT
SIMULATION
EXTERNAL
BLOCKING
FUNCTION
1
2
3
4
5
6
10 to 18
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Value
Unit
V 9
Supply Voltage
20
V
V 1
Reference Output
6
V
V 2
Identification Input
– 0.6, 0.6
V
V 3
Controlled Amplifier
3
V
V 4 ,V 5
8
V
V 7 ,V 8
V 9
I 2 , 3
–3,3
mA
I 4
5
mA
I 5
5
mA
I 7
1.5
A
I 8
– 1.5
A
T oper
Operating Ambient Temperature
0, 85
°
C
T stg
Storage Temperature
– 40, 150
°
C
T j
Junction Temperature
– 40, 125
°
C
THERMAL DATA
Symbol
Parameter
Value
Unit
R th (j–c)
Thermal Resistance Junction-pins
Max.
15
°
C/W
R th (j–a)
Thermal Resistance Junction–ambient
Max.
70
°
C/W
ELECTRICAL CHARACTERISTICS (T amb =25 o C)
Symbol
Parameter
Test Conditions
Min.
Typ. Max. Unit
V 9
Operating Supply Voltage Range
7.8
18
V
START CONDITION (according to test circuit of fig. 1)
I 9
Supply Current (V 1 not yet switched on)
V 9 =2V
V 9 =5V
V 9 =10V
1.5
2.4
0.5
2.0
3.2
mA
mA
mA
V 9
Switch Threshold (V 1 )
11
11.8 12.3
V
2/8
11043618.003.png
TDA4601
ELECTRICAL CHARACTERISTICS (T amb =25 o C ) (continued)
Symbol
Parameter
Test Conditions
Min.
Typ. Max. Unit
NORMAL OPERATION (V 9 = 10V, V cont = – 10V, V clock =
±
0.5V, f = 20kHz, duty cycle 1:2 after switch on)
I 9
Supply Current
V cont = – 10V
V cont =0V
110
50
135
75
160
100
mA
mA
V ref
Voltage Reference at Pin 1
I 1 < 0.1mA
I 1 = 5mA
4
4
4.2
4.2
4.5
4.4
V
V
V 3
Control Voltage
V cont = 0V
2.3
2.6 2.9
V
V 4
Collector Current Simulation Voltage
V cont = 0V, see note 1
1.8
2.2 2.5
V
D
V 4
Collector Current Simulation Voltage
V cont = 0V to –10V, see note 1
0.3
0.4 0.5
V
V 5
External Protection Threshold
6
7
8
V
V 7
Pin 7 Output Voltage
V cont = 0V, see note 1
2.7
3.3 4.0
V
V 8
Pin 8 output Voltage
V cont = 0V, see note 1
2.7
3.4 4.0
V
D
V 8
Pin 8 Output Voltage Change
V cont = 0V to –10V, see note 1
1.6
2
2.4
V
V 2
Feedback Voltage
see note 1
0.2
V
T K1
Reference Voltage Temperature Coefficient
10 –3
1/ o K
PROTECTION OPERATION (V 9 = 10V ; V cont = – 10V ; V clock =
±
0.5V ; f = 20kHz ; duty cycle 1 : 2)
I 9
Supply Current
V 5
3
1.8 V
14
22
28
mA
V 7
Switch–off Voltage
V 5
3
1.8 V
1.3
1.5 1.8
V
V 4
Switch-off Voltage
V 5
3
1.8 V
1.8
2.1 2.5
V
V 5
Blocking Voltage
V cont =0V
V 1
2 -
0.1
V 1
2
V
V 9
Supply Voltage for V 8 Blocked
V cont = 0 V
6.7
7.4 7.8
V
D
V 9
Supply Voltage for V 1 off While Further
Decreasing V 9
0.3
0.6
1
V
ELECTRICAL CHARACTERISTICS (according to test circuit of fig. 2)
t on
Secondary Voltage Switching Time
350 450 ms
D
V 2
Voltage Variation with Load
S 3 Closed, P 3 = 20 W
0.1 0.5
V
S 2 Closed, P 2 = 15 W
0.5
1
V
D V 2
Stand by Condition
S 1 Open P loa d =3W
20 30
V
f
Stand by Frequency
70
75
kHz
P P
Primary Power Consumption in Stand by
Condition
10
12
VA
Note 1 : Only DC component
Figure 1 : Test Circuit
Test Diagram : Overload Operation
V
18
17
16
15
14
13
12
11
10
V
0.5
0
0.5
10 20 30 40
60 70 80
t
1
2
3
4
5
67
8
9
V 4
3
V = -10V
=0
0.68 W
R
2
V
22pF
100k W
1
0
t
V 8
8
6
4
1
m
F
2
V REF I 1 V
V cont
V 9
0
t
3/8
11043618.004.png
TDA4601
Figure 2 : Test and Application Circuit
220VAC
4.7nF
4.7nF
B250/
C1000
18
17
16
15
14
13
12
11
10
2.7
TDA4601
1N4007
C2540
220
m
F (3)
1
2
3 4
5 6
7
8 9
0.68
W
200
W
1.2k
22pF
100
k
W
100
m
F
W
10k
W
/3W
6V
100
m
F / 25V
10
k
12
k
W
W
10nF (1)
1N4007
270k
W
100
m
F / 16V
10k
W
(2)
4.7
m
H
27
W
1
m
F / 35V
BY258-200
8.2nF
BY295-450
BU508
100
W
22nF
9
7
15
13
11
1
AZV
61-IC
16
2
12
6
4
270pF
BY258
-600
270pF
BY258
-600
270pF
BY258
-600
270pF
BY258
-600
470
m
F
470
m
F
470
m
F
470
m
F
18V
25V
150V
200V
56k
56k
W
W
100
W
S1
S1
S1
120
W
470
W
S1
33
W
1.5k
W
6.8k
W
56k
W
S3
S2
V 4
V
3
V
2
V
1
(1) C limits the max. collector current of BU508 at overshooting the permissible output power.
