282:
be varied between 0 and 1 or between 0 and 100%. Pulse-width modulation (PWM), or pulse-duration modulation (PDM), is a technique used to encode a message into a pulsing signal. Although this modulation technique can be used to encode information for transmission, its main use is to allow the control of the power supplied to electrical devices, especially to inertial loads such as motors. The average value of voltage (and current) fed to the load is controlled by turning the switch between supply and load on and off at a fast rate. The longer the switch is on compared to the off periods, the higher the total power supplied to the load. The PWM switching frequency has to be much higher than what would affect the load (the device that uses the power), which is to say that the resultant waveform perceived by the load must be as smooth as possible. Typically switching has to be done several times a minute in an electric stove, 120 Hz in a lamp dimmer, from few kilohertz (kHz) to tens of kHz for a motor drive and well into the tens or hundreds of kHz in audio amplifiers and computer power supplies.
31:
281:
In pulse-width modulation the switches are turned on at a constant chopping frequency. The total time period of one cycle of output waveform is constant. The average output voltage is directly proportional to the ON time of chopper. The ratio of ON time to total time is defined as duty cycle. It can
348:
amplifier instead. A chopper circuit is used to break up the input signal so that it can be processed as if it were an AC signal, then integrated back to a DC signal at the output. In this way, extremely small DC signals can be amplified. This approach is often used in electronic instrumentation
364:
of amplifiers becomes important when trying to amplify small signals with very high gain. Because this technique creates a very low input offset voltage amplifier, and because this input offset voltage does not change much with time and temperature, these techniques are also called "zero-drift"
62:
applications, since the switching element is either fully on or fully off, its losses are low and the circuit can provide high efficiency. However, the current supplied to the load is discontinuous and may require smoothing or a high switching frequency to avoid undesirable effects. In signal
847:
261:
For all the chopper configurations operating from a fixed DC input voltage, the average value of the output voltage is controlled by periodic opening and closing of the switches used in the chopper circuit. The average output voltage can be controlled by different techniques namely:
291:
In current limit control (CLC) technique, duty cycle is controlled by controlling the load current between maximum and minimum values. The chopper is switched ON and OFF periodically so that the load current is maintained between predetermined maximum and minimum values.
50:
circuit is any of numerous types of electronic switching devices and circuits used in power control and signal applications. A chopper is a device that converts fixed DC input to a variable DC output voltage directly. Essentially, a chopper is an electronic
63:
processing circuits, use of a chopper stabilizes a system against drift of electronic components; the original signal can be recovered after amplification or other processing by a synchronous demodulator that essentially un-does the "chopping" process.
368:
Auto-zero amplifiers use a secondary auxiliary amplifier to correct the input offset voltage of a main amplifier. Chopper-stabilized amplifiers use a combination of auto-zero and chopper techniques to give some excellent DC precision specifications.
688:
1402:
592:
365:
amplifiers (because there is no drift in input offset voltage with time and temperature). Related techniques that also give these zero-drift advantages are auto-zero and chopper-stabilized amplifiers.
956:
1325:. The inductor would be in parallel with the series diode and load. The same way by equating the average inductor current during the turn-on and turn-off time, we can get the average voltage by
1120:. The diode would be in parallel with the series inductor and load. The same way by equating the average inductor current during the turn-on and turn-off time, we can get the average voltage by
693:
1020:
526:
1170:
285:
In frequency modulation, pulses of a fixed amplitude and duration are generated and the average value of output is adjusted by changing how often the pulses are generated.
