JP2003007272A - Type battery pack having antistatic countermeasure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a space around a component required for antistatic countermeasures by a method for packaging arrangement, and to make a board compact in size. SOLUTION: This antistatic countermeasure type battery pack has antistatic countermeasure circuits C1, C2, R1-R4, ZD1, ZD2 in a signal line, and components of the same level of the antistatic countermeasure circuits C1, C2, R1-R4, ZD1, ZD2 on the signal line are arranged proximately. Thereby, electrostatic withstand voltage is very much increased, additional protection element or structure for is antistatic countermeasure is made unnecessary, a packaging space around the component can be reduced, and making the board size compact is made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antistatic battery pack having an antistatic circuit in a signal line.

[0002]

As a protection measure from static electricity, for example, in order to protect an IC having various functions from being destroyed by static electricity, an IC having various functions such as a melody circuit, a light emitting circuit and a vibration circuit is insulated in a hollow case. A static electricity eliminator (see JP-A-2000-340392) wrapped in a bag made of a material, and an electronic device with a clock for preventing IC destruction due to static electricity applied to an external terminal (JP-A-59-107).
No. 287) has been proposed.

The static eliminator is provided with a static electricity input electrode and a static electricity output electrode in a hollow case made of an insulating material, and a current limiting resistor and a voltage dividing resistor are connected in series between the electrodes, and is connected in parallel with the voltage dividing resistor. By connecting an IC to the above and enclosing it in an insulating bag together with a driving battery, electrostatic discharge in the hollow case is prevented.

In addition, the electronic equipment with a clock is connected to the external terminal by connecting the ground line to the case and connecting a device such as a capacitor or a Zener diode for discharging static electricity between the external terminal and the ground line. It is designed to prevent IC destruction due to static electricity.

[0005]

In a gas gauge circuit board for a battery pack, when a static electricity voltage applied from an input / output terminal to a signal line such as CLK or DATA is very high, a resistor inserted in the signal line is used. Rather than passing a current through a capacitor, zener diode, etc., the insulation breakdown of air from the component end to the wiring pattern on the board and other components may cause current to flow due to air discharge, resulting in IC malfunction or destruction. was there.

Therefore, conventionally, it is necessary to dispose a pattern or a part which is troubled when static electricity flows from a part which is discharged in the air, so that the board becomes large or the size of the board is reduced. There are problems such as high-density mounting, air discharge between components, and reduction in electrostatic breakdown voltage.

In the static eliminator, the internal circuit is wrapped with an antistatic bag to protect it from static electricity from the current limiting resistor starting from the input / output terminal. However, in the case of a battery pack, Since we are pursuing miniaturization of the board, we cannot secure a space to wrap it in an antistatic bag.

The electronic device with a clock is connected with a capacitor, a Zener diode or the like in order to prevent malfunction or destruction of the IC due to static electricity. However, when the board is downsized and the mounting density is increased, the mounting arrangement is not considered. If these protective elements are connected to the IC, air insulation will be destroyed between the resistance, capacitor, and Zener diode as a countermeasure against static electricity and the wiring pattern on the board and other parts, and air discharge will cause malfunction or destruction of the IC. There is a problem.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems and can reduce the space around the components necessary for countermeasures against static electricity by the mounting arrangement method, thus reducing the size of the board. Is possible.

Therefore, the present invention is characterized in that, in an antistatic battery pack having an antistatic circuit in a signal line, parts of the same level of the antistatic circuit on the signal line are arranged close to each other. The countermeasure circuit is characterized by including a resistor, a capacitor, and a Zener diode.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram for explaining an embodiment of a gas gauge circuit board for an anti-static type battery pack according to the present invention, FIG. 2 is a diagram for explaining the operation of the present invention, and FIG. 3 is a diagram showing components of the same level. It is a figure which shows the example at the time of not being a proximity arrangement. In the figure, 1 is a gas gauge IC or microcomputer, 2 is an input / output terminal, 3 is a CLK terminal, and 4 is a DAT.
A terminal, C1 and C2 are capacitors, R1 to R4 are resistors,
ZD1 and ZD2 represent Zener diodes.

In FIG. 1, a gas gauge ICor microcomputer 1 measures data such as a remaining amount of a battery pack, a charging / discharging state, a voltage and a current value of each cell, and the data is SMB.
It communicates with the device body (notebook personal computer, portable information terminal PDA, etc.) through a us (system management bus) interface. The input / output terminal 2 is a terminal for connecting the battery pack and the apparatus body. The CLK terminal is a clock terminal for serially communicating SBData (smart battery data) with the device body, and the DATA terminal is an SB for serial communication with the device body.
This is a terminal for Data. The capacitors C1 and C2 and the Zener diodes ZD1 and ZD2 are connected to the CLK terminal, DA
The static electricity that enters from the TA terminal is released to GND (-), and the resistors R1 to R4 are components that constitute the static electricity countermeasure circuit, which limit the current and reduce the static energy. The components on the signal line to which these static electricity countermeasure circuits are connected are arranged close to each other to facilitate air discharge. In this case, components of the same level are arranged close to each other on the circuit.

