[go: up one dir, main page]

WO2008009904A1 - Circuit de contrôle et procédé - Google Patents

Circuit de contrôle et procédé Download PDF

Info

Publication number
WO2008009904A1
WO2008009904A1 PCT/GB2007/002641 GB2007002641W WO2008009904A1 WO 2008009904 A1 WO2008009904 A1 WO 2008009904A1 GB 2007002641 W GB2007002641 W GB 2007002641W WO 2008009904 A1 WO2008009904 A1 WO 2008009904A1
Authority
WO
WIPO (PCT)
Prior art keywords
value
pulsed signal
rms
control circuit
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.)
Ceased
Application number
PCT/GB2007/002641
Other languages
English (en)
Inventor
Laurence John Joyce
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.)
City Technology Ltd
Original Assignee
City Technology Ltd
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 City Technology Ltd filed Critical City Technology Ltd
Publication of WO2008009904A1 publication Critical patent/WO2008009904A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/14—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature
    • G01N27/16—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of an electrically-heated body in dependence upon change of temperature caused by burning or catalytic oxidation of surrounding material to be tested, e.g. of gas

Definitions

  • This invention relates to a method of controlling an element in a gas sensor and to a pulse modulation control circuit for implementing the method. Specifically, the disclosed technique reduces the amount of power consumed by the circuit.
  • control circuit is primarily envisaged for use with a gas sensitive element.
  • control circuit could be used in other applications, such as the control of heating elements or anemometers.
  • the method and circuit are particularly well adapted for use with pellistor type gas sensors and, as such, the description below will focus on such applications.
  • the techniques could be used with other types of gas sensor including semistors, semiconductor sensors or electrochemical sensors.
  • the techniques could be used to maintain a high temperature solid oxide electrolyte sensor, such as a zirconium oxide sensor (commonly used in exhaust pipes), at its optimum operating temperature.
  • Calorimetric sensors such as pellistors
  • pellistors have long been used for the measurement of combustible gases.
  • the principles of operation are described, for example, in WO04/048955 and in "Calorimetric Chemical Sensors", PT. Walsh and T.A. Jones, Chapter 11 in “Sensors - A Comprehensive Survey” volume 2, editors W. Gopel, J. Hesse and J.N. Zemel.
  • a pellistor typically includes a gas sensitive element, which is provided with a catalytic coating on which combustible gases react, and (optionally) a compensator element which is catalyst- free.
  • the gas reaction on the gas sensitive element evolves heat which changes the resistance of the element, and this is monitored in a detection circuit. Gas does not react on the compensator element, but its resistance changes in response to changes in the ambient conditions, such as temperature and/or humidity, thereby providing a reference against which the output from the gas sensitive element can be compared.
  • the elements can be controlled under constant current or constant voltage regimes, in which case the varying resistance of the elements is used to evaluate the concentration of combustible gas in the atmosphere.
  • the two pellistor elements form part of a Wheatstone bridge circuit which generates a signal related to the difference between the resistance of the gas sensitive element and that of the compensator element.
  • the elements can be run in constant temperature mode, in which case the power supplied to each element is controlled such that the temperature (and therefore the resistance) of each remains constant. The variation in the power supplied required to maintain the element at constant temperature is used to evaluate the concentration of gas. This mode has the advantage that the pellistor elements remain at their optimum operating temperature throughout use.
  • a primary concern for users of pellistor sensors is the power consumption of the device. Particularly in portable devices, it is desirable to reduce the power consumed by the pellistor element in order that smaller batteries are required and hence smaller, lighter and cheaper sensing devices may be designed.
  • the primary aim of the approach described in the above International Application is to allow the two pellistor elements to be switched on and off individually, thereby offering the possibility of power saving. This is achieved by providing each element with its own individual pulse modulation controlled feedback circuit, which may be analogue or digital in nature and may be used to realise constant temperature, constant current or constant voltage control.
  • the gas sensitive element is continuously powered whilst the compensator element is operated for only a fraction of the time, such as ten seconds in every two minutes. This offers a power saving related to the beads themselves of approximately 40%.
  • the pellistor elements typically have relatively slow thermal response times, of the order of seconds or hundreds of milliseconds, depending on the bead size. In effect, this defines the period over which a reliable measurement of the resistance can be obtained and hence the necessary error signal for the feedback loop.
  • the pellistor element may be receiving an erroneous drive current. This would go undetected until the pellistor element "catches up" with the change in supplied power, during which time the resistance measurement (and so the measured gas concentration) would be incorrect.
  • a pulse modulation control circuit for connection to an element in a gas sensor, comprises: a pulse modulator for generating a pulsed signal from a voltage supply, the pulsed signal supplying power to the element; and a controller adapted to: monitor a parameter which varies with the temperature of the element, and compare the monitored parameter to a first set-point (SP 1 ) value to generate a first error value (E 1 ); monitor the pulsed signal generated by the pulse modulator, calculate a value
