JP2001174534A - Battery remaining capacity measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the scale of a firmware of a micro-controller provided for prediction of a battery remaining capacity, and to reduce the load for the prediction of the remaining capacity by a main processor. SOLUTION: This battery remaining capacity measuring device integrates a charged current value and a consumed current value flowing in a battery 1 integrated in an electronic equipment having the main processor 9, and predicts the battery remaining capacity by the main processor 9 by utilizing the integration result. The micro-controller 6 including a first integration circuit 4 is provided in order to integrate the detected current value. The main processor 9 is equipped with a second integration circuit 7 in order to integrate furthermore the integration result integrated by the first integration circuit 4 of the micro-controller 6, and predicts the battery remaining capacity based on the result integrated by the second integration circuit 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery remaining amount measuring device, and more particularly to integrating a charging current value and a consumption current value flowing through a battery incorporated in an electronic device having a main processor, and utilizing the integrated result. The present invention relates to a battery remaining power measuring device for predicting the remaining battery power by the main processor.

[0002]

2. Description of the Related Art In a lithium ion battery, the internal impedance of the battery is high, and the voltage change with respect to the battery remaining amount is small. Therefore, in general, it is common to accumulate the consumed current value and predict the remaining battery level from the result of the accumulation. Conventionally, a signal that has detected the charge / discharge current of a battery is amplified by an amplifier, this signal is input to a microcontroller, the integration of the current and the prediction of the remaining amount are calculated, and the result is passed to the main processor.

FIG. 5 is a diagram showing such a conventional remaining current measuring device. The charge current or discharge current flowing through the battery 1 is detected as a voltage across the resistor 2,
And after being amplified by the amplifier 3, the microcontroller 6
Is input to The microcontroller 6 includes an integrating circuit 4
And a remaining amount prediction circuit 5. The charging current value or the consumed current value is integrated by the integration circuit 4 of the microcontroller 6, and the integration result is passed to the remaining amount prediction circuit 5 that estimates the remaining amount based thereon. The integrated and predicted result is output to the main processor 9. In this way, the integration of the current flowing through the battery and the estimation of the remaining amount can be performed. However, this method increases the firmware of the microcontroller 6 and increases the cost.

There is also a method in which the operation is performed only by the main processor without using a microcontroller. However, since the operating frequency of the main processor is generally higher than that of the microcontroller, power consumption increases each time the main processor operates. Each time the remaining amount is calculated, the load on the battery increases. Also, as the operating frequency of the main processor increases, the peak current also increases, and the operating frequency of the integrating circuit must also be increased, thus increasing the load on the processor.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention solves the above problems and reduces the burden on the main processor for estimating the remaining amount, while providing a firmware for a microcontroller provided for estimating the remaining amount of the battery. The aim is to make the wear smaller.

[0006]

The battery remaining amount measuring device of the present invention integrates a charging current value and a current consumption value flowing through a battery 1 incorporated in an electronic device having a main processor 9, and uses the integrated result. Then, the remaining battery power is predicted by the main processor 9. A microcontroller 6 including a first integration circuit 4 for integrating the detected current values
Is provided. The main processor 9 calculates the integration result integrated by the first integration circuit 4 of the microcontroller 6,
Further, a second integration circuit 7 for integration is provided, and the remaining battery level is predicted based on the result integrated by the second integration circuit 7.

The microcontroller 6 has a low-pass filter 12 for averaging the detected current values.
An A / D converter 13 for converting the averaged current into a digital signal; and counting the converted digital signal in a subtraction direction or an addition direction depending on whether the battery is discharging or charging. And the adder / subtractor 14 of
The detected current values can be integrated.

[0008]

FIG. 1 is a diagram exemplifying a circuit configuration of a battery remaining amount measuring device according to the present invention. In the figure, battery 1
Is a lithium-ion battery, for example, which is incorporated in an electronic device having a main processor, such as a personal computer, for example. The resistor 2, the amplifier 3, and the microcontroller 6 are provided exclusively for measuring the remaining battery power, while the main processor 9 includes:
It is provided to fulfill the original function of the electronic device.

A charge current or a discharge current flowing through the battery 1 is detected as a voltage across the resistor 2 and is supplied to the amplifier 3.
Is amplified by the integrating circuit 4 of the microcontroller 6.
Is input to The charging current value or the consumption current value is integrated by the integration circuit 4, and the integration result is further integrated by the integration circuit 7 of the main processor 9. As described above, the present invention is characterized in that the integration is performed in two stages. The remaining amount prediction circuit 8 of the main processor performs the remaining amount prediction based on the result of the integration performed in two stages as described above.

