Method to reduce the amount of temperature/Vbat measurement
Original Publication Date: 2002-Sep-01
Included in the Prior Art Database: 2003-Jul-23
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).
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