  • V CALC root mean square (RMS) voltage (V RMS ) of the pulsed signal and compare the calculated RMS-related value (V CALC ) to a second set-point value (SP 2 ) to generate a second error value (E 2 ), the second set-point value (SP 2 ) being derived from the first error value (E 1 ); and control the pulse modulator in accordance with the second error value (E 2 ), thereby controlling the power consumed from the voltage supply by the element.
  • RMS root mean square
  • the invention further provides a method of controlling an element in a gas sensor, comprising: generating a pulsed signal from a voltage supply, the pulsed signal supplying power to the element; monitoring a parameter which varies with the temperature of the element; comparing the monitored parameter to a first set-point value (SP 1 ) to generate a first error value (E 1 ); monitoring the pulsed signal generated by the pulse modulator to calculate a value (V CALC ) related to the root mean square (RMS) voltage (V RMS ) of the pulsed signal; comparing the calculated RMS-related value (V CALC ) to a second set-point value
  • the pulse modulated signal can be adjusted to take account of changes to the voltage supply. This does away with the need for regulating the voltage rail, and thereby enables the sensor to achieve its full power saving potential.
  • the additional processing can be carried out using software without adding to the complexity of the pellistor pulse modulation drive circuit.
  • the invention potentially reduces costs in other parts of the instrument circuit by reducing the regulation demands on them. Effectively, the invention performs the functions of two feedback loops in order to accurately control power to the element. The first monitors a parameter such as the resistance of the element and compares this with a set point to generate an error value representative of the state of the pellistor element (compared to the ideal operational state of the element).
  • the second feedback loop monitors the pulsed signal generated by the pulse modulator, which is supplied to the pellistor element.
  • the monitored signal is independent of the thermal response time of the pellistor element.
  • the second feedback loop operates at a rate much faster than the resistance controlling loop. This makes it possible to compensate for changes in the voltage rail occurring at a frequency greater than the rate at which the bead can respond to thermal changes, such as may occur in an alarm scenario as described above.
  • This second feedback loop compares a value related to the root mean square voltage of the pulsed signal (which is directly related to its power) to a second set point value, which is derived from the output of the first feedback loop.
  • the eventual output from the second feedback loop therefore includes a correction for both the resistance variation and the voltage supply variation, and the pulse modulator can then adjust its output accordingly to maintain the resistance (or other monitored parameter) of the element substantially constant even when the voltage supply varies.
  • the pulse modulator comprises a pulse modulation driver and a switching device, the switching device being connected in series between the voltage supply and the element, and the pulse modulation driver being arranged to operate the switching device to generate the pulsed signal.
  • the switch in its "off state, the switch entirely isolates the element from the power supply, which provides an optimal power saving when the element is operated via a pulsed signal, and additionally the same switch can be used to turn off an element entirely if it is being used in an intermittent mode.
  • the parameter which varies with the temperature of the element is the resistance of the element.
  • the resistance of a gas sensitive element is directly related to the concentration of combustible gas in the atmosphere under test.
  • the controller calculates the resistance of the element from measurements of the voltage across and current through the element.
  • the RMS-related value (V CALC ) is the square of the RMS voltage (V RMS ) °f the pulse signal.
  • V RMS the RMS voltage
  • any other function of the root mean square voltage of the pulse signal could be used instead.
  • the controller calculates the RMS-related value (V CALC ) from measurements of the peak voltage and duty cycle of the pulsed signal.
  • the controller calculates the RMS-related value (V CALC ) according to the relationship v2
  • VCALC - ⁇ VR M S) 2 DC.(V ⁇ )
  • V RMS root mean square voltage
  • OC duty cycle
  • V p11 peak voltage of the pulsed signal.
  • the controller is adapted to control the pulse modulator such that the second error value (E 2 ) tends to zero.
  • the second error value (E 2 ) may be advantageous to have the second error value (E 2 ) tend to some other limit.
  • the controller is adapted to control the pulse modulator by adjusting the duty cycle of the pulsed signal.
  • this is achieved by adjusting the width of the pulses (i.e. pulse width modulation).
  • the controller could additionally or alternatively be adapted to control the pulse modulator by adjusting the frequency of the pulse signal.
  • the controller is adapted to control the pulse modulator in accordance with the second error value so as to maintain the monitored parameter of the element substantially constant.
  • the controller further provides the pulse modulation driver.
  • the power supply is unregulated, since the invention does away with the need for any regulation.
  • the element is a gas sensitive element. In other preferred embodiments of the invention, the element is a compensator element.
  • the controller comprises a first feedback loop for monitoring the parameter which varies with the temperature of the element, and comparing the monitored parameter to the first set point value (SP 1 ) to generate the first error value (E 1 ).
