EP0900476A2 - Spannungs-stromkonverter mit fehlerkorrektur - Google Patents

Spannungs-stromkonverter mit fehlerkorrektur

Info

Publication number
EP0900476A2
EP0900476A2 EP98903226A EP98903226A EP0900476A2 EP 0900476 A2 EP0900476 A2 EP 0900476A2 EP 98903226 A EP98903226 A EP 98903226A EP 98903226 A EP98903226 A EP 98903226A EP 0900476 A2 EP0900476 A2 EP 0900476A2
Authority
EP
European Patent Office
Prior art keywords
node
terminal
electrode coupled
transconductance amplifier
voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP98903226A
Other languages
English (en)
French (fr)
Inventor
Evert Seevinck
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips Electronics NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Koninklijke Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Priority to EP98903226A priority Critical patent/EP0900476A2/de
Publication of EP0900476A2 publication Critical patent/EP0900476A2/de
Withdrawn legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03FAMPLIFIERS
    • H03F3/00Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/34DC amplifiers in which all stages are DC-coupled
    • H03F3/343DC amplifiers in which all stages are DC-coupled with semiconductor devices only
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03FAMPLIFIERS
    • H03F3/00Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
    • H03F3/34DC amplifiers in which all stages are DC-coupled
    • H03F3/343DC amplifiers in which all stages are DC-coupled with semiconductor devices only
    • H03F3/347DC amplifiers in which all stages are DC-coupled with semiconductor devices only in integrated circuits

