Patent Application
20150349570
This application claims the priority of European patent application 12 004 897.0, filed Jul. 2, 2012, the disclosure of which is incorporated herein by reference in its entirety.
The present invention relates to a portable electronic device, to a method for operating a portable electronic device, and to a computer program element for operating a portable electronic device.
It is desired to conduct a precise measurement of the ambient temperature with a portable electronic device such as a mobile phone, a tablet computer or another portable computing device, which portable electronic device typically comprises an energy storage for supplying energy for operating the portable electronic device.
According to first aspects of the present invention methods are provided for operating a portable electronic device.
According to second aspects of the present invention, portable electronic devices are provided.
The portable electronic device comprises a temperature sensor for sensing an ambient temperature of the portable electronic device which temperature sensor typically provides a sufficient coupling to the environment of the portable electronic device, e.g. by being exposed to the ambient through openings in a housing of the device or other means.
However, it was found that heat radiated from an energy storage of the portable electronic device during a recharge process thereof, may impact the measurement of the ambient temperature. This may result in that the temperature sensed by the temperature sensor no longer reflects the real ambient temperature but reflects the real ambient temperature perturbed by heat released during recharging the energy storage, and even after the recharge process has been terminated in view of the heat dissipating slowly. Hence, the present portable electronic device comprises a compensator for compensating for such perturbance and for determining a compensated ambient temperature which preferably better reflects the real ambient temperature. This compensated ambient temperature represents an estimate of the real ambient temperature based on the sensed ambient temperature as supplied by the temperature sensor and by taking into account the heat generated during recharging the energy storage by means of information related to a charging current, or, alternatively or in addition by a temperature of the energy storage sensed by another temperature sensor. Such other temperature sensor preferably is arranged at or close to the energy storage in case the temperature of the energy storage shall be sensed and contribute to the compenastion. As a result, the sensed ambient temperature preferably may be corrected by a temperature value owed to the heat transferred from the energy storage to the temperature sensor during recharging.
The rechargeable energy storage of the portable electronic device may, for example, be a rechargeable battery which supplies energy consuming components of the portable electronic device with electrical energy. Preferably by means of a recharging detector it can be detected if the energy storage is in a process of being recharged. Such recharging detector may in one embodiment include a mechanical recharging detector for detecting if a socket of the portable electronic device is connected to a charging cable. Whenever a charging cable is plugged into the socket the portable electronic device is thereby connected to a main supply for charging the rechargeable energy storage. This recharging detector, hence, may detect a mechanical plug. In another variant, the recharging detector may detect if current is supplied from the socket to the energy storage. In another variant, the recharging detector may monitor a capacity, or more generally a charging level of the rechargeable energy storage and derive herefrom if the energy storage currently is charged. The recharge process may be detected in case of a sufficient change in the charging level, and specifically from an upward change in the charging level. In another variant, the detector may monitor a charging voltage of the battery and derive if the energy storage currently is recharged. The recharge process may be from a change in the charging voltage and specifically from an upward change in the charging voltage. In another embodiment, the charging current itself may be measured. In case the charging current deviates from zero a current recharge process is detected.
If the energy storage is detected to be in a process of being recharged the compensated ambient temperature preferably is determined not only dependent on the sensed ambient temperature and possibly compensation parameters representing a heat impact from heat sources in the portable electronic device other than the energy storage, but also dependent on information related to a charging current for recharging the energy storage, and/or the sensed temperature of the energy storage respectively. Hence, at least once a recharge process/state is detected, and preferably its start is detected, this recharge process preferably is reflected by corresponding parameters in the compensation of the sensed temperature signal dependent on information related to the charging current and/or the sensed temperature of the energy storage respectively. Preferably, the compensation is not terminated upon the detection of a termination of the recharge process but continues in view of the heat generated throughout the recharge process requiring some time to dissipate during which time this heat still perturbs the sensing of the ambient temperature.
Preferably, the information related to the charging current represents the charging current itself. In case of no recharge process being detected, it is preferred that no recharging owed compensation is applied. Here, the ambient temperature preferably is determined solely dependent on the sensed ambient temperature and possibly compensation parameters representing a heat impact from heat sources in the portable electronic device other than the energy storage.