  • the controller comprises a second feedback loop for monitoring the pulsed signal generated by the pulse modulator, calculating a value (V CALC ) related to the root mean square (RMS) voltage of the pulsed signal and comparing the calculated RMS related value (V CALC ) to a second set-point value (SP 2 ) to generate the second error value (E 2 ), the second set-point value (SP 2 ) being derived from the first error value (E 1 ).
  • a gas sensor assembly comprising a gas sensitive element arranged in series with the voltage supply, and a first pulse modulation control circuit as described above, connected to the gas sensitive element.
  • the gas sensor assembly further comprises a compensator element arranged in series with the voltage supply independently of the gas sensitive element, and a second pulse modulation control circuit as described above connected to the compensator element.
  • a compensator element arranged in series with the voltage supply independently of the gas sensitive element
  • a second pulse modulation control circuit as described above connected to the compensator element.
  • Figure 1 is a block diagram which schematically illustrates the functions of a conventional control circuit
  • Figure 2 is a graph showing the effect of a power supply disturbance on the power supplied to the sensor element in the arrangement shown in Figure 1 ;
  • FIG. 3 is a block diagram which schematically illustrates the functions of a control circuit according to an embodiment of the invention
  • Figure 4 is a graph showing the effect of a power supply disturbance on the power supplied to the sensor elements in the arrangement shown in Figure 3;
  • Figure 5 is a block diagram schematically illustrating in more detail the control circuit of Figure 3;
  • Figure 6 is a schematic circuit diagram illustrating an exemplary sensor device implementing the control circuit of the embodiment.
  • the major advantage of using a pulse modulation drive circuit for the control of pellistors is the power saving obtained compared with a normal
  • the sensor element 1 which may be a gas sensitive (detector) element or a compensator element, is powered by a pulsed drive signal from pulse modulator 2.
  • the pulse modulator 2 typically comprises a pulse modulation driver and a switching device, wherein the switching device is disposed in series with the sensor element 1 and a power supply (not shown in Figure 1). Further details of such an arrangement will be described below in relation to Figure 6.
  • each pellistor element is typically operated in one of constant temperature, constant current or constant voltage mode.
  • a parameter of the sensor element 1 is monitored and the pulsed signal adjusted (usually in terms of its duty cycle) to maintain the monitored parameter at a constant value.
  • a parameter controller module 3 is provided which receives input from feedback line 8 and compares the monitored parameter against a first set point value to generate an error value.
  • the pellistor is operated in constant temperature mode and, as such, the monitored parameter is the resistance of the element, R.
  • the resistance of the element 1 is monitored by taking measurements of the voltage across and the current through the element 1 and applying Ohm's Law.
  • the first set point value, SP 1 is a predetermined constant calculated during calibration (i.e.
  • the parameter controller module 3 outputs a first error value E 1 , which represents the difference between the monitored parameter (here the resistance) and the set point value, SP 1 .
  • This error signal E 1 is used to adjust the output of the pulse modulator 2 to modify the power supplied to the sensor element 1 in order to keep the resistance at a constant level. Typically this is achieved by modifying the duty cycle of the pulsed signal, although its frequency could additionally or alternatively be varied. In most cases, adjustment of the duty cycle will be effected by modifying the pulse width; i.e.
  • the amplitude of the pulsed signal could, in principle, be adjusted to control the power supplied to the element. It will be appreciated that this is not a preferred technique in the present case, since it is desired that the power supply be unregulated and as such controlling the amplitude may be difficult and inaccurate. However, this has been found to be effective where the power supply fluctuations are restricted to a narrow band [please confirm this paragraph is correct].
  • Figure 3 shows a functional block diagram of an embodiment of the invention which implements this concept.
  • the same reference numerals as used in Figure 1 are used to indicate the same components.
  • the sensor element 1 , pulse modulator 2 and parameter controller module 3 all correspond to the components shown in Figure 1.
  • a voltage controller module 4 is provided which takes an input from feedback line 9 which monitors the pulsed signal generated by the pulse modulator 2. As will be described in more detail below, certain features of the pulsed signal are used to calculate a value V CALC which is compared against a second set point value, SP 2 , to output a second error value E 2 .
  • the second set point value SP 2 is derived from the first error value E 1 output by the parameter controller 3.
  • the second error value E 2 includes a correction relating to the resistance (or other parameter) of the sensor element 1 , as well as a correction for any voltage disturbance detected in the pulsed signal.
  • the second error value E 2 is used to control the pulse modulator 2 such that changes in the element resistance are compensated for, and variations in the voltage supply are additionally compensated for.
  • Figure 4 shows the effect of the 300 mV power supply disturbance on the sensor element power in the arrangement of Figure 3, and it will be seen that there is a much reduced deviation experienced, which is quickly corrected for.
  • the technique is effective since the second feedback loop (consisting of voltage controller module 4 and feedback line 9) is independent of the long thermal response time of the sensor element 1.