In the integration in the integration circuit 4 of the microcontroller 6, a certain threshold value is provided, and when the threshold value is exceeded during the integration process, the main processor is notified. The main processor receives this notification and further integrates the current to estimate the remaining amount. The microcontroller operates like a kind of counter. As a result, the microcontroller can be downsized, while the operation frequency of the main processor for current integration is reduced, so that the processing load is reduced. In addition, since the microcontroller has a lower operating frequency than the main processor, current consumption for measurement can be reduced.

FIG. 3 is a flow chart for explaining the operation of the battery level measuring device of the present invention exemplified in FIG. 1, and FIG. 2 shows a list of variables and constants used for explaining the operation. It is a table.

First, in step S1 shown in FIG. 3, the integrating circuit 4 on the microcontroller side is initialized. The value “Xn” of the integrating circuit 4 is reset to “0”,
The threshold value “Pn” of the integrating circuit 4 is a predetermined set value “B”.
Is set to Next, after the battery voltage "V" is measured (S2), the main processor is turned on (S2).
3) Initialize the main processor (M1).

In step S4, the battery voltage "V"
Is sent to the main processor, and the main processor that has received the value determines and sets the provisional battery capacity from the V value (M2). That is, the integrated value of the integrating circuit 7 of the main processor is set to a predetermined value "C", and the integrated value of the charge and discharge after the main processor is initialized "
Zn ”is reset to“ 0 ”.

In step S5, it is determined whether the battery is in the discharged state or the charged state based on a separate detection signal such as the direction (polarity) of the current flowing through the battery, and if it is determined that the battery is in the charged state. The process proceeds to step S6, where the current value "A" flowing through the battery is measured. Then, the measured value "A" is added to the value "Xn" of the integrating circuit 4 (S7), and the operation result "Xn" is previously set in step S1 as the threshold "Pn" of the integrating circuit 4. It is determined whether the set value “B” has been exceeded (S8). If not,
The charge and discharge in step S14 are checked. If the charge is detected, the process returns to step S6 to continue measuring the current value. If it is a discharge, the process proceeds to step S11 to measure a current value.

When the operation result "Xn" exceeds the set value "B", data is sent to the main processor, and the integration circuit on the main processor performs integration (M5). That is, in step M2, the value of the integrating circuit of the main processor “Yn” (preliminarily set to the provisional battery capacity “C” determined from the value of the measured voltage “V”) is changed to the threshold “
Pn "(that is, the set value" B ") is added, and the integrated value of charge / discharge after the initialization of the main processor is"".
The same threshold “Pn” is added to Zn ”. Next, in step S9, after calculating Xn = Xn−Pn, charging and discharging are checked in step S14, and if charging, the process returns to step S6. If the discharge is detected, the process proceeds to step S11 to measure the current value.

When it is determined in step S5 that the battery is in the discharged state, the set value "B" is set to the value "Xn" of the integrating circuit 4 in step S10. At this time, the main processor performs an operation Yn = Yn-Pn of subtracting the threshold value “Pn” (that is, the set value “B”) from the value “Yn” of the integrating circuit. Thereafter, in step S11, the current value “A” is measured, and this value “A” is measured.
A ”is subtracted from the value“ Xn ”of the integrating circuit 4 (S
12). It is determined whether the subtracted result has become a negative value (S13). If it is determined that the result has not become a negative value, charging and discharging are checked in step S14. For example, the process returns to step S11, and the current value measurement is continued. If charging, the current value is measured in step S6.

If the value "Xn" of the integrating circuit 4 becomes a negative value, this data is sent to the main processor,
The counting is performed on the main processor side. That is, the threshold value “Pn” is calculated from the value “Yn” of the integrating circuit of the main processor.
(That is, the set value “B”) is subtracted. It is the integrated value of charge / discharge after the main processor is initialized. "
The same threshold “Pn” is subtracted from Zn ”. Next, in step S15, after calculating Xn = Xn + Pn, charging and discharging are checked in step S14, and if discharging, the process returns to step S11. If the charging is performed, the current value is measured in step S6.

