JP2699865B2 - Power supply system for in-vehicle portable wireless telephone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply system for an in-vehicle portable radio telephone such as a hand-held portable automobile telephone and, more particularly, to a stable power supply voltage when the supply voltage from an in-vehicle battery is drastically reduced. The present invention relates to a power supply system capable of supplying power.

[0002]

2. Description of the Related Art A car-mounted and detachable car phone device such as a hand-held portable car phone is composed of a car antenna, a portable radio telephone, and a car adapter.
The portable wireless telephone includes an antenna, a wireless device, a rechargeable battery, and the like. This portable radio telephone is usually in a vehicle-mounted state, and necessary power is supplied from a vehicle battery (hereinafter referred to as a vehicle-mounted battery). Also, when used off the vehicle adapter, the built-in rechargeable battery will be the power source,
The charging of the rechargeable battery is performed by the power supply voltage of the vehicle-mounted battery when the portable wireless telephone is connected to the vehicle-mounted adapter.

FIG. 3 is a block diagram showing an example of the configuration of a power supply circuit and a charging circuit for a rechargeable battery in this type of conventional mobile telephone device. In FIG. 1, reference numeral 10 denotes a portable radio telephone, reference numeral 20 denotes a power supply circuit system of an in-vehicle adapter, and reference numeral 30 denotes a part of a power supply system of an automobile. In particular, B denotes a vehicle battery, and IGN denotes an ignition switch.

[0004] In the power supply control system of the portable radio telephone 10, reference numeral 11 denotes a rechargeable battery built in the portable radio telephone.
2 is a first power supply circuit for supplying a power supply voltage to each part of the mobile phone, 13 is a power supply switch for switching the connection between the first power supply circuit 11 and either the rechargeable battery 11 or the power supply line 14 from the vehicle adapter, 15 is a power supply line 17
A first voltage detection circuit for detecting whether the portable radio telephone is connected to the vehicle-mounted adapter 20 by detecting the voltage of the
Reference numeral 6 denotes a second voltage detection circuit for detecting the voltage of the ignition power supply line to determine whether the ignition switch IGN is on or off. Reference numeral 18 denotes power supply switching based on signals from the first and second voltage detection circuits 15 and 16. 2 shows a control circuit that controls a switch 13 and a battery power switch 21 provided in the vehicle adapter 20.

In the power supply circuit system 20 of the vehicle-mounted adapter, reference numeral 21 denotes a vehicle-mounted battery B from a charging circuit 23 described later.
And a battery power switch for turning on / off the power supply to the second power supply circuit 22, a second power supply circuit 22 for supplying the power supply voltage from the vehicle-mounted battery as a power supply voltage for the portable wireless telephone, and a power supply switch 23 for controlling the power of the vehicle-mounted battery. Rechargeable battery 11
2 shows a charging circuit for supplying power to a battery.

In this power supply system, when the portable radio telephone 10 is connected to the vehicle adapter 20, the first
The voltage detection circuit 15 detects that the portable wireless telephone 10 has been connected to the vehicle-mounted adapter 20. When the ignition switch IGN is turned on, the second voltage detection circuit 16 detects that the ignition switch is turned on. Based on these detection signals, the control circuit 18 turns on the battery power switch 21 and switches the power switch 13 to the power supply line 14 side. As a result, the electric power of the vehicle-mounted battery B is supplied from the second power supply circuit 22 to the first power supply circuit 12, further supplied to the portable radio telephone 10, and supplied to the rechargeable battery 11 through the charging circuit 23. Charging is performed.

On the other hand, when the portable radio telephone 10 is not connected to the vehicle adapter 20, the first voltage detection circuit 1
5, the control circuit 18 turns off the battery power switch 21 and switches the power supply switch 13 to the rechargeable battery 11, and the rechargeable battery 11
Is supplied to the first power supply circuit 12 and supplied to the mobile wireless telephone 10. In addition, as a technique close to this kind of power supply system, there are techniques described in, for example, JP-A-3-40637 and JP-A-56-138343.

[0008]

In such a conventional power supply system for an in-vehicle portable radio telephone, when the portable radio telephone is connected to an in-vehicle adapter and receiving power from an in-vehicle battery, an engine starts. When a large power load is applied to the on-vehicle battery B, such as when the headlights are turned on, the electromotive voltage of the on-vehicle battery is instantaneously reduced, and the power supply voltage supplied to the portable wireless telephone fluctuates and decreases. The operation of the mobile wireless telephone becomes unstable and malfunctions occur. Also, if the situation is remarkable, the call state may be interrupted.

