JPS5961436A - Charger - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a charging device for rapidly charging a battery to be charged, such as a Ni-CD battery.

Conventional battery to be charged such as Ni-Cd battery ll': 1
'Depending on the battery temperature, the battery voltage VB at the time of completion of charging is V, , V2. Since the battery temperature changes as V, charging devices have been provided that are equipped with a battery temperature detection circuit to detect the temperature of the battery to be charged so that the charging control is responsive to the temperature characteristics. In a charging device in which the battery to be charged is housed in a battery pack and connected to the charger in a detachable manner, a battery temperature detection circuit must be installed inside the battery pack. If the electrical connection with the control means on the side is not good, charging control may not be performed correctly and the photoelectric battery may be overcharged, or if the charger is operated without the battery back connected. However, there was a risk that the connection terminals connecting the battery bag could be inadvertently short-circuited, leading to damage to the charger or other accidents.

The present invention has been made in view of these points, and its purpose is to be able to stop the charging operation of the charger when the battery temperature detection circuit is not connected, and to prevent overheating of the battery being charged. To provide a charging device that can prevent charging and damage to a charger.

The present invention will be explained below with reference to Examples. Figure 2 shows a block diagram of the present invention, which includes a step-down circuit (1) that steps down the AC power supply voltage, a rectifier circuit (2) that rectifies the AC stepped down by the step-down circuit +11, and a charging current. A current detection circuit (3) detects when the current is flowing (!) and a display circuit (4) that emits light based on the detection of this current detection circuit (3).
), a battery temperature detection circuit (5) that generates a constant current and is installed in the battery back BP, a current generation circuit (6) that uses the reference voltage to flow K, an input voltage obtained by dividing the pulsating power supply voltage by resistance, and the battery temperature. A voltage comparison circuit (8) that compares the reference voltage generated in the detection circuit (5) and operates the trigger signal generation circuit (7) when the input voltage exceeds the reference voltage, and a trigger signal generation circuit (7). A reverse blocking type three-terminal thyristor (9) (hereinafter referred to as thyristor (9)) conducts in response to a tri-force signal, and Ni is charged by a current flowing through the thyristor (9).
- By exploiting the incomplete connection between the battery to be charged (10) such as a Cd battery and the battery temperature detection circuit (5),
The sensor open detection circuit (consisting of 1) controls the risk (9), and controls charging by limiting the conduction of the thyristor (9) when the charging voltage VB of the battery to be charged (lO) is at a predetermined level. Fig. 8 shows a circuit that embodies the block in Fig. 1, and the operation of the embodiment circuit will be explained in detail using this concrete circuit. and power supply connection terminal a,
A rectifier circuit (2) steps down the AC voltage of the AC power supply connected to
) is full-wave rectified by the diode (121, (13i), and the pulsating current is used as the power supply voltage of charger A. Charger A is a device that removably attaches battery pack BP to battery pack B.
The battery to be charged (10) and the battery to be charged (1 (I
It is electrically connected to the battery temperature detection circuit (6) of j at the time of installation through connection terminals c, d, and e. Connect the iris resistor (9) between the output terminals of the rectifier circuit (2), the battery to be charged (107) in the battery bag BP, and the series circuit of the current detection resistor (0) of the current detection circuit (3). .Current detection circuit (3
) is 1! The rectifier circuit (
The base resistor (19) is connected in parallel to the transistor (18) connected between the output terminals of the transistor (18) and the current detection resistor θ6) through the base of the transistor (1 to 1).
It consists of a thyristor (9), a battery to be charged (
10) and the current detection resistor (16j), the transistor state turns on, and current flows to the light emitting diodes 06 and 1 through the transistor 0 barrel, indicating that charging is in progress. In the voltage comparison circuit (8), a divided voltage obtained by dividing the pulsating power supply voltage by the resistors (20) and 1) is applied to the base, and the positive voltage of the rectifier circuit (2) is applied to the base through the resistor (20). Connect the collector to the side output terminal, and connect the 1.
) is connected to the negative output terminal of the first transistor ( ).
A), each of the above resistors, H, (2b+), a variable resistor (2), and a capacitor (21) connected in parallel to the resistor (21).
33). A constant current flows from a reference current generation circuit (6) consisting of a constant current diode (341) into the series circuit of the variable resistor (24) and the battery temperature detection circuit +5+, and a voltage comparator circuit (8) flows into the series circuit. A voltage serving as a reference voltage is generated, and this reference voltage is compared with the base voltage of the transistor (26).
If it is higher than the added BE2M, the transistor (26
) is turned on, and conversely, when it is low, the transistor (26) is turned off. The tri-power signal generation circuit (7) connects a series circuit of a second transistor whose base is connected to the collector of the transistor (26) and a resistor (281) between the output terminals of the rectifier circuit (2), and generates a transistor ( 2
71 is connected to the gate of the thyristor (9) through a diode (29), and the thyristor (9) is ignited through the transistor (diode drain 9) when 27j is on. It has become. The open sensor circuit (11) is a variable resistor wire and a battery temperature detection circuit (11).
It consists of a resistor (30) and a transistor (2) that divides the voltage of the series circuit of (5) with (31+) and applies the voltage to the base, and when the battery temperature detection circuit (6) is disconnected, the base of the transistor (32) is - The potential rises and turns on the transistor 1321, which turns on the transistor 13.
2), the base of the transistor of the trigger signal generation circuit (7) is grounded, and the transistor 7) of the trigger signal generation circuit (7) is forced to connect to the battery temperature detection circuit (6). ) is turned off and charging is stopped when the battery is disconnected. Also at this time, the transistor (
The current detection circuit (3) detects the current flowing through c) and lights up the light emitting diode 06) of the display circuit (4),
Displays that the battery temperature detection circuit (5) is not connected.