Definitions

  • the invention relates to an electronic circuit comprising: an input terminal and a reference terminal for receiving an input current flowing through the input te ⁇ riinal and the reference terminal; an output terminal for generating an output current flowing through the output terminal and the reference terminal; a first transconductance amplifier having an output coupled to the input terminal and having inputs connected to receive a voltage difference between a first node and the reference node; a second transconductance amplifier having an output coupled to the output terminal and having inputs connected to receive said voltage difference between the first node and the reference node; and means for coupling the input terminal to the first node.
  • Figure 1 shows a known general technique.
  • An input voltage V s from source 2 is connected, via a series resistor 4, to an input terminal 6 and a reference terminal 8 of an electronic circuit which provides an output current i 2 at an output terminal 10 in response to an input current i j which flows into the input terminal 6.
  • the electronic circuit comprises a first transconductance amplifier 12 with an output 14 coupled to the input terminal 6, an inverting input 16 coupled to a first node 18 and a non-inverting input 20 coupled to the reference terminal 8 which serves as signal ground.
  • a short-circuit between the input terminal 6 and the first node 18 provides a zero signal difference between the input terminal 6 and the first node 18.
  • the electronic circuit further comprises a second transconductance amplifier 22 with an output 25 coupled to the output terminal 10, an inverting input 24 coupled to the first node 18 and a non-inverting input 26 coupled to the reference terminal 8.
  • the first and second transconductance amplifiers 12 and 22 have a transconductance g 2 and g 2 , respectively. They can be very simple, e.g.
  • the output, inverting input and non-inverting input of the transconductance amplifier corresponds to the collector, base and emitter, respectively, of a bipolar transistor or to the drain, gate and source, respectively, of a MOS transistor.
  • V A is the signal voltage difference between the first node 18 and the reference terminal 8 and R s is the resistance of series resistor 4.
  • the transconductance g 1 is normally not well-defined, temperature dependent and nonlinear. Therefore the current i j will suffer from distortion.
  • the ratio g 2 /g ⁇ enables variable gain to be achieved and is generally well-defined and linear since the peculiarities of transconductance g 1 are compensated by those of transconductance g 2 . It follows that also the output current i 2 will suffer from distortion.
  • the means for coupling comprises: means for measuring the voltage difference between the first node and the reference terminal; and means for inserting said voltage difference between the input terminal and the first node.
  • the invention is based on the recognition that the source of distortion is the signal voltage V A at the first node 18. This error signal is measured and added to the input voltage signal V s by inserting the measured error voltage between the input terminal 6 and the first node 18. This is shown in Figure 2. Now the current i j is given by:
  • V S ⁇ V A +V A VS R s R s
  • the means for measuring comprises a third transconductance amplifier having an output coupled to the first node and having inputs connected to receive said voltage difference between the first node and the reference node; and the means for inserting comprises a fourth transconductance amplifier having an output coupled to the first node and having inputs connected to receive a voltage difference between the input terminal and the first node.
  • the signals at the inputs of the third transconductance amplifier and the fourth transconductance amplifier are reversed copies of each other since the output currents of both transconductance amplifiers are equal but opposite in direction. So, the error signal at the first node appears in opposite direction between the input terminal and the first node, thereby counter-acting the effect of the error signal.
  • the transistors may be bipolar transistors or unipolar (MOS) transistors.
  • Figure 1 shows a circuit diagram of a conventional voltage-current converter
  • Figure 2 shows a circuit diagram of a voltage-current converter according to the invention
  • Figure 3 shows a circuit for elucidating the operation of the voltage- current converter according to the invention.
  • Figure 4 shows a circuit diagram of an embodiment of an voltage-current converter according to the invention
  • Figure 5 shows a circuit diagram of an embodiment of an voltage-current converter according to the invention.
  • Figure 6 shows a circuit diagram of an embodiment of an voltage-current converter according to the invention.
  • first main electrode and second main electrode correspond to the base, emitter and collector, respectively.
  • MOS transistors the control electrode, first main electrode and second main electrode correspond with the gate, source, and drain, respectively.
  • Figure 1 shows a known general technique for converting an input voltage V s into an output current i 2 .
  • the input voltage V s from a source 2 is connected, via a series resistor 4, to an input terminal 6 and a reference terminal 8 of an electronic circuit which provides an output current i 2 at an output terminal 10 in response to an input current i x which flows into the input terminal 6.
  • the electronic circuit comprises a first transconductance amplifier 12 with an output 14 coupled to the input terminal 6, an inverting input 16 coupled to a first node 18 and a non-inverting input 20 coupled to the reference terminal 8 which serves as signal ground.
  • a short-circuit between the input terminal 6 and the first node 18 provides a zero signal difference between the input terminal 6 and the first node 18.
  • the electronic circuit further comprises a second transconductance amplifier 22 with an output 25 coupled to the output terminal 10, an inverting input 24 coupled to the first node 18 and a non-inverting input 26 coupled to the reference terminal 8.
  • V A is the signal voltage difference between the first node 18 and the reference terminal 8 and R s is the resistance of series resistor 4.
  • the transconductance g l is normally not well-defined, temperature dependent and nonlinear. Therefore the current i j will suffer from distortion.
  • the ratio g 2 /g enables variable gain to be achieved and is generally well-defined and linear since the peculiarities of transconductance g x are compensated by those of transconductance g 2 . It follows that also the output current i 2 will suffer from distortion.
  • Figure 2 shows a circuit diagram of a voltage-current converter according to the invention. The technique employed is based on the recognition that the source of distortion is the signal voltage V A at the first node 18.
  • This error signal V A is measured, symbolically depicted with sensing or measuring means 28, and added to the input voltage signal V s by inserting the measured error voltage between the input terminal 6 and the first node 18, symbolically depicted with voltage source 30.
  • Figure 4 shows an implementation of the error correction technique through the use of two additional transconductance amplifiers.
  • the error voltage V A is measured by a third transconductance amplifier 32, which has a non-inverting input 34 connected to the node 18, an inverting input 36 connected to the reference terminal 8 and an output 38 connected to the node 18.
  • An opposite error voltage V A is inserted between the input terminal 6 and the node 18 by a fourth transconductance amplifier 40, which has a non- inverting input 42 connected to the input terminal 6, and an inverting input 44 and an output 45 connected to the node 18.
  • the output current from the output 38 of transconductance amplifier 32 flows into the output 46 of transconductance amplifier 40 and causes at the inputs 42 and 44 of transconductance amplifier 40 a voltage with an amplitude equal to the amplitude of the error voltage V A , but with opposite sign.
  • All four transconductance amplifiers 12, 22, 32 and 40 can be very simple.
  • the third transconductance amplifier 32 and the fourth transconductance amplifier 40 preferably have substantially equal transconductances g 0 in order to achieve the best error correction performance.
  • the transconductances g l and g 2 of the other two transconductance amplifiers 12 and 22 can be unequal in order to obtain current gain.
  • the overall transfer function of the voltage-current converter is given by:
  • Figure 5 shows a first transistor implementation of the four transconductance amplifier configuration of Figure 4.
  • the first transconductance amplifier 12 is implemented with transistor Tl, which has its emitter, base and collector connected to the reference terminal 8, the first node 18 and the input terminal 6, respectively.
  • the second transconductance amplifier 22 is implemented with transistor T2, which has its emitter, base and collector connected to the reference terminal 8, the first node 18 and a second node 48, respectively.
  • Transistor T3 and transistor T4 form the third transconductance amplifier 32.
  • the emitter, base and collector of transistor T3 are connected to the second node 48, a bias voltage terminal 50 and the output terminal 10, respectively.
  • the collector of transistor T2 which corresponds to the output 25 of the second transconductance amplifier 22, is thus coupled to the output terminal 10 via the main current path of transistor T3.
  • the emitter, base and collector of transistor T4 are connected to the reference terminal 8, the second node 48 and the first node 18, respectively.
  • Transistor T5 is the fourth transconductance amplifier 40 and has its emitter, base and collector connected to the first node 18, the input terminal 6 and a supply voltage terminal 52. Coupling the emitter current of transistor T5 to the first node 18 has substantially the same effect as coupling the collector current to the first node 18, as would be expected from Figure 4, because the emitter current and collector current if transistor T5 are nearly equal.
  • the bias voltage terminal 50 provides a bias voltage V B generated by means of two diode-connected transistors T7 and T8 series connected between the bias voltage terminal 50 and the reference terminal 8 and a bias current source 54 connected between the bias voltage terminal 50 and the supply voltage terminal 52.
  • the base-emitter voltage of transistor T2 is equal to V A . Since the current through transistor T2 flows through transistor T3, the base-emitter voltage of transistor T3 is also V A . This implies that the voltage at the second node 48 and also the base-emitter voltage of transistor T4 is equal to V B -V A .
  • the voltage V B -V A in turn appears at the base-emitter junction of transistor T5 since the currents through transistors T4 and T5 are substantially equal. It appears that the voltage at the input terminal 6 is fixed at the bias voltage V B and no longer dependent on the error voltage V A at the first node 18.
  • Figure 6 shows a second transistor implementation which differs from the implementation shown in Figure 5 in that the output current i 2 is not taken from the collector of transistor T3, but from the collector of a further transistor T6 which has its emitter, base and collector connected to the reference terminal 8, the first node 18 and the output terminal 10, respectively.
  • the collector of transistor T3 is connected to the supply terminal 52.
  • the current through transistor T2 is copied or multiplied in transistor T6.
  • the additional transistor T6 makes this circuit suitable for use at high frequencies.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Amplifiers (AREA)
  • Measurement Of Current Or Voltage (AREA)
EP98903226A 1997-03-13 1998-02-27 Spannungs-stromkonverter mit fehlerkorrektur Withdrawn EP0900476A2 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP98903226A EP0900476A2 (de) 1997-03-13 1998-02-27 Spannungs-stromkonverter mit fehlerkorrektur

