JPS644291Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a power supply circuit for a portable radio using a primary battery such as a dry battery as a power source.

There are many devices such as cordless phones and mobile phones that are powered by batteries. In this type of equipment, if the power supply voltage of the battery drops, satisfactory operation cannot be expected, so it is necessary to promptly replace the battery. At the same time, it is also important to reduce the power consumption of the device and extend the life of the battery. Therefore, in the past, cordless telephones and the like have intermittently performed a standby operation, which is much longer than the call operation, to perform so-called battery saving and reduce the power consumption of the device. However, after performing this battery saving for a long period of time, the power supply voltage of the battery may drop significantly when the call operation is started. At this time, if the device has a voltage drop alarm function, it will instruct the device to replace the battery, and notify it that the device will not operate satisfactorily. However, if you continue to drive the device for phone calls despite the above condition, the battery power supply voltage will recover.
It is known that it can be used again. This phenomenon occurs because zinc that dissolves on the surface of the cathode during light load discharge becomes a zinc compound and accumulates, reducing the discharge reaction surface of the cathode, which increases the internal resistance of the battery during heavy load. This process is explained as a process in which the zinc compound is diffused by the electric current and the internal resistance of the battery decreases. Conventionally, batteries have been replaced without paying attention to this phenomenon, which has been extremely wasteful.
Moreover, the battery's lifespan was incorrectly determined without making full use of the battery's capacity.

This invention was made with attention to the above circumstances,
The purpose of this is to recover the drop in battery voltage of the primary battery due to light load operation by forced discharge of the primary battery in equipment that uses a primary battery as a power source and performs battery saving operation, thereby extending the life of the primary battery. Another object of the present invention is to provide a power supply circuit for a portable radio device that can be used economically.

Hereinafter, a circuit according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic configuration, and numeral 1 indicates a primary battery that functions as a power source. This battery 1 is removably inserted into a battery holder provided in the main body (not shown) of a mobile phone. A transmitting circuit 3 is connected to the battery 1 via a switch 2, and a receiving circuit 5 is connected via a switch 4. These switches 2 and 4 are each controlled to be conductive by a switch control circuit 6. For example, switch 2 is rendered conductive in response to turning on a switch (not shown) when the main unit is in operation for a telephone call, thereby transmitting data. The circuit 3 is energized and a call signal is transmitted. Further, during this call operation, the switch 4 is controlled to be conductive, and thereby the receiving circuit 5 is also energized to receive a telephone signal. During this call operation, the transmitting circuit 3 and the receiving circuit 5 act as a heavy load on the battery 1, and a load current of, for example, several tens of milliamperes flows.

On the other hand, when the main body of the device is in standby mode, the switch 4 is intermittently turned on under the control of the switch control circuit 6. For example, after a pause of 3 seconds, the circuit is turned on for 1 second, and by repeating this, the receiving circuit 5 operates intermittently and waits for reception of a call signal. Battery saving through this standby operation greatly reduces the power consumption of the device, and at this time, the receiving circuit 5 is used as a light load on the battery 1, and a load current of, for example, several milliamperes flows through the receiving circuit 5. Further, a resistor 8 as a pseudo load is connected to the battery 1 via a switch 7.
For this switch 7, a discharge control circuit 10 having a switch control function continuously controls the conduction of the switch 7 for a predetermined period of time, for example, once every hour. That is, the discharge control circuit 10 includes a timer circuit 11
A pulse signal is emitted once every hour, and this is applied to the monostable multivibrator 12 (hereinafter abbreviated as MMV).
As a result, the MMV 12 converts it into a pulse signal with a time width corresponding to the circuit time constant, and applies this pulse signal to the switch 7. Therefore, switch 7 is
In response to the pulse signal from the MMV 12, the conductive state continues for a predetermined period of time. As the switch 7 continues to be conductive for a predetermined period of time, the battery 1 is forcibly discharged via the resistor 8, creating a pseudo heavy load state.

Note that the time counting operation of the timer circuit 11 is performed by a pulse signal from the MMV 12, which is input to the reset terminal of the timer circuit 11 via the OR circuit 13.
Alternatively, it is started at each trailing edge (for example, a falling edge) of the control pulse signal supplied from the switch control circuit 6 to the switch 2. In other words, each time a heavy load operation using the pseudo load is performed after one hour has passed during the light load intermittent operation, and each time a call is actually made and the call ends, the timer circuit 11 is activated. It will be reset and start counting for a new hour.

