EP0443239A1 - Current mirror with base current compensation - Google Patents
Current mirror with base current compensation Download PDFInfo
- Publication number
- EP0443239A1 EP0443239A1 EP90309886A EP90309886A EP0443239A1 EP 0443239 A1 EP0443239 A1 EP 0443239A1 EP 90309886 A EP90309886 A EP 90309886A EP 90309886 A EP90309886 A EP 90309886A EP 0443239 A1 EP0443239 A1 EP 0443239A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- master
- collector
- transistor
- current
- slave
- 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- Withdrawn
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Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F3/00—Non-retroactive systems for regulating electric variables by using an uncontrolled element, or an uncontrolled combination of elements, such element or such combination having self-regulating properties
- G05F3/02—Regulating voltage or current
- G05F3/08—Regulating voltage or current wherein the variable is dc
- G05F3/10—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics
- G05F3/16—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices
- G05F3/20—Regulating voltage or current wherein the variable is dc using uncontrolled devices with non-linear characteristics being semiconductor devices using diode- transistor combinations
- G05F3/26—Current mirrors
- G05F3/267—Current mirrors using both bipolar and field-effect technology
Definitions
- This invention relates to current mirror circuits with base current compensation for the transistor which carries a reference current.
- FIG. 1 A typical prior current mirror circuit is shown in FIG. 1.
- a reference current I REF is delivered from a current source 2 to a diode-connected bipolar transistor T1.
- the collector of T1 is connected to its base and receives I REF , while the emitter of T1 is connected through a resistor R1 to a negative voltage bus V-1.
- T1 may be considered as a master transistor, since it acts as a reference which controls the output of the current mirror.
- One or more slave transistors illustrated as a pair of bipolar transistors T2 and T3, have a common base connection with master transistor T1.
- the collector-emitter circuits of T2 and T3 are connected respectively to loads L1 and L2 on one side, and through resistors R2 and R3 to V- on the other side.
- resistors R1, R2 and R3 are generally inversely proportional to their respective transistor scalings, so that the base-emitter voltages of the various transistors are equal and the voltages across the resistors are also equal. This resistor arrangement helps to compensate for transistor processing variations.
- FIG. 1 current mirror There is an inherent error in the FIG. 1 current mirror, resulting from the base currents drawn by T1, T2 and T3.
- the combined base currents are subtracted from I REF before the reference current reaches the collector of T1, and thus reduce the T1 collector current. This in turn reduces the reference current seen by T2 and T3, dropping their slaved output currents to values which are proportionately less than the desired load currents.
- FIG. 2 A prior circuit design which compensates for this base current error is shown in FIG. 2.
- Another bipolar transistor T4 has been added to provide base current compensation for the current mirror transistors.
- the base of T4 is connected to receive a control signal from the output of current source 2, while its collector-emitter circuit is connected between a positive voltage bus V+ and the common base connection for T1, T2 and T3.
- the compensation transistor T4 is scaled so that it provides a current equal to the combined base currents of T1, T2 and T3, and thus ideally eliminates the base current error of FIG. 1.
- T4 obtains its base current from I REF , and thus introduces a second order error into the reference current through T1.
- T4 places restrictions on the voltages across T1 that introduce further inaccuracies.
- T2 and T3 are normally operated with collector-emitter voltages of about 2-3 volts, which is the voltage region at which the collector current (I c )/ collector-emitter voltage (V c-e ) curve becomes saturated, as illustrated in FIG. 3.
- the collector-base voltage of T1 is limited to a voltage drop of about 0.7 volts by the parallel base-emitter circuit of T4, and the base-emitter voltage drop of T1 is similarly limited to an approximately 0.7 volt diode drop.
- the total collector-emitter voltage across T1 is thus limited to about 1.4 volts, which is significantly less than the saturation level.
- the 0.7 volt collector-base restriction on T1 also introduces an error in the actual master/slave current ratio, since the collector-base voltages of T2 and T3 are typically greater than 0.7 volts.
- the transistor current gain ⁇ varies by a factor of between approximately 2 and 5. This can significantly change the base current taken by T4, and thus the reference current through the collector-emitter circuit of T1, thereby adding to the error already present in the circuit.
- the present invention seeks to provide a current mirror circuit which produces effective base current compensation for a bipolar master transistor, does not restrict the master transistor voltages to values less than the slave transistor voltages, is less subject to temperature-induced errors, and generally has a more accurate and predictable mirror ratio than the prior circuits.
