WO1990012459A1 - Convertisseur analogique-numerique - Google Patents

Convertisseur analogique-numerique Download PDF

Info

Publication number
WO1990012459A1
WO1990012459A1 PCT/US1990/001466 US9001466W WO9012459A1 WO 1990012459 A1 WO1990012459 A1 WO 1990012459A1 US 9001466 W US9001466 W US 9001466W WO 9012459 A1 WO9012459 A1 WO 9012459A1
Authority
WO
WIPO (PCT)
Prior art keywords
analog input
capacitor
conversion
microprocessor
circuit
Prior art date
Application number
PCT/US1990/001466
Other languages
English (en)
Inventor
Michael A. Loda
Original Assignee
Digital Appliance Controls, Inc.
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 Digital Appliance Controls, Inc. filed Critical Digital Appliance Controls, Inc.
Publication of WO1990012459A1 publication Critical patent/WO1990012459A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/12—Analogue/digital converters
    • H03M1/50—Analogue/digital converters with intermediate conversion to time interval
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/12—Analogue/digital converters
    • H03M1/18—Automatic control for modifying the range of signals the converter can handle, e.g. gain ranging

Definitions

  • This invention relates to analog to digital (A/D) converters and more
  • the ramp is fed to a comparator to detect
  • a counter develops a digital representation of this zero and that
  • Sensitivity adjustment also known as ranging
  • the input signal is first split and amplified to provide different
  • circuit incorporating, in a first configuration, the varying resistance sensor
  • the counter counts the clock cycles to generate a digital representation of the interval and therefore a representation of the
  • microprocessor ports into (or out of) the circuit to change the RC time
  • the converter may be expanded
  • Figure 1 is a schematic of the A/D converter of the present invention
  • FIG. 2 is a schematic of the A/D converter in accordance with the
  • microprocessor 12 of the type commonly known and in use in the industry * ,
  • B 0 and 1 are dual purpose and as an output pull low to discharge the
  • timing capacitor as hereafter described. As inputs they are polled to
  • the analog input to be measured is presented, in this embodiment, as
  • the changing resistance may vary with temperature
  • this varying resistance is connected to a zero potential indicated in the drawings as V .
  • the microprocessor circuit is
  • the A/D converter of this invention operates by determining the time
  • capacitance - is connected to the -5V supply V and is arranged to charge
  • resistance includes a timing resistor R ⁇ connected in series with the timing
  • a range determining resistor R ⁇ may be
  • Calibration is performed by first pulling ports B ⁇ and then B 0 low.
  • the resister on port B l is a current limiting resister and is used to drain
  • port B 0 is pulled low to V __•_> to fully discharge Cj.
  • timing capacitor Cr to begin charging through the timing resistor R ⁇ at a
  • This counter may be
  • A/D conversion operates in a manner similar to calibration except A o
  • capacitor is first discharged and a counter is started to count clock cycles.
  • Range detection is achieved by examining the time represented by the
  • time constant is achieved to produce a more sensitive second range.
  • A/D conversion is accomplished by discharging the capacitor (pulling
  • T 2 - (R s + R ⁇ ) (Cr) (In (V ⁇ j V ⁇ ) )
  • timing capacitor to charge to the logic "1" level and to provide that input
  • the converter is thereby improved.
  • CT 2 (C T c ) T 2
  • microprocessor input port threshold
  • microprocessor output that provides a longer charge time.
  • step two The value from step two is then used to access a lookup table

Landscapes

  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Analogue/Digital Conversion (AREA)

Abstract

L'invention concerne un circuit à microprocesseur comprenant un circuit de charge à condensateur incorporant, dans une première configuration, une résistance variable (RS) à mesurer. Dans une seconde configuration, ladite résistance variable (RS) est débranchée du circuit. Dans les deux configurations, on laisse le condensateur de minutage (CT) se charger, jusqu'à ce qu'un niveau de logique de microordinateur soit atteint. Pendant cet intervalle de charge, un compteur enregistre les cycles d'horloge afin de produire une représentation numérique de l'intervalle, et par consequent de la constante RC. Le fonctionnement dudit circuit dans la seconde configuration, sans résistance variable produit un étalonnage 'zéro' du circuit. Le fonctionnement dans la première configuration produit une représentation de la resistance variable. On obtient un sensibilité de plage par connexion de résistances supplémentaires (R1, R2...RN) dans le circuit (ou hors de celui-ci), afin de changer le temps de charge du condensateur.
PCT/US1990/001466 1989-03-31 1990-03-21 Convertisseur analogique-numerique WO1990012459A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US33173489A 1989-03-31 1989-03-31
US331,734 1989-03-31