Thus, according to the circuit with the above configuration, FIG.
As shown in FIG. 3c, the battery 1 is forcibly discharged at predetermined time intervals (for example, every hour) during standby operation to recover the voltage drop caused by the light load intermittent operation. That is, Fig. 2a shows the voltage output of the battery 1, Fig. 2b shows the pulse signal generated from the timer circuit 11, and Fig. 2c shows the voltage output of the battery 1.
Each pulse signal generated by MMV12 is shown. Further, the level indicated by the dashed-dotted line _VL in FIG. 2a indicates the reference voltage value. As shown in FIG. 2, the voltage output of the battery 1 is controlled by the switch 4.
It decreases every time an intermittent conduction operation is performed. It goes without saying that this voltage drop is due to the power supply voltage drop due to the operation of the receiving circuit 5. When the timer output pulse signal is emitted at regular intervals as shown in FIG. It decreases significantly due to the increase in internal resistance during intermittent operation. Then, from time t ₁ in the figure
_{The MMV of T}
An output pulse signal will be emitted. Due to the forced discharge of battery 1 during this period _T
The internal resistance of will decrease and the voltage output will gradually recover. Finally, the voltage is restored to a level that satisfies the normal operation of the device, and the device is put on standby for the next call operation.

As described above, according to the present circuit, it is possible to quickly recover from a drop in the power supply voltage of the battery 1 due to light load intermittent operation of the device. Therefore, the usable life of the battery 1 in equipment can be significantly extended, and economical operation can be achieved. Furthermore, accidents such as insufficient power supply voltage during communication operation of the device can be prevented, and its reliability can be sufficiently ensured. Moreover, as described above, it can be realized by very simple control and by a circuit with a simple configuration, so it has great practicality.

Note that the present invention is not limited to the above embodiments. For example, when battery 1 is forced to discharge,
Recovery of battery voltage, that is, reduction of internal resistance, saturates over time. Therefore, it is possible to detect the battery voltage during discharging and to stop the discharging operation when the rate of change over time becomes equal to or less than a predetermined value. Thereby, it is possible to reliably stop discharging when the battery voltage has sufficiently recovered, and it is possible to prevent wasteful flow of load current after recovery. Note that this case can be easily realized by using an A/D converter, a digital control circuit, and the like. Further, the duration of forced discharge may be variably set each time depending on the magnitude of the battery voltage at the start of discharge. In this case, this can be easily implemented by detecting the voltage at the start of discharge and converting this voltage value into time using a voltage/time conversion circuit. Here, the magnitude of the battery voltage at the start of discharge varies depending on the usage time of the battery, and therefore the time from the start of forced discharge until the voltage recovers varies.

Therefore, as described above, if the discharge time is determined according to the voltage at the start of discharge, efficient voltage recovery can be achieved. Further, in the embodiment described above, forced discharge is performed using the pseudo load (resistor 8), but the switches 2 and 4 may be controlled to be conductive to operate the actual load as a heavy load. As a result, there is no need to newly provide the resistor 8 and the switch 7 as a pseudo load, and the circuit configuration can be simplified. Further, although the above embodiment has been explained using a mobile phone as an example, it is of course applicable to other devices that use the battery 1 as a power source, and the configuration of the pseudo load and the discharge control circuit 10 can be varied. Needless to say, it can be transformed. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

As explained above, according to the present invention, in the power supply circuit of a portable radio device using a primary battery as a power source,
It is possible to recover the drop in battery voltage caused by the special usage condition of intermittent light load operation through forced discharge, thereby extending the battery replacement period and increasing economic efficiency as well as improving the operational reliability of the equipment. Moreover, it is possible to provide a highly practical power supply circuit for a portable radio device that can implement this with a simple configuration.

[Brief explanation of the drawing]

FIG. 1 is a schematic circuit configuration diagram showing an embodiment of the present invention, and FIGS. 2 a to 2 c are operational waveform diagrams showing the operation of the embodiment circuit. 1...Primary battery (battery), 2, 4...Switch,
3... Transmission circuit, 5... Receiving circuit, 6... Switch control circuit, 7... Switch, 8... Resistor (pseudo load), 10... Discharge control circuit, 11... Timer circuit, 12... Monos Table multivibrator (MMV), 13...OR circuit.

Claims (1)

[Claims for Utility Model Registration] (1) A battery power source consisting of a primary battery is provided, and the output voltage of this battery power source is continuously supplied to the transmitting circuit and the receiving circuit during communication, and only to the receiving circuit during non-communication. In a power supply circuit for a portable wireless device that is intermittently supplied to a power source, a pseudo load having an impedance comparable to the combined impedance of the transmitting circuit and the receiving circuit during communication, and a method for connecting this pseudo load to the battery power source. a switch, and a switch control circuit for forcibly discharging the battery power source via the pseudo load by turning on the switch for a predetermined period at a cycle sufficiently longer than the cycle of intermittent power supply operation to the receiving circuit when there is no communication. A power supply circuit for a portable radio device, characterized by the following: (2) Utility model registration claim (1), characterized in that the switch control circuit continues forced discharge only for a period of time until the time rate of change of the battery power supply voltage during forced discharge becomes equal to or less than a predetermined value. Power supply circuit for the portable radio device described. (3) The portable device according to claim 1, wherein the switch control circuit variably sets the duration of forced discharge depending on the magnitude of the battery power supply voltage at the start of discharge. Radio power supply circuit.