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP97200754 1997-03-13
EP97200754 1997-03-13
PCT/IB1998/000240 WO1998040967A2 (en) 1997-03-13 1998-02-27 Voltage-to-current converter with error correction
EP98903226A EP0900476A2 (de) 1997-03-13 1998-02-27 Spannungs-stromkonverter mit fehlerkorrektur

Publications (1)

Publication Number Publication Date
EP0900476A2 true EP0900476A2 (de) 1999-03-10

Family

ID=26146241

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98903226A Withdrawn EP0900476A2 (de) 1997-03-13 1998-02-27 Spannungs-stromkonverter mit fehlerkorrektur

Country Status (2)

Country Link
EP (1) EP0900476A2 (de)
WO (1) WO1998040967A2 (de)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5043652A (en) * 1990-10-01 1991-08-27 Motorola, Inc. Differential voltage to differential current conversion circuit having linear output
BE1007007A3 (nl) * 1993-04-16 1995-02-14 Philips Electronics Nv Gebalanceerde spanning-stroomomzetter met ruststroominstelling.
US5574678A (en) * 1995-03-01 1996-11-12 Lattice Semiconductor Corp. Continuous time programmable analog block architecture

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9840967A3 *

Also Published As

Publication number Publication date
WO1998040967A3 (en) 1998-12-17
WO1998040967A2 (en) 1998-09-17

Similar Documents

Publication Publication Date Title
JPS63283307A (ja) 信号変換回路
US4628279A (en) Wideband feedback amplifier
US6930555B2 (en) Amplifier power control circuit
JPH06188657A (ja) 自動利得制御回路に指数関数段を接続する回路,自動利得制御回路及び温度補償回路
US7068099B2 (en) Power amplifier module with distortion compensation
JPH0618015B2 (ja) 電 流 安 定 化 回 路
US4322688A (en) Cascode feed-forward amplifier
US5606288A (en) Differential transimpedance amplifier
EP0475507B1 (de) Verstärkerschaltung
US6060870A (en) Voltage-to-current converter with error correction
US4779057A (en) Cascode amplifier with nonlinearity correction and improve transient response
KR930002040B1 (ko) 증폭기
JP3404209B2 (ja) トランスインピーダンス増幅器回路
US4612496A (en) Linear voltage-to-current converter
US4370608A (en) Integrable conversion circuit for converting input voltage to output current or voltage
EP0051362B1 (de) Elektronische Verstärkungsregelungsschaltung
WO1998040967A2 (en) Voltage-to-current converter with error correction
CA1301862C (en) Logarithmic amplification circuit for obtaining output voltage corresponding to difference between logarithmically amplified values of two input currents
US4267521A (en) Compound transistor circuitry
US4439745A (en) Amplifier circuit
US4588909A (en) Distortion compensating circuit
US5977760A (en) Bipolar operational transconductance amplifier and output circuit used therefor
JPH04369105A (ja) 増幅器
US5164681A (en) Voltage-current conversion circuit
JP2596125Y2 (ja) 演算増幅回路

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A2

Designated state(s): DE FR GB NL

17P Request for examination filed

Effective date: 19981214

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 20020123