In a preferred embodiment, in response to the detection of the recharge process the recharge based compensation may be activated under the assumption it was not applied so far. In response to the detection of an absence of a recharge process, the recharge based compensation may be deactivated under the assumption it was active so far. In an alternative embodiment, however, the recharge based compensation may not actively be activated or deactivated but may permanently contribute to the compensation model. In this example, the ambient temperature permanently is calculated dependent on the charging current which charging current is zero or around zero in the absence of a recharge process and thus does not contribute to the compensation. Even if in this latter embodiment there may be no explicit recharge detection, the recharge detection still is implied given that the charging current is zero in the absence of a recharge process and is non-zero in the presence of a recharge process.
There may be portable electronic devices in which the charging current is not explicitly measured. Still the compensation is desired to be made dependent on the charging current given that the charging current is a measure for the heat released during the recharge process. Hence, in such situations it is preferred that the charging current is not measured but is determined subject to other information available. Such other information may, for example, be a nominal charging current value which may be supplied by a recharger. This nominal charging current value indicates a charging current that typically is provided by the recharger. In one embodiment, this nominal charging current value may be used for the compensation.
However, it is observed that the nominal charging current value may only reflect or come close to the real charging current as long as the energy storage is not fully charged. The higher a charging level of the energy storage is, the more the real charging current deviates from the nominal charging current value. Such deviation may result in an inaccurate compensation and as such in an inaccurate compensated ambient temperature value. In this scenario, a drop of the charging current may be owed to a corresponding control in the recharger which controls the charging current down dependent on the charging level or given that at already high charging levels the energy storage no longer is capable of storing load of additional energy and rather would this oversupplied electrical energy into heat which may damage the energy storage.
The charging level of the energy storage on the other hand is readily available e.g. from an operating system of the portable electronic device or from the energy storage itself. Most of todays portable electronic devices provide a charging level indicator displayed to the user in order to warn the user of a flat battery and encourage the user to recharge the device early on.
In this embodiment, therefore, the charging current typically is not measured but is preferably set to the nominal charging current value if the charging level of the energy storage is below a threshold which threshold preferably coincides with a threshold of the recharger for starting reducing the charging current. However, in case the threshold is met or exceeded by the charging level—which implies that the nominal charging current value no longer reflects the real charging current—, it is preferred that the charging current is set to a value less than the nominal charging current value.
Preferably, in this scenario the determined charging current is set to a value derived from a charging current versus charging level characteristic. Such characteristic may be stored in the device itself and initially be provided by the recharger supplier or be generated by way of measurements.
Hence, in these embodiments, the charging current is rather determined by means of related information than being directly measured. These embodiments may be modified by replacing the charging level by a charging voltage that may be measured, for example. Given that in many devices the charging level of the energy storage is derived from the charging voltage, e.g. the voltage of the battery, this measure may be taken alternatively to the charging level. Here, the charging current over charging voltage characteristic may assumed to be similar to the characteristic of the charging current over charging level. I.e., the charging current is assumed to be constant for low charging voltages and drops for higher charging voltages.
If, however, according to another embodiment, the charging current is directly measured, the measured charging current may be used as information impacting the compensation of the sensed ambient temperature.
In preferred embodiments, other components representing heat sources may be considered in the compensation of the sensed temperature. Such components may include one or more of the following:
a display of the portable electronic device, wherein power consumption related information of the display may be used for the compensation;
a central processing unit of the portable electronic device, wherein power consumption related information such as a load of the central processing unit may be used for the compensation;
a GPS module of the portable electronic device, wherein power consumption related information of the GPS module may be used for the compensation.
A selection of components which contribute to the compensation may depend on the heat generated in absolute terms or in relative terms.
It is preferred that the compensated ambient temperature may also be determined based on a thermal conductivity of a heat path between the energy storage and the temperature sensor, and/or between other components contributing to the compensation and the temperature sensor if any. This measure may make the determination of the compensated ambient temperature even more precise since it takes into account the heat flux that effectively arrives at the temperature sensor rather than the bare heat that is generated at the energy storage or other component respectively.