Next, the operation of the charging device of the present invention will be explained. battery pack BP
When the pulsating power supply voltage shown in Fig. 4(a) is generated from the rectifier circuit (2) during charging when the battery is attached and connected to the charger A, when the voltage of this pulsating power supply voltage rises, First, the base voltage of the voltage comparator circuit (8) will respond to the increase in the charging voltage of the capacitor +jG33), and therefore the current flowing through the constant current diode example shown in Fig. 4(c)K will be at a constant level. During the rising period until reaching , the base voltage does not exceed 1.
Therefore, the base current of the transistor (26) does not flow, and the collector current does not flow through the transistor, and the potential of the collector does not decrease. Therefore, when the pulsating voltage applied to the base of the transistor ρη of the tri-force signal generation circuit (7) exceeds the voltage drop between the base and emitter of the transistor (2η), it will immediately turn on, and the Sugi 1ν When the transistor (27) is turned on, the voltage at the connection point (2) between the first three-point resistor I281 and the first three-point resistor I281 of the transistor (2 transistors) is As shown in Figure (b), it rises as the pulsating power supply voltage rises.During this voltage rise, the voltage at the connection point ■ is the forward drop voltage of diode 4, ■F29, and the gate of the thyristor (9). Voltage drop between cathodes VG and battery voltage V
When the voltage exceeds the sum voltage of the thyristor (9), a gate current flows through the thyristor (9), turning it on and charging the battery to be charged (Qo) K.
and start charging. On the other hand, in the voltage comparator circuit (8), the voltage across the capacitor (33) is the reference voltage, that is, as shown in FIG.
When the voltage drop VBE28 between the base 1395 of transistor (A) is added to the flat level of the waveform shown in C) and exceeds the fc voltage, the transistor turns on and the collector potential of transistor (26) becomes low. Then, the transistor (2) is turned off, and the potential of the connection point (2) is set to "L".

Therefore, in the initial state where the voltage of the battery to be charged (10) is low, the thyristor (9) starts conducting at an earlier time, and conversely, as the battery voltage VB increases, the time when the thyristor (9) starts conducting becomes later. ■The peak value of the voltage at the connection point is the battery voltage VB and the forward drop voltage VF2 of the diode.
Voltage drop between G and the gate cathode of thyristor (9)
The thyristor (9) will not conduct when the sum of
Charging is stopped. That is, depending on the timing at which the transistor (26) of the voltage comparison circuit (8) turns on, a battery voltage Vs that can turn off the thyristor (9) can be set, and this battery voltage VB becomes the charging control voltage. Now, in the initial charging operation, the thyristor (9) turns on for each waveform of the pulsating current power supply, so the charging current flows almost continuously to the current detection resistor (15) of the current detection circuit (3) and is displayed. The light emitting diode 061 of the circuit (4) is turned on, and the light emitted from the light emitting diode 06) appears to be in a continuous light emitting state due to the afterimage of the human eye, and the user can know from this light emission that charging is in progress.

By the way, after the above-mentioned charging stop occurs at the end of charging, the thyristor (9) is turned on only when the voltage drops due to self-discharge of the battery to be charged [+0+, etc., and supplementary charging is performed. be. Here, the voltage comparison circuit (8
) The switching operation of turning off the transistor (26) is performed when the voltage is lower than the value of the pulsating power supply voltage when it is turned on, due to the time constant of discharging the charge of the capacitor (goods), so the trip signal is generated. The voltage of the transistor (27) in the circuit (7), that is, the voltage at the connection point ■, is that there is a difference of △V between the voltage when the transistor (26) is on and the voltage when it is off. Therefore, the trigger signal that turns on the thyristor (9) during the above-mentioned auxiliary charging becomes the heat voltage at the connection point (2), which is the first half of the pulsating voltage waveform, and as a result, the on period of the thyristor (9) during charging is The unit of the pulsating voltage waveform is, therefore, the amount of charge during that period is large, and the period until the next oscillation of the thyristor (9) occurs is relatively long. Two or more rest periods are obtained, and as a result, time is obtained to sufficiently absorb gas generated inside the battery to be charged (10), thereby preventing battery deterioration and overcharging. Figure 5(a) shows the initial charge! As for the current waveform, FIG. 4(b) shows a charging lachrymal shape at the end of charging.

