JPH06334585A - Information communication terminal device and its control method - Google Patents

Abstract

PURPOSE:To reduce the power consumption by monitoring ambient temperature, and raising the power source voltage when the ambient temperature is high and lowering the power source voltage to a designed power source voltage when low. CONSTITUTION:This device consists of a control circuit 5, a power source 3-1 which generates a low output voltage, a power source 3-2 which generates a high output voltage, a temperature sensor 2, a voltage control circuit 1, and a power source voltage changeover switch 4. The power source voltage changeover switch 4 is connected normally to the power source 3-1 (4.5V) which generates the low output voltage. The voltage control circuit 1 measures the temperature information 101 from the temperature sensor 2 and judges that the operation environment gets worse when prescribed temperature is exceeded, thereby switching the power source voltage changeover switch 4 to the power source 3-2 (5V) which generates the high output voltage. Consequently, the source voltage of the control circuit 5 becomes high, so the control circuit 5 can perform high speed operation and also operates normally even in the inferior environment. Namely, the power source voltage is adaptively controlled so that the operation margin that the circuit has approaches zero as much as possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable information communication terminal device such as a mobile phone which requires low power consumption and a control method thereof.

[0002]

2. Description of the Related Art Due to advances in semiconductor technology, downsizing of devices has progressed, and information communication terminal devices such as telephones, electronic organizers, word processors, and personal computers have become smaller and more portable. A battery is often used as a power source of these information communication terminal devices so that they can be used anytime and anywhere.
However, the battery is different from the AC power supply (AC100V)
There is a drawback that the usage time is limited (it cannot be used for a long time). Therefore, low power consumption is a problem common to these information communication terminals.

Conventionally, as shown in, for example, Japanese Unexamined Patent Publication No. 3-252285, the power is turned on only when the device is in operation.
When not in use, the power was turned off to achieve low power consumption.

[0004]

In the prior art, the power consumption is reduced while the device is not used, but there is no mention of suppressing the power consumption during operation.
The power saving when the device is actually operating has not been realized.

An object of the present invention is to realize power saving while the device is operating.

[0006]

In order to solve the above-mentioned problems, the present invention monitors the ambient temperature with a temperature measuring means, increases the power supply voltage when the ambient temperature is high, and realizes high-speed operation. When the temperature is low, up to the power supply voltage at the time of design (for example, the power supply voltage at the time of design is 4.5 V for the normal operation power supply voltage of 5 V) considering the operation margin of the circuit,
The power supply voltage is lowered to realize low power consumption.

Further, according to the present invention, a critical path is selected from the control circuit, the operating state is monitored by a critical path test circuit for testing the critical path, and when the critical path malfunctions, the power supply voltage is raised to the critical path. The power supply voltage is lowered when the path is in the normal state.

Further, according to the present invention, a changeover switch is provided so that the user can change the power supply voltage of the information communication terminal device by himself, and the power supply voltage switching decision right is given to the user.

Further, according to the present invention, a display is provided so that the user can monitor whether or not the device is operating normally when the power supply voltage is lowered so that the user can be informed of the malfunction condition.

Further, according to the present invention, a switch is provided so that two power supplies having the same output voltage can be connected in series and in parallel, and when the ambient temperature is high and the environment is poor, the power supplies are connected in series for high speed operation. When the ambient temperature is low, the power supplies are connected in parallel so that they can be used at a low voltage for a long time.

Further, according to the present invention, when the power switch is turned on, that is, before the information communication terminal actually operates, the ambient temperature is measured, the power supply voltage is increased when the temperature is high, and the power supply voltage is increased when the temperature is low. It lowers the voltage.

Further, according to the present invention, the ambient temperature is measured during the idle time of the processing of the CPU of the control circuit of the information communication terminal device, the power supply voltage is increased when the temperature is high, and the power supply voltage is decreased when the temperature is low. To do.

Further, according to the present invention, the ambient temperature is measured at regular time intervals, the power supply voltage is increased when the temperature is high, and the power supply voltage is lowered when the temperature is low.

[0014]

According to the present invention, according to the operating environment such as the ambient temperature, the power supply voltage is controlled so as to be adaptively lowered so that the operating margin of the circuit is as close to zero as possible.
Low power consumption can be realized.

Further, according to the present invention, the critical path having the smallest operation margin is selected, and the critical path is controlled to the lowest power supply voltage at which the critical path operates normally, so that low power consumption can be realized.

Further, according to the present invention, since the user can switch the power supply voltage of the information communication terminal device, it is possible to realize low power consumption.

Further, according to the present invention, it is possible to confirm whether or not the device is operating normally when the power supply voltage is lowered.
Malfunctions can be prevented.

Further, according to the present invention, the two batteries are switched between series and parallel to be used properly, so that the batteries can be used efficiently.

Further, according to the present invention, since the power supply voltage is set when the power switch is turned on, the processing capacity of the device does not deteriorate.