That is, the gas gauge IC or microcomputer 1
The resistors R1 and R3, the capacitor C1, and the Zener diode ZD1 are connected to the clock signal line between the CLK terminal and the CLK terminal.
Is connected to the static electricity prevention circuit, and similarly, SBGa between the gas gauge ICor microcomputer 1 and the DATA terminal is connected.
The ta signal line has resistors R2, R4 and a capacitor C.
2. A static electricity countermeasure circuit including a Zener diode ZD2 is connected. Here, for example, as shown in FIGS. 2A and 2B, the resistance R1 and the capacitor C of the static electricity countermeasure circuit in the clock signal line connected to the CLK terminal
1. The Zener diode ZD1 is a resistor R2, a capacitor C2, and a Zener diode ZD2 of the antistatic circuit in the SBData signal line connected to the DATA terminal.
Since these are the components of the same level on the circuit, these are arranged close to each other by several mm to 0.5 mm.

In FIGS. 2A and 2B, from the outside,
For example, when a person charged with static electricity touches the terminal, C
When static electricity is applied to the LK terminal or DATA terminal,
When the voltage is low, static electricity enters through the resistors R1 and R2, but when the voltage is high, air discharge occurs between and. By the way, the voltage that causes the air discharge increases with the distance, and the voltage value varies depending on the distance between the parts.
According to EC 61000-4-2), it was confirmed that air discharge occurs when static electricity of about 5 kV is applied.

When static electricity is discharged in the air to a part or pattern for which no static electricity countermeasure is taken, the data learned by the gas gauge ICor microcomputer 1 (full charge capacity, remaining capacity) disappears (reset), IC latch-up, etc. Occurs, and in the worst case, the IC is destroyed. As described above, when air discharge is generated between components of the same level on the circuit, the present invention can avoid the above-mentioned problem because static electricity countermeasures are taken at the discharge destination.

However, as shown in FIGS. 3A and 3B, when components of the same level are not properly arranged close to each other, for example, when static electricity is externally applied to the DATA terminal, they are separated by several mm. In a certain degree, since an air discharge is generated like from, the gas gauge ICor the CLK of the microcomputer 1
Static electricity will enter the pins without passing through the resistor R1. Therefore, the resistance R1 cannot reduce the energy, which causes a failure. Of course, in this case, the static electricity is weakened by the capacitor C1 and the Zener diode ZD1, but it is originally necessary to reduce the energy, and the resistance R1 which should be connected is originally required.
Is not working, it's not enough to cause no harm.

The present invention is not limited to the above embodiment, but various modifications can be made. For example, in the above embodiment, the clock signal line and the SBDa
Although it has been described that the signal line is applied to the ta signal line, other components such as the + line, the − line, the static electricity protection component of the protection circuit,
And, it can be similarly applied to parts and circuit patterns connected to output terminals such as ID resistors and thermistors. A battery pack usually has a protection circuit including an overcharge detection circuit, an overdischarge detection circuit, an overcurrent detection circuit, and a FET that turns on / off a power line. And Zener diode are mounted together.

[0018]

As is apparent from the above description, according to the present invention, in an antistatic battery pack having an antistatic circuit in a signal line, components of the same level in the antistatic circuit on the signal line are brought close to each other. Since it is placed, the electrostatic withstand voltage can be greatly improved, and since no special protection element or structure is required to be added as a countermeasure against static electricity, the mounting space around the components can be reduced and the board Can be downsized.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of a gas gauge circuit board for an antistatic battery pack according to the present invention.

FIG. 2 is a diagram for explaining the operation of the present invention.

FIG. 3 is a diagram showing an example in which components of the same level are not arranged close to each other.

[Explanation of symbols]

1 ... Gas gauge IC or microcomputer, 2 ... Input / output terminal, 3
... CLK terminal, 4 ... DATA terminal, C1, C2 ... Capacitor, R1-R4 ... Resistor, ZD1, ZD2 ... Zener diode

Claims (2)

[Claims] 1. An antistatic battery pack having an antistatic circuit in a signal line, wherein components of the same level of the antistatic circuit on the signal line are arranged close to each other. 2. The antistatic battery pack according to claim 1, wherein the antistatic circuit comprises a resistor, a capacitor, and a Zener diode.