JPS5810025B2 - Phone power supply method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a telephone power supply system that supplies power to a load using a rechargeable and dischargeable battery, and in particular, a telephone power supply system that allows various telephone battery charging methods to be selected as required. It is related to.

Some large public telephones with complex functions have a built-in storage battery as an internal power source.

Conventionally, such public telephones perform trickle charging by drawing direct current from the local office line, but since only a small amount of current can flow, the storage battery can be sufficiently charged, but if the telephone is used frequently, the capacity may run out. However, there was a drawback that the voltage dropped and the telephone circuits malfunctioned.

In view of the above points, the present invention has been made to solve such problems and eliminate such drawbacks.The purpose of the present invention is to configure a circuit so that three types of charging methods can be used, and to charge a telephone. By switching the switch to select one of these to charge the storage battery according to the usage condition, it can be adapted to any installation location, and is not limited by installation conditions, and the storage battery can be charged regardless of the usage condition. The present invention provides a telephone power supply system that does not cause a capacity shortage.

The details of the present invention will be explained below using examples.

The figure is a circuit diagram of a charging switching circuit of an embodiment of the telephone power supply system according to the present invention.

In the figure, Ll and R2 are the terminals of the office line, B is the battery power terminal that connects the telephone circuit load, E is the ground terminal, and
l.

X2 is a terminal for connecting an external charging circuit, GSl and GS2 are call switches that operate by hooking off the handset, T is a trickle-only switch that operates when only trickle charging is performed, and Pl and R2 are charged by an external charging power source. When the external charging switch is activated, R1 is a resistor with a high resistance value, and R2 is a resistor with a relatively low resistance value.

Furthermore, 1 is a full-wave rectifier circuit for charging, 2 is a storage battery for a telephone, and 3 is a telephone circuit.

In such a circuit connection, the connection state shown in the figure is the first charging method, that is, the storage battery 2, which can be charged and discharged, is connected to the office line via the resistor R1 and charged with a small current when not making a call, and the above-mentioned resistor is charged when making a call. A trickle floating charging method is shown in which charging is performed by switching from the R1 side to the telephone circuit 3 side and charging using the communication current.

Trickle charging current from the office line enters from terminal L1 and flows to terminal L2 via external charging switch P1, full-wave rectifier circuit 1, external charging switch P2, call switch GS1, and resistor R1.

As a result, the storage battery 2 is charged, but this trickle charging current is suppressed to a level that does not cause the station's AJ relay to operate by increasing the resistance value of the resistor R1, so the charging time can be longer, but the charging current is smaller. .

When the handset of the telephone is removed in this state, the call switch GS1 switches from contact a to contact o.

Note that in this charging method, the call switch GS2 is turned on in conjunction with this, although it is not related to the operation.

As a result, the telephone circuit 3 is connected to the office line and a telephone call is made.

During a call, a large call current of about 20 to 80 mA flows, so this is rectified by the full-wave rectifier circuit 1 and the storage battery 2 is sufficiently charged.

In the case of charging during a call, the reverse voltage from the storage battery 2 enters the circuit in series with the station's DC power supply voltage, so the distance to the station becomes longer by the voltage drop caused by the line impedance. It becomes equivalent to that.

For this reason, if the telephone is located far away from the station, the distance may become even longer, and the conversation may become unclear.

Next, the second charging method is a trickle-only charging method, in which the storage battery 2 is connected to the local office line via the resistor R1 and charged with a small current when not making a call, and the storage battery 2 is short-circuited to be in a non-charging state when making a call. If so, turn on the trickle switch T.

When not talking, the storage battery 2 is charged by the trickle charging current from the office line as described above, and when talking, the talking switch GS1 switches from contact A to contact A and the talking switch GS2 is turned on at the same time, so the full-wave rectifier circuit The battery circuits of storage battery 1 and storage battery 2 are short-circuited.

For this reason, no reverse voltage is applied to the telephone communication circuit, and clear telephone conversations can be made even with a telephone far from the telephone station, but a sufficient amount of charge cannot be obtained because the telephone is not charged with a large telephone current.

