JPH07106040B2 - Charger - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a charging device for charging a battery of an electronic device having a rechargeable battery.

2. Description of the Related Art A rechargeable battery, for example, a nickel-cadmium battery, deteriorates in performance when it is charged with a large current for a longer time than necessary. Therefore, there has been a conventional charging device that is provided with a voltage detecting means for detecting the voltage of a battery and displays the completion of charging to the user when the voltage of the battery becomes equal to or higher than a predetermined voltage. Further, there has been one configured to automatically stop charging when the voltage of the battery exceeds a predetermined voltage.

By the way, in order to quickly recover the discharged battery,
It is necessary to flow a large charging current for rapid charging, and in the case of rapid charging, it is necessary to accurately determine the charging completion state of the battery in order to prevent overcharging of the battery.

Further, as shown in the invention described in Japanese Patent Application No. 50-548480, a counting input that operates at the time of energization and generates a relaxation pulse at a predetermined number during a time corresponding to the charging time of a battery The count value is added by the generator, the inverter circuit that operates at the time of power failure and outputs at a timing that reaches a predetermined number during the time corresponding to the discharge time of the battery, and the relaxation oscillation pulse from the count input generator. In addition, there is a counter that has a counter that subtracts the count value by the output of the inverter circuit, performs rapid charging until the count value of the counter reaches a predetermined value, and performs floating charging when the count value reaches the predetermined value.

Problems to be Solved by the Invention However, in the case of detecting the voltage of the battery,
It is difficult to accurately determine the charge completion state of the battery unless the correlation between the charge completion state of the battery and the voltage at that time is accurately known for each battery used. In addition, for example, in a nickel-cadmium battery, the voltage rises rapidly immediately after the start of charging, and the change in the voltage is very small just before the end of charging, so that it is highly accurate to accurately detect the voltage at the completion of charging. A reference battery or the like is required, which is very expensive. Further, when a plurality of batteries are connected in series and used, variations in the characteristics of the batteries affect the voltage value in the charging completed state. Therefore, in a replaceable battery pack or the like in which a plurality of batteries are connected in series, the voltage value in the charge completed state greatly differs for each battery pack used, and it is more difficult to determine the character of the charge completed state.

Further, in the configuration as shown in the invention described in Japanese Patent Laid-Open No. 50-54848, the count value is added or subtracted by changing the timing of the pulse input to the counter according to the state of the device such as charging and discharging. However, since a generating circuit for generating pulses with different timings is required for each state, the circuit becomes complicated and the cost for the additional circuit increases. In particular, if the device has multiple operating states, that is, if the battery has multiple discharging states,
Is there a circuit that generates a pulse for each discharge state?
It was necessary to provide a frequency divider and change the frequency division ratio setting for each operation. In addition, since the switching between charging and discharging can be switched selectively depending on the power failure state or the energized state,
No consideration has been given to the prediction of the remaining amount when charging is performed while the device is operating, that is, charging is performed while discharging.

The present invention has been made in view of the above problems, and with a simple configuration, even when charging while discharging, it is possible to accurately predict the remaining amount of the battery, and with a simple configuration, battery An object of the present invention is to provide a charging device capable of automatically performing rapid charging while preventing overcharging.

Means for Solving the Problems In order to solve the above-mentioned conventional problems, the present invention subtracts a value corresponding to the discharge state of the device from the count value when the timing signal is output from the timing signal generating means. At the same time as the charging state, the value corresponding to the charging current value is added to the count value, and if the count value does not reach the preset charging completion value, quick charging is performed and the charging completion value is reached. In some cases, floating charging is performed.

Effect With the above-described configuration, the present invention can perform proper charging regardless of the battery characteristics and the accuracy of battery voltage detection. Also,
An accurate count value can be maintained even if there are a plurality of discharge states or discharge and charge are performed simultaneously.

Example An example of using the charging device of the present invention in a cordless telephone will be described below.

First, a description will be given based on the block diagram of FIG. In FIG. 1, 1 is a rechargeable battery, 2 is charging current supply means, 3
Is a charging transmission switching means, 4 is a discharging state detecting means, 5 is a charging current detecting means, and 6 is a counting means. The charging current supply line is connected to the battery 1 from the charging current supply means 2 through the charging current switching means 3. The charging current detection means 5 detects the presence or absence of a charging current to the battery 1 and sends the detection signal to the counting means 6. On the other hand, the discharge state detecting means 4 sends the data corresponding to the discharge state of the battery 1 to the counting means 6.

The counting means 6 is in a state where a signal indicating that there is a charging current is coming from the charging current detecting means 5, that is, at the time of charging, only when the count value does not reach the preset charging completion value, the charging current switching means 3 To charge the battery rapidly and add a predetermined value to the present count value. If the charging completion value has already been reached, the charging current switching means 3 is instructed to perform floating charging, and it is not added to the count value.

