U.S. patent application number 14/410963 was filed with the patent office on 2015-12-03 for method for operating a portable electronic device.
The applicant listed for this patent is Sensirion AG. Invention is credited to Dominic BONI, Dominik NIEDERBERGER, Andrea SACCHETTI.
Application Number | 20150349570 14/410963 |
Document ID | / |
Family ID | 48288691 |
Filed Date | 2015-12-03 |
United States Patent
Application |
20150349570 |
Kind Code |
A1 |
NIEDERBERGER; Dominik ; et
al. |
December 3, 2015 |
METHOD FOR OPERATING A PORTABLE ELECTRONIC DEVICE
Abstract
In a method for operating a portable electronic device an
ambient temperature (T.sub.S) of the portable electronic device (2)
is sensed by means of a temperature sensor (1). It is further
detected if a rechargeable energy storage (22) of the portable
electronic device (2) is in a process of being recharged. If the
energy storage (22) is detected to be in a process of being
recharged a compensated ambient temperature (T.sub.A) is determined
dependent on at least the sensed ambient temperature (T.sub.S) and
dependent on information (P.sub.i) related to a charging current
for recharging the energy storage (22).
Inventors: |
NIEDERBERGER; Dominik;
(Zurich, CH) ; BONI; Dominic; (Dielsdorf, CH)
; SACCHETTI; Andrea; (Zurich, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sensirion AG |
Stafa |
|
CH |
|
|
Family ID: |
48288691 |
Appl. No.: |
14/410963 |
Filed: |
April 18, 2013 |
PCT Filed: |
April 18, 2013 |
PCT NO: |
PCT/CH2013/000064 |
371 Date: |
December 23, 2014 |
Current U.S.
Class: |
320/153 |
Current CPC
Class: |
G01K 1/20 20130101; G06F
1/1684 20130101; G01D 3/036 20130101; H02J 7/00 20130101; G06F
1/206 20130101; G01K 13/00 20130101; Y02D 10/00 20180101; G06F
1/1626 20130101; H02J 7/0072 20130101 |
International
Class: |
H02J 7/00 20060101
H02J007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 2, 2012 |
EP |
12004897.0 |
Claims
1. Method for operating a portable electronic device, comprising:
sensing an ambient temperature of the portable electronic device by
means of a temperature sensor, detecting 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 determining a compensated ambient temperature
dependent on at least the sensed ambient temperature and dependent
on information related to a charging current for recharging the
energy storage.
2. Method according to claim 1, wherein the charging current is
determined subject to a charging level and/or a charging voltage of
the energy storage, and wherein the compensated ambient temperature
is determined dependent on the determined charging current.
3. Method according to claim 2, wherein the charging current is set
to a nominal charging current value if the charging level or the
charging voltage respectively is less than a threshold.
4. Method according to claim 2, wherein the charging current is set
to a value less than the nominal charging current value if the
charging level or the charging voltage respectively is equal to or
above a threshold.
5. Method according to claim 2, wherein the charging current is set
to a value derived from a charging current versus charging level
characteristic or a charging current versus charging voltage
characteristic respectively if the charging level is equal to or
above a threshold.
6. Method according to claim 3, wherein the nominal charging
current value is received from a recharger connected to the
portable electronic device during a process of being recharged.
7. Method according to claim 1, wherein the charging current is
measured, and wherein the compensated ambient temperature is
determined dependent on the measured charging current.
8. Method according to claim 2, wherein the determination or the
measuring of the charging current is only performed if the energy
storage is detected to be in a process of being recharged.
9. Method for operating a portable electronic device, in particular
according to claim 1, comprising: sensing an ambient temperature of
the portable electronic device by means of a temperature sensor,
sensing a temperature of a rechargeable energy storage of the
portable electronic device by means of another temperature sensor
detecting if the rechargeable energy storage is in a process of
being recharged, if the energy storage is detected to be in a
process of being recharged determining a compensated ambient
temperature dependent on at least the sensed ambient temperature
and dependent on the sensed energy storage temperature.
10. Method according to claim 1, wherein the compensated ambient
temperature represents the sensed ambient temperature adjusted by a
temperature value representing an impact of heat released at least
from the energy storage during the process of being recharged and
propagated via a heat path to the temperature sensor.
11. Method according to claim 1, wherein frequency contributions of
the sensed ambient temperature with a frequency f>0 Hz are
adjusted dependent on the sensed ambient temperature.
12. Computer program element for operating a portable electronic
device, comprising computer program code means for implementing the
following steps when executed on a processor of a portable
electronic device: receiving a signal representing an ambient
temperature of the portable electronic device sensed by a
temperature sensor of the portable electronic device, 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
determining a compensated ambient temperature dependent on at least
the sensed ambient temperature and dependent on information related
to a charging current for recharging the energy storage.
