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ET8016-2009 1
Structured Electronic DesignStructured Electronic Design
Accurate amplificationAccurate amplification
ET8016-2009 2
Right choice
Orthogonalization
Optimization
Right choice
Orthogonalization
Optimization
ET8016-2009 3
• Clear definition of the function
• The criteria
NNSBC +
= log2
The criteriaThe criteria
ET8016-2009 4
bandwidth – noise – distortionbandwidth – distortion - noisenoise - bandwidth – distortionnoise – distortion - bandwidthdistortion - noise – bandwidthdistortion – bandwidth - noise
bandwidth – noise – distortionbandwidth – distortion - noisenoise - bandwidth – distortionnoise – distortion - bandwidthdistortion - noise – bandwidthdistortion – bandwidth - noise
Design procedure?Design procedure?
Design?Specs verification
ET8016-2009 5
Structured design methodStructured design method
Orthogonality
Hierarchy
ET8016-2009 6
Specs Verification
HierarchyHierarchy
1MΩ
+
_ +
_
4.7MΩ 1MΩ
1nFvout
1MΩ
4.7MΩ
1MΩ
1nFvout
Q1Q2
Rs
Rt
Rl
ET8016-2009 7
What is an amplifier?What is an amplifier?
ET8016-2009 8
Information from source to load
• Signal power is enlarged
• Information stays unaltered
A,B,C,D indicate gainA,B,C,D constantA,B,C,D accurately known
A,B,C,D indicate gainA,B,C,D constantA,B,C,D accurately known
A BC D
Accurate amplificationAccurate amplification
⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛=⎟⎟
⎠
⎞⎜⎜⎝
⎛
out
out
in
in
iv
DCBA
iv
ET8016-2009 9
ClassificationClassification1. A,B,C,D indicate gain2. A,B,C,D constant3. A,B,C,D accurately known
1. A,B,C,D indicate gain2. A,B,C,D constant3. A,B,C,D accurately known
11
11
11
22
22
22
33
3333
33
33
33
33
33
ET8016-2009 10
Accurate elements Elements with gain
AccuracyGain
⎟⎟⎠
⎞⎜⎜⎝
⎛DCBA
⎟⎟⎠
⎞⎜⎜⎝
⎛DCBA
⎟⎟⎠
⎞⎜⎜⎝
⎛DCBA ( ) ( )
( ) ( )⎟⎟⎠⎞
⎜⎜⎝
⎛,....,,,,....,,,,....,,,,....,,,
cccc
cccc
VITDVITCVITBVITA
ωωωω
( ) ( )( ) ( )⎟⎟⎠
⎞⎜⎜⎝
⎛,....,,,,....,,,,....,,,,....,,,
dddd
dddd
VITDVITCVITBVITA
ωωωω
Classification of available componentsClassification of available components
( ) ( )( ) ( )⎟⎟⎠
⎞⎜⎜⎝
⎛,....,,,,....,,,,....,,,,....,,,
dddd
dddd
VITDVITCVITBVITA
ωωωω
ET8016-2009 11
The big question…The big question…
How can we combine the propertiesof the two orthogonal sets
in one system in a perfect way?
How can we combine the propertiesof the two orthogonal sets
in one system in a perfect way?
A,B,C,D indicate gainA,B,C,D constantA,B,C,D accurately known
A,B,C,D indicate gainA,B,C,D constantA,B,C,D accurately known
ET8016-2009 12
2R
1R
yU xU
2
1 2
Rx yR RU U+=
Accurate reduction
ET8016-2009 13
2R
1R
yU xU inU
1 2
2
R Ry inRU U+=
Accurate reduction
2
1 2
Rx yR RU U+=
Accurate amplification
ET8016-2009 14
2R
1R
inUNorrator
Nullator
1 2
2
R Ry inRU U+=
yU
Accurate amplification
ET8016-2009 15
• Nullor + passive components ⇒ accurate amplifier
• The perfect method
• Nullor = simplest model for active circuit
Negative feedbackNegative feedback
1 2
2
R Rout inRU U+=
2R
1R inUoutU
ET8016-2009 16
HierarchyHierarchy
Passive elements Active elementsSpecs verification
• Accurate reduction • Gain
• ONLY passive elements • ONLY active elements
Only!!Only!!
