JPS6238627A - Battery-driven transmitter and receiver - Google Patents

Abstract

PURPOSE:To detect accurately the service life of a battery by catching the increase in the internal resistor of the battery as a change in a voltage by a large current flowing at transmission. CONSTITUTION:A battery 1 energizes normally only a part of a reception circuit 4 and a control circuit 3 composing of a device such as a microcomputer. In the reception state, a current consumption, that is, a current flowing to the battery 1 is minimized. Then, a control switch 31 controlled by the control circuit 3 is opened and a battery voltage detector 2 is not operated. When a transmitter/receiver is in the transmission state and a transmission circuit 5 is operated by a transmission instruction from the control section 3, a larger current in comparison with that at the reception is consumed. In this case, the control circuit 3 brings the control switch 31 in the connection state, the voltage detection circuit 2 is activated to compare the battery voltage V2 with a preset reference voltage V5. When the battery voltage V2 is lowered than the reference voltage Vs, the output of the voltage detection circuit 2 drives the control circuit 3 so as to superimpose the battery replacement signal on the normal communication signal for transmission.

Description

[Detailed description of the invention] [Field of application of the invention] The present invention relates to a transmitter/receiver that operates on a battery.

In particular, the present invention relates to a battery operated transceiver suitable for measuring the life of its battery.

[Background of the invention]

In a transmitter/receiver that operates on a battery, it is essential to avoid the device becoming inoperable near the end of its battery life. Before the battery life runs out.

It is also desirable to indicate battery replacement. Incidentally, related conventional devices of this type include, for example, Japanese Utility Model Application No. 51-59818.

[Purpose of the invention]

The purpose of the present invention is to suitably shorten the battery life of the battery during transmission.
An object of the present invention is to provide a battery-operated transceiver that has a high level of performance.

[Summary of the invention]

By focusing on the relationship between battery life and the increase in internal resistance of the battery, we have made it possible to detect the battery life more effectively by capturing the increase in internal resistance of the battery as a change in voltage due to the large current flowing during transmission. It's what I did.

[Embodiments of the invention]

First, the present invention will be explained in detail. In a transmitter/receiver operated by a battery, only the receiving circuit and its related circuits are normally operated to function as a receiver. In this receiving state, the current consumption is as low as possible in consideration of battery life. Here, the current consumption during this receiving operation state is denoted by , and the battery voltage at that time is denoted by .

Next, when the two devices enter the transmitting state, the current consumption at that time is I21, and the battery voltage is v2. Since the transmission power is much larger than in the receiving A8 state, l I
2 has a much larger value than ■.

In order to explain the principle of the present invention more clearly, let E be the open voltage of the battery, and r be the internal resistance of the battery. Therefore, the following formula holds.

V = E-1. r ・・・・・・・・・(1) V2=E
-I2r-(2) FIG. 2 illustrates these relationships.

As shown in FIG. 2, it is a general characteristic of batteries that the internal resistance r increases as the battery is used, that is, as the battery life ends.

The battery life is detected by detecting this increase in internal resistance as a voltage change by passing a large current 2 through the battery.

In other words, since ■□ is minute compared to I2, equation (1) becomes V, = E - I, r = E - (3), and the battery operating voltage depends on the battery internal resistance r. , not really relevant. However, since I2 in equation (2) is a much larger current than □ can be detected as an even larger change in the ratio.

The present invention is an application of the above principle, and detects the battery voltage 2 during large current consumption only during transmission, and detects the preset reference voltage V.
The following two embodiments of the present invention will be described with reference to FIG. 1, in which the battery life can be more suitably detected through comparative evaluation with s. Fig. 1 shows a battery-operated transceiver (FF) machine that operates on a battery 1. Normally, only a receiving circuit 4 and a part of a control circuit 3 such as a microcomputer are operated to function as a receiver. In the reception state, the current consumption, that is, the current flowing through the battery 1, is operated with as little current as possible in consideration of battery life.In this state, the control switch 31 controlled by the control circuit 3 is open. , the battery voltage detector is not working.

Next, the control circuit 3 is controlled by the received signal inputted from the antenna 6, or the transceiver is switched to a transmitting state by a command unique to the control circuit 3. Transmission/reception (The li machine enters the transmitting state, and the transmitter a circuit 5 is activated by a transmission instruction from the control 3.

Transmission power is radiated from antenna 6. A larger current is consumed when transmitting power is radiated compared to when receiving power. Also, at the time of this large current consumption, the control switch 31 is brought into a connected state by the control circuit 3, and the voltage detection circuit 2 is operated to compare the battery voltage v2 with a preset reference voltage V. When the battery voltage 2 becomes lower than the reference voltage Vs, the output of the voltage detection circuit 2 drives the control circuit 3 and converts the battery replacement signal into a normal communication signal to generate an alarm instructing battery replacement. Superimpose and send. Note that this transmitted battery replacement signal is received by another receiver and used to generate an alarm.

〔Effect of the invention〕

According to the present invention, since it is possible to more accurately capture the battery voltage change value as the battery usage time elapses during transmission, there is an effect that the detection of the battery life becomes more accurate.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a battery-powered transmitter/receiver for explaining an embodiment of the present invention, and FIG. 2 is a characteristic curve of battery voltage with respect to battery usage time, and a battery voltage characteristic curve for explaining the present invention in detail. This is an internal characteristic curve. 1... Battery 2... Battery voltage detection circuit 3... Control circuit using a microcomputer etc. 4... Receiving circuit 5... Transmitting circuit 6... Receiving antenna 7... Transmitting antenna

Claims (1)

[Claims] A battery-operated transmitter-receiver, characterized in that the transmitter-receiver operates on a battery, and is further provided with a detection means for detecting a change in battery voltage due to large current consumption during transmission and comparing it with a set reference voltage.