TDA4605_03 [STMICROELECTRONICS]
CONTROL CIRCUIT FOR SWITCH MODE POWER SUPPLIES USING MOS TRANSISTORS; 控制电路使用MOS晶体管的开关模式电源
| 型号： | TDA4605_03 |
| 厂家： | 
ST |
| 描述： | CONTROL CIRCUIT FOR SWITCH MODE POWER SUPPLIES USING MOS TRANSISTORS |
| 文件： | 总7页 (文件大小：119K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
TDA4605
CONTROL CIRCUIT FOR SWITCH MODE
POWER SUPPLIES USING MOS TRANSISTORS
■ Fold-Back Characteristic provides Overload
Protection for External Diodes
■ Burst Operation under Short-Circuit and no
Load Conditions
■ Loop Error Protection
■ Switch-off in case of too low Line Voltage
(Under Voltage Switch-off)
■ Line Voltage Compensation of Overload Point
■ Soft-Start for smooth Start-up
■ Chip Over-Temperature Protection (Thermal
DIP28
(Plastic Package)
Shutdown)
■ On-Chip Parasitic Transformer Oscillation
Suppression Circuitry
■ Decrease of Regulated Voltage for low Power
ORDER CODE: TDA4605
Consumption
DESCRIPTION
The IC TDA4605 controls the MOS Power Tran-
sistor and performs all necessary regulation and
monitoring functions in free running flyback con-
verters. Since good load regulation over a wide
load range is attained, this IC is particularly suita-
ble for Consumer as well as Industrial Power Sup-
plies.
SO8
(Plastic Micropackage)
Alternative source of the TDA4605 is also availa-
ble from SIEMENS Semiconductors Consumer
Electronics A.G.
ORDER CODE: TDA4605D
Figure 1. Pin Connections
REGULATION INPUT
PRIMARY CURRENT SIMULATION
PRIMARY VOLTAGE MONITORING
GROUND
1
2
3
4
8
7
6
5
ZERO CROSSING DETECTOR INPUT
SOFT-START
SUPPLY VOLTAGE
OUTPUT
September 2003
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1
TDA4605
PIN CONFIGURATION
Pin
Number
Description
Regulating voltage : information input concerning secondary voltage.
By comparing the regulating voltage obtained from the regulating winding of the transformer with the
internal reference voltage, the output pulse width on Pin 5 is adapted to the load of the secondary side
(normal, overload, short circuit, no load)
1
Primary current simulation : information input regarding the primary current. The primary current rise in the
primary winding is simulated at Pin 2 as a voltage rise by means of external RC element. When a value is
reached that is derived from the regulating voltage at Pin 1, the output pulse at Pin 5 is terminated. The RC
element serves to set the maximum power at the overload point.
2
3
Primary voltage detector : input for primary voltage monitoring. When the line voltage is too low the IC is
switched-off by comparing V with an internal reference. Voltage at Pin 3 is used for overload point
3
compensation.
4
5
Ground
Output : push-pull output for charge and discharge of the gate capacitance of the power MOS transistor.
Supply voltage : Supply voltage input. From it are derived a stable internal reference voltage (V
) and the
REF
switching threshold V , V , V max and V min for the supply voltage detector.
6A
6E
6
6
6
if V > V the V
is switched on and switched off when V < V . In addition the logic is only enable for
6
6E
REF
6 6A
V min < V < V max.
6
6
6
Soft-start : input for soft-start and integration network. Start-up will begin with short pulses by connecting a
capacitor between Pin 7 to ground. This capacitor together with a resistor connected between Pin 7 and
error amplifier output also as acts an integrator network for regulation.
7
8
Zero detector : Input for the oscillator feedback. After starting oscillator, every zero transit of the feedback
voltage (falling edge) triggers an output pulse at Pin 5. The trigger threshold is at typically - 50mV
Figure 2. Block Diagram
6
2
5
TDA4605
Reference
Voltage
(typ. 3V)
Supply
Voltage
Monitor
Primary
Current
Recopy
Output Stage
and
Current Limit
V2B
VREF
Starting
Impulse
V6min V6A V6E V6max
V
st
4
Logic
Generator
Current
Source
Regulating
& Overload
Amplifier
VR
Stop
Comp.