ET8016-2009 17
1) design of feedback network with nullor in the loop
2) design of the active circuit
Nullor: absolute design freedom
• No noise
• No distortion
• No bandwidth limitations
Amplifier design in two orthogonal stepsAmplifier design in two orthogonal steps
ET8016-2009 18
The general negative feedback systemThe general negative feedback system
sE cE
0tA
β
LEiEA
00
0
c
s
i
E
s E
c
Lt
EA
E
E
Eβ
=
=
=
=0L c
i s c
c i
t sE EE E βE
E
AE
A
E
= +
= +=
0tA : The direct transfer
ET8016-2009 19
sE cE
0tA
β
LEiEA
01
1tL
ts
AE AAE A
ββ β⎛ ⎞
= = + ⎜ ⎟−⎝ ⎠
The overall gain AtThe overall gain At
ET8016-2009 20
The loopgain LThe loopgain L
sE cE
0tA
β
LEiEA
L
01
1L
t ts
E AA AE A
ββ β⎛ ⎞
= = + ⎜ ⎟−⎝ ⎠0
11t
Lt
s
LL
AEAE β
⎛ ⎞= = + ⎜ ⎟−⎝ ⎠
ET8016-2009 21
0lim1
L tt tA AAβ→∞
∞= − =
The asymptotic gain At∞The asymptotic gain At∞
01
1tL
ts
LL
AEAE β
⎛ ⎞= = + ⎜ ⎟−⎝ ⎠sE cE
0tA
β
LEiEA
L
ET8016-2009 22
sE cE
0tA
β
LEiEA
L
The asymptotic gain modelThe asymptotic gain model
01
tt AAβ∞ = −
0
1 1tt
tLA A
L LA
∞
−= +
− −0
1 (!)tA β−
ET8016-2009 23
LLAA tt −
−= ∞ 1
Passive elements Active elementsNullorNullor
Hierarchy, OrthogonalityHierarchy, Orthogonality
sE cE
0tA
β
LEiEA
L 01
tt AAβ∞ = −
ET8016-2009 24
Amplifier design in two steps
1) design of with nullor in the loop
2) design of the nullor approximation
Nullor: absolute design freedom• No noise• No distortion• No bandwidth limitations
LLAA tt −
−= ∞ 1
∞tA
ET8016-2009 25
Nullor design
Hierarchical designHierarchical design
LLAA tt −
−= ∞ 1
∞tA
First passive elements Then active elementsSpecs verification
ET8016-2009 26
More detailed hierarchy..More detailed hierarchy..
Feedback network Nullor designSpecs verification
Specs 1 2 verificationC1 C2 C3 B
NNSBC +
= log2bandwidth – noise – distortionbandwidth – distortion - noisenoise - bandwidth – distortionnoise – distortion - bandwidthdistortion - noise – bandwidthdistortion – bandwidth - noise
bandwidth – noise – distortionbandwidth – distortion - noisenoise - bandwidth – distortionnoise – distortion - bandwidthdistortion - noise – bandwidthdistortion – bandwidth - noise
ET8016-2009 27
Determination amplifier type:
• Specification input and output quantities
• Specification of the transfer
What may have influence and what not?
Step 1Step 1
What may have influence and what not?What may have influence and what not?