13. Computer program element for operating a portable electronic
device, in particular according to claim 12, comprising computer
program code means for implementing the following steps when
executed on a processor of a portable electronic device: receiving
a signal representing an ambient temperature of the portable
electronic device sensed by a temperature sensor of the portable
electronic device, 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
determining a compensated ambient temperature dependent on at least
the sensed ambient temperature and dependent on the sensed energy
storage temperature.
14. Portable electronic device, comprising: a rechargeable energy
storage for operating the portable electronic device, a recharging
detector for detecting if the energy storage is in a process of
being recharged, a temperature sensor for sensing an ambient
temperature of the portable electronic device, a compensator for
determining a compensated ambient temperature dependent on at least
the sensed ambient temperature and information related to a
charging current for recharging the energy storage if the energy
storage is detected to be in a process of being recharged.
15. Portable electronic device according to claim 14, comprising
means for supplying one or more of a charging level and a charging
voltage of the energy storage, wherein the compensator is adapted
to determine the charging current subject the charging level or the
charging voltage respectively, and wherein the compensator is
adapted to determine the compensated ambient temperature dependent
on the determined charging current.
16. Portable electronic device according to claim 15, wherein the
compensator is adapted to determine the charging current by setting
the charging current to a nominal charging current value if the
charging level or the charging voltage respectively is less than a
threshold, and/or by setting the charging current to a value less
than the nominal charging current value if the charging level or
the charging voltage respectively is equal to or above the
threshold.
17. Portable electronic device, in particular according to, claim
14, comprising a rechargeable energy storage for operating the
portable electronic device, a recharging detector for detecting if
the energy storage is in a process of being recharged, a
temperature sensor for sensing an ambient temperature of the
portable electronic device, another temperature sensor for sensing
a temperature of the energy storage, a compensator for determining
a compensated ambient temperature dependent on at least the sensed
ambient temperature and on the sensed energy storage
temperature.
18. Portable electronic device according to claim 14, wherein the
compensator comprises a model for determining a heat propagation as
a function of time from the energy storage to the temperature
sensor.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] 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.
TECHNICAL FIELD
[0002] 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.
BACKGROUND ART
[0003] 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.
DISCLOSURE OF THE INVENTION
[0004] According to first aspects of the present invention methods
are provided for operating a portable electronic device.
[0005] According to second aspects of the present invention,
portable electronic devices are provided.
[0006] 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.
[0007] 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.
[0008] 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.
[0009] 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.
[0010] 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.
[0011] 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.
[0012] 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.
[0013] 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.
[0014] 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.
[0015] 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.
[0016] 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.
[0017] 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.
[0018] 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.
[0019] 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:
[0020] a display of the portable electronic device, wherein power
consumption related information of the display may be used for the
compensation;
[0021] 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;
[0022] a GPS module of the portable electronic device, wherein
power consumption related information of the GPS module may be used
for the compensation.
[0023] A selection of components which contribute to the
compensation may depend on the heat generated in absolute terms or
in relative terms.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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 (T.sub.S). This feature
may be applied for accelerating the determination of the
compensated ambient temperature.
[0028] 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.
[0029] 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.
[0030] 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.
[0031] 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.
[0032] 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.
[0033] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The detailed description refers to embodiments of the
present invention. Such description makes reference to the annexed
drawings, wherein:
[0035] FIG. 1 illustrates a mobile phone according to an embodiment
of the present invention in diagram a), an associated thermal block
diagram in diagram b), and an associate compensator in diagram
c),
[0036] FIG. 2 shows a chart of different temperature signals over
time illustrating the compensating effect according to embodiments
of the present invention,
[0037] FIG. 3 shows a flow chart of a method for operating a
portable electronic device according to an embodiment of the
present invention, and
[0038] FIG. 4 shows a block diagram of a portable electronic device
according to an embodiment of the present invention.
DETAILED DESCRIPTION
[0039] FIG. 1a) 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.TM. AG under the tradenames SHTC1 (temperature and
humidity sensor) or STS21 (as temperature only sensor), provides a
sensed ambient temperature T.sub.S. The sensed ambient temperature
T.sub.S may not reflect the real ambient temperature T.sub.R
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
T.sub.R changes quickly.
[0040] 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.
[0041] 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 T.sub.S, and a
determined charging current I in the case of a recharge process
detected. In addition, the compensation may receive information
P.sub.1, P.sub.2 related to the power consumption of the other
components 21 and 23. The compensator 4 supplies at its output the
compensated ambient temperature T.sub.A.
[0042] 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.
[0043] The compensated ambient temperature T.sub.A 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)
[0044] with u(k) denoting the inputs at time step k, y(k) denoting
the output T.sub.A, 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.
[0045] 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:
TABLE-US-00001 while not stopped { u=Read_Input( ); // Read input
y=C*x+D*u; // Calculate output x=A*x+B*u; // State Update
T.sub.A=y; // Ambient Temperature = y }
[0046] The compensated ambient temperature T.sub.A may be displayed
on the display 21.
