JPH0410299B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an overdischarge prevention circuit for a portable radio or the like used in combination with a power source battery.

Configuration of Conventional Example and Its Problems FIG. 1 is a system diagram of a conventional charging device for a portable wireless device, and this conventional example will be described below.
In Figure 1, A is a power battery, B is a power switch, C is a power control circuit, D is a radio, E is an antenna, F is a press talk switch, G is a portable radio, and H is a portable radio G. I is a portable adapter, a and b are connection terminals of the portable adapter I with the power supply battery A, and c, d, and e are connection terminals of the portable radio G with the portable adapter I.

In the above configuration, power switches B and H are turned on (ON) to supply power to radio device D as a load via power supply control circuit C, and in order to avoid over-discharge, it is necessary to It is necessary to provide an overdischarge prevention circuit. In particular, in such radio equipment, the current consumption during reception is several hundred mA, but when transmitting with the pre-talk switch F turned on, several amperes flow, so the power supply control circuit C
Two types of reference voltages are provided for reception and transmission, respectively, and the output voltage of a power supply battery such as a storage battery is compared with this reference voltage, and when the output voltage of the power supply battery drops below the respective reference voltage, the wireless Although the power supply to the aircraft was stopped, there were many problems as shown below.

(a) It is necessary to prepare two reference voltages, which complicates the circuit configuration and requires a large number of adjustment steps.

(b) Detect whether the radio is in the receiving state or transmitting state by detecting the operating state of the press talk switch F, and input this information to the power supply control circuit C via the connection terminal e, and incorporate it into the power supply control circuit C. The circuit was complicated because it was necessary to switch the comparators.

(c) During transmission, etc., the overdischarge prevention circuit would operate without warning, making calls impossible, making it unsuitable for important communications.

(d) Even if the power switch H in the radio device D is turned off, if one forgets to turn off the power switch B in the power adapter I, there is a drawback that the power of the storage battery is unnecessarily consumed and deteriorated.

Purpose of the Invention The present invention is intended to eliminate the above-mentioned problems of the conventional example, and in particular, to remove a portable radio device such as an in-vehicle radio device that does not have an overdischarge prevention function from a car and install it in a portable case containing a small storage battery. When used as a built-in device, a portable adapter incorporating an over-discharge prevention circuit is inserted between the storage battery and the radio to prevent over-discharge.It has a simple configuration and can also be used as a complete portable radio. The purpose of this invention is to provide a usable overdischarge prevention circuit.