  • the voltage correction is updated at the same frequency as the pulsed signal generated by the pulse modulator 2. As such, any variations in the power supply are very quickly corrected for.
  • the power supply must be capable of providing a minimum level of power such that the pellistor element can run in its intended mode when the pulsed signal has a reasonable duty cycle. That is, the necessary power should be supplied to the element without having to select a very high (e.g. >80%) or very low (e.g. ⁇ 20%) duty cycle. This is because the duty cycle has to be monitored by the controller and this is difficult at such extremes since either the pulses or the troughs become too short to measure accurately.
  • the duty cycle of the pulsed signal be between 25% and 75% and the power supply should be able to supply sufficient power to allow for this.
  • Figure 5 shows in more detail the relationship between the parameter controller module 3 and the voltage controller module 4.
  • these functions will be carried out by a controller (typically a microcontroller, but this could comprise discrete components), however they are shown as separate functional components here for clarity.
  • the functions are implemented in software such that no changes to the hardware are required.
  • the parameter of the sensor 1 (usually the resistance, R) is evaluated by monitoring the current through and/or the voltage across the sensor element 1.
  • the parameter controller module 3 compares this value input from feedback line 8 with a first set point value SP 1 , typically abut 25 Ohms where the monitored parameter is resistance.
  • a first error value E 1 is generated and, if necessary, this is converted into a voltage using Ohm's law.
  • the first error value E 1 will be zero and the second set point value SP 2 equals the calibration constant C.
  • the calibration voltage is therefore determined by the first set point, SP 1 , in that a voltage is supplied which maintains the element at the same temperature (and resistance) at which it would sit if it were powered by a DC signal rather than a pulsed signal.
  • the voltage controller module 4 compares the second set point value SP 2 with a value V CALC which is derived from monitoring the pulsed signal generated by the pulse modulator 2.
  • V CALC which is derived from monitoring the pulsed signal generated by the pulse modulator 2.
  • V RMS root mean square
  • the RMS voltage (V RMS ) can be derived from measurements of the pulse signal according to the relationship where DC is the duty cycle of the pulse signal (i.e. the proportion of each cycle wherein the pulse is "high") and V PK is the peak voltage of the pulsed signal (i.e. the amplitude).
  • V CALC the value input to the voltage controller module 4, V CALC , is preferably a function of the square of the RMS voltage (V RMS ).
  • the second set point value SP 2 must also be in units of (volts) 2 .
  • the output from parameter controller 3 (first error signal E 1 ,, is therefore squared and likewise the value C equals the square of the calibration voltage.
  • the result of the comparison between V CALC and SP 2 is a second error value E 2 which is used to control the pulse modulator so as to adjust the pulsed signal to compensate for changes in the monitored parameter of the sensor element 1 and in the power supply.
  • a calibration terminal 7 is provided, which shorts the parameter controller 3 out of the circuit.
  • the calibration voltage is thus applied in the form of a pulsed signal across the sensor 1 with any variations being corrected for by the voltage controller module 4.
  • the resulting resistance (or other parameter) of the sensor element 1 is measured and this value is used as the first set point value SP 1 for future operation of the device. As described above, this value is typically about 25 Ohms for a gas sensitive element operating in constant temperature mode.
  • FIG. 6 shows a schematic circuit diagram of a sensor device having a detector (gas sensitive) element 11 and a compensator element 12, each of which is disposed in an individual circuit between a power supply 17 and ground G.
  • Each circuit is provided with a respective switch, 13 and 14 in series with the element and the power supply such that, when the switch is in its off state, the respective element is entirely isolated from the power supply.
  • the detector and compensator elements can be operated individually and power can be saved by the use of certain intermittent operating regimes.
  • each parallel circuit further comprises a load resistor 15,16 which together with the respective element act as a voltage divider such that parameters can be measured across the load resistance instead of across the element.
  • load resistor 1516 which together with the respective element act as a voltage divider such that parameters can be measured across the load resistance instead of across the element.
  • there are other well known methods of measuring current which do not require load resistors and these components are therefore optional.
  • a processor 18 takes inputs 20,21 from each circuit and outputs pulsed signals 19 to the two switching devices 13 and 14. Control of each switch results in a pulsed signal through each of the parallel circuits and so provides power to the detector and compensator elements 11,12.
  • the pulse modulator of Figures 3 and 5 is in practice implemented by processor 18 in conjunction with the respective switch 13,14.
  • the resulting pulsed signal is monitored on lines 20 and 21 from which current measurements can also be taken.
  • the peak voltage (V PK ) across each pellistor element is measured by the processor via an ADC.
  • the processor 18 can calculate V CALC and the resistance R and perform the functions as set out in Figures 3 and 5 above.
  • the resulting gas sensing device makes it possible to realise the full energy saving potential of the individual pulse modulation circuits.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