However, at the end of charging, a charging current flows intermittently with respect to the pulsating current waveform, and the light emitting diode 06) of the display circuit (4) does not blink, indicating that charging is complete. can be known.

By the way, when performing such quick charging, the battery voltage to be controlled varies depending on the temperature as shown in Figure 1:
V2. V3... Therefore, it is necessary to set the temperature characteristics of the control operation in accordance with the battery temperature characteristics, but in the charging device of the present invention, this is done by the following method. The switching timing of the transistor (27) of the trigger signal generation circuit (7) for triggering the thyristor (9) on the side of the overcharger A is determined by the on/off timing of the transistor (26) of the voltage comparator circuit (3-channel transistor (26)). The on/off of the thyristor (9) is determined by the voltage at the 0 point and the battery voltage VB.
1 It is determined by the relationship between the voltage drop Vc between the gate and cathode of the thyristor (9), the forward voltage drop of the diode (29), and the sum voltage of F29! However, assuming that there is no temperature change in the battery pack BP and there is a temperature change in the charger A, each transistor (2G) (voltage drop between the two-power base 1399, VBE26, VBE2. and the diode switch 9 ), and the voltage drop between the gate and cathode of the thyristor (9) vG changes depending on a predetermined temperature coefficient.
This affects the switching operation of the thyristor (9) and the switching operation of the thyristor (9).

Therefore, the conditions for each element are set so that the temperature characteristics of these elements are corrected to make the temperature characteristics of the control operation of charger A zero with respect to temperature changes on the charger A side. For example, as shown in Figure 8. In the case of a circuit, set the collection constant so that the following conditions are satisfied.

R2oaTclT aT aTBy the way, the battery voltage VB at the time of completion of charging changes depending on the temperature of the battery, and it is necessary to change the charging control voltage accordingly, as explained in FIG. 1. However, in the present invention, the battery temperature A detection circuit (5) is provided in the battery back BP, and the reference voltage of the voltage comparison circuit (8) is determined by using the temperature characteristics of the diode and variable resistor (support) of the battery temperature detection circuit (6). change the timing of the switching operation of the transistor acupuncture needle,
In other words, the peak value (battery voltage VB , the voltage drop vG between the gate and cathode of the thyristor (9), and the forward voltage drop VF2 of the diode diode 9). ．． (maximum reference voltage compared with the sum voltage of There is.

In addition, for the difference in the number of batteries, the resistance (20) and (2
1) Division ratio and diode (29), (23)
The setting may be made in the same manner as described above by changing the quantity of , and the fine adjustment may be made by changing the current value of the constant current diode to match the temperature characteristics. Furthermore, VBE2. represents the voltage drop between the base and emitter of the transistor (26), R2o and R2I represent the resistance values of the resistors (20) and (21), and VF represents the forward voltage drop of the tie wire.

As described above, the present invention provides an open detection means on the charger side to detect that the battery temperature detection circuit is disconnected, and stops charging based on the detection output of the sensor open detection means. Therefore, in the case of a detachable battery pack that is separate from the charger, if the battery temperature detection circuit is not connected to the charger side, charging will be stopped to prevent battery damage due to overcharging of the battery to be charged. Moreover, even if there is an inadvertent short circuit of the battery connection terminal when the battery pack is not attached, the charger will not be destroyed and it will be safe.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the temperature characteristics of the battery to be charged, Fig. 2 is a circuit block diagram of an embodiment of the present invention, Fig. 3 is a specific circuit diagram of the same as above, and Figs. 4 (a) to (C). and FIGS. 5(a) to (b)
) is the time chart for explaining the operation as above, A is the charger, BP is the battery pack, (6) is the battery temperature Suita circuit, (I is the sensor open detection circuit, (3o) (at ) is a resistor, (3 is a transistor, (341 is a constant current diode. Agent Patent Attorney Ishi 1) Long Figure 1 is a surprise!... Figure 3-207- Figure 4 Figure 5

Claims (2)

[Claims] (1) Consists of a charger and a battery bag that is detachably attached to and connected to the charger.
In a charging device in which a battery temperature detection circuit for detecting the temperature of a battery is provided in a battery pack, and a charger is provided with a control means for controlling charging in response to the temperature detected by the battery temperature detection circuit, the charger is provided with: (a) A charging device characterized by providing a sensor open detection means for detecting that a battery temperature detection circuit is not connected, and stopping charging based on a detection output of the sensor open detection means. (2) The sensor open detection means is composed of a resistive voltage divider circuit connected in series to a constant current diode, and a transistor connected to the divided voltage output of the resistor voltage divider circuit to the pace, which is connected in parallel to the resistive voltage divider circuit described in 1iij. 2. The charging device according to claim 1, wherein said battery temperature detection circuit is connected to said battery temperature detection circuit.