Composition of the Invention In order to achieve the above object, the present invention provides a method for obtaining power ON information of a radio device from the supply terminal voltage of the power supply, and a method for obtaining power OFF information of the radio device from the ON state of the backup current of the radio device. In addition to controlling the supply of power from the power supply, in order to prevent overdischarge, there is a short timer that measures the time for a short time when the battery voltage drops below one reference voltage, and a long timer that integrates the time when the battery voltage drops over a long period of time. A timer is provided, and the timer can be switched between a short timer and a long timer depending on the conditions when the radio is powered on, and an alarm can be generated if necessary when the battery voltage drops, interposed between the storage battery and the radio. This provides the effect of preventing overdischarge of the storage battery.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In Fig. 2, 1 is a power supply battery such as a storage battery used as a power source, 100 is an overdischarge prevention circuit, 200 is a (portable) radio, 2 is a power switch for the radio 200, and 3 is a keep as a current control means. Relay (holding relay), 4 is the contact of keep relay 3, 5a
is the load of the radio device 200, and 5b is the load of the radio device 200.
0 is a memory such as RAM installed inside the radio device to store information that should always be retained, 6 and 7 are diodes for supplying current to the memory 5b, and 8 is a voltage for the backup power supply. The stabilizing circuit stabilizes the supply voltage through the diode 6 even during charging, and supplies a small amount of power to the memory 5b and the like. Reference numeral 9 denotes a current detector for detecting minute currents, which usually consists of a well-known minute current detection circuit such as a transistor or IC, and is supplied with power from the power supply battery 1 via the power line f. When flowing, it is output to the pulse generator 10. (As an example of the configuration of the current detector 9, it is configured with one PNP transistor,
A configuration is known in which the emitter is connected to a power supply line f, the collector is connected to a pulse generator 10 as a load, and the base is connected to a line g. In this case, the base is grounded via wire g, then via power switch 2 and load 5a in the radio device 200 in this order. Therefore, when the switch 2 is closed, a minute current flows in the line g (in the base), and an amplified collector current flows in the collector, which is output to the pulse generator 10. ) 10 is a pulse generator that generates a pulse signal for setting the keep relay 3 based on the output of the current detector 9;
constitutes an ON detection circuit. Reference numeral 11 is a low voltage detection circuit that detects a drop in battery voltage, and is set in advance to a reference point (=E _R ) close to the final voltage of power supply battery 1, and outputs when the output voltage V _O becomes equal to or less than E _R . arise. 12 is a long timer and is usually set to about 5 minutes. The long time timer 12 accumulates time from the time when the low voltage detection circuit 11 operates and outputs an output signal, and outputs an output signal when the timer is up. 13 is a short time timer, contact 4
It starts operating when voltage is applied by turning on the power switch 2, and outputs the output to the switch 14 after about 5 seconds have elapsed. 14 is a switch for the output of the long-term timer 12 and the short-term timer 13, and is composed of, for example, a well-known AND circuit that inputs the output of the short-term timer 13 and the output of the low voltage detection circuit 11. Short timer 1 during supply
3 and the output of the low voltage detection circuit are both high, a pulse is output. Its operation will be detailed below. The short time timer 13 and the switch 14 constitute a short time timer means. Reference numeral 15 denotes an OFF detection circuit for detecting OFF of the power switch 2 of the radio device 200, and has a similar configuration to the ON detection circuit 9. In addition,
The OFF detection circuit 15 is activated by applying voltage from the power supply battery 1 to the power line h, and outputs a pulse when the power switch 2 is turned off. (As an example of the configuration of the OFF detection circuit 15, if the emitter of a PNP transistor is connected to the power supply line h, the OR circuit 16 is connected to the collector, and the base is connected to the diode 7 similarly to the ON detection circuit 9, Similarly, when the base becomes low impedance, it supplies an amplified load current to the collector.) Therefore, the current flowing through the diode 7 is detected and an output pulse is sent to the OR circuit 16.
16 is an OR circuit, which sends a pulse to the reset input e of the keep relay 3 when a pulse is input from any one of the long timer 12, the switch 14, and the OFF detection circuit 15. Releases the ON status and makes it inactive. As a result, the contact 4 of the keep relay 3 is restored from b to c, and the output to the radio 200 is turned off.
A buzzer circuit 17 is connected to the output of the low voltage detection circuit 11.

Next, the operation of the above circuit will be explained.

(a) When starting to supply power to the radio.

When power switch 2 is turned on, current detector 9
detects the current change via line g, outputs a DC output, and further sends a set signal (pulse) from pulse generator 10 to keep relay 3.
At this time, the contact a of the contact 4 of the keep relay 3 is switched from the c side (open end) to the b side, and the power supply battery 1
The power supply voltage E _O (=output voltage V _O ) is sent to the load 5a. Therefore, by turning on the power switch 2, the over-discharge prevention circuit 100 and the radio device 200 are automatically powered on. The power supply voltage E _O at this time is also applied to the detection circuit 11 and the short time timer 13. The subsequent operation is the third one.
As shown in the time charts A to D in the figure, it varies depending on the time and power supply voltage E _O.

In these figures, (a), (b), (c), and (d) respectively indicate the output of the low voltage detection circuit 11, the output of the short-time timer 13, the output of the switch 14, and the operating status of the long-term timer 12. represent.

() Initial operation, when E _O < E _R As shown in Figure 3A, the power supply voltage is high;
Since the low voltage detection circuit 11 does not output, the long timer 12 does not start, and therefore the switch 1
4 also does not output the output pulse of the short time timer 13, so the power supply is intermittent.