Further, according to the present invention, since the power supply voltage switching processing is performed during the idle time of the processing of the CPU of the control circuit,
The processing capacity of the device is not reduced.

Further, according to the present invention, since the power supply voltage is switched at a constant time interval, it does not operate at a low voltage for a long time, and malfunctions can be prevented.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The conventional portable information terminal device is designed with an operating margin in the power supply voltage so that it can operate in a bad environment. For example, the power supply voltage is low (for example, 4.5V)
By the way, it was designed to operate normally, and in reality, it was operated at a higher voltage (for example, 5 V).

However, these devices are rarely used in a bad environment, for example, outdoors in the desert, the tropics, or the summer, and usually have a relatively good environment, such as offices, homes, automobiles, etc. It is often used in different places. In this case, keeping the power supply voltage at 5V is a waste of power consumption, and the power supply voltage of 4.5V at the time of design allows a sufficient normal operation.
If the power supply voltage is 4.5V, it is possible to save about 20% in power consumption.

The present invention utilizes such an operating margin at the time of designing to control the power supply voltage to reduce the power consumption.

An embodiment of the present invention will be described with reference to FIG.
The portable information communication terminal of the present invention comprises a control circuit 5, a power supply 3-1 having a low output voltage, a power supply 3-2 having a high output voltage, a temperature sensor 2, a voltage control circuit 1, and a power supply voltage changeover switch 4. There is. Normally, the power supply voltage changeover switch 4 is connected to the power supply 3-1 (4.5 V) having a low output voltage. The voltage control circuit 1 measures the temperature information 101 from the temperature sensor 2, determines that the operating environment has deteriorated when the temperature becomes higher than a predetermined temperature (for example, 40 degrees), and the power supply voltage changeover switch 4
Is switched to the power supply 3-2 (5V) having a high output voltage. As a result, the power supply voltage of the control circuit 5 increases, so that the control circuit 5 can operate at high speed, and operates normally even in a bad environment.

FIG. 2 shows a voltage switching sequence.
This figure shows how the power supply voltage switched with respect to changes in ambient temperature. The horizontal axis represents time.
The threshold value for switching the power supply voltage is 40 degrees. Initially, since the ambient temperature is lower than 40 degrees, the power source 3-1 is selected and the power source voltage is 4.5V. At time t1, the ambient temperature becomes higher than 40 degrees, the power supply switches from 3-1 to 3-2, and the power supply voltage becomes 5V. After that, until time t2, 5
When V is maintained and the ambient temperature falls below 40 degrees at time t2, the power supply again switches from 3-2 to 3-1 and the power supply voltage becomes 4.5V.

The second embodiment of the present invention measures the critical path and switches the power supply voltage. This embodiment will be described with reference to FIG. The portable information communication terminal of the present invention comprises a control circuit 5, a power supply 3-1 having a low output voltage, a power supply 3-2 having a high output voltage, a voltage control circuit 1, and a power supply voltage changeover switch 4. The control circuit 5 is a CPU (C
entral processing unit) 10, ROM 11, RAM 1
2. It is composed of dedicated hardware 13 such as an arithmetic unit. C
PU10 is ROM11, RAM12, exclusive hardware 1
3. Control the voltage control circuit 1.

The dedicated hardware 13 is usually composed of a plurality of arithmetic units. Among them, the one having the smallest operation margin is defined as the critical path circuit 14. The critical path circuit 14 includes a selector 20 and a latch 2 that switch between a normal data path and a path for critical path check.
1, 23 and arithmetic unit 22. The critical path is the arithmetic unit 22 between the latch 21 and the latch 23.
Suppose

When the critical path check signal is turned on, the selector 20 loads test data from the CPU 10 into the latch 21. After the calculation, the CPU 10 reads the calculation result 201 stored in the latch 23,
It is compared with the expected value stored in the OM 11 (or RAM 12), and if they match, it is considered that the computing unit 22 is operating normally, and if they do not match, it is considered that a malfunction has occurred. If it malfunctions, turn the power supply from 3-1 to 3-2.
Then, the voltage is switched to 5 V and the critical path is checked again.

As described above, while confirming the operation of the critical path circuit 14, the device is operated and the power supply voltage within the range where malfunction does not occur is selected to realize low power consumption.

Further, in this embodiment, the critical path is the arithmetic unit, but if the ROM and RAM are the critical paths, the CPU may check by reading / writing the memory.

The third and fourth embodiments will be described with reference to FIG. The third embodiment controls the power supply voltage with an external switch. The portable information communication terminal of the present invention is
Control circuit 5, low output voltage power supply 3-1, high output voltage power supply 3-2, voltage control circuit 1, power supply voltage changeover switch 4, voltage selection switch 40, voltage selection switch interface circuit 41, display LED 50, display It is composed of a circuit 51. The CPU 10 in the control circuit 5 reads the state of the voltage selection switch 40 via the voltage selection switch interface circuit 41. In the off state, the voltage control circuit 1 is instructed to select the power supply 3-1 having a low power supply voltage, and in the on state, the voltage control circuit 1 is selected to select the power supply 3-2 having a high power supply voltage. Instruct. As described above, according to the present invention, the user can switch the power supply voltage.

