JPH04331391A - battery powered personal computer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) This invention relates to a personal computer that uses a secondary battery (hereinafter referred to as a battery) as a power source, and in particular, the present invention relates to a personal computer that uses a secondary battery (hereinafter referred to as a battery) as a power source. This invention relates to a battery-powered personal computer for detecting and controlling the state of charge of a battery by being built into a battery.

(Prior Art) In recent years, various types of personal computers that are easily portable and have removable batteries have been developed. This type of personal computer has a function of monitoring the remaining capacity of a battery using a power supply controller.

The power supply controller is usually equipped with a 1-chip microcomputer. The removable battery used electrical chemical changes. Typical batteries include nickel-cadmium batteries (hereinafter referred to as Ni-Cd batteries) and nickel-hydrogen batteries (hereinafter referred to as Ni-H batteries).

Hereinafter, a conventional battery charging control method and a low battery detection method will be explained using FIGS. 8, 9, 10, and 11.

First of all, as a method of battery charging control,
Conventionally, this was done by detecting ±ΔV.

-ΔV here is the characteristic of voltage change when charging the battery as shown in Figure 11, and the amount of negative voltage change per unit time (
(voltage drop of 10 mV per battery cell). +ΔV
Similar to -ΔV, is the amount of change in positive voltage per unit time. The power supply controller reads the signal (sampling data) sent from the voltage detection circuit at regular intervals and measures the time required for the battery voltage to change a certain value. The power supply controller detects +ΔV when the time required for the change has two consecutive positive changes. Further, when the time required for the change causes two consecutive negative changes, the power supply controller detects -ΔV. Conventionally, the fully charged state of the battery was determined in this way. However, currently the mainstream battery is the personal computer body (hereinafter referred to as
It is called the main body. ) has a device configuration that can be attached and detached.

For this reason, the battery had to be removed from the main unit, fully charged with another charger, and then reattached to the main unit. In this case, even if it is fully charged with a charger other than the main unit, the main unit will
There was no way to know the state of charge of the battery. As a result, charging was performed again on the main body side, and charging was continued until a voltage change of ±ΔV was detected again. When the battery became overcharged and became hot, a thermostat (hereinafter referred to as a temperature sensor) installed outside the battery detected the danger and stopped charging.

Next, a low battery detection method will be explained.

First, the battery characteristics shown in FIGS. 8 and 9 will be briefly explained.

The battery characteristics in FIG. 8 show how the battery voltage changes over time. The vertical axis shows battery voltage and the horizontal axis shows time.

From this figure, the greater the current discharged from the battery, the lower the battery voltage will be. Point A on the vertical axis indicates the voltage at which the personal computer will no longer operate properly if the battery voltage drops further.

At point C on the horizontal axis, the current emitted from the battery is 600
It shows the time when the battery voltage becomes A when it is mA. Point B on the horizontal axis is the reference point for determining whether the battery is low or not, and the maximum value of the current emitted from the battery is 6
When the voltage is set to 00 mA, the operation of the personal computer can be guaranteed for at least (C-B) even if it is determined that the battery is in a low battery state.

FIG. 9 shows the change in voltage of a battery with different charging times. Point A on the vertical axis is the voltage at which the personal computer will no longer operate normally if the battery voltage drops further. Point B' on the horizontal axis is the battery voltage that is determined to be a low battery. The time from when the battery is determined to be low until the personal computer stops operating (Cn-Bn: n=1, 2, 3, 4) is longer as the battery takes longer to charge.

In view of the battery characteristics shown in FIGS. 8 and 9 above, a flowchart of a conventional low battery detection method shown in FIG. 10 will be explained.

Leading the current emitted from the battery pack (step 400). A low battery reference voltage is determined from the read current value (step 410). Next, read the battery voltage (step 420). The difference between the battery voltage read last time and the battery voltage read this time is determined (step 430). The error is corrected from the battery voltage change amount obtained here, and the low battery reference voltage is changed (step 440). Then, the corrected low battery reference voltage and battery voltage are compared (step 450). Notifies the main CPU of the low battery status when the battery voltage becomes low (
step 460). After executing the resume function, the main CPU notifies the power supply controller of a system power-off command.

