JPH0937343A - Cordless telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cordless telephone set capable of simplifying its circuit configuration and reducing cost by constituting an ID code modulating circuit and a charging current control circuit only with one circuit. SOLUTION: A master set 20 is provided with a power supply circuit 30, an ID writing/charging current controlling circuit 27 for modulating a charging current to a slave set 1 and transmitting an ID code, a charging voltage checking circuit 28 for checking charging voltage, etc., and when the charging terminals 26, 8 of the master set 20 and the slave set 1 are made in contact with each other, a charging current is supplied. The slave set 1 is provided with a chargeable battery 11, an ID detecting circuit 9 for detecting an ID code based upon the level change of the charging current, and so on. When the circuit 28 detects the start of charging, a CPU 29 sends the ID code of the master set 20 to the circuit 27 to modulate the charging current. The circuit 9 in the slave set 1 detects the level change of the charging current and demodulates the ID code.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cordless telephone configured to identify a partner device by wirelessly communicating an identification signal between a master device and a slave device.

[0002]

2. Description of the Related Art In a conventional cordless telephone, a switching transistor is connected between a charging line on the base unit side and the ground, and when writing an ID code to the handset unit, charging of the handset unit side battery is performed in parallel. Then, the transistor is operated based on the ID code of the parent device to modulate the voltage of the charging line, and the ID code is transmitted by reading this voltage change by the child device (Japanese Patent Laid-Open No. 62-20431). Gazette).

FIG. 9 shows a charging current control circuit in a conventional cordless telephone. The parent device includes a transistor 92 for modulating the charging current, a CPU (central processing unit) 91 that drives the transistor 92 based on the ID code, and the like. Further, the slave unit controls the transistor 82 for controlling the charging current, and controls the transistor 82 and detects the change in the charging voltage and reads the ID code C.
It includes a PU 81 and a rechargeable battery 83. The parent device and the child device are provided with charging terminals 93 and 84 which can contact each other.

The CPU 81 of the child device controls the charging mode according to the elapsed time. For example, immediately after the power switch of the parent device is turned on, the charging mode is set to rapid charging, and after a certain period of time, the trickle charging is set. Have control. The charging mode is switched by controlling the conduction of the transistor 82. When the transistor 82 is on, the electric resistance becomes almost 0, and the voltage supplied from the parent device is applied to the battery 83 as it is. This charging mode is called high speed charging.

On the other hand, when the transistor 82 is off,
The supply voltage from the parent device is supplied to the battery 83 in a state where the voltage drops through the bypass resistor 84. This charging mode is called trickle charging.

[0006]

In such a cordless telephone, I is not connected to the main unit side in one charging line.
A transistor 92 for D code modulation exists, and a transistor 82 for charging current control exists on the slave unit side.
Therefore, the circuits having the function of current control are duplicated, leading to power loss and an increase in the number of parts.

An object of the present invention is to provide a cordless telephone in which the circuit for ID code modulation and the charging current control circuit are realized by one circuit to simplify the circuit and reduce the cost.

[0008]

According to the present invention, a rechargeable battery is provided in a slave unit, a power supply circuit for charging the battery is provided in the master unit, and an identification signal is provided between the master unit and the slave unit. In a cordless telephone configured to identify the other device by wirelessly communicating with each other, the battery of the child device is charged while the charging terminal of the parent device and the charging terminal of the child device are in contact with each other. A cordless telephone is also provided with a charging current control circuit for modulating a charging current and transmitting an identification signal to a slave unit, and multivalued and controlling the charging current. Further, the present invention is a cordless telephone characterized by binarizing and controlling the charging current.

According to the present invention, since the ID code modulation circuit and the charging current control circuit can be realized by one circuit,
The power loss, the number of parts, and the manufacturing cost can be reduced.

Further, by switching the charging current into multiple values and controlling it, it is possible to easily realize switching of a plurality of charging modes. Therefore, the charging conditions can be optimized extremely finely, and the life of the battery can be further extended.

Further, by binarizing and controlling the charging current, it is possible to easily realize two charging modes, for example, switching between high speed charging and trickle charging.

