Fujitsu Corporation

Masafumi Okumura

Hidekiyo Ozawa

Mituo Saeki

Shigeo Tanaka

Hidetoshi Yano

Mitsuo Saeki

Hideo Fukuda

A microcomputer in a device body operates so as to store every update of a maximum discharge current value (I(A)) of a secondary battery (the whole plurality of cells), and operates so as to indicate the ratio value of the remaining capacity defined in a remaining capacity definition table with respect to a discharge voltage value (V (V)) of the secondary battery while reducing the ratio value in accordance with the maximum discharge current value (I(A)) when obtaining the discharge voltage value (V (V)) from a protection circuit.

Residual quantity display system

To provide a technology for obtaining a remaining capacity of a battery with high accuracy. A battery remaining capacity predicting apparatus predicting a remaining capacity of a battery based on an open-circuit voltage of the battery, detects a charge current or a discharge current of the battery, integrates the currents, obtains an estimated value of the open-circuit voltage that corresponds to an integrated value of the currents on the basis of conversion information representing a capacity necessary for the open-circuit voltage of the battery to change by a predetermined capacity, obtains a measured value of the open-circuit voltage on the basis of the detected current and information on internal impedance, and obtains the remaining capacity of the battery based on the estimated value of the open-circuit voltage by correcting the information on the internal impedance so that the measured value of the open-circuit voltage is equalized to the estimated value of the open-circuit voltage, or by correcting the conversion information so that the estimated value of the open-circuit voltage is equalized to the measured value of the open-circuit voltage.

Battery remaining capacity predicting apparatus

A battery control device includes a unit to measure a voltage of a battery, a unit to measure an electric current of the battery, and a control unit to calculate an open-circuit voltage of the battery based on the voltage and the electric current of the battery, and to calculate a battery residual quantity ratio of the battery by use of relative information and the calculated open-circuit voltage, wherein the control unit calculates a charge quantity ratio of the battery by subtracting a battery residual quantity ratio at charge ending time from a battery residual quantity ratio at charge starting time, calculates a value obtained by multiplying the charge quantity ratio by a correction coefficient as a charging-discharging count of the battery, and integrates the charging-discharging count each time the charging-discharging count is calculated.

Battery control device, battery control method, battery pack, electronic apparatus and control circuit for calculating charging-discharging count of battery

A protection method for preventing battery cells from over-discharging and being overcharged, a control circuit, and a battery unit are provided. In the protection method, when a set signal '1' is supplied to a set terminal, a flip-flop outputs '1'. The gate of a discharge control FET then becomes &#x201c;1&#x201d;, so that the discharge control FET is OFF regardless of a discharge control signal supplied from a voltage monitor circuit. When a reset signal &#x201c;1&#x201d; is supplied to a reset terminal, the flip-flop outputs &#x201c;0&#x201d;. The discharge control FET is then switched on and off in accordance with the output of a discharge control circuit of the voltage monitor circuit. In this manner, battery cells connected to an electronic device do not over-discharge, even when they are left unused for a long period of time. Thus, the battery unit can be prevented from deteriorating and shortening the life thereof.

Protection method, control circuit, and battery unit

Battery unit having means for preventing over-discharge

An electronic equipment is connectable to a battery unit which includes an electronic circuit and a battery, and is provided with a power supply circuit to supply a power supply voltage directly to the electronic circuit.

Electronic equipment and battery unit

A protection method for preventing battery cells from over-discharging and being overcharged, a control circuit, and a battery unit are provided. In the protection method, when a set signal &ldquo;1&rdquo; is supplied to a set terminal, a flip-flop outputs &ldquo;1&rdquo;. The gate of a discharge control FET then becomes &ldquo;1&rdquo;, so that the discharge control FET is OFF regardless of a discharge control signal supplied from a voltage monitor circuit. When a reset signal &ldquo;1&rdquo; is supplied to a reset terminal, the flip-flop outputs &plus;0&rdquo;. The discharge control FET is then switched on and off in accordance with the output of a discharge control circuit of the voltage monitor circuit. In this manner, battery cells connected to an electronic device do not over-discharge, even when they are left unused for a long period of time. Thus, the battery unit can be prevented from deteriorating and shortening the life thereof.

A charging-and-discharging device in an electronic apparatus includes a rechargeable battery and a charging device for charging the battery. The charging-and-discharging device includes a switching circuit electrically isolating one terminal side of the battery from a ground side of the electronic apparatus. The charging-and-discharging device further includes a charge control section controlling the isolating of the one terminal side of the battery from the ground side of the electronic apparatus by turning off the switching circuit during charging of the battery. In the charging-and-discharging device, the one terminal side of the battery is isolated from the ground side of the electronic apparatus by the switching circuit during charging of the battery and a closed loop including the charging device and the battery is established to charge the battery.

Charging-and-discharging device for an electronic apparatus, and an

A power supply device includes a secondary battery and a charger, and can further utilize an external D.C. power supply. A switch is interposed between a negative electrode of the secondary battery and the ground. This switch is turned OFF when the external D.C. power supply is connected to the power supply device, and is turned ON when the external D.C. power supply is removed from the power supply device. The charger controls the charge of the secondary battery from the external D.C. power supply by regulating the potential of the negative electrode of the battery. A contact remains OFF while the external D.C. power supply is connected to the power supply device. In consequence, a current does not directly flow from the external D.C. power supply to the secondary battery. Therefore, a back-flow prevention diode, which otherwise results in power consumption, need not be disposed between the secondary battery and the load.

Power supply device having low internal power consumption and electronic

A power supply apparatus includes a battery, a voltage converter for converting the output of the battery to a different D.C. voltage by ON/OFF action of a main voltage converter control switch circuit, and a device for estimating a remaining capacity of the battery. The remaining battery capacity estimation device detects a non-load voltage of the battery when the main voltage converter control switch circuit is OFF, and estimates the remaining capacity of the battery.

Power supply apparatus and electronic appliance equipped with the power

A power source device capable of using both an external DC power source and a battery contained therein, and an electronic device using this power source device. A circuit is provided to measure the battery voltage, to calculate the remaining capacity of the battery and to indicate the remaining capacity. Means is provided which detects the state where no battery is mounted in the power source device, and short-circuits the input side of the battery voltage-measuring circuit. When no battery is mounted, therefore, a voltage leaking from the external DC power source is not erroneously measured as the battery voltage, and the remaining amount of power of the battery is correctly calculated.

Remove power source device having improved capacity indication

A battery protection circuit for protecting a battery is proposed. The circuit includes a detecting circuit for detecting a battery condition and producing a detected voltage in relation to the battery condition, a comparator comparing the detected voltage with a given voltage, and a switching circuit controlling a connection between the battery and electrical elements. In the battery protection circuit, when the comparator determines that the battery needs to be protected from the battery condition, the switching circuit turns off to disconnect the battery from the electrical elements.

Growing community of inventors

Kawasaki, Japan

Masafumi Okumura