In such a method or configuration, a temperature sensor is not built into the battery pack. For this reason, the battery voltage changed depending on the temperature, and it was not possible to correctly detect the low battery reference voltage or the fully charged state.

When charging the battery at low temperatures, battery performance deteriorated. Conversely, charging batteries at high temperatures could cause them to explode. In particular, Ni
When the -H battery was placed in an overcharged state, the charging capacity tended to decrease.

Furthermore, when determining the fully charged state of a battery using ±ΔV, there are cases where malfunction occurs due to noise or the like, or when the charging characteristic curve is gentle, erroneous detection occurs. When recharging a fully charged battery, the change in charging voltage is subtle, so ±Δ
Detection at V becomes difficult. As a result, the battery became overcharged.

(Problems to be Solved by the Invention) The present invention eliminates the drawbacks of the prior art as described above, incorporates a temperature sensor into the battery pack, and accurately detects the charging state and low battery state of the battery. The purpose of the present invention is to provide a battery-powered personal computer with improved usability.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a battery-driven personal computer that has a built-in battery as a power source and supplies power voltage to each unit of the personal computer. , an adapter circuit that converts a household AC power supply to a DC power supply, a charging circuit that is supplied with the DC power from the adapter circuit and charges the battery, and a charging state of the battery from the charging circuit and the battery. a first detection means for detecting the state of power supply to the unit from the battery, a second detection means for detecting the temperature of a battery built in the battery, and a detection result of the first and second detection means; Based on the present invention, there is provided a battery-powered personal computer characterized by comprising a charging control means for sending a control signal to the charging circuit, and determining the capacity state of the battery by temperature detection.

Further, a first battery-powered personal computer according to the present invention is characterized in that the battery includes a nickel-metal hydride battery and the temperature sensor.

Further, in the present invention, in a battery-powered personal computer that includes a built-in battery as a power source and supplies power supply voltage from the battery to each unit of the personal computer, a discharge current state of the power supply voltage supplied from the battery to the units is provided. a first determining means for determining a low battery reference voltage based on the detection result of the first detecting means; and a second detecting means for detecting the temperature of the battery; a second determining means for determining a corrected voltage value of the low battery reference voltage based on a detection result of the second detecting means; a voltage value obtained by adding the low battery reference voltage and the corrected voltage value; and means for comparing the discharge voltage value with a battery discharge voltage value, and notifies a low battery state when the discharge voltage value is lower than the corrected low battery reference voltage. Provide personal computers.

Further, in the present invention, in a battery-driven personal computer that includes a built-in battery as a power source and supplies a power supply voltage from the battery to each unit of the personal computer, there is provided a means for measuring time, and a means for measuring a specific time. The battery comprises means for detecting the temperature of the battery when measured, means for storing the detected temperature value of the battery, and means for comparing the temperature values stored for each time series, Provided is a battery-powered personal computer characterized in that the fully charged state of the battery is controlled by the temperature state of the battery.

Further, in the present invention, in a battery-driven personal computer that includes a built-in battery as a power source and supplies power voltage from the battery to each unit of the personal computer, the present invention provides a means for storing an operating temperature range state of each of the units; means for detecting the ambient temperature state of the unit; and means for comparing the detected detected temperature with the operating temperature range state stored in the storage means, and based on the comparison result of the comparison means, each unit To provide a battery-powered personal computer, which is characterized in that its temperature is adjusted to optimum usage conditions.

(Function) In the device configured in this way, the temperature sensor is built into the battery. Detects the temperature of the battery inside the battery. Charge control to the battery is performed based on the detected temperature value. As a result, abnormal battery temperature rise due to overcharging of the battery can be prevented.

Furthermore, when configured as described above, voltage correction of the low battery reference voltage is performed based on the battery temperature detection within the battery. As a result, the low battery period can be accurately determined, improving the usability of the personal computer.

Furthermore, when configured as described above, the operating temperature range state of each unit of the computer is stored. Detects the ambient temperature status of each unit. The detected temperature value and the operating temperature range status of each unit are determined. As a result, the temperature is adjusted to the optimum usage condition of each unit.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the system configuration of an embodiment of the present invention.