ET8016-2009 28
Specification input and output quantitiesSpecification input and output quantities
dQidt
=QvC
=C C
ET8016-2009 29
Specification of the transferSpecification of the transfer
V V V I I V I I
A B C D
ET8016-2009 30
Step 1: the right choiceStep 1: the right choice
• Feed back network determines transfer
• Source impedance no influence
• Load impedance no influence
• Best nullor implementation• No and no influence on L by source and load impedance
√
0tA
ET8016-2009 31
V V
VV
V I
VI
I V
IV
I I
II
v A v B i C iD
Best nullor implementationBest nullor implementation
ET8016-2009 32
Technological limitsTechnological limits
ET8016-2009 33
V V
VV
V I
VI
I V
IV
I I
II
Nullor implementation close to technologyNullor implementation close to technology
v Bv B v B v B
Zs
Zl
Zs
Zl
• Remember the best choice• Know the penalty for the others!• Remember the best choice• Know the penalty for the others!
ET8016-2009 34
The active part is a nullorThe active part is a nullor
Step 2, the feed back networkStep 2, the feed back network
V V V I I V I I
A B C D
ET8016-2009 35
Ideal feedback componentsIdeal feedback components
Transformer Gyrator
010
n
n
⎛ ⎞⎜ ⎟⎜ ⎟⎜ ⎟⎝ ⎠
• No power dissipation• No noise production• No noise enlargement• No excess voltages or currents• Galvanic separation
• No power dissipation• No noise production• No noise enlargement• No excess voltages or currents• Galvanic separation
01 0
R
R
⎛ ⎞⎜ ⎟⎜ ⎟⎜ ⎟⎝ ⎠
ET8016-2009 36
Voltage amplifierVoltage amplifier
LRinv sR
n1• No power dissipation• No noise production• No noise enlargement• No excess voltages or currents• Galvanic separation
• No power dissipation• No noise production• No noise enlargement• No excess voltages or currents• Galvanic separation
ET8016-2009 37
LR
invLR
invLR
inv
n1
Noise influenceNoise influence
• No power dissipation• No noise production• No noise enlargement• No excess voltages or currents• Galvanic separation
• No power dissipation• No noise production• No noise enlargement• No excess voltages or currents• Galvanic separation
ET8016-2009 38
Noise influenceNoise influence
LR
inv
n1
LR
inv
n1
LR
inv
n 11n
1
LR
inv
n1• No power dissipation• No noise production• No noise enlargement• No excess voltages or currents• Galvanic separation
• No power dissipation• No noise production• No noise enlargement• No excess voltages or currents• Galvanic separation
ET8016-2009 39
Noise influence impedance networkNoise influence impedance network
LR
invLR
inv
n1
ET8016-2009 40
Trans-impedance amplifierTrans-impedance amplifier
1R
sI sR LR outV
• No power dissipation• No noise production• No noise enlargement• No excess voltages or currents• Galvanic separation
• No power dissipation• No noise production• No noise enlargement• No excess voltages or currents• Galvanic separation
ET8016-2009 41
Ideal versus reality: transformerIdeal versus reality: transformer
Not always feasible• Parasitic impedances• Limited frequency range• Non-linearity (saturation)• Technological problems
ET8016-2009 42
Ideal versus reality: gyratorIdeal versus reality: gyrator
i C
iC
• Needs controlled sources (active elements)• Practical implementation produces noise• Non-linearity• Bandwidth restrictions
ET8016-2009 43
“Poor mans” gyrator“Poor mans” gyrator
iv
Feature lost : No power dissipationFeature lost : No noise productionFeature lost : No noise enlargementFeature lost : No excess voltages or currents
☺ Galvanic separation
ET8016-2009 44
“Very poor mans” gyrator“Very poor mans” gyrator
Feature lost: No power dissipationFeature lost : No noise productionFeature lost : No noise enlargementFeature lost : No excess voltages or currentsFeature lost : Galvanic separationDirect connection between input and output node
iv
ET8016-2009 45
Why use the ideal transformers and gyrator?Why use the ideal transformers and gyrator?
Absolute minimum of:
• Power consumption
• Current swing
• Voltage swing
• Noise If already this it not enough…..
