JPH0615114U - Battery pack - Google Patents

Abstract

(57) [Abstract] [Purpose] When the battery is fully charged, the charge characteristic of the capacitor is used to stabilize the voltage to a predetermined value and obtain a predetermined power supply voltage. [Structure] The voltage of the battery 2 detected at the connection point of the second and third resistors R2 and R3, the fourth resistor R4 and the constant voltage element Z.
The reference voltage obtained at the connection point of D is compared with the comparator IC
1 compares. If the voltage of the battery 2 is equal to or higher than the predetermined value, the first transistor Q1 operates through the inverter IC2, the capacitor C is charged through the first resistor R1, and the voltage of the predetermined value is output from the diode D1. afterwards,
When the voltage of the battery 2 reaches a predetermined value, the second transistor Q2
Operates, and the amount of electricity charged in the capacitor C is returned to the battery 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a battery pack, and more particularly to a battery pack for a portable information processing device such as a portable computer or a laptop computer that requires a + 5V power source.

[0002]

[Prior art]

 Conventionally, this type of battery pack is used in a portable information processing device 14 such as a portable personal computer or a laptop personal computer having a built-in DC / DC converter 6 as shown in FIG. Then, since + 5V is not directly generated by the voltage of the battery 2, the battery voltage should be determined only by considering the battery life and the price.

However, the electric component 5 which has conventionally required + 5V ± 5% has come to operate at + 5V ± 10% recently, and DC of 4 to 5 batteries 2 connected in series as shown in FIG. A portable information processing device 4 without a / DC converter has been used.

[0004]

[Problems to be solved by the device]

 Therefore, when the battery 2 is fully charged, the battery voltage is close to 1.4V per cell, and when 5 batteries are connected in series, the voltage of the battery pack 11 becomes 7V.

Therefore, even if the backflow prevention element D2 is mounted in series, there is a problem that + 5V ± 10% cannot be satisfied and the electric component 5 is destroyed in the worst case.

[0006]

[Means for Solving the Problems]

 In order to achieve the above object, the battery pack of the present invention includes a battery, a detection circuit for detecting the voltage of the battery, and the battery based on the detection signal of the detection circuit when the battery voltage is below a predetermined value. A first transistor for extracting the output voltage of the second transistor, a second transistor that operates based on the detection signal of the detection circuit when the battery voltage is equal to or higher than a predetermined value, and an emitter between the second transistor and ground. It is characterized by comprising a series circuit of a resistor and a capacitor connected to each other, and a diode having an anode connected to the connection point of the resistor and the capacitor and for taking out the output voltage of the battery.

The detection circuit includes a series circuit of second and third resistors connected in parallel to the battery, and a comparator having a negative input terminal connected to a connection point of the second and third resistors. A fourth resistor connected between the positive input terminal of the comparator and the positive electrode of the battery; a constant voltage element connected between the positive input terminal of the comparator and the negative electrode of the battery; The output terminal of the comparator and the base of the second transistor are connected to the input terminal, and the output terminal is composed of an inverter connected to the base of the first transistor.

[0008]

[Action]

 According to this invention, the voltage of the battery 2 at the time of full charge can be set to + 5V ± 10% at the output stage of the backflow prevention element D2, and the voltage of the battery 2 at the time of full charge can be taken into consideration in the DC / DC converter. The portable information processing device 4 equipped with the converter 6 can be driven without the DC / DC converter 6.

[0009]

【Example】

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a charging characteristic diagram of a capacitor-C, FIG. 3 is a discharging characteristic diagram of a battery pack 1 of the present invention, and FIGS. 4 and 5 are conventional circuits. 6 and 6 show discharge characteristics of the conventional battery pack 11.

According to one embodiment of the present invention, as shown in the circuit diagram of FIG. 1, a detection circuit 3 for a battery 2 is mounted inside a battery pack 1 to detect a region H in FIG. The output is being switched.

The negative electrode of the comparator IC1 of the detection circuit 3 is connected to the positive electrode of the battery 2 via the second resistor and is also grounded via the third resistor R3.

The positive electrode of the comparator IC1 is connected to the positive electrode of the battery 2 via the resistor R4, and is also grounded via the constant voltage element ZD.

The output terminal of the comparator IC1 is connected to the base of a second transistor Q2 whose emitter is connected to the output end of the battery pack 1 and whose collector is connected to the positive electrode of the battery 2.

The output terminal of the comparator IC1 is connected to the base of the first transistor Q1 via the inverter IC2.

The emitter of the first transistor Q1 is connected to one end of the first resistor R1, and the collector is connected to the positive electrode of the battery 2.

The other end of the first resistor R1 is connected to the output end of the battery pack 1 via the diode D1 and grounded via the capacitor C.