In the figure, 5 is a battery pack, which is connected to a power controller and a DC/DC converter, and is connected to a DC/DC converter.
Supply DC power to the DC converter. 7 is a power supply controller, which connects the main CPU via the system bus 37.
The overcharge state and low battery state of the battery 5 are detected based on the voltage, current and temperature of the battery pack 5, and the voltage capacity state of the battery pack 5 is notified to the main CPU. The power supply controller 7 has a built-in 4-bit power control CPU 21.

9 is a DC/DC converter, and battery pack 5
Generates the constant voltage DC power necessary to operate the main unit from the DC power supplied from the main unit.

The main CPU 35 has a function of notifying the user of the voltage capacity state of the battery pack sent from the power supply controller 7.

FIG. 2 is a detailed block diagram of the power supply controller shown in FIG. 1 according to the embodiment of the present invention.

In the figure, 1 is an AC adapter
It is connected to a household AC power supply of 100V and supplies the rated DC voltage to the charging circuit. AC adapter 1 is placed outside the personal computer main body.

3 is a charging circuit, which converts the +18V power supply voltage to DC/DC.
Supply to converter. A reverse current prevention transistor 13a is connected in series to the +18V output terminal of the charging circuit 3.

A voltage detection circuit is connected in parallel to the +18V output terminal of the charging circuit 3. A voltage detection circuit 11a detects the output voltage of the charging circuit 3 at regular intervals. Voltage detection circuit 11a
The voltage value detected by the A/D of the power supply controller 7
Supplied to the converter. The charging circuit 3 charges the battery pack 5 based on the charging control signal from the power supply controller 7.
Controls the charging current to. 14 is a p-channel field effect transistor (FET), which is a protection circuit that forcibly stops charging the battery. Reference numeral 5 denotes a battery pack, which includes a first temperature sensor and a Ni-H battery for battery-driving the personal computer. When ACadapter 1 is not connected to the main body, DC voltage is supplied from battery pack 5 to DC/DC converter 9. 15 is a Ni-H battery, and the battery pack 5 includes 12 cells. battery pack 5
A current detection circuit 11c is connected in series with the battery - terminal, and a voltage detection circuit 11b is connected in parallel with the battery + terminal. A voltage detection circuit 11b detects the charging/discharging voltage of the battery pack 5 at regular intervals. A current detection circuit 11c detects the charging/discharging current of the battery pack 5 at regular intervals. The voltage value and current value detected by the current detection circuit 11c and the voltage detection circuit 11b are respectively supplied to the A/D converter of the power supply controller 7.

A reverse current prevention transistor 13b is connected in series with the + terminal of the battery pack 5. 17a is a first temperature sensor that detects the temperature of the battery 15 and uses it as a basis for determining whether the battery pack 5 is in a fully charged state or a low battery state. The temperature value detected by the first temperature sensor 17a is supplied to the A/D converter of the power supply controller 7. 1st
One terminal of the temperature sensor 17a is grounded (GND).
is grounded to. 17b is a second temperature sensor;
It is used to accurately determine the resistance value of the first temperature sensor 17a, which depends on the ambient temperature. The battery temperature recognition method of the power supply controller 7 is based on the first temperature sensor 1.
This is done using the voltage value output from 7a. The resistance value of the first temperature sensor 17a depends on the ambient temperature outside the battery pack. For example, when the resistance temperature is 0°C, the voltage value supplied to the A/D converter of the power supply controller 7 is 3.6
It is 5V. Furthermore, when the resistance temperature is 40°C, the voltage value supplied to the A/D converter of the power supply controller 7 is 0.7
It is 8V. When the output voltage value takes into account fluctuations due to temperature, the voltage drop value of the first temperature sensor 17a is corrected based on the temperature detected by the second temperature sensor 17b, and the power supply controller 7 calculates the accurate temperature inside the battery pack 5. can be recognized. The correction value is stored in the ROM of the power supply controller 7. Furthermore, the second temperature sensor 17b detects the ambient temperature of each unit of the personal computer. Each unit here refers to a high-density mounting board (P
CB), FDD, HDD, etc. (not shown). The power supply controller 7 reads the temperature value detected from the second temperature sensor 17b and compares it with the operating temperature range value (not shown) of each unit stored in the ROM 25. If each unit exceeds the operating temperature range, the power controller 7
notifies the user with a warning sound, and after executing resume, automatically stops power supply to the main unit. 27 is an A/D converter, which converts analog values into digital values, and is connected to the CPU 21 via the internal bus 4. Internal bus 4 further includes RAM, ROM, parallel I/O interface (PIO), and programmable interrupt timer (PIO).
connected to IT). Reference numeral 23 denotes a RAM, which measures time for one second each time an interrupt signal is generated from the PIT.

