SE511945C2 - Temperature control circuit - Google Patents

Temperature control circuit

Info

Publication number
SE511945C2
SE511945C2 SE9803597A SE9803597A SE511945C2 SE 511945 C2 SE511945 C2 SE 511945C2 SE 9803597 A SE9803597 A SE 9803597A SE 9803597 A SE9803597 A SE 9803597A SE 511945 C2 SE511945 C2 SE 511945C2
Authority
SE
Sweden
Prior art keywords
operational amplifier
temperature
voltage
temperature control
control circuit
Prior art date
Application number
SE9803597A
Other languages
Swedish (sv)
Other versions
SE9803597D0 (en
SE9803597L (en
Inventor
Christian Eskildsen
Keld Christensen
Original Assignee
Electrolux Ab
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 Electrolux Ab filed Critical Electrolux Ab
Publication of SE9803597D0 publication Critical patent/SE9803597D0/en
Publication of SE9803597L publication Critical patent/SE9803597L/en
Publication of SE511945C2 publication Critical patent/SE511945C2/en

Links

Classifications

    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/1906—Control of temperature characterised by the use of electric means using an analogue comparing device
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
    • G05D23/24—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element having a resistance varying with temperature, e.g. a thermistor
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
    • G05D23/00—Control of temperature
    • G05D23/19—Control of temperature characterised by the use of electric means
    • G05D23/1906—Control of temperature characterised by the use of electric means using an analogue comparing device
    • G05D23/1909—Control of temperature characterised by the use of electric means using an analogue comparing device whose output amplitude can only take two discrete values

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Automation & Control Theory (AREA)
  • Control Of Temperature (AREA)
  • Relay Circuits (AREA)
  • Electronic Switches (AREA)

Abstract

Traditional bridge circuits for temperature control in which a temperature dependent resistor is used to detect temperature may suffer from a lack of convergence in reaching stability. According to the invention improvements are obtained in that the temperature dependent resistor (Pt 500) is part of a feedback loop around a first operational amplifier (IC1), and a second operational amplifier (IC2) is coupled as a comparator between a reference voltage and the output of the first operational amplifier (IC1), driving an output transistor (T1) for switching a power relay for the heating current.

Description

15 511 945 2 placerat pà den plats där man önskar styra temperaturen. En operationsförstärkare IC2 jämför spänningen på utgången på en operationsförstärkare ICl med spänningen från en spännings- delare Pl. Spänningen på utgången på IC1 härleds från strömmen genom resistanselementet Pt5OO i dennas negativa återkopplings- slinga och spänningen från spänningsdelaren härleds från samma opeationsförstärkare genom. att spänningarna på dennas två ingångar är lika (med en noggrannhet som bestäms av förstärka- rens “open loop"-förstärkning). Motstånden är så valda att vid en förutbestämd temperatur spänningen från spänningsdelaren är lika med spänningen över resistanselementet Pt500. Detta är en inställningspunkt som utnyttjas som referensinsignal till styrslingan. En ändring av inställningspunkten ställer in en annan temperatur. Vid den nedre änden av spänningsdelaren åstadkommer två seriekopplade dioder ett spänningsfall så att utspänningen från spänningsdelaren inte kan anta värdet noll vilket skulle kunna få komparatorn IC2 att bottna. Utsignalen från komparatorn försätter en transistor Tl i ledande eller spärrat tillstànd för strömmatning av en reläspole S. 15 511 945 2 located at the place where you want to control the temperature. An operational amplifier IC2 compares the voltage at the output of an operational amplifier IC1 with the voltage from a voltage divider P1. The voltage at the output of IC1 is derived from the current through the resistance element Pt5OO in its negative feedback loop and the voltage from the voltage divider is derived from the same operation amplifier through. that the voltages at its two inputs are equal (with an accuracy determined by the "open loop" gain of the amplifier.) The resistors are so selected that at a predetermined temperature the voltage from the voltage divider is equal to the voltage across the resistance element Pt500. At the lower end of the voltage divider, two series-connected diodes cause a voltage drop so that the output voltage from the voltage divider cannot assume the value zero which could cause the comparator IC2 to bottom out. the comparator puts a transistor T1 in the conducting or blocked state for current supply of a relay coil S.

Claims (1)

1. lO 3 511 945 P a t e n t k r a v Temperaturstyrningskrets som ett (Pt500) utnyttjar temperatur- beroende motstånd för styrning av energitillförseln kännetecknad därav, (Pt500) àterkopplingsslingan för en operationsförstärkare (IC1) och av (Pl), till en förbrukare, att det temperatur- beroende nmtstândet bildar en del av den negativa att en spänningsdelare som är ansluten till den positiva ingàngsanslutningen på operationsförstärkaren (IC1), matas med ström som härleds fràn strömmen genom det temperaturberoende motståndet (Pt500) på sådant sätt att utspänningen från spänningsdelaren (Pl) kan jämföras med utspänningen från operationsförstärkaren (IC1) i en ytterligare komparator- förstärkare (IC2) vars utspänning styr energitillförseln till förbrukaren.Temperature control circuit as a (Pt500) utilizes temperature-dependent resistors for controlling the power supply characterized therefrom, the (Pt500) feedback loop for an operational amplifier (IC1) and by (P1), to a consumer, that the temperature The dependent voltage forms part of the negative that a voltage divider connected to the positive input terminal of the operational amplifier (IC1) is supplied with current derived from the current through the temperature dependent resistor (Pt500) in such a way that the output voltage from the voltage divider (P1) can be compared. with the output voltage from the operational amplifier (IC1) in an additional comparator amplifier (IC2) whose output voltage controls the energy supply to the consumer.
SE9803597A 1997-02-27 1998-10-21 Temperature control circuit SE511945C2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DK21897 1997-02-27
PCT/DK1998/000079 WO1998038557A1 (en) 1997-02-27 1998-02-27 A temperature control circuit

Publications (3)

Publication Number Publication Date
SE9803597D0 SE9803597D0 (en) 1998-10-21
SE9803597L SE9803597L (en) 1998-10-21
SE511945C2 true SE511945C2 (en) 1999-12-20

Family

ID=8091074

Family Applications (1)

Application Number Title Priority Date Filing Date
SE9803597A SE511945C2 (en) 1997-02-27 1998-10-21 Temperature control circuit

Country Status (5)

Country Link
AU (1) AU6205298A (en)
DE (1) DE19880404T1 (en)
NO (1) NO314817B1 (en)
SE (1) SE511945C2 (en)
WO (1) WO1998038557A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100483591C (en) * 2006-06-29 2009-04-29 中国科学院半导体研究所 Temperature switch

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2035529B (en) * 1978-09-22 1982-11-24 Pye Ltd Providing cooled air in an outside broadcast vehicle
US4297851A (en) * 1979-08-20 1981-11-03 Whirlpool Corporation Temperature sensing circuit with high noise immunity
JPS6277604A (en) * 1985-09-30 1987-04-09 Shimadzu Corp Proportional controller
JPH05259563A (en) * 1992-03-10 1993-10-08 Hitachi Ltd Controlling circuit for optical output of semiconductor

Also Published As

Publication number Publication date
WO1998038557A1 (en) 1998-09-03
SE9803597D0 (en) 1998-10-21
AU6205298A (en) 1998-09-18
NO984977L (en) 1998-10-26
SE9803597L (en) 1998-10-21
NO984977D0 (en) 1998-10-26
DE19880404T1 (en) 1999-04-15
NO314817B1 (en) 2003-05-26

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Legal Events

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