JPH07239735A - Battery controller - Google Patents

Abstract

PURPOSE:To correct the offset voltage of a battery voltage and detect an accurate low battery voltage, a full charging voltage, etc., to accurately stop charging and discharging a battery on the basis of them, and to prevent a system from running away owing to an excessive drop in the battery voltage. CONSTITUTION:This battery controller is equipped with a battery voltage offset correcting circuit 3 which inputs an offset reference voltage V1 to an A-D converter 2 to calculate an offset error correction quantity DELTAP1 on the basis of the output voltage P1 at this time and then the voltage Vn from the battery 1 is sent to the A-D converter 2 to calculate a correct battery voltage Pkn corrected with the offset error correction quantity DELTAP1 as to the current output voltage Pn, and, charging/discharging control over the battery 1 is performed on the basis of the battery voltage Pkn after the correction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery controller for detecting the voltage of a battery and controlling charge / discharge. When operating a portable personal computer such as a notebook computer with a battery, the voltage of the battery is A-D converted,
It is desired to automatically correct the offset voltage, detect that the accurate battery voltage matches the LOW battery voltage and the full charge voltage, and stop the discharge and charge of the battery.

[0002]

2. Description of the Related Art Conventionally, in a device such as a notebook computer, a discharge voltage of a nickel-cadmium battery or a nickel-hydrogen battery is detected, and when the discharge voltage becomes equal to the LOW battery voltage or the DEAD battery voltage, the LOW battery voltage or the DEAD battery voltage is detected. I was displaying an alarm to that effect.

[0003]

In the case of detecting the LOW battery voltage or the DEAD battery voltage described above, the reference voltage Vref is conventionally used without correcting the offset voltage with respect to the fluctuation of the A / D converter or the reference voltage. Originally converted to a digital value, an alarm was displayed when the battery voltage of this digital value coincided with the LOW battery voltage or the DEAD battery voltage. Therefore, as shown in FIG. 4, when the voltage is actually detected, There is a problem that an error of the offset voltage as shown by the dotted line occurs in comparison with the reference voltage of the solid line in the figure, and a situation in which it cannot be accurately detected occurs. For this reason, the exact LOW battery voltage and DEA
D Battery voltage cannot be detected, LOW battery voltage is detected even though the remaining battery level is still remaining, and discharge has stopped. There was a problem that the power supply became unstable at the time when the battery voltage could not be detected and the LOW battery voltage was detected, causing the system to run away.

The present invention solves these problems.
Correct the offset voltage of the battery voltage, detect that the accurate battery voltage matches the LOW battery voltage or full charge voltage, and based on this, accurately stop the discharge of the battery,
The purpose is to stop charging and to prevent system runaway due to excessively low battery voltage.

[0005]

[Means for Solving the Problems] Means for solving the problems will be described with reference to FIG. In FIG. 1, the AD converter 2 converts an input voltage into a digital voltage based on the input reference voltage Vref and outputs the digital voltage.

The battery voltage offset correction circuit 3 corrects the offset error of the battery 1. The offset correction reference voltage generation circuit 6 generates offset correction reference voltages V1 and V2.

[0007]

According to the present invention, as shown in FIG. 1, the battery voltage offset correction circuit 3 generates the offset correction reference voltage V1 generated by the offset correction reference voltage generation circuit 6.
Is input to the A / D converter 2 and the offset error correction amount ΔP1 is calculated based on the output voltage P1 at that time, and then the voltage Vn from the battery 1 is input to the A / D converter 2 With respect to the output voltage Pn, the correct battery voltage Pkn corrected by the offset error correction amount ΔP1 is calculated, and the charge / discharge control of the battery 1 is performed based on the calculated corrected battery voltage Pkn.

Further, the battery voltage offset correction circuit 3
Respectively input the offset correction reference voltages V1 and V2 generated by the offset correction reference voltage generation circuit 6 to the AD converter 2, and output voltages P1 and P2 at that time, respectively.
After calculating the offset error correction amount ΔPn based on, the voltage Vn from the battery 1 is input to the AD converter 2 and the output voltage Pn at that time is corrected by the offset error correction amount ΔPn to obtain a correct battery. The voltage Pkn is expressed as Pkn = Pn-ΔPn ΔPn = {(ΔP2-ΔP1) / (V2-V1)} (V
n−V1) + ΔP1 and the calculated corrected battery voltage Pk
The charging / discharging control of the battery 1 is performed based on n.

In these cases, the discharge or charge of the battery 1 is stopped when the battery voltage after the digital correction of the battery 1 matches the LOW battery voltage or the full charge voltage.

Therefore, the offset of the A / D converter 2 is automatically corrected, and it is detected that the accurate battery voltage matches the LOW battery voltage or the full charge voltage. Based on these, accurate battery discharge stop, It is possible to stop charging and prevent system runaway due to too low battery voltage.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the construction and operation of an embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 shows a block diagram of an embodiment of the present invention.
In FIG. 1, a battery 1 is a battery to be charged / discharged. The A / D converter 2 converts the input voltage into a digital battery voltage based on the input reference voltage Vref and outputs the digital battery voltage. Here, the input terminals A-D0 that can be sequentially switched are used. , A-D1 and A-D2 3
It has a pair and a terminal for inputting the reference voltage Vref. These three input terminals A-D0, A-D
Which voltage of 1 or A-D2 is A-D converted is A
It is performed by the -D select signal, and the A-D converted values at that time are sequentially taken out.