The default value of the software counter 23 is 0.

A ROM 25 stores a table 25a for detecting a low battery reference voltage and a table 25b for correcting the low battery reference voltage. Furthermore, R
The OM 25 also stores a table (not shown) for temperature-correcting the voltage value output from the first temperature sensor 17a. 21 is a CPU, which converts the analog value from the current detection circuit 11c into a digital value using the A/D converter 27 and takes it in, refers to the conversion table 25a in the ROM 25, and determines the low battery reference voltage corresponding to the detected current value. get. The CPU 21 recognizes whether the detachable battery pack 5 is connected or disconnected. When the battery pack 5 is not connected to the main body, the voltage value pulled up to +5V by the pull-up resistor 19 is input to the power supply controller 7. At this time, the CPU 21 determines that the battery pack 5 is not connected to the main body. When the battery pack 5 is connected to the main body, it is pulled up to +5V, and current flows from the + terminal through the first temperature sensor 17a. A voltage drop (analog value) occurs by the resistance of the first temperature sensor 17a. This analog value is input to the A/D converter 27 and converted into a digital value. Based on the converted digital value, the CPU 21 refers to the table in the ROM 25 and detects that the battery pack 5 is connected to the main body and the temperature value inside the battery pack. The CPV 21 programs the PIT 31 so that an interrupt occurs at one second intervals, and executes the flowchart shown in FIG. 7 in response to the interrupt signal from the PIT 31. At this time, the CPU 21
A software counter 23a is provided in M23, and one second is added to the software counter 23a each time an interrupt signal is generated. The CPU 21 includes voltage detection circuits 11a, b,
The charging circuit 3 and the DC/DC converter 9 are controlled based on information sent from the current detection circuit 11c and the temperature sensor 17a. CPU21 is currently using battery pack 5
When it is determined that the battery is being charged, the DC
/Controls the DC converter 9 and stops power supply to the main unit. Additionally, when the charging current cannot be turned off due to a disconnection in the charging control signal line to the charging circuit 3, the CPU 21 sends a logic level "1" to the FET 14 via the D/A converter 29 to forcibly stop the charging current. do. The low battery correction table 25b stores values calculated in advance in consideration of the difference in charging time and the resolution of the A/D converter 27 (1 digit=98 mV). In this embodiment, CPU2
1 reads the battery temperature and refers to the low battery correction value table 25b in the ROM 25 to obtain the correction voltage of the low battery reference voltage.

With this configuration, when some of the battery cells 15 fail, the first temperature sensor 17a built in the battery pack 5 detects the heat generated from the failed battery cell 15, and the power controller stops charging. As a result, there is an effect that accidents caused by overcharging of the battery pack 5 can be prevented. Further, the second temperature sensor 17b detects the ambient temperature state of each unit of the personal computer and has the effect of adjusting the temperature to the optimum usage state of each unit.

FIG. 3 is a charging characteristic curve diagram of the Ni-H battery used in the embodiment of the present invention. This charging characteristic curve diagram shows changes in battery cell voltage and temperature when the battery ambient temperature is 20°C. The cell temperature during charging rises rapidly from near full charge. When fully charged, the cell temperature drops to 0 per minute.
．． The temperature rises by 9℃.

FIG. 4 is a discharge characteristic curve diagram of the Ni-H battery used in the embodiment of the present invention. This discharge characteristic curve diagram shows changes in battery voltage at different battery temperatures. Point G on the vertical axis is the voltage at which the personal computer will no longer operate properly if the battery voltage drops further. Points D1 and D2 on the horizontal axis are battery voltages that are determined to be low battery. The time from when the battery is determined to be low until the personal computer stops working (En-D)
n: n=1, 2) is longer for batteries with higher temperatures.