La présente invention concerne un circuit de contrôle de modulation d'impulsions à connecter à un élément dans un capteur de gaz, ainsi qu'un procédé de contrôle correspondant. Le circuit de contrôle comprend un modulateur d'impulsion pour générer un signal pulsé provenant d'une source de tension, le signal fournissant de l'énergie à l'élément, ainsi qu'un contrôleur. Le contrôleur est adapté pour contrôler un paramètre qui varie selon la température de l'élément, et compare le paramètre contrôlé à une première valeur de point de consigne (SP1) pour générer une première valeur d'erreur (E1) ; il contrôle le signal pulsé généré par le modulateur d'impulsion, calcule une valeur (VCALC) liée à la tension (VRMS) de moyenne quadratique (RMS) du signal pulsé et compare la valeur calculée (VCALC) liée à la RMS à une seconde valeur de point de consigne (SP2) pour générer une seconde valeur d'erreur (E2), la seconde valeur de point de consigne (SP2) étant dérivée de la première valeur d'erreur (E1) ; il contrôle ensuite le modulateur d'impulsion en accord avec la seconde valeur d'erreur (E2), en contrôlant ainsi l'alimentation consommée par l'élément à partir de la source de tension.
PCT/GB2007/002641 2006-07-17 2007-07-13 Circuit de contrôle et procédé Ceased WO2008009904A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB0614214.5 2006-07-17
GB0614214A GB0614214D0 (en) 2006-07-17 2006-07-17 Control circuit and method