The capacitor-C charges electricity according to the charging characteristic as shown in FIG. 2 by the first resistor R1 which determines the charging characteristic of the capacitor-C.

When this charging characteristic is made to be a characteristic contradictory to the H region, the discharging characteristic of the battery pack 1 without the H region is obtained as shown in FIG.

The operation will now be described with reference to FIG. 1. The voltage of the battery 2 detected at the connection point of the second and third resistors R2 and R3, the fourth resistor R4 and the constant voltage element ZD. The comparator IC1 compares the reference voltage obtained at the connection point.

Next, if the voltage of the battery 2 is a predetermined value or more, the first transistor Q1 operates through the inverter IC2, the capacitor C is charged through the first resistor R1, and the voltage of the predetermined value becomes It is output from the diode D1.

After that, when the voltage of the battery 2 reaches a predetermined value, the second transistor Q2 operates, and the quantity of electricity charged in the capacitor C is reduced to the discharge line of the battery 2 by the diode D1 and H Effective utilization is achieved without consuming electric power in the area.

In the circuit diagram of FIG. 4 which is a conventional example, the voltage from the battery pack 11 is input to the DC / DC converter 6 via the backflow prevention element D2 of the portable information processing device 14, and the DC / DC converter 6 is supplied. Power is supplied to the electric component 5 through the switch 6.

Therefore, the efficiency of the DC / DC converter 6 has a great influence on the battery life and heat generation control.

In addition, recently, a portable information processing device in which the DC / DC converter 6 is not mounted as shown in FIG. 5 and the power is directly supplied to the electric component 5 by the battery pack 11 4 has appeared.

Therefore, in such a system, the backflow prevention element D2 is provided in multiple stages to reduce the voltage of the battery at the time of full charge due to the forward voltage drop.

However, when the battery voltage drops, the backflow prevention element D2 may decrease the voltage supplied to the electric component 5.

FIG. 6 shows the discharge characteristics of a normal battery 2. The area G has a voltage width of +5 V ± 10%, and the portable information processing device 4 uses the DC / DC converter for the voltage from the point A to the voltage B. It will be possible to drive directly without the data.

Therefore, the battery life changes from point E to point F.

Further, the region where the voltage is higher than the point A (region H) cannot be directly supplied to the electric component 5 without the DC / DC converter 6.

[0031]

[Effect of device]

 As described above, according to the present invention, the battery voltage at full charge is controlled by the capacitor so that the battery voltage at full charge becomes + 5V ± 10% at the output stage of the backflow prevention element. In addition, the portable information processing device can be driven without a DC / DC converter. .

Further, by eliminating the efficiency problem of the DC / DC converter which deteriorates the battery life and the mounting area of the DC / DC converter, the portable information processing device can be downsized and It also has a great effect on cost reduction.

[Brief description of drawings]

FIG. 1 is a circuit diagram of the present invention.

FIG. 2 is a charging characteristic diagram of a capacitor.

FIG. 3 is a discharge characteristic diagram of a battery of the battery pack of the present invention.

FIG. 4 is a conventional circuit diagram.

FIG. 5 is a conventional circuit diagram.

FIG. 6 is a discharge characteristic diagram of a battery of a conventional battery pack.

[Explanation of symbols]

 1,11 Battery pack 2 Battery 3 Detection circuit 4,14 (Portable information processing device) 5 Electric component 6 DC / DC converter C Capacitor D1 Diode D2 (Backflow prevention element) IC1 Comparator IC2 Inverter Q1 First transistor Q2 Second transistor R1 First resistance R2 Second resistance R3 Third resistance R4 Fourth resistance ZD constant voltage element

Claims (2)

[Scope of utility model registration request] 1. A battery, a detection circuit for detecting a voltage of the battery, and a first transistor for extracting an output voltage of the battery based on a detection signal of the detection circuit when the battery voltage is equal to or lower than a predetermined value. A series connection of a second transistor that operates based on a detection signal of the detection circuit when the battery voltage is equal to or higher than a predetermined value, and a first resistor and a capacitor connected between the emitter of the second transistor and ground. A battery pack comprising: a circuit; and a diode having an anode connected to a connection point between the first resistor and the capacitor, for extracting an output voltage of the battery. 2. A comparator in which the detection circuit has a series circuit of second and third resistors connected in parallel to the battery, and a negative input terminal is connected to a connection point of the second and third resistors. A fourth resistor connected between the positive input terminal of the comparator and the positive electrode of the battery; a constant voltage element connected between the positive input terminal of the comparator and the negative electrode of the battery; The battery pack according to claim 1, wherein an output terminal and a base of the second transistor are connected to an input terminal, and an output terminal is connected to a base of the first transistor.