- the FET insulated gate field effect transistor
- the FET gate is connected to the collector of the master bipolar transistor, but draws no current therefrom.
- the gate-source circuit of the FET is connected to provide a compensating base current to the bipolar mirror transistors.
- the FET is geometrically scaled so that the collector-base voltages of the master and slave bipolar transistors are generally equal, and to establish the collector-emitter voltages of the bipolar transistors at values at which the bipolar transistors operate in the vicinity of their saturated regions. Since the collector-base voltage of the master bipolar transistor is no longer limited to about 0.7 volts, the errors associated with such a limitation are also removed.
- FIG. 4 The preferred embodiment of the invention is illustrated in FIG. 4, in which elements that are common with the elements of FIGs. 1 and 2 are identified by the same reference numerals.
- current source 2 delivers a reference current through the collector-emitter circuit of a bipolar master transistor T1.
- Bipolar slave transistors T2 and T3 have a common base connection with T1, and provide load currents to loads L1 and L2, respectively.
- the transistor emitters are connected to negative voltage bus V- through respective process-compensating resistors R1, R2 and R3.
- Reference current source 2 is implemented as a temperature compensated, source compensated current source which is carefully set up to obtain an exact desired value.
- This precise reference current is preserved by using an insulated gate FET such as metal oxide FET (MOSFET) M1 to supply base compensation current to the bipolar transistors.
- M1 has its gate connected between the collector of master bipolar transistor T1 and the reference current source 2, its drain connected to positive voltage bus V+, and its source connected to the common base connection of T1, T2 and T3.
- the back gate is connected to the body of the substrate upon which the circuit is formed, which is typically held at V-. Since the current through an insulated gate FET such as M1 is controlled by the gate voltage, without drawing any gate current, all of I REF flows through master bipolar transistor T1, thus preserving the accuracy of the reference current that reaches the current mirror.
- an insulated gate FET as a base compensation current device permits a much more desirable control over the voltages for master transistor T1.
- M1 is scaled so that, given its desired base current compensation current flow as established by the value of V+, the gate-source voltage of M1 equals the desired collector-base voltage for T1.
- This M1 gate-source voltage is imposed upon the parallel collector-base circuit of T1.
- the gate-source voltage of M1 (and thus the collector-base voltage of T1) will generally be set at about 1.3-2.3 volts so that M1 operates in the vicinity of its saturated region, as illustrated in FIG. 3.
- the precise value selected for the collector-base voltage of T1 will set that voltage equal to the collector-base voltages of slave transistors T2 and T3, and thus preserve the designed proportionality of the mirror.
- M1 The exact scaling of M1 that will produce this voltage level is highly dependent upon the particular process used to fabricate the circuit; several "BICMOS" processes are known that can be used to fabricate bipolar and CMOS devices on the same chip. Given a particular process and a knowledge of the invention, a scaling for M1 can readily be determined that will produce the desired gate-source voltage level.
- M1 is illustrated as an enhancement device, and can be used to provide a collector-emitter voltage for T1 in the two-three volt range. If a substantially lower collector-emitter voltage for T1 is desired, or even a marginally negative voltage, M1 could be implemented as a depletion device.
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Nonlinear Science (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Automation & Control Theory (AREA)
- Control Of Electrical Variables (AREA)
- Amplifiers (AREA)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US48188290A | 1990-02-20 | 1990-02-20 | |
US481882 | 1990-02-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0443239A1 true EP0443239A1 (en) | 1991-08-28 |
Family
ID=23913765
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP90309886A Withdrawn EP0443239A1 (en) | 1990-02-20 | 1990-09-10 | Current mirror with base current compensation |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0443239A1 (ja) |