647:
1462:
1438:
1230:
1206:
1056:
882:
463:
677:
624:
1493:
1323:
1296:
1261:
1118:
1091:
410:
338:
430:
535:
842:{\displaystyle {\begin{aligned}L{\frac {di}{dt}}&=V_{ave}-V_{s}\\{\frac {\Delta i}{T_{OFF}}}&={\frac {V_{ave}-V_{s}}{L}}.\\\end{aligned}}}
465:. The chopper switch would be in parallel with the series diode and load. Whenever the chopper switch is on, the output is shorted. Using
1624:
Circuit techniques for reducing the Effect of Op-Amp
Imperfections: Autozeroing, Correlated Double Sampling and Chopper Stabilization
1331:
887:
478:
964:
1604:
17:
341:
349:
where stability and accuracy are essential; for example, it is possible using these techniques to construct
1657:
1528:
1126:
189:
247:
1271:
Taking a general buck-boost chopper which works as stepup and down chopper, let the voltage source
233:
884:
is the time were a load voltage is zero. Equating both average current and taking the duty cycle
288:
Variable pulse width and frequency combines both changes in the pulse width and repetition rate.
1594:
308:
amplifiers. Some types of signals that need amplifying can be so small that an incredibly high
266:
629:
1509:
1447:
1410:
1215:
1178:
1028:
854:
435:
35:
30:
652:
599:
1471:
1301:
1274:
1239:
1096:
1069:
680:
466:
388:
361:
312:
is required, but very high gain DC amplifiers are much harder to build with low offset and
220:
1576:
8:
1545:
US Patent 7132883 - Chopper chopper-stabilized instrumentation and operational amplifiers
683:
in determining inductor voltage with respect to average current within the turn-on time,
345:
315:
415:
372:
Some example chopper and auto-zero amplifiers are LTC2050, MAX4238/MAX4239 and OPA333.
354:
309:
225:
193:
1298:
be in series with the chopper switch, reverse biased diode, and the load with voltage
1662:
1600:
1565:
228:
59:
1504:
1093:
which is in series with the chopper switch, inductor, and the load with voltage
305:
300:
One classic use for a chopper circuit and where the term is still in use is in
1651:
210:
206:
43:
1554:
1465:
1233:
1635:
Chopper-Stabilized
Amplifiers with a Track-and-hold Signal Demodulator
1641:
1623:
1529:"Voltage Control of Chopper - Time Ratio & Current Limit Control"
66:
470:
214:
200:
55:
that is used to interrupt one signal under the control of another.
1642:
1441:
1209:
185:
Chopper circuits are used in multiple applications, including:
1644: - IEEE J. Solid-State Circuits, vol. 35 No. 12, Dec 2000
52:
1397:{\displaystyle V_{ave}={\frac {\alpha V_{s}}{1-\alpha V_{s}}}}
587:{\displaystyle {\frac {\Delta i}{T_{ON}}}={\frac {V_{s}}{L}}}
350:
1627:
530:
and taking the average current within the turn-off time,
951:{\displaystyle \alpha ={\frac {T_{ON}}{T_{ON}+T_{OFF}}}}
1066:
Taking a general step-down chopper with voltage source
1474:
1450:
1413:
1334:
1304:
1277:
1242:
1218:
1181:
1129:
1099:
1072:
1031:
967:
890:
857:
691:
655:
632:
602:
538:
481:
438:
418:
391:
318:
385:Take a general step-up chopper with voltage source
1487:
1456:
1432:
1396:
1317:
1290:
1255:
1224:
1200:
1164:
1112:
1085:
1050:
1015:{\displaystyle V_{ave}={\frac {V_{s}}{1-\alpha }}}
1014:
950:
876:
841:
671:
641:
618:
586:
520:
457:
424:
404:
332:
71:Comparison between step up and step down chopper:
67:Comparison (step down chopper and step up chopper)
1649:
679:. Whenever the chopper switch is off and using
626:is the time were a load voltage is present and
1266:
432:, diode and the load with average voltage
141:For regenerative braking for motor load.
130:Required for boosting the output voltage
274:Variable frequency, variable pulse width
29:
521:{\displaystyle L{\frac {di}{dt}}=V_{s}}
14:
1650:
138:For motoring operation, for motor load
1592:
412:which is in series with the inductor
295:
256:
1588:
1586:
1584:
1165:{\displaystyle V_{ave}=\alpha V_{s}}
1061:
340:noise, and reasonable stability and
1640:A. Bakker, K. Thiele, J. Huijsing,
649:the change current with respect to
24:
1637:- Allegro Technical Paper STP 99-1
762:
633:
542:
380:
174:Battery charging/voltage boosters
25:
1674:
1581:
34:Schematic of an inverter using a
1058:is the average output voltage.