[0012]

FIG. 1 is a block diagram showing an embodiment of the present invention. The signal processing system of the master device 20 includes an antenna 22 for transmitting and receiving radio waves from the slave device 1, a receiving circuit 23 for demodulating a signal received by the antenna 22, and a signal for modulating a signal from a voice control circuit 25 to form an antenna. 22 to send signals to the telephone line, and to send signals from the telephone line to the transmission circuit 24.
The audio control circuit 25 for sending to

The power supply system of the master unit 20 modulates the charging current to the slave unit 1 by supplying a constant voltage to the entire master unit and charging the battery 11 of the slave unit 1, and I
An ID writing / charging current control circuit 27 that transmits a D code (identification signal), a charging voltage confirmation circuit 28 that confirms the charging voltage, a CPU (central processing unit) 29 that controls the operation of the entire parent device, and the like. It is configured and the charging terminal 26 on the base unit side
The charging current is supplied when the charging terminal 8 on the slave unit contacts each other.

On the other hand, the signal processing system of the slave unit 1 includes an antenna 2 for transmitting and receiving radio waves from the master unit 20, and an antenna 2.
The receiving circuit 3 that demodulates the signal received in step 1, the transmitting circuit 4 that modulates the signal from the voice control circuit 5 and sends the signal to the antenna 2, the signal from the receiving circuit 3 that is sent to the speaker 6, or from the microphone. The audio control circuit 5 sends a signal to the transmission circuit 4 and the like.

Further, the power supply system of the slave unit 1 is a rechargeable battery 11 connected to the charging terminal 8, an ID detection circuit 9 for detecting an ID code based on the level change of the charging current, and the operation of the entire slave unit. It is composed of a CPU 10 for controlling the.

The cordless telephone configured as described above enables wireless communication while the master unit 20 and the slave unit 1 are separated from each other, while the slave unit when the charging terminals 8 and 26 contact each other. The battery 11 of No. 1 is charged.

The charging voltage confirmation circuit 28 constantly monitors the charging voltage, and when the supply voltage of the charging terminal 26 is a predetermined value or more, it is determined that the charging terminals 8 and 26 are not in contact with each other. If the supply voltage of the charging terminal 26 is less than the predetermined value, it is determined that the charging terminals 8 and 26 are in contact with each other, and the CPU 29 is notified of the charging start detection. CPU 29
When detecting the start of charging, sends the ID code of the master device 20 to the ID writing / charging current control circuit 27.

FIG. 2 is a graph showing the voltage change at the charging terminal 26. FIG. 2A shows before charging is started, and a constant voltage Vo is supplied to the charging terminal 26 from the ID writing / charging current control circuit 27. FIG. 2B shows the state after the start of charging, and the ID writing / charging current control circuit 27 is the CPU.
Based on the ID code from 29, the charging voltage is controlled by two predetermined voltages, that is, a high level H and a low level L, and the charging voltage is supplied to the charging terminal 26.

On the other hand, the ID detection circuit 9 of the slave unit 1 constantly monitors the voltage applied to the charging terminal 8, detects a high level or a low level at regular intervals from the fall of the charging voltage, and the master unit 20 The ID code sent from is demodulated.
The ID code thus detected is sent to the CPU 10 and written in a storage circuit such as a non-volatile memory.

Next, switching control from the ID writing operation to the charging operation will be described. When switching to the normal charging operation after the transfer of the ID code, there are considered a method of controlling by time and b) a method of controlling by the transfer code.

First, regarding the method a), when the charging voltage confirmation circuit 3 detects the start of charging the slave unit 1, the CPU 29
As shown in FIG. 3, the ID code is transmitted within a predetermined period from time t1 to time t2, and the charging operation is switched to after time t2.

Regarding the method b), as shown in FIG. 4, the charging voltage confirmation circuit 2 of the master unit 20 is used to start charging the slave unit 1.
8, the ID code is sent from the parent device 20 to the child device 1, and the ID code detected by the ID detection circuit 9 is detected by the CPU 10.
Send to Then, the child device side notifies the parent device 20 of the receipt of the ID code by means such as wireless communication. Next, when the master unit confirms receipt of the ID of the slave unit, after switching to the charging mode,
Start charging in a predetermined charging mode.

