JPH03160846A - Cordless telephone system - Google Patents

Abstract

PURPOSE:To detect dirt of a charging terminal and to attain warning display by providing a circuit detecting a contact resistance between charging terminals and a means applying warning display when the detected contact resistance exceeds a prescribed limit to a mobile station. CONSTITUTION:A voltage detection circuit 10 in a mobile station 2 sets conditions such as current consumption of a station 2 different from each product, a current by standby and talking time and a change in the charging current due to a voltage change in the charging battery 3 or the like. Then while a change in the charging current flowing between charging terminals 4, 5 in each case is corrected, a contact resistance 9 between the terminals 4, 5 is calculated from the terminal voltage at the terminal 5. Thus, when the terminal voltage at the terminal 5 exceeds a prescribed limit, that is, the resistance 9 between the terminals 4, 5 exceeds a limit, the circuit 10 lights a light emitting diode 11 and sends a signal. Thus, the diode 11 is lighted and the user recognizes it that the terminals 4, 5 are dirt by observing the lighting and the battery 3 is charged properly by cleaning the terminals 4, 5 to remove the dirt.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a cordless telephone device that uses a rechargeable battery as a power source for a mobile station.

BACKGROUND OF THE INVENTION Conventionally, rechargeable batteries in cordless telephone devices of this type have been charged with a constant charging current determined by a charging current control circuit built into a base station or mobile station.

FIG. 2 shows a schematic configuration of such a conventional cordless telephone device. In FIG. 2, 1 is a base station, 2 is a mobile station, 3 is a rechargeable battery, 4 and 5 are charging terminals for flowing charging current from base station 1 to mobile station 2, and 6 is a charging terminal inside base station 1. 7 is a power supply device such as an AC adapter that supplies power to the base station 1; 8 is a fixed resistor that sets the charging current; and 9 is a contact resistance between the charging terminals 4 and 5.

Next, the operation of the above conventional example will be explained. When the mobile station 2 is placed at a predetermined position of the base station 1, the charging terminals 4 and 5 come into contact, and current flows to the power supply device 7, the charging circuit 6, and the charging terminals 4 and 5, and is controlled by the fixed resistor 8. The battery 3 is charged with a constant charging current.

The same applies when the mobile station 2 is charged by connecting it to a charger such as a dedicated charging stand or a charging adapter.

In this way, even in the above-mentioned conventional cordless telephone device, the rechargeable battery built into the mobile station can be charged by placing the mobile station on or connecting it to a base station or a charger.

Problems to be Solved by the Invention However, in the above-mentioned conventional cordless telephone device, dirt etc. adhere to the charging terminals 4 and 5 provided in the base station 1 and the mobile station 2, respectively, and the contact resistance 9 between the two pieces increases. When this increases, there are problems in that the charging current decreases and it takes a long time to fully charge, or that insufficient charging causes the battery to run out during a call, making it impossible to make a call. If this condition continues, the lubricant stuck to the charging terminals 4 and 5 will
As the contact resistance 9 becomes higher, the charging current finally increases to the 7f# current of the mobile station 2 and the charge current of the mobile station 3.
If the current becomes lower than the sum of the leakage currents, charging becomes impossible. In addition, the increase in contact resistance between the charging terminals 4 and 5 is generally understandable, and since it takes a long time to charge, there is the problem that the battery 3 may be discarded, mistakenly thinking that it has reached the end of its life. there were.

Such a problem also occurs when the battery 3 built into the mobile station 2 is charged with a charger such as a dedicated charging stand or a charger.

The present invention solves these conventional problems.
The second object of the present invention is to provide an excellent cordless telephone device that is capable of detecting dirt on the charging terminal and displaying a warning.

Means for Solving the Problems In order to achieve the object described above, the present invention includes a circuit for detecting a contact resistance value between charging terminals in a mobile station, and a circuit for detecting a contact resistance value between charging terminals when the detected contact resistance value exceeds a certain limit. and a means for displaying a warning.

Operation The present invention has the above-mentioned configuration and can be used as follows.
-1ru. In other words, when the contact resistance increases due to dirt adhering to the charging Z; When the value exceeds a certain limit, this fact is displayed on the police report display means. The user sees or hears this warning display, understands that the charging terminal is dirty, and cleans the charging terminal. As a result, the contact resistance between the charging terminals returns to its original value, the charging current becomes appropriate, and the charging time becomes longer.
This prevents the battery from running out due to insufficient charging.