The battery voltage offset correction circuit 3 is for correcting the offset error of the battery 1, and based on a value obtained by A / D converting the offset correction reference voltages V1 and V2 in accordance with a flow chart of FIG. 3 described later. The offset error is corrected.

The CPU 4 determines that the correct battery voltage after being corrected by the battery voltage offset correction circuit 3 is L.
When the OW battery voltage and the full-charge voltage match, the charging / discharging control of the battery 1 (stopping discharge of the battery 1, stopping charging, etc.) is performed.

The DC-DC converter 5 receives the voltage from the battery 1 and converts it into a DC voltage having a different voltage. Here, the reference voltage Vref and the offset correction input to the AD converter 2 are used. The reference voltage Vref input to the reference voltage generator 6 for use is generated.
Here, a reference voltage Vref equal to both is generated and input.

The offset correction reference voltage generating circuit 6 is
The offset correcting reference voltages V1 and V2 are generated based on the input reference voltage Vref. The generated offset correction reference voltages V1 and V2 are input to the A / D converter 2, and the battery voltage offset correction circuit 3
However, according to the A-D selector signal, the A-D converted values of the voltage from the battery 1 and the offset correction reference voltages V1 and V2 from the offset correction reference voltage circuit 6 are sequentially taken in, and the offset error correction amounts ΔP1 and ΔPn are obtained. Generate and correct battery voltage.

The voltage dividing circuit 7 divides the battery voltage of the battery 1 into a voltage range that can be measured by the AD converter 2 by resistance division. Next, the offset correction will be described in detail with reference to FIG.

(1) An offset voltage correction straight line is obtained based on the two offset correction reference voltages V1 and V2.
The offset error correction amount ΔPn of the A / D converter 2 is calculated,
The case of offset correction will be described.

As shown in FIG. 2, the offset correction reference voltage V1 generated by the offset correction reference voltage generation circuit 6 is input to the A / D converter 2 and the A / D conversion value at that time is designated as P1. To do. At this time, if the correct AD conversion value that does not include an error with respect to the offset correction reference voltage V1 is Pk1 (preliminarily calculated or previously measured), the offset error correction amount ΔP1 is ΔP1 = Pk1-P1 (equation 1) is obtained.

Similarly, as shown in FIG. 2, the offset correction reference voltage V2 generated by the offset correction reference voltage generation circuit 6 is input to the A / D converter 2 and the A / D conversion value at that time is input. Be P2. At this time, a correct A that does not include an error with respect to the offset correction reference voltage V2
When the -D conversion value is set to Pk2 (calculated or measured in advance), the offset error correction amount ΔP2 is calculated as ΔP2 = Pk2-P2 (Equation 2).

When the voltage to be measured is Vn, the offset error correction amount ΔPn is ΔPn = {(ΔP2-ΔP1) / (V2-V1)} × (Vn- V1) + ΔP1 (Equation 3)

Therefore, the offset-corrected voltage Pk
n is calculated as Pkn = Pn−ΔPn (Equation 4).

(2) A case will be described in which the offset error correction amount ΔP1 of the AD converter 2 is obtained based on one offset correction reference voltage V1 and the offset is corrected. As shown in FIG. 2, the offset correction reference voltage V1 generated by the offset correction reference voltage generation circuit 6 is generated.
Is input to the A / D converter 2 and the A / D converted value at that time is set to P1. At this time, the offset correction reference voltage V1
If the correct AD conversion value that does not include the error for Pk1 is set (calculated or measured in advance), the offset error correction amount ΔP1 is calculated as ΔP1 = Pk1−P1 (Equation 5).

When the voltage to be measured is Vn, the offset-corrected voltage Pkn is obtained from (Equation 5) as Pkn = Pn−ΔP1 (Equation 6).

Next, the detection of the battery voltage after the correct offset correction of the battery 1 under the configuration of FIG. 1 will be described in detail according to the order shown in the flowchart of FIG. Here, a case will be described as an example where the offset-corrected voltage Pkn is measured by (Equation 6) obtained in (2) described above.

In FIG. 2, S1 detects the offset measurement voltage. This is the offset correction reference voltage V1 generated by the offset correction reference voltage generation circuit 6.
The battery voltage offset correction circuit 3 takes in an A-D converted value P1 obtained by A-D converting the A-D converted by the A-D converter 2.

At S2, the offset value is calculated. As described on the right side, this is substituted into (Equation 5) to calculate the offset error correction amount ΔP1 of ΔP1 = Pk1−P1.

In step S3, the voltage is measured. This measures the battery voltage Pn which AD-converted the battery voltage as described on the right side. In S4, the voltage value is corrected. As described on the right side, this is the correction of the battery voltage measured in S3, that is, (Equation 6) Pkn = Pn-ΔP1 is substituted (the offset error correction amount ΔP1, calculated in S2,
The battery voltage Pn measured in S3 is substituted) to obtain the battery voltage Pkn after offset correction.