344:. It's much easier to build an
180:
1599:. Tata McGraw-Hill Education.
1570:
1559:
1548:
1539:
1521:
241:Battery-operated electric cars
13:
1:
1616:
1515:
109:Expression for output voltage
1626: - Proceedings of the
190:Switched mode power supplies
7:
1630:, vol. 84 No. 11, Nov. 1996
1593:Singh, M. D. (2008-07-07).
1498:
1267:Step-up / step-down chopper
375:
10:
1679:
252:Lighting and lamp controls
98:Position of chopper switch
234:Variable-frequency drives
1633:A. Bilotti, G. Monreal,
642:{\displaystyle \Delta i}
27:Electromechanical device
1495:is the source voltage.
1457:{\displaystyle \alpha }
1433:{\displaystyle V_{ave}}
1263:is the source voltage.
1225:{\displaystyle \alpha }
1201:{\displaystyle V_{ave}}
1051:{\displaystyle V_{ave}}
877:{\displaystyle T_{OFF}}
458:{\displaystyle V_{ave}}
87:Range of output voltage
1489:
1458:
1440:is the average output
1434:
1398:
1319:
1292:
1257:
1226:
1208:is the average output
1202:
1166:
1114:
1087:
1052:
1016:
952:
878:
843:
673:
672:{\displaystyle T_{ON}}
643:
620:
619:{\displaystyle T_{ON}}
588:
522:
459:
426:
406:
334:
267:Pulse-width modulation
199:Speed controllers for
104:In parallel with load
39:
1510:Vibrator (electronic)
1490:
1488:{\displaystyle V_{s}}
1459:
1435:
1399:
1320:
1318:{\displaystyle V_{o}}
1293:
1291:{\displaystyle V_{s}}
1258:
1256:{\displaystyle V_{s}}
1227:
1203:
1167:
1115:
1113:{\displaystyle V_{o}}
1088:
1086:{\displaystyle V_{s}}
1053:
1017:
953:
879:
844:
681:Kirchhoff Voltage Law
674:
644:
621:
589:
523:
467:Kirchhoff Voltage Law
460:
427:
407:
405:{\displaystyle V_{s}}
335:
238:D.C. voltage boosting
221:electronic amplifiers
205:Driving brushless DC
157:Quadrant of operation
33:
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1448:
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536:
479:
436:
416:
389:
362:input offset voltage
316:
271:Frequency modulation
1658:Electronic circuits
1535:. 25 February 2022.
333:{\displaystyle 1/f}
194:DC to DC converters
171:Motor speed control
124:External inductance
112:VL dc = D × V volts
101:In series with load
1622:C. Enz, G. Temes,
1485:
1454:
1430:
1394:
1315:
1288:
1253:
1222:
1198:
1162:
1110:
1083:
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1012:
948:
874:
839:
837:
669:
639:
616:
584:
518:
455:
422:
402:
330:
302:chopper amplifiers
296:Chopper amplifiers
257:Control strategies
226:Switched capacitor
119:= V/(1 – D) volts
40:
1596:Power Electronics
1392:
1062:Step-down chopper
1010:
946:
830:
785:
717:
582:
562:
503:
425:{\displaystyle L}
178:
177:
79:Step down chopper
60:power electronics
16:(Redirected from
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1610:
1590:
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1574:
1568:
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1537:
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1533:Electronics Mind
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1111:
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983:
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248:Railway traction
244:Battery chargers
152:Single quadrant
82:Step up chopper
74:
73:
21:
1678:
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1669:
1668:
1667:
1648:
1647:
1619:
1614:
1607:
1591:
1582:
1575:
1571:
1566:MAX4238/MAX4239
1564:
1560:
1553:
1549:
1544:
1540:
1527:
1526:
1522:
1518:
1505:Braking chopper
1501:
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1128:
1125:
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512:
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476:
469:in determining
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417:
414:
413:
396:
392:
390:
387:
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383:
381:Step Up Chopper
378:
351:pico-voltmeters
322:
317:
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298:
259:
183:
149:Single quadrant
146:Type of chopper
118:
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28:
23:
22:
18:Chopper control
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11:
5:
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329:
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211:stepper motors
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93:V to +∞ volts
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68:
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26:
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3:
2:
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1606:9780070583894
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224:
222:
218:
216:
212:
208:
207:torque motors
204:
202:
198:
195:
191:
188:
187:
186:
173:
170:
167:
166:
163:1st quadrant
162:
159:
156:
155:
151:
148:
145:
144:
140:
137:
134:
133:
129:
126:
123:
122:
114:
111:
108:
107:
103:
100:
97:
96:
92:
89:
86:
85:
81:
78:
76:
75:
72:
64:
61:
56:
54:
49:
45:
38:as a chopper.
