Electronic Circuits EE359A Bruce McNair B206 bmcnair@stevens.edu 201-216-5549 Lecture 18 436
Bistable circuit If v + > 0, v 0 = V max à v + > 0 If v + < 0, v 0 = -V max à v+ < 0 437
Bistable circuit physical analogy 438
Bistable circuit transfer function 439
Noninverting bistable circuit transfer function 440
Using bistable to clean up noisy signals 441
Relaxation oscillator R V c V B C t 442
Relaxation oscillator R V c V B C t 443
Astable multivibrator 444
Astable multivibrator 445
Astable multivibrator Square wave output 446
Triangle/square wave generator Integrator 447
Monostable multivibrator 448
The 555 timer IC 449
R-S Flip flop R Q S Q S R Q n Q n 0 0 0 1 1 0 1 1 Q n-1 Q n-1 0 1 1 0 undefined 450
R-S Flip flop R Q S Q R Q S Q 451
555 as a monostable multivibrator 452
555 as an astable multivibrator 453
Non-linear wave shaping 454
Diode shaping networks 455
Output Stages and Power Amplifiers Ch 12 456
Multistage amplifiers - rationale High input Z for minimal loading High power output (differential input for noise immunity) High gain (in multiple stages) Low output Z for minimal impact from load 457
Multistage amplifiers - rationale High input Z for minimal loading High power output (differential input for noise immunity) High gain (in multiple stages) Low output Z for minimal impact from load 458
General considerations in (output) power amplifiers in out 459
General considerations in (output) power amplifiers out in out in Linearity 460
General considerations in (output) power amplifiers DC power in out in out Efficiency Signal power out in Linearity 461
General considerations in (output) power amplifiers DC power in Heat (and cooling) out in out Efficiency Signal power out in Linearity 462
General amplifier tradeoffs 360 0 conduction angle Best linearity Lowest efficiency 180 0 conduction angle Moderate linearity Moderate efficiency <180 0 conduction angle Poor linearity Best efficiency 463
General amplifier tradeoffs 360 0 conduction angle Best linearity Class A Lowest efficiency 180 0 conduction angle Moderate linearity Class B Moderate efficiency <180 0 conduction angle Poor linearity Class C Best efficiency 464
Class A amplifier 465
Class A amplifier Bias circuit 466
Class A amplifier Bias circuit Emitter follower amplifier 467
Class A amplifier vo = vi vbe1 468
Class A amplifier 469
Class A amplifier Large linear range Q 1 turns off 470
Class A efficiency Output voltage 471
Class A efficiency Output voltage Collector-emitter voltage 472
Class A efficiency Output voltage Collector-emitter voltage Collector current 473
Class A efficiency Output voltage Collector-emitter voltage Collector current 474
Class A efficiency Output voltage Collector-emitter voltage Collector current Power dissipation 475
Class A efficiency P P L η = S Power delivered to load Power supplied to circuit For a sinusoidal signal with peak voltage P L = 2 2 = R L 2 2R L Supply power is P = 2V I S CC η P L P S = Efficiency is 2 2R L 2V CC I = 1 4 IR L V CC 476
Class A efficiency P P L η = S Power delivered to load Power supplied to circuit For a sinusoidal signal with peak voltage P L = 2 2 = R L 2 2R L Supply power is P = 2V I S CC η P L P S = Efficiency is 2 2R L 2V CC I = 1 4 IR L V CC 477
Class A efficiency P P L η = S Power delivered to load Power supplied to circuit For a sinusoidal signal with peak voltage P L = 2 2 = R L 2 2R L Supply power is P = 2V I S CC η P L P S = Efficiency is 2 2R L 2V CC I = 1 4 IR L V CC 478
Class A efficiency P P L η = S Power delivered to load Power supplied to circuit For a sinusoidal signal with peak voltage P L = 2 2 = R L 2 2R L Supply power is P = 2V I S CC η P L P S = Efficiency is 2 2R L 2V CC I = 1 4 IR L V CC 479
Class A efficiency η P L P S = 2 2R L 2V CC I = 1 4 IR L V CC But V CC and IR L So η 1 4 Best efficiency when = V CC = IR L 480
Class A efficiency η P L P S = 2 2R L 2V CC I = 1 4 IR L V CC But V CC and IR L So η 1 4 Best efficiency when = V CC = IR L Class A isn t practical for stages that develop any appreciable amount of power 481
Class B output stage 482
Class B output stage Push Pull 483
Class B transfer characteristic 484
Class B dead band 485
Class B operation 10 5 ClassB( x) 0 5 10 10 5 0 5 10 x 4 2 h( t) 0 2 4 0 0.2 0.4 0.6 0.8 t 0 ( ) 20 log A j 20 40 60 0 10 20 30 j 486
Class B operation 10 5 ClassB( x) 0 5 10 10 5 0 5 10 x 4 2 h( t) 0 2 4 0 0.2 0.4 0.6 0.8 t 0 ( ) 20 log A j 20 40 60 0 10 20 30 j 487
Class B efficiency 488