In S5, it is determined whether the battery voltage is LOW.
In the case of YES, since the battery voltage after the offset correction matches the LOW battery voltage, the LOW battery process (such as stopping the discharge of the battery 1) is performed in S6. on the other hand,
If NO, the process proceeds to S7.

In step S7, it is determined whether the voltage is the full charge voltage. In the case of YES, since the battery voltage after the offset correction matches the full charge voltage, the full charge process (stopping charging of the battery 1 or the like) is performed in S8. On the other hand, in the case of NO, the process ends.

As described above, A / D conversion is performed when the offset correction reference voltage V1 is generated by the offset correction reference voltage generation circuit 6 based on the same reference voltage Vref as the reference voltage Vref of the A / D converter 2. After substituting the AD conversion value P1 converted by the converter 2 into (Equation 5) to calculate the offset error correction amount ΔP1, the battery voltage Pn converted by the AD converter 2 from the battery voltage of the battery 1 is calculated as Substituting into equation 6), the battery voltage P after offset correction
Calculate kn. When the calculated offset-corrected battery voltage Pkn becomes equal to the LOW battery voltage when the battery 1 is discharged, LOW battery processing (such as stopping the discharge of the battery 1) is performed or becomes equal to the full charge voltage when the battery is charged. Full charge process (battery 1
It is possible to stop the discharge and charge of the battery 1 based on the battery voltage after the accurate offset correction, and prevent over-discharge and overcharge of the battery 1, Battery 1 deterioration and battery 1
It is possible to prevent runaway of the system that is supplied with power from.

[0032]

As described above, according to the present invention,
The offset correction reference voltage V1 generated by the offset correction reference voltage generation circuit 6 (or V1 and V
2) is input to the AD converter 2 and the output voltage P at that time is input.
After calculating the offset error correction amount ΔP1 (or ΔPn) based on 1 (or P1 and P2), the battery 1
The voltage Vn from V is input to the A / D converter 2 and the offset voltage correction amount ΔP is applied to the output voltage Pn at that time.
Correct battery voltage P corrected by 1 (or ΔPn)
Since the configuration for calculating kn is adopted, the offset of the AD converter 2 is automatically corrected to constantly detect the battery voltage without an offset error, and based on the accurate battery voltage after the offset correction, When the battery voltage matches the LOW battery voltage or the full-charge voltage, it is possible to accurately stop the discharge and charge of the battery, prevent deterioration of the battery 1, and prevent system runaway due to too low battery voltage. It becomes possible to do.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of offset correction according to the present invention.

FIG. 3 is a flowchart for explaining the operation of the present invention.

FIG. 4 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 1: Battery 2: A-D converter 3: Battery voltage offset correction circuit 4: CPU 5: DC-DC converter 6: Offset correction reference voltage generation circuit 7: Voltage division circuit V1, V2: Offset correction reference voltage Vref: reference voltage

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location H02J 7/10 B

Claims (3)

[Claims] 1. A battery controller for controlling charging / discharging by detecting a battery voltage, wherein an input reference voltage Vref is input with respect to an input voltage.
A-D converter (2) for converting into a digital voltage and outputting the digital voltage, an offset correction reference voltage generation circuit (6) for generating an offset correction reference voltage V1, and an offset correction reference voltage generation The offset reference voltage V1 generated by the circuit (6) is input to the AD converter (2), the offset error correction amount ΔP1 is calculated based on the output voltage P1 at that time, and then the battery (1 ) Is input to the A / D converter (2) and the output voltage Pn at that time is corrected by the offset error correction amount ΔP1 to obtain a correct battery voltage Pkn.
And a battery voltage offset correction circuit (3) for calculating, and performing charge / discharge control of the battery (1) based on the calculated corrected battery voltage Pkn. 2. A battery controller for detecting a voltage of a battery and controlling charging / discharging, wherein an input reference voltage Vref is input with respect to an input voltage.
A-D converter (2) that converts the voltage into a digital voltage and outputs the digital voltage, an offset correction reference voltage generation circuit (6) that generates the offset correction reference voltages V1 and V2, and the offset correction reference The offset reference voltages V1 and V2 generated by the voltage generation circuit (6) are set to A-
The offset error correction amount ΔPn is input to the D converter (2) based on the two output voltages P1 and P2 at that time.
Then, the voltage Vn from the battery (1) is calculated as
With respect to the output voltage Pn input to the -D converter (2) at that time, the correct battery voltage Pkn corrected by this offset error correction amount ΔPn is Pkn = Pn-ΔPn ΔPn = {(ΔP2-ΔP1) / (V2- V1)} (V
n-V1) + ΔP1 battery voltage offset correction circuit (3)
And a charge / discharge control of the battery (1) based on the calculated corrected battery voltage Pkn. 3. The discharge stop or charge stop of the battery (1) when the battery voltage after the digital correction of the battery (1) coincides with the LOW battery voltage or the full charge voltage. Alternatively, the battery controller according to claim 2.