() Initial operation, when E _O < E _R As shown in Figure 3B, since the power supply voltage is low from the beginning, the low voltage detection circuit 11 is activated, and therefore the long timer starts and at the same time the short timer 13 starts. will also start. When 5 seconds have elapsed, both the output pulse of the short-time timer 13 and the output of the low voltage detection circuit are input to the switching circuit 14, and as a result, the output pulse is input to the OR circuit 16. Due to the output, the keep relay 3 is activated by the signal input to the reset terminal e, so that the contact 4 switches from B to C, and as a result, the power supply battery 1 is connected to the radio 200 without waiting for the time-up of the long timer 12. Voltage supply is stopped.

() In the case of mid-operation, E _O > E _R As shown in FIG. 3C, while the radio device 200 is in operation, A
The same is true for .

() During operation, when E _O < E _R The power supply voltage changes while power is being supplied to the radio 200.
When E _O falls below the reference voltage E _R , the low voltage detection circuit 11 is activated as shown in FIG. On the other hand, the short-time timer 13 outputs a pulse once after 5 seconds have elapsed, but since it is generally thought that a drop in the power supply voltage occurs after the initial operation (after 5 seconds), at this point it is already
The pulse output in (b) is falling, and as a result, the switch 14 does not output. This results in the operation of the short-time timer being ignored, and after waiting for the time-up of the long-term timer 12, the OR circuit operates as described above and the supply of power supply voltage is stopped. If the load current decreases due to switching from transmission to reception of the radio during the timekeeping operation of the long-term timer 12, the power supply voltage _EO exceeds _ER again and the timekeeping operation of the long-term timer is reset. Therefore, if the power supply battery 1 drops to a level equivalent to the reference voltage during transmission in the conventional example, even if the mode is switched to reception, the power supply voltage will not recover to the reference voltage _ER and the power supply will time out and the power supply will be stopped. become.

As described above, when the power supply switch 2 is turned on, the overdischarge prevention circuit 100 turns off the power when the power supply voltage is low and the short-time timer 13 elapses, but during the power supply, the long-time timer Wait for the period to pass and then turn off the power supply.

Furthermore, when the low voltage detection circuit 11 detects E _O <E _R , it is turned ON only while E _O is decreasing.
The buzzer circuit 17 generates an alarm sound based on this signal to warn of voltage drop. When the voltage is restored, the alarm will also stop.

(b) When stopping the power supply to the radio When the power switch 2 is in the ON state, a high voltage is applied to the voltage stabilizing circuit 8 through the diode 6, while the diode 7 is reverse biased and has a high impedance, that is, it is turned OFF. It's summery. Therefore, there is no current passing through diode 7,
The OFF detection circuit does not operate. Next, when communication is finished and power switch 2 of the radio is turned OFF, diode 6 is turned OFF and diode 7 is turned OFF.
goes from OFF to ON. The OFF detection circuit 15 is
This signal is detected (in the case of the above example, the base current is detected) and a pulse signal is sent to the OR circuit 16. This causes OR circuit 16 to switch to keep relay 3.
A pulse signal is sent to the reset terminal e of the The keep relay 3 is reset as described above by this pulse signal, and the contact a of the changeover switch 4 is
returns from the b side to the c side and stops outputting to the power switch 2 of the load 5a.

As described above, turning off the power switch 2 automatically turns off the power to the radio 200.
It turns OFF.

Note that if the voltage is supplied via the voltage stabilizing circuit 8 and diode 6 for backup of the memory 5b in the radio 200, the current consumption of the built-in storage battery of the radio 200 can be reduced after the overdischarge prevention circuit operates (keep relay). When the contact point 3 is OFF), the power consumption of the battery is kept to a minimum of about several tens of microA, which has the advantage of minimizing the power consumption of the battery and also ensuring the power supply to the memory circuit 5b of the battery.

This embodiment has the above-mentioned configuration, and the configuration is simplified because only one type of reference voltage is required, and there is no need to connect the press talk signal line to the overdischarge prevention circuit and to detect transmission and reception. In addition to the above effects, the following effects can also be obtained.

