voltage references (ch. 23) - chungbuk.ac.krbandi.chungbuk.ac.kr/~ysk/aana23.pdf · 2011-02-23 ·...
TRANSCRIPT
Voltage References (Ch. 23)g
김 영 석김 영 석
충북대학교 전자정보대학
2011.3.1. .
Email: [email protected]
전자정보대학 김영석 23-1
Contents23.1 MOSFET-Resistor Voltage References
23.2 Parasitic Diode-Based References
전자정보대학 김영석 23-2
PTAT/CTATPTAT(Proportional to absolute temperature)
CTAT(Complementary to absolute temperature)
전자정보대학 김영석 23-3
23.1 MOSFET-Resistor Voltage References23.1.1 The Resistor-MOSFET Divider
)(2
21 −=−
= VVR
VVDDI THNREFREF
Dβ
)4.23(11
=∂
∂=
Δ+=∴
TV
VTCV
VVV
REFREF
THNREF
Ex 23.1
∂TVREF
CppmTCVVV
REF
REF
°≈≈
/50085.1
R
CmVT
VNote THN
∂
°−≈∂
∂
1
/1:
CmVVCmVV
CppmTR
RTCR
TDiode °≈∂
°−≈∂
°≈∂∂
=
/0850/61
/20001
전자정보대학 김영석 23-4
CmVT
CmVT
≈∂
≈∂
/085.0,/6.1
23.1.2 The MOSFET-Only Voltage Divider
ββ
/
)(2
)(2
21
2221
⋅+−
−−=−
ββ
ββ
THNTHP
THPREFTHNREF
VVVDD
VVVDDVV
)1123(11//
21
21
∂
+
+=∴
ββββ
REF
THNTHPREF
VTCV
VVVDDV
4.1/:0
)11.23(
21 ==
=∂
=
ββREF
REF
REFREF
TCV
TVTCV
High Sensitivity to VDD
전자정보대학 김영석 23-5
23.1.3 Self-Biased Voltage ReferencesBMR(Beta-Multiplier Reference)
Low Sensitivity to VDD
? )1 StabilizedHow
↓↑↑↑↑↑↑
+<↓↓↓↓=>↑=>↑=> 21214,342
)2
)(, MMggdgg
VDDtoySensitivit
RRRvvivv Q
↓↑=>↑↑=>↑↑=>↑=> 4,34214,3 , dgggddd ivvviv
전자정보대학 김영석 23-6
Ex 23.2
Cascoding Not Useful for Short Channel Process
Use the Added Amplifier
전자정보대학 김영석 23-7
BMREx 23.3
CppmTCVmVV
REF
REF
°−≈=
/800500
전자정보대학 김영석 23-8
BMRAlternate Topology
)(,
)( ,
21212
2121
RRRvvivv
IICurrentSameRVV
MMggRoutg
DDGG
+<↓↓↓↓=>↓=>↑=>
==>=
Qggg
전자정보대학 김영석 23-9
23.2 Parasitic Diode-Based ReferencesParasitic PNP BJT의 VBE 이용
Diode in SPICE
4PNPDIODE02D2PNPDIODE 0 1 D1
eII nVV TD=
== 1N 18-1EIS D PNPDIODE .MODEL4PNPDIODE0 2 D2
/
CmVdTdV
eII
D
SDTD
°−=
=
/6.1
전자정보대학 김영석 23-10
Lower Voltage Reference Design
VREF=300mV
전자정보대학 김영석 23-11
23.2.1 Long-Channel BGR DesignCTAT: Diode-Referenced Self-Biasing
CTATeIR
VI nVVS
DREF
TD== )(/
CppmTCIIInVVV
REF
SREFTDREF
°−===
/4000)/ln(
PTAT: Thermal Voltage-Referenced Self-Biasing
PTATTKnkI
eIIRIVV
REF
nVVSDDDD
TD
⋅⋅
=
=+=
)(ln)( , /
221
TqR
KLnkV
PTATTqR
I
REF
REF
⋅⋅⋅
=ln
)(
CppmTCIqR
REF °≈ /1300
전자정보대학 김영석 23-12
Long-Channel BGRBandGap Reference
VVV
VKnLVRLIVV TDDREF
∂∂∂+=
⋅⋅⋅+=⋅⋅+=PTAT) CTAT(ZTC
ln33
TVCmVTVCmVTV
TVKnL
TV
TV
TD
TDREF
∂∂°=∂∂°−=∂∂
∂∂⋅⋅⋅+
∂∂
=∂
∂=
/)/085.0 / ,/6.1/(
ln0
3
3
CCLnK
TVTVKnL
T
D
°===
=∂∂∂∂
−=⋅⋅∴
/1214.9,1,8
8.18//ln 3
CppmTCVVV REFREF °≈≈ /17,2.1
전자정보대학 김영석 23-13
Alternative BGR
전자정보대학 김영석 23-14
23.2.2 Short-Channel BGR
VNKNnVV
RLVI
RKnVI
DTREF
DCTAT
TPTAT
ln
,ln
1
1
⋅+⋅⋅=
⋅=
⋅=
TV
LNKN
TVn
TV
VL
KNnVV
DTREF
DTREF
ln0
ln
1
1
∂∂⋅+⋅⋅
∂∂
=∂
∂=
+
LnKTVTVKnL
T
D
4.9,1,8
8.18//ln 1
===
=∂∂∂∂
−=⋅⋅∴
VVforLVKnV
VN REFDT
REF 5.0 91.3/ln 1
==+⋅
=
전자정보대학 김영석 23-15
Short-Channel BGR
전자정보대학 김영석 23-16