In the fourth embodiment, the CPU 10 monitors the critical path of the dedicated hardware 13 and displays the LED 50 via the display control circuit 51 when a malfunction occurs. As a result, the user can immediately know whether or not the device has malfunctioned, and when it malfunctions, the power supply voltage can be immediately increased.

Next, an example of the configuration of the power source and the power source changeover switch of the fifth embodiment is shown in FIG. 5 and will be described. The power source 3 and the power source changeover switch 4 are composed of a battery 3-1 ', a battery 3-2', a switch 4-1, and a switch 4-2. Here, the voltage of the two batteries is described as 2.5V, but any voltage may be used. When the voltage control circuit 1 selects a high voltage, the switch 4-1 is opened and the switch 4-2 is connected to the positive pole of the battery 3-1 '. As a result, the two batteries are connected in series, and the voltage output voltage VCC becomes double the voltage (5V). When the voltage control circuit 1 selects a low voltage, the switch 4-1 is closed and the switch 4-2 is connected to the ground. As a result, the two batteries are connected in parallel, and the voltage output voltage VCC becomes 2.5V, but the battery operates for twice as long as usual.

In the present embodiment, the power supply is described as a battery that outputs a specific voltage, but a switching regulator may be used to control the power supply voltage so as to take a continuous value in an analog manner.

The sixth, seventh, and eighth embodiments relating to the power supply voltage switching timing will be shown and described below.

(1) Immediately after the power-on switch of the power supply is pressed (sixth embodiment) When the power is turned on, the ambient temperature or the critical path is checked and the power is switched, so that the processing overhead of the apparatus does not occur. .

(2) Free time for processing by the CPU 10 (seventh
Embodiment) Since the ambient temperature or the critical path is checked during the idle time of the processing of the CPU 10 and the power supply is switched, the processing overhead of the device does not occur.

(3) Every specific time interval (eighth embodiment) Since the ambient temperature or the critical path is checked at a specific time interval to switch the power supply, the control circuit malfunctions even if the power supply voltage is lowered. Even if you do, the period is short.

Which of these timings is selected depends on the application of the device. Moreover, you may combine each method.

Further, the present invention is not limited to an information communication terminal, but can be applied to a device that operates on a battery, such as household electric appliances and games.

[0042]

According to the present invention, it is possible to reduce power consumption during operation of a portable information communication terminal device,
The same battery as before can be used for a long time in the information communication terminal device.

[Brief description of drawings]

FIG. 1 is a block diagram of an information communication terminal according to an embodiment of the present invention, which measures ambient temperature and reduces power consumption by voltage control.

FIG. 2 is a time chart of FIG.

FIG. 3 is a block diagram of a second embodiment of the present invention of an information communication terminal in which a critical path is measured and power consumption is reduced by voltage control.

FIG. 4 is a block diagram of third and fourth embodiments of the present invention of an information communication terminal capable of voltage control by an external switch and monitoring an internal state by LED display.

FIG. 5 is a power supply circuit and its switching circuit diagram of a fifth embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Voltage control circuit, 2 ... Temperature sensor, 3 ... Power supply, 4 ... Power supply changeover switch, 5 ... Control circuit, 200 ... Information communication terminal.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masao Hotta 1-280, Higashi Koigokubo, Kokubunji City, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (8)

[Claims] 1. An information communication terminal device comprising: a temperature measuring unit for measuring an ambient temperature; a power source for a plurality of output voltages; and a voltage control unit for switching the power source voltage according to the ambient temperature. 2. An information communication terminal device comprising: a means for testing a critical path; a power supply having a plurality of output voltages; and a voltage control means for raising a power supply voltage when the critical path malfunctions. 3. An information communication terminal device, comprising: a power supply having a plurality of output voltages; and a switch for switching the power supplies. 4. An information communication terminal device comprising a power supply of a plurality of output voltages and a display for displaying malfunction of a circuit. 5. An information communication terminal device comprising: a plurality of power supplies and a power supply connection switching means for switching the power supplies in parallel or in series. 6. An information communication terminal device, comprising: measuring an ambient temperature when a power switch is turned on, increasing the power supply voltage when the temperature is high, and decreasing the power supply voltage when the temperature is low. Control method. 7. A method of controlling an information communication terminal device, comprising measuring an ambient temperature during a free time of processing, increasing the power supply voltage when the temperature is high, and lowering the power supply voltage when the temperature is low. . 8. A method for controlling an information communication terminal device, comprising measuring an ambient temperature at regular time intervals, increasing the power supply voltage when the temperature is high, and lowering the power supply voltage when the temperature is low.