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Method to reduce the amount of temperature/Vbat measurement

IP.com Disclosure Number: IPCOM000018501D
Original Publication Date: 2002-Sep-01
Included in the Prior Art Database: 2003-Jul-23
Document File: 1 page(s) / 157K

Publishing Venue

Siemens

Related People

Thomas Stichelbout: AUTHOR

Abstract

Temperature measurement is necessary in a mobile phone to control the frequency stability and other parameters. Until now the temperature measurement is done with a specific Analog-Digital-Converter (ADC) or with a receiver chain (RX chain). Using the RX chain implies that an extra ADC is not needed but the RX chain is not so often available for measurements. The temperature measurement can only be done when the RX chain is not receiving and the same RX chain is also used for other measure- ments such as voltage measurement on the battery (Vbat). The proposed method uses an extrapolated the tem- perature/battery voltage curve from previous meas- urements (figure 1). As the temperature variation versus time depends a lot on the user scenario, sev- eral models of extrapolation are available to best suit this evolution at a given time. A very simple model to extrapolate the temperature curve is a linear ap- proximation based on the last two previous tempera- ture measurements. For each model an error is cal- culated and is used as an input to a neuronal network which will decide which model fits the evolution best or if extra temperature measurement should be used instead. The amount of measurements can be reduced when the temperature variation fits the models avail- able.

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Industrie

Method to reduce the amount oftemperature/Vbat measurement

Idee: Thomas Stichelbout, DK–Aalborg

Temperature measurement is necessary in a mobilephone� to� control� the� frequency� stability� and otherparameters. Until now the temperature measurementis� done� with� a specific Analog-Digital-Converter(ADC) or with a receiver chain (RX chain). Usingthe� RX� chain� implies� that� an� extra� ADC is notneeded but the RX chain is not so often available formeasurements.� The� temperature measurement canonly be done when the RX chain is not receiving andthe same RX chain is also used for other measure-ments such as voltage measurement on the battery(Vbat).

The proposed method uses an extrapolated the tem-perature/battery voltage curve from previous meas-urements (figure 1).� As� the� temperature� variationversus time depends a lot on the user scenario, sev-eral models of extrapolation are available to best suitthis evolution at a given time. A very simple modelto extrapolate the temperature curve is a linear ap-proximation based on the last two previous tempera-ture measurements. For each model an error is cal-culated and is used as an input to a neuronal networkwhich will decide which model fits the evolution bestor if extra temperature measurement should be usedinstead. The amount of measurements can be reducedwhen the temperature variation fits the models avail-able.

Fig. 1: Measurement method

Siemens� Technik Report� � � � � Jahrgang 5� Nr.18� � � � � August 2002