FIG. 5 shows the low battery voltage correction value for the battery temperature stored in the low battery correction value table 25b. For example, if the read battery temperature is 70° C. or higher, +686 mV is added to the low battery reference voltage.

If it is below -3°C, +0V is added.

FIG. 6 is a flowchart of a low battery detection method according to an embodiment of the present invention.

FIGS. 7a and 7b are flowcharts of a charging control method according to an embodiment of the present invention.

Hereinafter, the operation of the embodiment of the present invention will be explained in detail.

First, the flowchart shown in FIG. 6 will be explained. The CPU 21 reads the battery discharge current value sent from the current detection circuit 11c via the A/D converter 27 (step 300).

The CPU 21 refers to the table 21a and determines the low battery reference voltage from the discharge current value read in step 300 (step 310). First temperature sensor 17a
detects battery temperature. The CPU 21 reads the detected battery temperature via the A/D converter 27 (step 320). The CPU 21 refers to the table 25b and determines a low battery correction value from the battery temperature read in step 320 (step 330). And CPU2
1 adds the low battery correction value determined in step 330 to the low battery reference voltage value determined in the previous step 310 (step 340).

The CPU 21 reads the battery output voltage value sent from the voltage detection circuit 11b via the A/D converter 27 (step 350). After step 350, the CPU
21 compares the battery voltage value with a low battery reference voltage value (step 360). If it is determined in step 360 that the battery voltage value is greater than or equal to the low battery reference voltage value, the low battery detection process ends.

In such a configuration, the low battery reference voltage is determined based on the battery temperature of the battery pack 5. As a result, the state of the battery can be accurately grasped, and the operating time of the battery can be extended.

Next, the flowchart shown in FIG. 7 will be explained.

First, the CPU 21 reads the flag (
(hereinafter referred to as FLG) (not shown)
step 500). The state of this FLG is set to "0" under the following conditions.

■The battery pack 5 is built into the main body.

■AC adapter 1 is connected to charging circuit 3.

■The voltage value input from AC adapter 1 to the charging circuit is normal.

(2) The voltage value input from the charging circuit 3 to the DC/DC converter 9 is normal.

■The battery temperature in the battery pack 5 is in the range of 0°C to 55°C.

■Battery pack 5 is not fully charged.

When all the above conditions are met, FLG="0" is the CPU
Set by 21. RAM2 at step 500
If it is determined that FLG 3 is "0", the present charging control process proceeds to step 510. Also, FLG=
If it is "1", the process returns to step 500 again. Step 5
At step 10, it is determined whether an interrupt signal from the PIT 31 has occurred. If it is determined in step 510 that an interrupt signal has occurred, the charging control process proceeds to step 210.
Proceed to. When the CPU 21 recognizes the interrupt signal, the RAM 2
The software counter 23a of No. 3 is incremented by 1 (step 510). Further, if it is determined in the previous step 510 that no interrupt signal has been generated, the present charging control process proceeds to step 530. Here, it is determined whether the count number of the soft counter 23a is 60 times (one minute) or more (step 530). Step 53
If it is determined that the count number of the soft counter 23a is less than 1 minute at 0, the present charging control process returns to step 510. Further, if it is determined in step 530 that the count number of the soft counter 23a is one minute or more, the present charging control process proceeds to step 540. Here, the CPU 21 reads the battery temperature detected by the first temperature sensor 17a in the battery pack 5. Then, it is determined whether the difference value between the battery temperature read last time (1 minute ago) and the battery temperature read in step 540 is 0.9° C. or more (steps 540 to 550). In step 550, the battery temperature difference value is stored in the register of the CPU 21 (
(not shown).

If it is determined in step 550 that the difference in battery temperature is less than 0.9°C, the charging control process proceeds to step 5.
Proceed to 80. Here, the CPU 21 resets the software counter 23a.