In general, a portable radio telephone always holds information for maintaining a call state, such as a designated channel and a transmission power level. Therefore, even if the call state cannot be maintained due to an instantaneous drop in power supply voltage, It is configured to be able to return to the call state again based on the held information immediately before the call state. However, in this case, since a predetermined time is required for the return operation based on the information immediately before the call state, it is difficult to avoid a malfunction during that time, and a short-time call disconnection due to a drop in the power supply voltage. Was difficult to avoid.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a power supply system for an in-vehicle portable radio telephone which prevents malfunctions in the radio telephone even when the power supply voltage drops for a short time. Another object of the present invention is to provide a power supply system for an in-vehicle portable radio telephone that can prevent a call disconnection when a short-time drop in power supply voltage occurs.

[0011]

According to the power supply system of the present invention, a portable radio telephone having a built-in rechargeable battery and a power supply circuit and configured to be detachable from a vehicle is provided. In this case, the power supply circuit is separated from a rechargeable battery, connected to a vehicle-mounted battery mounted on a vehicle, and includes a vehicle-mounted adapter having a function of charging the rechargeable battery by the charging circuit. A switch for short-circuiting a circuit, and comparing means for comparing a supply voltage from the on-vehicle battery with a reference voltage. When the comparison means detects that the supply voltage from the on-vehicle battery is lower than the reference voltage, Is turned on for a certain period of time, and the power of the rechargeable battery connected to the charging circuit is supplied to the power supply circuit.

Here, the switch and the comparing means are provided on a vehicle-mounted adapter or provided on a portable radio telephone. Also, a backflow prevention diode is connected between the switch, the charging circuit of the vehicle adapter, and the second power supply circuit.

[0013]

When the voltage of the in-vehicle battery is reduced while the portable radio telephone is connected to the vehicle-mounted adapter, the switch is immediately turned on by the detection signal from the comparison means, and the power supply circuit of the portable radio telephone is connected to the rechargeable battery. Then, the portable wireless telephone is driven by the power of the rechargeable battery. Therefore, irrespective of a decrease in the voltage of the on-vehicle battery, normal operation of the mobile wireless telephone is ensured, and call disconnection is avoided.

[0014]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a first embodiment of the present invention.
In FIG. 1, reference numeral 10 denotes a portable wireless telephone, reference numeral 20 denotes a vehicle-mounted adapter, and reference numeral 30 denotes a part of a power supply system of an automobile. In the power supply system 30 of the vehicle, B is a vehicle-mounted battery, and IGN is an ignition switch.

In the power supply control system of the portable radio telephone 10, reference numeral 11 denotes a rechargeable battery built in the portable radio telephone 10;
Reference numeral 2 denotes a first power supply circuit that supplies a power supply voltage to each unit of the mobile wireless telephone 10. Reference numeral 13 denotes a power supply that switches a connection between the rechargeable battery 11 or a power supply line 14 from an onboard adapter and the first power supply circuit 12. A changeover switch 15 is a first power supply detection circuit for detecting the voltage of the power supply line 17 to determine whether or not the portable radio telephone 10 is connected to the vehicle adapter 20. A detection circuit 16 is for detecting the voltage of the ignition power supply line. A second voltage detection circuit for determining whether an ignition switch IGN is on or off;
And a control circuit for controlling the power switch 13 and the battery power switch 21 provided in the onboard adapter 20 based on signals from the second voltage detection circuits 15 and 16. The power supply control system of the portable radio telephone 10 has the same configuration as that of the conventional one.

In the power supply circuit system 20 of the vehicle-mounted adapter, reference numeral 21 denotes a vehicle-mounted battery B and a charging circuit 23 described later.
And a battery power switch for turning on / off the power supply to the second power supply circuit 22, a second power supply circuit 22 for supplying a supply voltage from the vehicle-mounted battery as a power supply voltage for the portable wireless telephone, and a supply power 23 from the vehicle-mounted battery. A charging circuit for supplying a voltage to the rechargeable battery 11, 24 and 25 are backflow preventing diodes connected to the respective output sides of the charging circuit 23 and the second power supply circuit 22, and 26 is a backflow preventing diode 2
A switch which is connected between outputs 4 and 25 to short-circuit the rechargeable battery 11 and the power supply line 14 from the onboard adapter; 27
Is a voltage comparator that compares the supply voltage from the vehicle-mounted battery B with the reference voltage 29, 28 is a monostable multivibrator that holds the output for a fixed time when the output of the voltage comparator 27 changes, and 29 indicates the reference voltage.