In this case, even if the battery circuit is short-circuited, the full-wave rectifier circuit 1
Therefore, the storage battery 2 will not be discharged.

Next, in the case of the third charging method, that is, the external charging method in which the storage battery 2 is charged by an external charging power source, the external charging switch P
1 switches from contact C to contact d, and external charging switch P
2 similarly switches from contact e to contact f in conjunction with this.

As a result, a circuit is closed from the terminal X1 to the terminal X2 via the external charging switch P1, the full-wave rectifier circuit 1, the external charging switch P2, and the resistor R2, and the storage battery 2 is charged from the external charging power source.

Since the resistor R2 has a relatively low resistance value, the charging current can be increased as necessary, so that the storage battery 2 can be charged in a short time.

When the storage battery 2 cannot be sufficiently charged using the two methods described above, it can be charged externally automatically or manually at any time.

In this case, you will not be able to make phone calls while charging.

Note that if you turn on the trickle switch T, you can talk even while charging.

As described above, each of the above three methods has its advantages and disadvantages, so it is possible to select one of them for charging depending on the usage situation of the phone.

That is, a first switch (trickle-only switch T) that switches between the first and second charging methods, and a second switch (external charging switch P1) that instructs the third charging method.
゜P2) allows selection of any charging method.

That is, the trickle floating charging method is suitable for telephones in urban areas because they are frequently used and the call time is long.

These telephones generally have short distances from the central office, so reverse voltage during calls does not pose much of a problem.

In addition, if the battery is used infrequently in rural areas, the trickle-only charging method is suitable because it consumes less current.

Since these telephones are generally located at a long distance from the station, there is a voltage drop due to the line, which causes problems with unclear calls using the trickle/float charging method, but with the trickle-only charging method, reverse voltage is not connected during a call, so this problem occurs. There are no problems.

Furthermore, for telephones that are located far from the station and are frequently used, it is appropriate to charge them using an external charging method in a timely manner using an external charging power source.

As described above, according to the telephone power supply system of the present invention, when not making a call, it is connected to the local office line through a high resistance and charged with a small current, and when making a call, it is switched from the high resistance side to the telephone circuit side and the telephone circuit is charged by the talking current. A first charging method that charges the battery, and a second charging method that connects the battery to a local office line through the high resistance when not making a call and charging with a small current, and short-circuiting the battery circuit to put the battery in a non-charging state when making a call; and a third charging method for charging using an external charging power source, and a first switch for switching between the first and second charging methods, and a second switch for instructing the third charging method to select an arbitrary charging method. By making it possible to select the charging method, the charging method can be adapted to any location where the phone is installed, and there are no restrictions on the installation conditions. This has the effect of preventing malfunctions of the telephone without causing insufficient capacity of the internal storage battery.

It is also extremely effective in that it does not limit the voltage drop of the battery charging circuit, that is, the subscriber line limit.

[Brief explanation of the drawing]

The figure is a circuit diagram of a charging switching circuit of an embodiment of the telephone power supply system according to the present invention. 1...Full-wave rectifier circuit, 2...Storage battery,
3... Telephone circuit, Ll, R2, Xl, X2.
...Terminal, B...Battery power supply terminal, E...
...Ground terminal, GSl, GS2...Telephone switch, T...Trickle switch, Pl
, R2... External charging switch, R1, R2...
····resistance.

Claims (1)

[Claims] 1. In a telephone power supply system that supplies power to the load using a rechargeable and dischargeable battery, when not making a call, the battery is connected to the office line through a high resistance and charged with a small current, and when making a call, the battery is connected to the office line through a high resistance side, and when making a call, the battery is connected to the office line through a high resistance side. The first charging method is to switch to the telephone circuit side and charge using the talking current, and the other is to charge the battery with a small current by connecting it to the office line through the high resistance when not making a call, and short-circuiting the battery and leaving it in a non-charging state when making a call. and a third charging method for charging with an external charging power source, a first switch for switching between the first and second charging methods, and a third charging method for instructing the third charging method. A telephone power supply system characterized in that an arbitrary charging method can be selected using the switch No. 2.