As described above, the integrating circuit 4 on the microcontroller side basically performs steps S6 to S6 in the charged state.
S8 and S14, or steps S11 to S11 in the discharge state
The operation of S14 is repeated, and when a carry or a carry of the integrating circuit determined in step S8 or S13 occurs, a notification is sent to the main processor, and the main processor further performs integration. This reduces the access frequency of the main processor. In the main processor, the integrated value “Zn” of the charge / discharge after the initialization of the main processor and the provisional capacity determined from the value of the battery voltage “V” are set to the initial value “C” according to the usual technique. Based on Yn ″ and the amount of change in battery voltage, the nominal capacity value and remaining battery value of the battery can be corrected.

When the battery is in the charging mode, the charger can be easily turned on / off. By doing this, the charger is stopped for a short period of time at certain fixed time intervals, and the battery voltage can be accurately measured, thereby making it possible to more accurately predict the remaining battery power.

FIG. 4 is a diagram specifically illustrating the configuration of the microcontroller 6 shown in FIG. The signal input from the amplifier 3 shown in FIG.
2, the current is averaged. The averaged current is converted into a digital signal by the A / D converter 13. Next, this digital signal is
It is input to the adder / subtractor 14. Currently, if the battery is discharging, the adder / subtracter 14 counts in the subtraction direction, and if the battery is charging, it counts in the addition direction.

For example, if “100” is set as the threshold value of the adder / subtractor 14 and the battery is being charged,
Assuming that the current value “6” is continuously output from the A / D converter 13, the adder / subtractor 14 calculates 17 times (6 ×
17 = 102) Counting will exceed the set threshold. At this time, the adder / subtractor 14 outputs CARRYBIT to the main processor, and the integrating circuit 7 of the main processor 9 in FIG.
Add. The adder / subtractor 14 that has passed the data starts counting again from “2” which is obtained by subtracting “100” from the count value “102”.

Under the same conditions as above, in the case of the discharging state, the threshold value "100" is first set as the count value of the adder / subtractor 14, and the value is changed every time the current value "6" is detected. After subtracting and counting 17 times, when the negative count value becomes "-2", BORROW is sent to the main processor.
Output BIT. The integrating circuit 7 of the main processor 9
Upon receiving this, 100 is subtracted from the integrated value. The adder / subtractor 14 that has passed the data sets the count value “−2” to “2”.
Counting is restarted from "98" to which 100 has been added.

The main processor can correct the nominal capacity value and the remaining amount value of the battery from the integrated value in the main processor and other information such as the battery voltage and the change amount thereof.

[0024]

According to the present invention, there is provided a microcontroller including a first integration circuit for integrating the detected current value, and the main processor calculates the integration result integrated by the first integration circuit of the microcontroller. Further, a second integration circuit for integration is provided, and the remaining battery level is predicted based on the result integrated by the second integration circuit. Therefore, the following effects are obtained.

1) The microcontroller can be downsized.

2) The operation load of the main processor for current integration is reduced, so that the processing load is reduced.

3) The operating frequency of the microcontroller is lower than that of the main processor, so that the current consumption for measurement can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a circuit configuration of a battery remaining amount measuring device according to the present invention.

FIG. 2 is a table showing a list of variables and constants used for explaining the operation of the battery remaining amount measuring device of the present invention illustrated in FIG. 1;

FIG. 3 is a flowchart for explaining the operation of the battery remaining amount measuring device of the present invention illustrated in FIG. 1;

FIG. 4 is a diagram specifically illustrating the configuration of the microcontroller shown in FIG.

FIG. 5 is a diagram showing a current remaining amount measuring device according to a conventional technique.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 battery 2 resistor 3 amplifier 4 integrating circuit 5 remaining amount predicting circuit 6 microcontroller 7 integrating circuit 8 remaining amount predicting circuit 9 main processor 12 low-pass filter 13 A / D converter 14 adder / subtractor

Claims (2)

[Claims] 1. A battery remaining amount meter for integrating a charging current value and a consumed current value flowing through a battery incorporated in an electronic device having a main processor, and predicting the remaining battery amount by the main processor using the integration result. The apparatus further includes a microcontroller including a first integration circuit for integrating the detected current value, wherein the main processor further integrates an integration result integrated by the first integration circuit of the microcontroller. A battery remaining amount measuring device comprising a second integrating circuit, wherein the remaining battery amount is predicted based on a result integrated by the second integrating circuit. 2. A micro-controller comprising: a low-pass filter for averaging a detected current value; and an A / A filter for converting the averaged current into a digital signal.
2. A digital converter comprising: a D converter; and an adder / subtractor for counting the converted digital signal in a subtraction direction or an addition direction according to whether the battery is discharging or charging, and integrates the detected current values. The battery remaining amount measuring device according to 1.