Next, the operation of this embodiment will be described.
When the portable wireless telephone 10 is connected to the vehicle-mounted adapter 20 and the ignition switch IGN is turned on, this state is detected by the first voltage detection circuit 15 and the second voltage detection circuit 16, and the first voltage detection circuit 15 and the second voltage detection circuit 16 In response to a signal from the two-voltage detection circuit 16, the control circuit 18 turns on the battery power switch 21 and
3 is switched to the power supply line 14 side. Therefore, the power of the vehicle-mounted battery B is supplied to the second power supply circuit 22, supplied to the first power supply circuit 12 through the backflow prevention diode 25, and further supplied to the portable wireless telephone. Further, the electric power of the vehicle-mounted battery B is supplied to the charging circuit 23 and supplied to the charging battery 11 through the backflow prevention diode 24, whereby the charging of the charging battery 11 is performed.

When power is supplied from the vehicle-mounted battery B through the vehicle-mounted adapter 20, the supply voltage from the vehicle-mounted battery B is momentarily reduced from the reference voltage 29 by operations such as engine start and headlight lighting. Then, the voltage comparator 27 immediately detects this state based on the comparison with the reference voltage 29 and sends a detection signal to the monostable multivibrator 28. The monostable multivibrator 28 receives this detection signal and turns on the switch 26 for a certain time. As a result, the rechargeable battery 11 is connected to the first power supply circuit 12 through the switch 26 and the changeover switch 13, and as a result, the power from the rechargeable battery 11 is supplied to the portable wireless telephone.

When the operation of the monostable multivibrator 28 for a certain period of time is completed, the voltage of the vehicle battery B is also restored at this time. The portable wireless telephone 10 is operated by receiving the power supply. When the switch 26 is turned on, the charging circuit 23 and the second power supply circuit 22 are connected to the first power supply circuit 1.
Although the circuit is short-circuited to 2, the circuit does not cause any trouble because the backflow prevention diodes 24 and 25 are connected to the respective circuits.

Therefore, even if the supply voltage from the on-vehicle battery B drops momentarily due to the consumption of large power at the time of starting the engine or turning on the headlights, the voltage comparator 2
7 and the operation of the monostable multivibrator 28, the switch 26 is turned on instantaneously, and the power supply voltage of the rechargeable battery 11 built in the portable radio telephone 10 is supplied to the portable radio telephone 10. Is not reduced, and malfunction and disconnection of a call can be prevented.

When the portable radio telephone 10 is not connected to the vehicle adapter 20, the first voltage detection circuit 1
5, the control circuit 18 turns off the battery power switch 21 and switches the power supply switch 13 to the rechargeable battery 11, and the rechargeable battery 11
Is supplied to the first power supply circuit 12 and supplied to the portable wireless telephone. As a result, the portable wireless telephone is supplied with power by the rechargeable battery 11.

FIG. 2 is a block diagram of a second embodiment of the present invention. In this embodiment, portions equivalent to those in the first embodiment are denoted by the same reference numerals. That is, 10 is a portable radio telephone, 20 is a vehicle-mounted adapter, and 30 is a part of a power supply system of an automobile. B is a vehicle battery, and IGN is an ignition switch.

In this embodiment, a rechargeable battery 11, a first power supply circuit 12, a power supply switch 13, a first power supply detection circuit 15, a second voltage detection circuit 16, and a control circuit 18 are provided in the power supply control system 10 of the portable radio telephone. In addition, in the above embodiment, there are provided reverse current blocking diodes 24 and 25, a switch 26, a voltage comparator 27, a monostable multivibrator 28, and a reference power supply 29 provided in the vehicle-mounted adapter 20.
Further, the power supply circuit system of the vehicle-mounted adapter 20 includes a battery power switch 21, a second power supply circuit 22, and a charging circuit 23.

Also in the second embodiment, when the in-vehicle adapter 20 and the portable radio telephone 10 are connected and the ignition switch IGN is turned on, the power of the in-vehicle battery B is supplied to the second power supply circuit 22 and the backflow prevention diode 25, the power is supplied to the first power supply circuit 12, and further supplied to the portable radio telephone 10. Further, the electric power of the vehicle-mounted battery B is supplied to the charging circuit 23, and the reverse current blocking diode 24
Is supplied to the rechargeable battery 11, whereby the rechargeable battery 11 is charged.