37:
32:
19:
1634:
1595:
1572:
1561:
1550:
1541:
1532:
1523:
1406:
1328:
1270:
1174:
1123:
1065:
1024:
961:
850:
685:
595:
532:
529:
475:
384:
371:
367:
359:
355:Hall sensors
304:. These are
301:
299:
290:
287:
284:
280:
260:
192:, including
184:
181:Applications
168:Applications
160:1st quadrant
127:Not required
90:0 to V volts
70:
57:
47:
41:
277:CLC control
44:electronics
1652:Categories
1617:Literature
1516:References
1466:duty cycle
1234:duty cycle
1452:α
1379:α
1376:−
1358:α
1220:α
1150:α
1007:α
1004:−
892:α
814:−
763:Δ
743:−
634:Δ
543:Δ
473:voltage,
342:bandwidth
215:actuators
201:DC motors
1663:Choppers
1499:See also
471:inductor
376:Formulas
219:Class D
36:vibrator
1555:LTC2050
1464:is the
1442:voltage
1232:is the
1210:voltage
229:filters
48:chopper
1603:
1577:OPA333
1407:where
1175:where
1025:where
851:where
596:where
53:switch
1628:IEEE
1601:ISBN
1468:and
1236:and
360:The
353:and
310:gain
46:, a
213:in
209:or
135:Use
58:In
42:In
1654::
1583:^
1531:.
1444:,
1212:,
958:,
357:.
346:AC
306:DC
1609:.
1481:s
1477:V
1426:e
1423:v
1420:a
1416:V
1387:s
1383:V
1373:1
1366:s
1362:V
1352:=
1347:e
1344:v
1341:a
1337:V
1311:o
1307:V
1284:s
1280:V
1249:s
1245:V
1194:e
1191:v
1188:a
1184:V
1158:s
1154:V
1147:=
1142:e
1139:v
1136:a
1132:V
1106:o
1102:V
1079:s
1075:V
1044:e
1041:v
1038:a
1034:V
1001:1
995:s
991:V
985:=
980:e
977:v
974:a
970:V
941:F
938:F
935:O
931:T
927:+
922:N
919:O
915:T
908:N
905:O
901:T
895:=
870:F
867:F
864:O
860:T
833:.
828:L
822:s
818:V
809:e
806:v
803:a
799:V
792:=
781:F
778:F
775:O
771:T
766:i
751:s
747:V
738:e
735:v
732:a
728:V
724:=
714:t
711:d
706:i
703:d
697:L
665:N
662:O
658:T
637:i
612:N
609:O
605:T
580:L
575:s
571:V
565:=
558:N
555:O
551:T
546:i
514:s
510:V
506:=
500:t
497:d
492:i
489:d
483:L
451:e
448:v
445:a
441:V
420:L
398:s
394:V
328:f
324:/
320:1
196:.
117:o
115:V
20:)
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