On the other hand, at the time of discharging, the counting means 6 subtracts the value corresponding to the discharge current value based on the data sent from the discharge state detecting means 4.

The counting means 6 repeats the above processing at a predetermined cycle. Then, during charging, the number corresponding to the charging current value is added in a constant cycle, and during discharging, the number corresponding to the discharging current value is subtracted in the same cycle.
Will indicate the remaining amount of. Then, when the count value does not reach the charge completion value, that is, when it is determined that the battery 1 is not sufficiently charged, the quick charge is commanded, and the command is continued until the count value reaches the charge completion value.

Reference numeral 7 is a timing signal generating means for giving a timing signal to the counting means 6 so as to perform addition or subtraction in a predetermined cycle.

Next, a specific configuration will be described based on the block diagram shown in FIG. In FIG. 2, reference numeral 8 is a base unit of the cordless telephone. Reference numeral 9 denotes a current supply device that converts an AC power supply from a commercial power supply into a DC power supply and supplies the DC power supply as a charging current.
10 and 11 are resistors for limiting the charging current. 12 is a resistor 11
An electronic switch connected to both ends of the resistor 11 short-circuits both ends of the resistor 11 according to a command from the outside. When both ends of the resistor 11 are short-circuited, only the resistor 10 works for limiting the charging current. In this state, the resistor 10 is set so that the charging current has a value for rapid charging. In addition, when both ends of the resistor 11 are not short-circuited, both the resistor 10 and the resistor 11 work to limit the charging current.
Set the value of 11. The above is provided in the base unit 8. 13a and 13b are terminals for charging current provided in the base unit 8, 14
Is also a terminal provided on the base unit 8 and to which a signal for driving the electronic switch 12 is input.

Reference numeral 15 is a child device that can be attached to and detached from the parent device 8. The configuration of the child device 15 will be described below. 16 is a control device equipped with a microprocessor, 17 is a receiver, and 18 is a transmitter. 19 is a rechargeable battery, and a nickel-cadmium battery is used. The battery 19 supplies electric power to the control device 16, the receiver 17, and the transmitter 18. 20
Is a power switch for operating the receiver 17, and 21 is a power switch for operating the transmitter 18. Reference numeral 22 is a signal line for notifying the control device 16 that the power supply voltage has been applied to the receiver 17, and 23 is a signal line for notifying the control device 16 that the power supply voltage has been applied to the transmitter 18.

24 is a diode for blocking the reverse current from the battery 19, which is inserted in series to the charging line to the battery 19. 25a, 25
Reference numeral b is a terminal for connecting the terminals 13a and 13b on the base unit 8 side to conduct 24 a charging current from the base unit 8. 26 is a resistor for extracting a part of the charging current from between the terminal 25a and the diode 24.
It is a line for flowing to 27. Reference numeral 28 is a signal line for transmitting the voltage generated in the resistor 27 to the control device 16 as a signal indicating the presence / absence of charging current. Further, 29 is a signal line for the control device 16 to control the electronic switch 12, and 30 is a terminal at the tip of the signal line 29 which comes into contact with the terminal 14 on the base unit 8 side.

The operation will be described below with reference to FIGS. 3 and 4.
In this embodiment, the control device 16 shown in FIG. 2 controls the electronic switch 12 according to the flow charts shown in FIGS. 3 and 4 to switch the charging current. x is the control device 16
It is a value indicating the remaining amount of the battery 1 stored inside. Q1 is a value corresponding to the discharge current value when the receiver 17 is operating. On the other hand, Q2 is a value corresponding to the discharge current value when the transmitter 18 is operating. Since the power consumption of the transmitter 18 is much larger than that of the receiver 17, Q2 is a value larger than Q1. Also
Qc is a value corresponding to the rapid charging current to the battery 19. Further, M is a value predetermined according to the storage capacity of the battery 19, and the control device 16 determines that the charging of the battery 19 is completed when the value of x becomes equal to M.

a is data transmitted to the control device 16 through the signal line 28 and indicating whether or not the charging current to the battery 19 is present. When the charging voltage is applied from the parent device 8, a charging current flows into the battery 19 and a current also flows into the resistor 27, and a voltage is generated in the resistor 27, so that a = 1. The value of a is 0 when the charging voltage is not applied. Further, b is data for controlling the electronic switch 12 output from the control device 16 and is 1
The electronic switch 12 is short-circuited when, and opened when 0.

c is data that is input to the control device 16 and indicates the operation of the receiver 17, and becomes 1 when the power switch 20 is closed and a power supply voltage is applied to the receiver 17. Also, d is the same control device
This data is input to 16 and indicates the operation of the transmitter 18, and becomes 1 when the power switch 21 is closed and an electrolytic voltage is applied to the transmitter 18.