1
Zero
Crossing
Detector
Overload
Point
Correction
Low Voltage
Protection
Monitoring
Vu
3
7
8
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1
TDA4605
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
Pin
1
Value
-0.3, +3
-0.3
Unit
V
V
V
V
V
V
V
1
2
3
4
6
7
2
V
3
-0.3
V
Supply Voltage
4
-0.3
V
6
-0.3, +20
V
V
7
-0.3
I
I
I
I
I
I
I
I
1
3
3
mA
mA
mA
A
1
2
2
3
4
5
6
7
8
3
3
t ≤ 50µs, V ≤ 0.1
4
- 1.5
-0.5, +1.5
0.5
p
Supply Current
t ≤ 50µs, V ≤ 0.1
5
A
p
t ≤ 50µs, V ≤ 0.1
6
A
p
7
3
mA
mA
8
-3, +3
+125
-40, +125
o
T
Junction Temperature (autom. thermal disjunction)
Storage Temperature
C
j
o
T
C
stg
THERMAL DATA
Symbol
Parameter
Value
Unit
o
R (j-a)
Junction-ambient Thermal Resistance
80
45
C/W
C/W
th
o
R (j-c)
Junction-case Thermal Resistance
Ambient Temperature
th
o
T
-20, +85
C
amb
oC
ELECTRICAL CHARACTERISTICS (V = 10V, T
= 25 , unless otherwise specified)
CC
amb
Symbol
Parameter
Test Conditions
Min. Typ. Max. Unit
START-UP HYSTERESIS
I
Start-up Current Drain
Switch-on Voltage
Switch-off Voltage
Switch-on Current
Switch-off Current
V = V
0.6 0.8 mA
6E0
6
6E
V
V
11
12 13
V
6E
6A
4.5
5
5.5
V
I
I
V = V
11
10
mA
mA
6E1
6
6E
V = V
6A1
6
6A
VOLTAGE CLAMP (V = 10V, IC Switched off)
6
V (Max.) At Pin 2 (V < V
)
)
I = 1mA
5.6 6.6
5.6 6.6
9
9
V
V
2
6
6E
6E
2
V (Max.) At Pin 3 (V < V
I = 1mA
3
3
6
CONTROL RANGE
V
Control Input Voltage
400 410 420 mV
1R
V
= d(V - V )/dV
2S 2B 1
R
-V
Voltage Gain of the Control Circuit in the Control Range
43
dB
R
f = 1kHz
PRIMARY CURRENT SIMULATION VOLTAGE
Basic Value
OVERLOAD RANGE AND SHORT CIRCUIT OPERATION
V
0.955 1.00 1.03
V
2B
V
Peak Value in the Range of Secondary Overload
Maximum Ramp Amplitude
V = V - 10mV
2.8 2.95 3.1
1.82 1.95 2.08
V
V
2O
1
1R
DV
V
- V
2O 2B
2
Peak Value in the Range of Secondary Short
Circuit Operation
V
V = 0
2.3 2.5 2.7
V
2S
1
FOLDBACK POINT CORRECTION
-I Foldback Point Correction Current
V = 3.7V
300 500 650 µA
2
3
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1
TDA4605
oC
ELECTRICAL CHARACTERISTICS (V = 10V, T
= 25 , unless otherwise specified) - Continued
CC
amb
Symbol
Parameter
Test Conditions
Min. Typ. Max. Unit
GENERALLY VALID DATA (V = 10V)
6
VOLTAGE OF THE ZERO Transition DETECTOR
V
V
V
Positive Clamping Voltage
Negative Clamping Voltage
Threshold Value
I = 1mA
0.75
-0.2
50
V
V
8P
8N
8S
8
I = -1mA
8
40
3
mV
TUL
-I
Suppression of Transformer Ringing
Input Current
3.8 4.5 µs
V = 0
0
4
µV
8
8
PUSH-PULL OUTPUT STAGE
SATURATION VOLTAGES
V
V
V
Pin 5 Sourcing
Pin 5 Sinking
Pin 5 Sinking
I = -0.1A
1.5 2.0
1.0 1.2
1.4 1.8
V
V
V
SatU
SatU
SatU
5
I = 0.1A
5
I = 0.5A
5
OUTPUT SLOW RATE
dV /dt
Rising Edge
Falling Edge
70
V/µs
V/µs
5
-dV /dt
100
5
REDUCTION OF CONTROL VOLTAGE
-I Current to reduce the Control Voltage
PROTECTION CIRCUIT
Undervoltage Protection for V :
V = 1V
50
µA
1
7
6
V (Min.)
7.0 7.25 7.5
15 16 16.5
V
V
6
Voltage at Pin 5 = V (Min.) if V < V (Min.)
5
6
6
Overvoltage Protection for V :
6
V (Max.)
6
Voltage at Pin 5 = V (Min.) if V > V (Max.)
5
6
6
Undervoltage Protection for V
:
AC
V
V = 0V
970 1005 1040 mV
3A
2
Voltage at Pin 5 = V (Min.) if V < V
5
3
3A
Over Temperature : at the given chip temperature the
IC will switch V to V (Min.)
o
Oj
150
C
5
5
Voltage at Pin 3 if one of the protection functions was
V
I = 750µA
0.4 0.8
8
V
3Sat
3
triggered ; (V will be clamped until V < V
)
3
6
6A
I
Current Drain during Burst Operation
V = V = 0V
mA
6
3
2
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1
TDA4605
FUNCTIONAL DESCRIPTION
In free running fly-back converters, the TDA4605
assumes control of a MOS power transistor and all
necessary regulation and monitoring functions.
In different load ranges, the SMPS will behave as
follows:
– No-Load Operation: The power supply unit os-
cillates in non continuous mode at a typical fre-
quency of 20 to 40kHz. Depending upon the
transformer winding and the regulated voltage di-
vider, the output voltage can be slightly above
the nominal value.
The serial circuit of power transistor and primary
winding of the flyback transformer is connected to
the input voltage. During the switch-on period of
the transistor, energy is stored in the transformer
and during the switch-off period it is fed to the load
via the secondary winding. By varying the switch-
on time of the power transistor, the IC controls
each portion of energy transferred to the second-
ary side such that the output voltage remains near-
ly independent of load variations.
– Normal Operation: Starting from typ. 200kHz,
the switching frequency falls with increasing load
and decreasing AC voltage. The duty cycle de-
pends primarily on the AC voltage. The output
voltage is only slightly load-dependent.
The required control information is taken from the
input voltage during the switch-on period and from
a regulation winding during the switch-off period. A
new cycle begins as soon as the energy stored in
the transformer has been totally delivered to the
secondary side.
– Overload Point: Maximum output power is
available at this point of the output characteris-
tics
– Overload: The energy transferred per operation
cycle is limited at the top. Therefore, the output
voltage will fall with secondary overloading.
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TDA4605
PACKAGE MECHANICAL DATA
8-PINS - PLASTIC DIP
Figure 3. 8-Pin Package
8-PINS - PLASTIC SO
Figure 4. 8-Pin Plastic Micropackage
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TDA4605
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