(a) In the conventional example, when adding the portable adapter I, in order to prevent the consumption of the power supply battery A, the power switch H of the portable radio device G is installed on the portable adapter I and the portable radio device G, respectively. Radio G
If you turn off only the power switch H on the side and forget to turn off the switch B on the portable adapter I, the power of the storage battery may be wasted and deteriorated unnecessarily, but in the configuration of this embodiment, the power switch 2 on the side of the radio This kind of problem does not occur because it only requires Therefore, there is no need for information lines such as press talk buttons, the circuit is simple, and no modification is required to make it portable.

(b) Once power is supplied to the radio device 200, the power supply voltage E _O becomes E _O < E _R with respect to the reference voltage E _R
Until the accumulated time reaches, for example, 5 minutes (long time), it will turn off with a short voltage drop.
Therefore, important communication can be ensured even near the operation threshold of the overdischarge prevention circuit 100.

(c) In conventional overdischarge prevention circuits, when the power supply voltage drops below the standard, transmission may be automatically cut off or reception may be cut off even during a call, but in this embodiment, the E _O during, especially during transmission
When <E _R occurs, an alarm sounds to warn of low battery voltage, which is useful for notifying the other party of the low battery voltage and ending the communication early.

(d) After the over-discharge prevention circuit of the portable adapter I according to the conventional method operates, the over-discharge prevention circuit of the portable adapter I
When I turned on the power switch of the radio, I was unable to receive data or there was no response when I sent a message.
There were times when I mistakenly thought that something had broken down. In the above configuration, after turning on the power, for example, power switch 2 is turned off for about 5 seconds (the time of the short timer).
By turning it ON, it is possible to determine whether the problem is due to a drop in battery voltage or a malfunction in the radio device 200.

Effects of the Invention As is clear from the above embodiments, the present invention has a structure in which the short-time timer and the long-time timer are switched depending on the conditions when the wireless device is powered on. In other words, in the past, two reference voltages were provided for reception and transmission, and the lower reference voltage was used during transmission to extend the transmission time. The above-mentioned conventional method can be improved by distinguishing between the case where the reference voltage is divided from the beginning and the case where the reference voltage is divided during use so that the power supply is not stopped until the predetermined timer period has elapsed. It was made to correspond to the two standard values. This corresponds to time management (timer management) in which a predetermined time of a long-term timer is selected in consideration of the discharge characteristics of the battery. As a result, the in-vehicle radio can be used as a completely portable radio equipped with an overdischarge prevention mechanism, and it also has the effect of simplifying the circuit configuration and reducing the number of adjustment steps.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional wireless device, FIG. 2 is a block diagram of an overdischarge prevention circuit according to an embodiment of the present invention, and FIGS. 3A to 3D are timing charts of the same circuit. 1...Power battery, 2...Power switch, 3...
Keep relay, 4...Contact, 5...Load, 6,7
...Diode, 8...Voltage stabilization circuit, 9...
Current detector, 10...Pulse generator, 11...Low voltage detection circuit, 12...Long time timer, 13...
...Short time timer, 14...Switcher, 15...
OFF detection circuit, 17...buzzer circuit.

Claims (1)

[Claims] 1. Connected between the power supply battery and the load of the radio device via the power switch of the radio device, and controlling the power supply voltage of the power supply battery so that it is applied to the load when set to SET and not applied when set to reset. current control means; an ON detection circuit that detects ON of the power switch and sets the current control means; inputting the output voltage of the current control means and comparing it with a reference voltage; a low-voltage detector that outputs an output from the low-voltage detector; a long-term timer that starts timing when there is an output from the low-voltage detector and waits for a predetermined long period of time to output an output; and a long-term timer that is set to a shorter time than the long-term timer. a short-time timer unit that starts upon application of the output voltage and outputs an output if there is an output from the low-voltage detector after a predetermined short time has elapsed; an OFF detection circuit that detects OFF of the power switch; and a long-time timer unit. , an output of the short-time timer means, and the three outputs of the OFF detection circuit, and an OR circuit that takes the OR of the three outputs and sets the current control means to reset based on the output. .