In another embodiment, the compensated ambient temperature may additionally be determined based on a thermal capacity of one or more of thermal capacitances in the portable electronic device. Such thermal capacitance may be represented by any element of the portable electronic device being capable of storing thermal energy. For example, a housing of the portable electronic device or parts thereof may be considered as a thermal capacitance. The thermal capacitance does not necessarily consume electrical power but may be heated by components which consume electrical power. The thermal capacitance may store the supplied thermal energy over some time. Such heat may be transferred to the temperature sensor via a thermal conducting path especially when the temperature at the temperature sensor is lower than the temperature of the thermal capacitance. Preferably, it is only the major thermal capacitances that are taken into account for determining the compensated ambient temperature. Generally, it depends on the design of the portable electronic device how many other components, thermal paths or thermal capacitances are available in the portable electronic device and which of these are selected for contributing to the compensation.
In another preferred embodiment, a sensed temperature of at least one further temperature sensor, or a sensor allowing for determining a temperature, such as a thermal flux sensor, arranged in the device may be used for determining the compensated ambient temperature, especially when such temperature sensor is available in the device anyway. Such temperature sensor may include a temperature sensor that is arranged in the portable electronic device for measuring the temperature at a specific location, or the temperature of a specific component, such as, for example, a central processing unit of the device.
In a preferred embodiment, frequency contributions in the sensed ambient temperature with a frequency f>0 Hz are adjusted dependent on the sensed ambient temperature (TS). This feature may be applied for accelerating the determination of the compensated ambient temperature.
Preferably, the portable electronic device may be one of a mobile phone, and especially a smart phone, a handheld computer, an electronic reader, a tablet computer, a game controller, a pointing device, a photo or a video camera, a computer peripheral, a digital music player, a wrist watch, a key fob, a head set.
According to a further aspect of the present invention, a computer program element is provided for operating a portable electronic device, which computer program element, which preferably is stored on a computer storage medium, comprises computer program code means for receiving a signal representing an ambient temperature of the portable electronic device sensed by a temperature sensor of the portable electronic device, and for receiving information if a rechargeable energy storage of the portable electronic device is in a process of being recharged. If the energy storage is detected to be in a process of being recharged a compensated ambient temperature is determined dependent on at least the sensed ambient temperature and dependent on information related to a charging current for recharging the energy storage.
According to a further aspect of the present invention, a computer program element is provided for operating a portable electronic device, which computer program element, which preferably is stored on a computer storage medium, comprises computer program code means for receiving a signal representing an ambient temperature of the portable electronic device sensed by a temperature sensor of the portable electronic device, and for receiving a signal representing a temperature of a rechargeable energy storage of the portable electronic device sensed by means of another temperature sensor. If the energy storage is detected to be in a process of being recharged a compensated ambient temperature is determined dependent on at least the sensed ambient temperature and dependent on the sensed energy storage temperature.
Generally, in any of the methods, the portable electronic devices and the computer program elements, the temperature sensor may in an alternative not be provided and/or arranged for sensing the ambient temperature but may be provided and/or arranged for sensing a temperature of a component of the device or of a location within the device. Again, heat generated by (other) components may impact such measurement. Hence, it is again preferred that a compensator is provided for determining a compensated temperature dependent on at least the sensed temperature and information related to the electrical power consumed by at least one of the (other) components.
Other advantageous embodiments are listed in the dependent claims as well as in the description below. The described embodiments similarly pertain to the device, the method, and the computer program element. Synergetic effects may arise from different combinations of the embodiments although they might not be described in detail.
Further on it shall be noted that all embodiments of the present invention concerning a method might be carried out in the order of the steps as described. Nevertheless this has not to be the only essential order of steps but all different orders of the method steps shall be comprised in the scope of the claims and be disclosed by the method claims.