JP (1) | JPH03244207A (ja) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0629938A2 (en) * | 1993-06-18 | 1994-12-21 | Texas Instruments Incorporated | Compensation for low gain bipolar transistors in voltage and current reference circuits |
DE4329639A1 (de) * | 1993-09-02 | 1995-03-09 | Telefunken Microelectron | Schaltungsanordnung mit gesteuerten Pinch-Widerständen |
US5627732A (en) * | 1994-05-27 | 1997-05-06 | Sgs-Thomson Microelectronics S.A. | Multiple output current mirror |
EP1213636A2 (en) * | 2000-12-07 | 2002-06-12 | Texas Instruments Deutschland Gmbh | Current mirror circuit |
WO2003005569A1 (en) * | 2001-07-02 | 2003-01-16 | Raytheon Company | Auxiliary circuitry for monolithic microwave integrated circuit |
FR3063552A1 (fr) * | 2017-03-03 | 2018-09-07 | Stmicroelectronics Sa | Generateur de tension/courant ayant un coefficient de temperature configurable |
CN113050747A (zh) * | 2019-12-26 | 2021-06-29 | 比亚迪半导体股份有限公司 | 基准电压电路 |
EP2711722B1 (fr) * | 2012-09-19 | 2022-05-25 | Commissariat À L'Énergie Atomique Et Aux Énergies Alternatives | Circuit de mesure de tension différentielle |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4735911B2 (ja) * | 2000-12-28 | 2011-07-27 | 日本電気株式会社 | 駆動回路及びこれを用いた定電流駆動装置 |
JP4842083B2 (ja) * | 2006-10-17 | 2011-12-21 | ルネサスエレクトロニクス株式会社 | カレントミラー回路 |
JP2008166905A (ja) * | 2006-12-27 | 2008-07-17 | Sanyo Electric Co Ltd | カレントミラー回路 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4008441A (en) * | 1974-08-16 | 1977-02-15 | Rca Corporation | Current amplifier |
US4673867A (en) * | 1986-06-30 | 1987-06-16 | Motorola, Inc. | Current mirror circuit and method for providing zero temperature coefficient trimmable current ratios |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS62276908A (ja) * | 1986-02-19 | 1987-12-01 | Hitachi Ltd | 半導体回路 |
-
1990
- 1990-09-10 EP EP90309886A patent/EP0443239A1/en not_active Withdrawn
- 1990-10-22 JP JP2284117A patent/JPH03244207A/ja active Pending
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4008441A (en) * | 1974-08-16 | 1977-02-15 | Rca Corporation | Current amplifier |
US4673867A (en) * | 1986-06-30 | 1987-06-16 | Motorola, Inc. | Current mirror circuit and method for providing zero temperature coefficient trimmable current ratios |
Non-Patent Citations (1)
Title |
---|
J. MILLMAN et al.: "Integrated electronics", 26th printing, 1971, pages 322-328, McGraw-Hill International Book Co., JP * |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0629938A3 (en) * | 1993-06-18 | 1997-08-20 | Texas Instruments Inc | Compensation of low gain bipolar transistors in voltage and current reference circuits. |
EP0629938A2 (en) * | 1993-06-18 | 1994-12-21 | Texas Instruments Incorporated | Compensation for low gain bipolar transistors in voltage and current reference circuits |
DE4329639A1 (de) * | 1993-09-02 | 1995-03-09 | Telefunken Microelectron | Schaltungsanordnung mit gesteuerten Pinch-Widerständen |
US5451908A (en) * | 1993-09-02 | 1995-09-19 | Temic Telefunken Microelectronic Gmbh | Circuit arrangement with controlled pinch resistors |
US5627732A (en) * | 1994-05-27 | 1997-05-06 | Sgs-Thomson Microelectronics S.A. | Multiple output current mirror |
EP1213636A3 (en) * | 2000-12-07 | 2004-08-04 | Texas Instruments Deutschland Gmbh | Current mirror circuit |
EP1213636A2 (en) * | 2000-12-07 | 2002-06-12 | Texas Instruments Deutschland Gmbh | Current mirror circuit |
WO2003005569A1 (en) * | 2001-07-02 | 2003-01-16 | Raytheon Company | Auxiliary circuitry for monolithic microwave integrated circuit |
KR100857054B1 (ko) * | 2001-07-02 | 2008-09-05 | 레이던 컴퍼니 | 모놀리식 마이크로파 집적 회로용 보조 회로 |
EP2711722B1 (fr) * | 2012-09-19 | 2022-05-25 | Commissariat À L'Énergie Atomique Et Aux Énergies Alternatives | Circuit de mesure de tension différentielle |
FR3063552A1 (fr) * | 2017-03-03 | 2018-09-07 | Stmicroelectronics Sa | Generateur de tension/courant ayant un coefficient de temperature configurable |
US10355649B2 (en) | 2017-03-03 | 2019-07-16 | Stmicroelectronics Sa | Voltage/current generator having a configurable temperature coefficient |
CN113050747A (zh) * | 2019-12-26 | 2021-06-29 | 比亚迪半导体股份有限公司 | 基准电压电路 |
CN113050747B (zh) * | 2019-12-26 | 2022-05-20 | 比亚迪半导体股份有限公司 | 基准电压电路 |
Also Published As
Publication number | Publication date |
---|---|
JPH03244207A (ja) | 1991-10-31 |
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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 |
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AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB IT NL |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 19920229 |