[0047] 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 T.sub.1 of the
energy storage 22. Here, the compensator 4 may determine the
ambient temperature T.sub.A at least dependent on the sensed
ambient temperature T.sub.S and the sensed temperature T.sub.1.
[0048] In a temperature T over time t chart according to FIG. 2, in
which time t is represented by discrete time steps k*.DELTA.t, a
sample real temperature characteristic T.sub.R in the ambient of a
portable electronic device is shown by the straight line. The
dashed line represents a corresponding ambient temperature T.sub.S
as sensed by a temperature sensor of the mobile device. It becomes
apparent from the chart in FIG. 2 that due to internal heating the
temperature sensor detects an ambient temperature T.sub.S higher
than the real ambient temperature T.sub.R. Interval I1 may, for
example, represent a time interval, in which the mobile device is
operated at average load. However, in interval I2, it assumed that
a battery of the mobile device at least temporarily is recharged.
This results in the sensed ambient temperature T.sub.S even more
deviating from the real ambient temperature T.sub.R: At the end of
interval I2, the real ambient temperature T.sub.R drops, for
example, due to the user of the mobile device entering a basement.
The sensed ambient temperature T.sub.S follows a temperature drop
in the real ambient temperature T.sub.R only slowly. The
dashed-dotted line, on the other hand, illustrates a compensated
ambient temperature T.sub.A which is determined by using a
compensator such as illustrated in diagram 1c), which is based on a
thermal model of the portable electronic device. It can be seen,
that from the beginning of the operation of the portable electronic
device, a deviation of the compensated ambient temperature T.sub.A
from the real ambient temperature T.sub.R is minimized, at least
the compensated ambient temperature T.sub.A is lower than the
sensed ambient temperature T.sub.S.
[0049] In interval I3, the compensated ambient temperature T.sub.A
much quicker aligns with the drop in the real ambient temperature
T.sub.R. This effect may be caused by implementing a temperature
dependent compensation of dynamic contributions of the sensed
ambient temperature T.sub.S 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
T.sub.A responds faster to changes in the real ambient temperature
T.sub.R, and consequently in the sensed ambient temperature
T.sub.S. For such temperature dependent compensation of the
dynamics of the sensed ambient temperature signal, it is referred
to US Patent Publication US 2011/0307208.
[0050] FIG. 3 illustrates a flow chart of a method for operating a
portable electronic device according to an embodiment of the
present invention. In step S1 the device is switched on. In step
S2, an ambient temperature is measured. In step S3 it is verified
if a battery of the device is in a process of being recharged. If
no such recharge process is detected (N), in step S4 a compensated
ambient temperature is calculated dependent on the sensed ambient
temperature, and potentially compensated for heat propagated to the
temperature sensor from components other than the energy storage.
In step S5 the compensated ambient temperature is displayed to the
user on a display of the device. If a recharge process is detected
instead (Y), in step S6 a compensated ambient temperature is
calculated dependent on the sensed ambient temperature and at least
further dependent on a nominal charging current value and a
charging level or charging voltage of the energy storage. The
sensed temperature may also here additionally be compensated for
heat propagated to the temperature sensor from components other
than the energy storage. In step S7 the compensated ambient
temperature is displayed to the user on the display.
[0051] FIG. 4 shows a schematic hardware oriented block diagram of
a portable electronic device 2 according to an embodiment of the
present invention. Here, a central processing unit 23 in form of a
microprocessor is connected via electrical conductors 27 to a
temperature sensor 1 and other sensors. A wireless interface 25 is
connected to the microprocessor, too. A socket 26 for receiving a
charging cable is connected to a rechargeable battery 22. Whenever
a charging cable is plugged into the socket 26 and the portable
electronic device 2 is thereby connected to a main supply the
rechargeable battery 22 will be charged. A recharging process
detector 28 is provided for detecting a recharge process. As
indicated by the dotted line arrows, the detector 28 may, for
example, detect if a charging cable is plugged into the socket 26
and as such detect a mechanical plug. In another variant, the
detector 28 may detect if current is supplied from the socket 26 to
the rechargeable battery 22. In another variant, the detector 28
may monitor a capacity, or more generally a charging level of the
rechargeable battery 2 and derive from this state if the
rechargeable battery 2 currently is charged. Any such indicator as
to the detection of a charging process is submitted to the central
processing unit 23 as is the charging level of the battery 22. In
addition, the charging process detector 28 may supply a nominal
charging current value to the central processing unit 23 received
by a recharger plugged into the socket 26. The central processing
unit 23 analyzes the signals supplied by the temperature sensor 1
and the recharging process detector 78 by executing a corresponding
routine. The routine which is also denoted as compensator is stored
in a memory 29 connected to the central processing unit 23 via a
bus system 24.
[0052] 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.
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