Embodiment FIG. 1 schematically shows the configuration of an embodiment of the present invention, and the same components as in the conventional example shown in FIG. 2 are given the same reference numerals. In FIG. 1, 1 is a base station, 2 is a mobile station, and 3 is a base station.
1 is a rechargeable battery, 4 and 5 are charging terminals for flowing charging current from base station 1 to mobile station 2, 6 is a charging circuit in base station 1, and 7 is an AC adapter etc. that supplies power to base station 1. In the power supply device, 8 is a fixed resistor that sets the charging current, and 9 is a contact resistance between the charging terminals 4 and 5.

10 is a voltage detection circuit for detecting the contact resistance value 9 between the charging terminals 4 and 5, and 11 is a light emitting diode that displays a warning based on the output from the voltage detection circuit IO.

Next, the operation of the above embodiment will be explained. The inter-terminal voltage of the charging terminal 5 is constantly monitored by the voltage detection circuit 10, and the contact resistance 9 between the charging terminals 4 and 5 is detected from the change in the inter-terminal voltage. When dirt or the like adheres to the charging terminals 4 and/or 5 and the contact resistance 9 between them increases, the voltage between the charging terminals 5 decreases due to a voltage drop, which is detected by the voltage detection circuit 10.

The voltage detection circuit 10 sets conditions regarding the current consumption of the mobile station 2, current values during standby and during talking, and changes in the charging current due to changes in the voltage of the battery 3, etc., which differ for each product, and in each case. , while correcting the change in the value of the charging current flowing between the charging terminals 4 and 5.
The contact resistance 9 between the charging terminals 4 and 5 is determined from the voltage between the terminals. Then, when the voltage between the terminals of the charging terminal 5 exceeds a certain limit, that is, the charging terminal 4
When the contact resistance 9 between 5 and 5 exceeds a certain limit, the detection circuit 10
sends a signal to light the light emitting diode 11. The user sees that the light emitting diode 11 is lit and knows that the charging terminals 4 and 5 are dirty, so the user closes the charging terminals 4 and 5.
Clean it and remove any dirt stuck there. As a result, the contact resistance 9 between the charging terminals 4 and 5 returns to its original value,
The battery 3 can be charged using an appropriate charging current.

In this way, according to the above embodiment, the voltage detection circuit ii81
0 constantly monitors the voltage across the charging terminal 5 while correcting various conditions such as current consumption.
, 5 is detected, and when the value exceeds a certain limit, the light emitting diode 11 is turned on to display a warning, so the user can immediately see if the charging terminals 4 and 5 are occupied. By understanding this, you can clean the charging terminal and restore the charging function.

In the above embodiment, the contact resistance 9 between the charging terminals 4 and 5 is
Although the voltage detection circuit 10 is used as a circuit for detecting the voltage, the same effect can be obtained by providing a current detection circuit for detecting the current flowing through the charging terminal 51 instead.

Further, as the warning display means, various display lamps, buzzers, etc. can be used in addition to the light emitting diode l1.

Effects of the Invention As is clear from the above examples, the present invention has the following effects. In other words, the mobile station is equipped with a circuit that detects the contact resistance value between the charging terminals and a means for displaying a warning when the detected contact resistance value exceeds a certain limit. Even if the contact resistance increases due to dirt on the charging terminals provided, a circuit installed in the mobile station will detect this and will issue a warning display when the contact resistance exceeds a certain limit. This will be displayed, so
The user can see or hear this warning display, understand that the charging terminal is dirty, clean the charging terminal, and restore the charging function to its original state. This eliminates the trouble of cleaning the charging terminal regularly, and the charging current becomes appropriate, so charging time may take longer, or the battery may be thrown away because it is mistaken for a battery, or may be insufficient. It is possible to prevent the battery from running out during a call due to excessive charging.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a charging portion of a cordless telephone device according to an embodiment of the present invention, and FIG. 2 is a schematic block diagram of a charging portion of a conventional cordless telephone device. DESCRIPTION OF SYMBOLS 1... Base station, 2... Mobile station, 3... Rechargeable battery, 4... Base station side charging terminal, 5... Mobile station side charging terminal, 6... Charging circuit, 7... ... Power supply device, 8... Fixed resistor, 9... Contact resistance between charging terminals, 10... Voltage detection circuit (contact resistance detection circuit), l1... Light emitting diode (warning display means).

Claims (1)

[Claims] A base station connected to a telephone line, and a rechargeable battery that is wirelessly connected to the base station and is a built-in power source, contacts its own charging terminal with a charging circuit in the base station or a charging terminal of an independent charger. Alternatively, a mobile station that can be charged by being connected to the mobile station, a circuit provided in the mobile station to detect a contact resistance value between the charging terminals, and a means for displaying a warning when the contact resistance value exceeds a certain limit. A cordless telephone device.