Publications (1)

Publication Number Publication Date
WO2008009904A1 true WO2008009904A1 (fr) 2008-01-24

Family

ID=36955821

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2007/002641 Ceased WO2008009904A1 (fr) 2006-07-17 2007-07-13 Circuit de contrôle et procédé

Country Status (2)

Country Link
GB (1) GB0614214D0 (fr)
WO (1) WO2008009904A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU630612A2 (ru) * 1976-09-21 1978-10-30 Ивановский энергетический институт им.В.И.Ленина Импульсный регул тор
US4305724A (en) * 1980-08-04 1981-12-15 Delphian Partners Combustible gas detection system
US4541988A (en) * 1983-12-13 1985-09-17 Bacharach Instrument Company Constant temperature catalytic gas detection instrument
WO2001092865A1 (fr) * 2000-06-02 2001-12-06 Austech Instruments Pty Ltd Dispositif de commande pour filament
US20040113802A1 (en) * 2002-12-10 2004-06-17 Industrial Scientific Corporation Gas detection instrument and method for its operation

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU630612A2 (ru) * 1976-09-21 1978-10-30 Ивановский энергетический институт им.В.И.Ленина Импульсный регул тор
US4305724A (en) * 1980-08-04 1981-12-15 Delphian Partners Combustible gas detection system
US4541988A (en) * 1983-12-13 1985-09-17 Bacharach Instrument Company Constant temperature catalytic gas detection instrument
WO2001092865A1 (fr) * 2000-06-02 2001-12-06 Austech Instruments Pty Ltd Dispositif de commande pour filament
US20040113802A1 (en) * 2002-12-10 2004-06-17 Industrial Scientific Corporation Gas detection instrument and method for its operation

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Week 197932, Derwent World Patents Index; AN 1979-G8974B, XP002452095 *

Also Published As

Publication number Publication date
GB0614214D0 (en) 2006-08-23

Similar Documents

Publication Publication Date Title
US6812708B2 (en) Combustible-gas measuring instrument
EP1028244B1 (fr) Méthode de contrôle et de diagnostic du chauffage d'une sonde d'échappement d'un moteur
US5140535A (en) Process, use of the same and apparatus for lambda value detection
US20180299404A1 (en) Sensor apparatus and sensor unit
US20080226505A1 (en) Gas Sensor Assembly With Catalytic Element
EP0314919A2 (fr) Circuit de détecteur de gaz combustible à stabilisation de température
CN112187227B (zh) 用于氧传感器的补偿器电路和方法
US8538665B2 (en) Control circuit for an electrochemical gas sensor and method for adjusting an electrochemical gas sensor
WO2008009904A1 (fr) Circuit de contrôle et procédé
US12004271B2 (en) Power control device and power control method
US20190107505A1 (en) Sensor control device and sensor unit
US11391632B2 (en) Temperature sensor circuit
JPH114574A (ja) スイッチング電源制御方式
EP3751265B1 (fr) Procédé et système de capteur d'oxygène
JP2020030137A (ja) 水素センサ
US20250012756A1 (en) Sensor system
JP2841394B2 (ja) 安定化電源回路
JP2003535332A (ja) フィラメント制御装置
JP2005083989A (ja) 熱電対の入力回路
JP4096717B2 (ja) 電源装置及びそれに用いるｄｃ／ｄｃコンバータ制御方法
KR20110026563A (ko) 메모리 모듈의 공급 전압 조절 장치 및 그 방법
JPH07190975A (ja) 鋳物砂水分量の測定装置
US11353420B2 (en) Oxygen sensor system and method
CN119998755A (zh) 用于脉宽调制系统中误差补偿的系统和方法
US20070040103A1 (en) Technique for reducing a parasitic DC bias voltage on a sensor

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07766219

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

NENP Non-entry into the national phase

Ref country code: RU

122 Ep: pct application non-entry in european phase

Ref document number: 07766219

Country of ref document: EP

Kind code of ref document: A1