The detailed description refers to embodiments of the present invention. Such description makes reference to the annexed drawings, wherein:
a) shows a diagram illustrating a mobile phone according to an embodiment of the present invention. The mobile phone includes a temperature sensor 1, an energy storage 22 and a central processing unit 23 and a display. One or more of these components 21, 22, 23 may radiate heat during operation of the mobile phone amongst other components. The temperature sensor 1, which for example may be one of a commercially available sensor from Sensirion™ AG under the tradenames SHTC1 (temperature and humidity sensor) or STS21 (as temperature only sensor), provides a sensed ambient temperature TS. The sensed ambient temperature TS may not reflect the real ambient temperature TR because of a self-heating of the energy storage 22 during recharge which perturbs the measuring with the temperature sensor 1. Another reason may be a slow dynamic that slows down a temperature response of the temperature sensor 1 when the real ambient temperature TR changes quickly.
In this context, a “thermal” block diagram of the mobile phone of diagram 1a) is shown diagram 1b). The heat generating components 21, 22, 23 are thermally connected to the temperature sensor 1 and possibly to each other by heat paths HP on which heat flux is propagated.
Preferably, a heat flux propagating to the temperature sensor 1 may be determined and be compensated for by a compensator 4 as is shown in diagram 1c). The compensator 4 may be an entity, represented by hardware, software, or a combination of both, which receives at least the sensed ambient temperature TS, and a determined charging current I in the case of a recharge process detected. In addition, the compensation may receive information P1, P2 related to the power consumption of the other components 21 and 23. The compensator 4 supplies at its output the compensated ambient temperature TA.
In general, the compensator 4 may make use of a dynamic thermal model of the mobile device such as, for example, is shown in diagram 1b). The dynamic thermal model may mathematically be described by a differential equation system. The model may in one embodiment comprise one or more, and preferably the most relevant heat sources, and in another embodiment additionally one or more, and preferably the most relevant thermal conductivities, and in another embodiment additionally one or more, and preferably the most relevant heat capacities, as well as it comprises the temperature sensor that is well coupled to the ambient, and it may comprise one or more optional temperature sensors that may be available in the mobile device.
The compensated ambient temperature TA may then be estimated from these inputs by using the following Equation 1) as compensator 4:
x(k+1)=Ax(k)+Bu(k)
y(k)=Cx(k)+Bu(k) Collectively Equation 1)
with u(k) denoting the inputs at time step k, y(k) denoting the output TA, and x(k) denoting an internal state vector. A is an n-by-n matrix, B an n-by-m matrix, C an 1-by-n matrix and D an 1-by-m matrix, where n is the number of states that depends on the complexity of the model and m the number of inputs. Typical inputs may be, for example, an intensity of a display, a time derivative of a battery charge level, a central processing unit load, or other power management information. Additional temperature sensors at hot spots of the portable electronic device may improve the compensation results.
Hence, in one embodiment, the portable electronic device is modelled as a thermal system with heat sources, and optionally with heat capacities and/or thermal conductivities. From this model, a time-discrete compensator according to the state space description of Equation 1) is derived, that can easily be implemented on a microprocessor of the portable electronic device by using the following software code:
The compensated ambient temperature TA may be displayed on the display 21.
Alternatively to the measuring of information related to the power consumed by the energy storage 22, or in addition, another temperature sensor 3 may be provided which other temperature sensor 3 may act as a sensor for sensing the temperature T1 of the energy storage 22. Here, the compensator 4 may determine the ambient temperature TA at least dependent on the sensed ambient temperature TS and the sensed temperature T1.
In a temperature T over time t chart according to
In interval I3, the compensated ambient temperature TA much quicker aligns with the drop in the real ambient temperature TR. This effect may be caused by implementing a temperature dependent compensation of dynamic contributions of the sensed ambient temperature TS in the compensator. A dynamic contribution is understood as any contribution in the spectral range with a frequency f>0 Hz. In case of a fast varying ambient temperature such as the step function at the end of interval I2, the compensator is enabled to accelerate the thermal dynamics of the mobile device such that the compensated ambient temperature TA responds faster to changes in the real ambient temperature TR, and consequently in the sensed ambient temperature TS. For such temperature dependent compensation of the dynamics of the sensed ambient temperature signal, it is referred to US Patent Publication US 2011/0307208.
While there are shown and described presently preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 12004897.0 | Jul 2012 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CH2013/000064 | 4/18/2013 | WO | 00 |