In FIG. 3, first, when the control device 16 starts operation,
As the value of x, the value of M corresponding to the completion of charging of the battery 19 is stored. Immediately after the operation starts, it is difficult to store an accurate value corresponding to the remaining amount of the battery 19 in x, and even if the battery 19 is not in the charge completed state, the operation is started on the assumption that the battery 19 is in the charge completed state. Do not carelessly perform quick charging.

Next, after a predetermined time T (sec) has elapsed in the delay routine, the routine proceeds to the charging current setting routine shown in FIG. In the charging current setting routine, first, it is determined whether or not the charging current is being supplied. When the slave unit 15 is separated from the master unit or when the commercial power is not applied to the master unit 8, a ≠ 1, so that the process directly returns to the main routine. On the other hand, when the charging current is supplied and a = 1, if x = M already, b is set to 0 and the electronic switch 12
Open, and command to perform floating charging. When a = 1 and x ≠ M, b is set to 1 and
Short the electronic switch 12 to command quick charge, and x
Add Qc to and return to the main routine.

After the above charging current setting routine, the operation state of the receiver 17 and the transmitter 18 is discriminated. The receiver 17 is operating, c
If = 1 then Q1 is subtracted from x. Also transmitter
If 18 operates and d = 1, Q2 is subtracted from x. Then, the process returns to the delay routine again and the time T (se
After the step c), the charging current setting routine starts again.

In the present embodiment, the above processing is repeatedly performed, and addition and subtraction of x are performed every T (sec). That is, since the value Q1 or Q2 corresponding to the discharge current value is subtracted and the value Qc corresponding to the charge current value is added at every predetermined T (sec), the value of x is always stored in the battery 19. It indicates the remaining charge. Then, for example, when the operation of the transmitter 18 is started in the state of x = M and only the transmitter 18 is operated for 30T (sec), the value of x becomes M-30Q2, and the difference between x and M is 30Q2
Indicates the amount of electric charge flowing out from the battery 19 when the transmitter 18 is operated for 30 T (sec). Thus the control device
16 always keeps track of the amount of charge discharged from the battery 19, and charges that amount by rapid charging,
Can recover 19 quickly. Further, the charging in the state of x = M is performed by the floating charging current. Although the performance of the battery 19 deteriorates due to overcharging, when the battery 19 is charged with a small current of a certain value or less, such performance hardly deteriorates. By the way, even when the handset 15 is not used, electric power is required for the control device 16 to operate. Therefore, the value of the floating charging current is set to a value obtained by adding the charging current that does not deteriorate the performance of the battery 19 and the current required to operate the control device 16. Further, as described above, when the operation is started, x = M regardless of the actual remaining amount of the battery 19.
However, since a small charging current always flows in the battery 19, the charging is completed after a certain amount of time.

Advantageous Effects of Invention The present invention subtracts a value corresponding to the discharge state of the device from the count value when the timing signal of the timing signal generating means is output, and at the same time, the value corresponding to the charging current value is obtained in the charging state. In addition to adding to the count value, if the count value does not reach the preset charge completion value, quick charging is performed, and if the count value has reached the charge complete value, floating charging is performed. Proper charging can be performed regardless of the accuracy of battery voltage detection. In addition, even if there are multiple discharge states or if discharge and charge are performed at the same time, it is possible to maintain accurate count values, and even if there are multiple discharge states, increase the number of pulse generation circuits or divide the frequency. There is no need to provide a device, the configuration can be simplified, and proper charging can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram of a charging device in an embodiment of the present invention, FIG. 2 is a block diagram of a cordless telephone device using the charging device, and FIG. 3 is a flowchart showing an operation of the charging device in the cordless telephone device. FIG. 4 is a flowchart showing a subroutine in the flowchart. 1 ... Battery, 2 ... Charging current supply means 3 ... Charging current switching means 4 ... Discharge state detecting means 5 ... Charging current detecting means 6 ... Counting means 7 ... Timing signal generating means

Claims (1)

[Claims] 1. A rechargeable battery, and a charging current supply means,
Charging current switching means for switching the amount of current supplied by the charging current supply means to a rapid charging current value and a floating charging current value, and a suitable charging current switching means for corresponding to the discharging current value of the battery based on the operating state of the device. A discharge state detecting means for outputting data, a charging current detecting means for detecting the presence or absence of a charging current to the battery, a timing signal generating means for generating a timing signal, and an output of the timing signal from the timing generating means. When there is, a counting unit that subtracts the count value according to the data from the discharge state detection unit and adds a count value corresponding to the charging current value if there is a command from the charging current detection unit that there is a charging current. The counting means further issues a command to the charging current switching means to supply a current value for rapid charging when the counted value does not reach the preset charging completion value. , Charging device, characterized in that commanding a floating charging current value in the charging current switching means in a state of reaching the fully charged value.