Publications (1)

Publication Number Publication Date
WO1990012459A1 true WO1990012459A1 (fr) 1990-10-18

Family

ID=23295157

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1990/001466 WO1990012459A1 (fr) 1989-03-31 1990-03-21 Convertisseur analogique-numerique

Country Status (1)

Country Link
WO (1) WO1990012459A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001022595A1 (fr) * 1999-09-21 2001-03-29 Yun Rong Circuit numerique de conversion d'une valeur de capacite, d'une valeur de resistance et d'une valeur d'inductance en valeurs numeriques
EP1633051A1 (fr) * 2004-09-06 2006-03-08 Berner Fachhochschule Hochschule für Technic und Architektur Biel Modulateur du type Sigma-Delta et convertisseur A/N du type Sigma-Delta

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3685048A (en) * 1970-09-30 1972-08-15 Bendix Corp Self-calibrating analog to digital converter with predetermined transfer characteristics
US3725903A (en) * 1971-02-09 1973-04-03 Bendix Corp Self-calibrating analog to digital converter
US3913096A (en) * 1972-08-02 1975-10-14 Telemecanique Electrique Measuring device for use with an electrical transducer having parabolic resistance response
US4129864A (en) * 1976-03-03 1978-12-12 The United States Of America As Represented By The Secretary Of Commerce High speed, wide dynamic range analog-to-digital conversion
US4675649A (en) * 1985-09-11 1987-06-23 Halliburton Company Apparatus and method for interfacing a transducer
US4779074A (en) * 1985-08-13 1988-10-18 The Babcock & Wilcox Company Low level voltage pulse-converter
US4817040A (en) * 1986-03-20 1989-03-28 Lucas Industries Public Limited Company Vehicle condition monitoring system
US4849757A (en) * 1987-03-25 1989-07-18 Texas Instruments Incorporated Integrated dual-slope analog to digital converter with r/c variance compensation

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3685048A (en) * 1970-09-30 1972-08-15 Bendix Corp Self-calibrating analog to digital converter with predetermined transfer characteristics
US3725903A (en) * 1971-02-09 1973-04-03 Bendix Corp Self-calibrating analog to digital converter
US3913096A (en) * 1972-08-02 1975-10-14 Telemecanique Electrique Measuring device for use with an electrical transducer having parabolic resistance response
US4129864A (en) * 1976-03-03 1978-12-12 The United States Of America As Represented By The Secretary Of Commerce High speed, wide dynamic range analog-to-digital conversion
US4779074A (en) * 1985-08-13 1988-10-18 The Babcock & Wilcox Company Low level voltage pulse-converter
US4675649A (en) * 1985-09-11 1987-06-23 Halliburton Company Apparatus and method for interfacing a transducer
US4817040A (en) * 1986-03-20 1989-03-28 Lucas Industries Public Limited Company Vehicle condition monitoring system
US4849757A (en) * 1987-03-25 1989-07-18 Texas Instruments Incorporated Integrated dual-slope analog to digital converter with r/c variance compensation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001022595A1 (fr) * 1999-09-21 2001-03-29 Yun Rong Circuit numerique de conversion d'une valeur de capacite, d'une valeur de resistance et d'une valeur d'inductance en valeurs numeriques
EP1633051A1 (fr) * 2004-09-06 2006-03-08 Berner Fachhochschule Hochschule für Technic und Architektur Biel Modulateur du type Sigma-Delta et convertisseur A/N du type Sigma-Delta
WO2006026885A1 (fr) * 2004-09-06 2006-03-16 Berner Fachhochschule, Hochschule Für Technik Und Architektur Modulateur s? et convertisseur s? a/n

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