SGS-THOMSON TEA2018A Technical data
TEA2018A
CURRENT MODE SWITCHING
POWER SUPPLY CONTROL CIRCUIT
.DIRECT DRIVE OF THE EXTERNAL
.SWITCHING TRANSISTOR
POSITIVE AND NEGATIVE OUTPUT CUR-
.RENTS UP TO 0.5 A
.CURRENT LIMITATION TRANSFORMER DEMAGNETIZATION
.SENSING
FULL OVERLOAD AND SHORT-CIRCUIT
.PROTECTION
.PROPORTIONAL BASE CURRENT DRIVING LOW STANDBY CURRENT BEFORE START-
.ING (< 1.6 mA) THERMAL PROTECTION
DESCRIPTION
The TEA2018A is an 8-pin DIP low-cost integrated circuit designed for the control of switch mode power supplies.
Due to its current mode regulation, the TEA2018A facilitates design of power supplies with following
.features :
.High stability regulation loop
Automatic input voltage feed-forward in dis-
.continuous mode fly-back
Automatic pulse-by-pulse current limitation Typical applications : Video Display Units, TV sets, typewriters, microcomputers and industrialapplications
Where synchronization is required, use the TEA2019. For more details, see application note AN406/0591
DIP8
(Plastic Package)
ORDER CODE : TEA2018A
PIN CONNECTIONS
OSCILLATOR |
1 |
8 |
ERROR AMPLIFIER NON-INVERTING INPUT |
GROUND |
2 |
7 |
DEMAGNETIZATION SENSING |
COLLECTOR CURRENT SENSING |
3 |
6 |
POSITIVE SUPPLY VOLTAGE |
NEGATIVE SUPPLY VOLTAGE |
4 |
5 |
OUTPUT |
2018A-01.EPS
May 1993 |
1/7 |
TEA2018A
BLOCK DIAGRAM
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VCC |
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TEA2018A |
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6 |
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DEMAGNETIZATION |
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VCC |
VREF |
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I S |
7 |
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2.4V |
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SENSING |
INTERNAL |
MONITORING |
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BIAS |
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VCC |
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0.1V |
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ºGoodº |
Undervoltage |
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R t C t |
1 |
OSCILLATOR |
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Ic |
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RECOPY |
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FLIP-FLOP |
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5 OUTPUT |
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MAXIMUM |
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DELAY |
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DUTY CYCLE |
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1 |
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70% |
1 |
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500ns |
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COMPARATOR |
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8 |
G 50 |
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THERMAL |
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SHUTDOWN |
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2.4V |
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-1V |
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VOLTAGE |
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LIMITATION |
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3 |
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2 |
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4 |
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ISENSE |
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GROUND |
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VCC |
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ABSOLUTE MAXIMUM RATINGS |
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Symbol |
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Parameter |
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Value |
Unit |
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VCC+ |
Positive Supply Voltage |
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15 |
V |
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VCC- |
Negative Supply Voltage |
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-5 |
V |
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IO(peak) |
Peak Output Current (duty cycle < 5%) |
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±1 |
A |
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II |
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Input Current (Pin 3) |
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±5 |
mA |
Tj |
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Junction Temperature |
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+150 |
oC |
Toper |
Operating Ambient Temperature Range |
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-20, +70 |
oC |
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Tstg |
Storage Temperature Range |
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-40, +150 |
oC |
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2018A-02.EPS
2018A-01.TBL
THERMAL DATA
Symbol |
Parameter |
Value |
Rth (j-a) |
Junction-ambient Thermal Resistance |
80 |
Unit oC/W
2018A-02.TBL
ELECTRICAL OPERATING CHARACTERISTICS
Tamb = 25oC, potentials referenced to ground (unless otherwise specified) (see test circuit)
Symbol |
Parameter |
VCC+ |
Positive Supply Voltage |
VCC- |
Negative Supply Voltage |
VCC(start) |
Minimum Positive Supply Voltage required for starting (VCC+ rising) |
VCC(stop) |
Minimum Positive Voltage below wich device stops operating (VCC+ falling) |
Min. |
Typ. |
Max. |
Unit |
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6.6 |
8 |
15 |
V |
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-1 |
-3 |
-5 |
V |
-03.TBL |
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6 |
6.6 |
V |
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4.2 |
4.9 |
5.6 |
V |
2018A |
2/7
TEA2018A
ELECTRICAL OPERATING CHARACTERISTICS
Tamb = 25oC, potentials referenced to ground (unless otherwise specified) (see test circuit)
Symbol |
Parameter |
Min. |
Typ. |
Max. |
Unit |
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VCC+ |
Hysteresis on VCC+ Threshold |
0.7 |
1.1 |
1.6 |
V |
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ICC(sb) |
Stand-by Supply Current before starting (VCC+ < VCC(start)) |
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1 |
1.6 |
mA |
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Vth(IC) |
Current Limitation Threshold Voltage (Pin 3) |
-1100 -1000 |
-880 |
mV |
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R(IC) |
Collector Current Sensing Input Resistance |
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1000 |
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Ω |
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V7(th) |
Demagnetization Sensing Threshold |
75 |
100 |
125 |
mV |
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IS |
Demagnetization Sensing Input Current (Pin 7 = 0V) |
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1 |
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μA |
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τmax |
Maximum Duty Cycle |
60 |
70 |
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% |
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AV |
Error Amplifier Gain |
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50 |
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II+ |
Error Amplifier Input Current (non-inverting input) |
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2 |
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μA |
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VREF |
Internal Reference Voltage |
2.3 |
2.4 |
2.5 |
V |
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VREF |
Reference Voltage Temperature Drift |
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10 |
-4 |
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o |
T |
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V/ C |
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tOSC |
Oscillator Free-running Period ( R = 59kΩ, C = 1.2nF) |
44 |
48 |
52 |
μs |
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fOSC |
Oscillator Frequency Drift with Temperature (VCC+ = +8V) |
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0.05 |
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%/oC |
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T |
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fOSC |
Oscillator Frequency Drift with VCC+ (+8V < VCC+ < +14V) |
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0.5 |
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%/V |
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VCC |
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ton(min) |
Minimum Conducting Time (Ct = 1nF) |
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2 |
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μs |
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2018A-04.TBL
RECOMMENDED OPERATING CONDITIONS
Symbol |
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Parameter |
Min. Typ. Max. |
Unit |
VCC+ |
Positive Supply Voltage |
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8 |
V |
VCC- |
Negative Supply Voltage |
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-3 |
V |
IO |
Output Current |
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0.5 |
A |
foper |
Operating Frequency |
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30 |
kHz |
TEST CIRCUIT
V8 |
V7 |
V6 |
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22nF |
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470Ω |
10Ω |
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22nF |
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8 |
7 |
6 |
5 |
2018A-05.TBL
TEA2018A
59kΩ |
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1% |
2 |
3 |
4 |
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1 |
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1.2nF |
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4.7nF |
22nF |
470nF |
1% |
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100Ω |
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V1 |
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V3 |
V4 |
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2018A-03.EPS
3/7
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