(2) Adjustement of secondary voltage.
(3) Must be discharged before IC change.
4/8
W
11043618.005.png
TDA4601
CIRCUIT DESCRIPTION
The TDA 4601 regulates, controls, and protects the
switching transistor in reverse converter power
supplies at starting, normal, and overload opera-
tion.
clamped DC voltage and an AC voltage rising in a
sawtooth waveform, which may vary up to a maxi-
mum amplitude of 4V (ref. voltage).
A reduction of the secondary load down to 20 watts
causes the switching frequency to rise to about
50kHz at an almost constant pulse duty factor
(period to on-time approx. 3). A further reduction of
the secondary load down to about 1 watt results in
changing the switching frequency to approx.
70kHz, and additionally the pulse duty factor rises
to approx. 11. At the same time the collector peak
current falls below 1A.
In the trigger the output level of the regulating
amplifier, the overload recognition, and the collec-
tor current simulation are compared and instruc-
tions are given to the control logic. There is an
additional triggering and blocking possibility by
means of pin 5. The output at pin 8 is blocked at a
voltage of less than 2.2V at pin 5.
Depending on the start-up circuit, the zero crossing
identification, and the release with the aid of the
trigger, the control logic flip flops are set which
control the base current amplifier and the base
current shut-down. The base current amplifier
moves the sawtooth voltage V 4 to pin 8. A current
feed-back having an external resistance of R =
0.68 W is inserted between pin 8 and pin 7. The
resistance value determines the maximum ampli-
tude of the base driving current for the switching
transistor.
Starting Behaviour
During the start-up, three consecutive operation
states are passed.
1. An internal reference voltage is built up which
supplies the voltage regulator and enables the
supply to the coupling electrolytic capacitor and
the switching transistor. Up to a supply voltage
of V 9
9
12V and enables all parts of the IC to be
supplied from the control logic with a thermally
stable and overload protected current supply.
3. Release of control logic. As soon as the
reference voltage is available, the control logic
is switched on through an additional stabilization
circuit. Thus, the IC is ready for operation.
This start-up sequence is necessary to guarantee
the supply through the coupling electrolytic capaci-
tor to the switching transistor. Correct switching of
the transistor is only guaranteed in this way.
Normal Operation
Zero crossing of the feedback coil is registered at
pin 2 and passed to the control logic.
At pin 3 (regulation of input, overload, and standby
recognition) the rectified amplitude variations of the
feedback coil are applied. The regulating amplifier
works with an input voltage of about 2V and a
current of about 1.4 mA.
Together with the collector current simulation pin 4,
the overload recognition defines the operating re-
gion of the regulating amplifier depending on the
internal reference voltage. The simulation of the
collector current is generated by an external RC
network at pin 4 and internally set threshold volt-
ages. By increasing the capacitance (10nF) the
max. collector current of the switching transistor
rises, thus setting the required operating range.
The extent of the regulation lies between a 2V
Protective Measures
The base current shut-down, released by the con-
trol logic, clamps the output of pin 7 at 1.6V and
thus blocks driving of the switching transistor. This
protective measure will be released if the voltage
at pin 9 reaches a value 3 typ. 7.4V or if voltages
of 3 typ. 2.2V occur at pin 5. In the case of a short
circuit of the secondary windings of the P.S.U., the
IC continuously monitors the fault condition.
With the load completely removed from the secon-
dary winding of the P.S.U., the IC is set to a low
pulse duty factor. The total power consumption of
the P.S.U. is held below 6 to 10 watts in both
operating conditions. After having blocked the out-
put, causedat a supply voltage 3 typ. 7.4V, a further
voltage reduction with D V 9 = 0.6V results in switch-
ing off the reference voltage (4V).
5/8
12V, the current I 9 is less than 3.2mA.
2. Release of the internal reference voltage
V 1 = 4V. This voltage is abruptly available when
V 9
9
11043618.001.png

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