At this time, if the supply voltage from the vehicle-mounted battery B falls below the reference voltage 29 for a moment due to operations such as engine start or headlight lighting, the voltage comparator 27 compares the voltage with the reference voltage 29. This state is immediately detected based on the
Is operated, and the switch 26 is turned on for a predetermined time.
As a result, the rechargeable battery 11 is connected to the first power supply circuit 12 through the switch 26 and the power supply switch 13, and as a result, power is supplied to the portable wireless telephone 10 from the rechargeable battery 11. Is the same.

Therefore, even if the supply voltage from the on-vehicle battery B drops momentarily due to the consumption of large power at the time of starting the engine or turning on the headlights, the voltage comparator 2
7 and the operation of the monostable multivibrator 28, the switch 26 is turned on instantaneously, and the power supply voltage of the rechargeable battery 11 built in the portable radio telephone 10 is supplied to the portable radio telephone. It is possible to prevent malfunction and disconnection of the call without lowering.

[0027]

As described above, according to the present invention, when the voltage of the vehicle battery is reduced while the portable radio telephone is connected to the vehicle adapter, the switch circuit is immediately turned on by the detection signal from the comparison means. The portable wireless telephone is connected to a rechargeable battery having a built-in power supply circuit, and the power of the rechargeable battery drives the portable wireless telephone, so that a stable power supply voltage is supplied to the portable wireless telephone regardless of the voltage drop of the onboard battery. Can be maintained. For this reason, even when the supply voltage from the vehicle-mounted battery is momentarily reduced due to the consumption of large power at the time of engine start or headlight lighting, the operation of the vehicle-mounted mobile radiotelephone becomes unstable and malfunctions, This has the effect of preventing the call state from being interrupted.

Here, if the switch circuit and the comparison means are provided in the vehicle-mounted adapter, the effect of the present invention can be obtained by using the conventional portable radio telephone as it is. Conversely, if the switch circuit and the comparison means are provided in the portable radio telephone, the effect of the present invention can be obtained by using the conventional adapter as it is. In addition, by connecting a reverse current blocking diode between the switch circuit and the charging circuit of the vehicle adapter and the second power supply circuit, when the switch circuit is turned on, the reverse current blocking diode is connected to the charging circuit of the vehicle adapter and the second power supply circuit. Problems are prevented from occurring.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of a power supply system according to the present invention.

FIG. 2 is a block diagram of a power supply system according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a conventional power supply system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Mobile radiotelephone 11 Rechargeable battery 12 First power supply circuit 13 Power supply switch 15 First voltage detection circuit 16 Second voltage detection circuit 18 Control circuit 20 In-vehicle adapter 21 Battery power switch 22 Second power supply circuit 23 Charging circuit 24, 25 Backflow Blocking diode 26 switch 27 voltage comparator 28 monostable multivibrator 29 reference voltage 30 car B car battery IGN ignition switch

Claims (5)

(57) [Claims] 1. A portable radio telephone having a built-in rechargeable battery and a power supply circuit and configured to be detachable from a vehicle, and the power supply circuit is separated from the rechargeable battery when the portable radio telephone is mounted on the vehicle. In a power supply system for a vehicle-mounted portable wireless telephone, comprising a vehicle-mounted adapter connected to a vehicle-mounted battery mounted on a vehicle and having a function of charging the rechargeable battery by a charging circuit, the charging circuit and the power supply circuit A switch for short-circuiting, and comparing means for comparing a supply voltage from the vehicle-mounted battery with a reference voltage,
When the comparison unit detects that the supply voltage from the vehicle-mounted battery is lower than the reference voltage, the switch is turned on for a certain period of time to supply the power of the rechargeable battery connected to the charging circuit to the power supply circuit. A power supply system for an in-vehicle portable wireless telephone characterized by having the above-described configuration. 2. The power supply system for a vehicle-mounted portable radio telephone according to claim 1, wherein said switch and said comparison means are provided in a vehicle-mounted adapter. 3. The power supply system for a vehicle-mounted portable wireless telephone according to claim 1, wherein said switch and said comparing means are provided in said portable wireless telephone. 4. The portable radio telephone has switch means for switching a power supply circuit between a rechargeable battery and a second power supply circuit provided in a vehicle-mounted adapter, and the switch is connected so that the switch means can be short-circuited. A power supply system for an on-vehicle portable radio telephone according to claim 2 or 3. 5. The power supply system for a vehicle-mounted portable wireless telephone according to claim 4, wherein a backflow prevention diode is connected between the switch circuit, the charging circuit of the vehicle-mounted adapter, and the second power supply circuit.