After the reset process in step 580, the charging control process proceeds to step 510. Further, if it is determined in the previous step 550 that the battery temperature difference value is 0.9° C. or more, the present charging control process proceeds to step 560. In this step, the difference value of the previous battery temperature stored in the register of the CPU 21 is called, and it is determined again whether it is 0.9° C. or higher (step 560). If it is determined in this step 560 that the previous battery temperature difference value was not 0.9° C., the present charging control process proceeds to step 580. Also, in this step 560, the difference value of the previous battery temperature is 0.9.
℃, the CPU 21 sends a charging stop command to the charging circuit 3 via the D/A converter 29. After receiving the charge stop command, the charging circuit 3 stops charging the battery pack 5 (step 570).

With this configuration, the fully charged state of the battery is determined based on the temperature. As a result, overcharging of the battery can be prevented. In particular, overcharging reduces the charging capacity of the battery.
-Effective for the H battery 15.

[Effects of the Invention] As described above, according to the present invention, by incorporating a temperature sensor into the battery pack, it is possible to accurately detect the state of charge of the battery, thereby providing a battery-powered personal computer with improved usability. There is an effect that can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the system configuration of a battery-powered personal computer according to the present invention. FIG. 3 is a charging characteristic curve diagram of the Ni-H battery used in the embodiment of the present invention. FIG. 4 is a discharge characteristic curve diagram of the Ni-H battery used in the embodiment of the present invention. FIG. 5 is a correspondence table between battery temperature variation and low battery correction value. FIG. 6 is a flowchart of a low battery detection method according to an embodiment of the present invention. FIGS. 7a and 7b are flowcharts of a charging control method according to an embodiment of the present invention. FIG. 8 and FIG. 9 are battery characteristic diagrams cited for explaining the present invention, respectively. The tenth is a flowchart of a conventional low battery detection method. FIG. 11 is a charging voltage characteristic diagram cited in the conventional charging control method. 1...AC adapter, 3...charging circuit, 5...battery pack, 7...power controller, 9...DC/DC converter, 15...Ni-H battery, 17...temperature sensor,
21...Power control CPU, 23...RAM, 25
...ROM, 27...A/D converter, 29...D/A converter, 31...PIT, 33...PIO, 35...Main C
PU Agent Patent Attorney Kensuke Norichika Hajime Yamashita

Claims (5)

[Claims] 1. A battery-driven personal computer that includes a built-in battery as a power source and supplies power voltage to each unit of the personal computer, comprising: an adapter circuit for converting a household AC power source to a DC power source; a charging circuit that charges the battery; a first detection means that detects the state of charge from the charging circuit to the battery and the state of power supply from the battery to the unit;
A second detection means for detecting the temperature of a battery built into the battery, and a charging control means for sending a control signal to the charging circuit based on the detection results of the first and second detection means, A battery-powered personal computer characterized in that the capacity state of the battery is determined by temperature detection. 2. A battery-powered personal computer according to claim 1, wherein said battery includes a nickel-metal hydride battery and said temperature sensor. 3. In a battery-driven personal computer that includes a built-in battery as a power source and supplies power supply voltage from the battery to each unit of the personal computer, a discharge current state of the power supply voltage supplied from the battery to the unit is detected. a first determining means for determining a low battery reference voltage based on a detection result of the first detecting means; a second detecting means for detecting the temperature of the battery; a second determining means for determining a corrected voltage value of the low battery reference voltage based on the detection result of the second detecting means; a voltage value obtained by adding the low battery reference voltage and the corrected voltage value; a battery-powered personal computer, comprising means for comparing the discharge voltage value with a discharge voltage value, and notifies a low battery state when the discharge voltage value is lower than the corrected low battery reference voltage. . 4. A battery-powered personal computer that includes a built-in battery as a power source and supplies power voltage from the battery to each unit of the personal computer, comprising means for measuring time, and said measuring means for measuring a specific time. when the battery is fully charged, comprising: means for detecting the temperature of the battery; means for storing the detected temperature value of the battery; and means for comparing the temperature values stored for each time series. A battery-powered personal computer characterized in that a charging state is controlled by a temperature state of the battery. 5. A battery-driven personal computer that includes a built-in battery as a power source and supplies power voltage from the battery to each unit of the personal computer, further comprising means for storing operating temperature range states of each unit; comprising means for detecting an ambient temperature state, and means for comparing the detected detected temperature with the operating temperature range state stored in the storage means, and based on the comparison result of the comparison means, the optimal A battery-powered personal computer that is characterized by temperature control depending on the state of use.