√ √
(The specifications)
(The specifications)
ET8016-2009 46
Z1
Z2
Z
v
iv
v
Z
Z1
Z2i
i v
i
Common feed back networksCommon feed back networks
ET8016-2009 47
ET8016-2009 48
LR
inv
SR
Common feed back networks : Reduced `flexibilityCommon feed back networks : Reduced `flexibility
NNSBC +
= log2
LR
inv
SR
LR
inv
n1
SR
LR
n1
SRinv
Non-inverting voltage amplifier
Inverting voltage amplifier Non-inverting voltage amplifier
ET8016-2009 49
Impedance networks: • Produce noise (R)• Enlarge contribution existing noise sources• Dissipate power (R)• Create excess voltage or current• Galvanic coupling
Impedance networks: • Produce noise (R)• Enlarge contribution existing noise sources• Dissipate power (R)• Create excess voltage or current• Galvanic coupling
Negative feedback networksNegative feedback networks
ET8016-2009 50
A,B,C,D < 1A,B,C,D constantA,B,C,D accurately known
A,B,C,D < 1A,B,C,D constantA,B,C,D accurately known
Information from source to load
• Signal power is enlarged
• Information stays unaltered
A BC D
Accurate AmplificationAccurate Amplification
ET8016-2009 51
Accurate elements Elements with gain
AccuracyGain
⎟⎟⎠
⎞⎜⎜⎝
⎛DCBA
⎟⎟⎠
⎞⎜⎜⎝
⎛DCBA
⎟⎟⎠
⎞⎜⎜⎝
⎛DCBA ( ) ( )
( ) ( )⎟⎟⎠⎞
⎜⎜⎝
⎛,....,,,,....,,,,....,,,,....,,,
cccc
cccc
VITDVITCVITBVITA
ωωωω
( ) ( )( ) ( )⎟⎟⎠
⎞⎜⎜⎝
⎛,....,,,,....,,,,....,,,,....,,,
dddd
dddd
VITDVITCVITBVITA
ωωωω
Common classification of available componentsCommon classification of available components
( ) ( )( ) ( )⎟⎟⎠
⎞⎜⎜⎝
⎛,....,,,,....,,,,....,,,,....,,,
dddd
dddd
VITDVITCVITBVITA
ωωωω
ET8016-2009 52
Accurate elements Elements with gain
AccuracyGain
⎟⎟⎠
⎞⎜⎜⎝
⎛DCBA
⎟⎟⎠
⎞⎜⎜⎝
⎛DCBA
⎟⎟⎠
⎞⎜⎜⎝
⎛DCBA ( ) ( )
( ) ( )⎟⎟⎠⎞
⎜⎜⎝
⎛,....,,,,....,,,,....,,,,....,,,
cccc
cccc
VITDVITCVITBVITA
ωωωω
( ) ( )( ) ( )⎟⎟⎠
⎞⎜⎜⎝
⎛,....,,,,....,,,,....,,,,....,,,
dddd
dddd
VITDVITCVITBVITA
ωωωω
Exactly according to the definitionExactly according to the definition
( ) ( )( ) ( )⎟⎟⎠
⎞⎜⎜⎝
⎛,....,,,,....,,,,....,,,,....,,,
dddd
dddd
VITDVITCVITBVITA
ωωωω
An amplifier is a non-dynamic circuit.Why would there be dynamic elements in the feedback network?
An amplifier is a non-dynamic circuit.Why would there be dynamic elements in the feedback network?
ET8016-2009 53
Impedance networks: • Produce noise (R)• Enlarge contribution existing noise sources• Dissipate power (R)• Create excess voltage or current• Galvanic coupling• Dynamic elements will cause specific problems later
Impedance networks: • Produce noise (R)• Enlarge contribution existing noise sources• Dissipate power (R)• Create excess voltage or current• Galvanic coupling• Dynamic elements will cause specific problems later
ET8016-2009 54
Nullor design
ConclusionConclusion
Known:
• Topology
• Best nullor implementation
• Voltage and current swing
• Power consumption
• Minimal noise level
• Penalties for “second-best” choices
Specs 1 2 verificationC1 C2 C3 B√√
ET8016-2009 55