Next, the control of the charging mode during the charging operation will be described. Also in this case, c) a method of controlling by time and d) a method of controlling by a transfer code can be considered.

First, regarding the method c), as shown in FIG. 5, the CPU 29 of the parent device 20 sends out the ID code in a predetermined period from time t1 to time t2, and then charges it with a high level voltage from time t2. Switch to quick charge mode,
From time t3, the trickle charge mode in which the battery is charged with a low level voltage is switched to. In this way, two charging modes can be controlled.

Regarding the method of d), as shown in FIG. 6, the ID code is transmitted during a predetermined period from time t4 to time t5, the low level voltage is held from time t5 to time t6, and the time t6 is maintained. To the time t7, the ID code is sent again. Here, assuming that the leading ID code is "10101010", if the subsequent ID code is set to "11111111", the time t6 to t6.
The average charging voltage of 7 is high. If the subsequent ID code is set to "00000000", the time t6 to t7
The average charging voltage of is low. Further, it is possible to switch between low level and high level during the period from time t5 to t6. Therefore, in the method of d), not only the two modes of the quick charge mode and the trickle charge mode but also the charge mode can be changed almost continuously by controlling the modulation pulse width.

FIG. 7 is a flow chart showing an example of a method of controlling the charging mode with a transfer code, and FIG. 8 is an explanatory diagram showing the operation contents thereof. The variable i is set to the initial value 0 in step s1 of FIG.
The ID code is sent from 0 to the slave unit 1, 1 is added to the variable i in step s3, and steps s2 and s3 are repeated three times until the variable i becomes 3 in step s4. Thus, FIG.
As shown in (a), the ID code is transmitted three times.

Next, in step s5, the variable i is set to an initial value 0, and in step s6, a charging mode switching command is sent, then the charging current control A (for example, quick charging mode) is switched, and in step s7 the variable i is set. 1 is added, and steps s6 and s7 are repeated T times until the variable i reaches the predetermined value T in step s8, and a fixed time elapses. Next, in step s9, the charging current control B (for example, trickle charging mode) is switched. Thus, FIG.
As shown in (b), another charging mode is set after a certain period of time has passed since the ID code was sent.

[0028]

As described above, according to the present invention, since the ID code modulation circuit and the charging current control circuit can be realized by one circuit, the power loss, the number of parts and the manufacturing cost can be reduced. In addition, by switching the charging current into multiple values and controlling it, it is possible to easily realize switching between a plurality of charging modes. Therefore, the charging conditions can be optimized extremely finely, and the life of the battery can be further extended.

Further, by binarizing and controlling the charging current, it is possible to easily realize two charging modes, for example, switching between high speed charging and trickle charging.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a graph showing a voltage change of a charging terminal 26.

FIG. 3 is a graph showing an example of switching control from an ID writing operation to a charging operation.

FIG. 4 is an explanatory diagram showing another example of switching control from an ID writing operation to a charging operation.

FIG. 5 is a graph showing an example of control of a charging mode during a charging operation.

FIG. 6 is a graph showing another example of control of the charging mode during the charging operation.

FIG. 7 is a flowchart showing an example of a method of controlling a charging mode with a transfer code.

8 is an explanatory diagram showing the operation content of FIG. 7. FIG.

FIG. 9 is a diagram showing a charging current control circuit in a conventional cordless telephone.

[Explanation of symbols]

 1 Handset 2, 22 Antenna 3, 23 Reception circuit 4, 24 Transmission circuit 5, 25 Voice control circuit 6 Speaker 7 Microphone 8, 26 Charging terminal 9 ID detection circuit 11 Battery 27 ID writing / charging current control circuit 28 Charging voltage confirmation circuit

Claims (2)

[Claims] 1. A slave unit is provided with a rechargeable battery, a master unit is provided with a power supply circuit for charging the battery, and an identification signal is wirelessly communicated between the master unit and the slave unit. In a cordless telephone configured to identify the device, the battery on the device side is charged and the charging current is modulated while the charging terminal on the device side and the charging terminal on the device side are in contact with each other. A cordless telephone, comprising a charging current control circuit for transmitting an identification signal to a slave, and controlling the charging current by multi-valued control. 2. The cordless telephone according to claim 1, wherein the charging current is binarized and controlled.