JPS645414Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of an acoustic coupling device using a battery power source.

Acoustic coupling devices are used for data transmission using telephones, etc., but with the advent of portable data collection devices that use battery power, portable acoustic coupling devices that also use battery power have been developed. It has come to be.

However, with battery-powered acoustic coupling devices, the battery voltage may drop during use, causing the risk that normal operation may no longer be possible.However, when the battery voltage drops below a predetermined value, the device immediately stops operating to prevent malfunction. If the battery voltage drops below a predetermined value, an alarm will be displayed immediately and the transmission will be stopped after a certain period of time. There is a growing demand for an acoustic coupling device that stops operating.

The present invention has the purpose of completely satisfying such conventional demands, and includes a voltage detection circuit that detects when the battery voltage has fallen below a predetermined value, and an alarm indicator that displays an alarm based on the detection output of the voltage detection circuit. By providing a timer that is activated by the detection output of the voltage detection circuit and then stops the operation of the acoustic coupling transmission speaker according to time-up, an alarm is immediately displayed when the battery voltage drops below a predetermined value, and This provides an extremely effective acoustic coupling device that stops transmitting operation after a certain period of time has elapsed.

Hereinafter, details of the present invention will be explained with reference to figures showing embodiments.

FIG. 1 is a block diagram showing the configuration. A microphone M is acoustically coupled to the handset of the telephone set to pick up a received signal, and a speaker SP is acoustically coupled to the handset of the telephone set to transmit a transmitted signal. The output of the microphone M is demodulated by a modulation/demodulation circuit MD and then passed through an interface circuit I/F and input/output I/O to an external device. On the other hand, a signal from an external device that is given to the input/output I/O is passed through the interface circuit I/F to the modulation/demodulation circuit
The signal is applied to the MD, where it is modulated into a carrier wave of audio frequency, then amplified by the transmission amplifier TA, and sent to the speaker SP via the switch circuit SW to drive the speaker SP.

In addition, the sound level sent out from speaker SP is
The maximum level is regulated by telephone line standards, and the level monitoring circuit LW and switch circuit SW are used to stop the operation of the speaker SP when the transmitted sound level increases above this maximum level.
The level monitoring circuit LW constantly monitors the output of the transmitting amplifier TA and detects it when it exceeds a specified level, and uses this detection output to turn off the switch circuit SW and turn off the speaker SP.
It is designed to stop the operation of the

The above are included in a general acoustic coupling device, but in addition to this in Figure 1,
A voltage detection circuit VD, an alarm indicator DP and a timer TM are provided, which allow the voltage of battery B to be
When it is detected that V _B has fallen below a predetermined value, the alarm indicator DP is activated, and after a certain period of time has elapsed, the switch circuit SW is turned off and the operation of the speaker SP is stopped.

In other words, the voltage detection circuit VD detects the voltage of battery B.
When V _B falls below a predetermined value, this is detected and a detection output is generated.This detection output immediately causes the alarm display DP to display an alarm, and the detection output also causes the timer TM to be activated. Each part is configured to start up, control the switch circuit SW based on time-up after a certain period of time, and turn it off.

FIG. 2 is a circuit diagram showing a specific example, in which the transmission amplifier TA is composed of a differential amplifier A and resistors _R1 to _R3 , and a switch circuit SW.
is composed of series resistors R ₄ and R ₅ , a transistor Q whose collector and emitter are inserted between these connection points and the common circuit, and resistors R ₆ and R ₇ for limiting the base current. When the base voltage is “L” (low level), transistor Q is off and the switch circuit SW is on. However, when the base voltage is “H” (high level), the transistor Q is turned off. Q is turned on, and the switch circuit SW is turned off.

In the level monitoring circuit LW, _the battery voltage _VB is stabilized by resistor _R8 and constant voltage diode _ZD1 , and is then
The reference voltage of the comparator _CP1 is set by _RV1 , while the output of the transmission amplifier TA is branched by a capacitor _C1 , detected by a resistor _R10 and a diode _D1 , and the detected output is connected to resistors _R11 and _R12 .
After being smoothed by capacitor _C2 , this voltage is applied to the comparison input of comparator _CP1 . When the output of the transmitting amplifier TA exceeds a specified level, the voltage at the comparison input exceeds the reference voltage, causing the output of comparator _CP1 to change from "L" to "H", turning on transistor Q.

In contrast, in the voltage detection circuit VD, the reference voltage of the comparator CP ₂ is set based on the battery voltage V _B by the resistor R ₁₃ and the constant voltage diode ZD ₂ , while the battery voltage V _B is set by the resistor R ₁₄ The voltage is divided by the variable resistor RV ₂ and given to the comparison input of the comparator CP _2. For example, the constant voltage diode ZD ₂
If the Zener voltage of is 1.2V, and the lower limit of the battery voltage V _B that guarantees normal operation is 4.7 to 5.6V, when this reaches 4.7V, the comparison input voltage of comparator CP ₂ is 1.2V. It is set to be less than or equal to V.

Therefore, if the battery voltage V _B is a predetermined value,
When the voltage drops below 4.7V, the output of the comparator CP ₂ changes from “L” to “H” and the battery voltage is transferred to the light emitting diode LD as the alarm indicator DP via the resistor R ₁₅ .
In order to cut off the current flowing through V _B , the light emitting diode LD dims, thereby reducing the battery voltage.
A message indicating that V _B has fallen below a predetermined value is displayed.

In addition, in the timer TM, the battery voltage V _B
is divided by resistors R ₁₆ and R ₁₇ and comparator CP ₃
On the other hand, the voltage detection circuit VD
When the detection output of becomes “H”, resistor _R18
The terminal voltage of capacitor _C3 , which _is charged via
Assuming that the terminal voltage of capacitor C ₃ reaches the reference voltage or higher after a certain period of time after the detection output of voltage detection circuit VD becomes "H" with respect to the reference voltage when it becomes 4.7V, resistor R ₁₈ and A time constant is determined by capacitor _C3 .

Note that the diode _D2 is used for resetting to quickly discharge the charge in the capacitor _C3 .

For this reason, the timer TM uses the voltage detection circuit VD
The comparator starts up in response to the detection output of
When the output of CP ₃ changes from “L” to “H”, transistor Q turns on and the switch circuit turns on.
SW turns off and speaker SP stops operating.

Therefore, a voltage drop in battery B is immediately indicated by dimming of the light emitting diode LD, an alarm is issued, and the speaker SP stops operating after completing a series of data transmissions, indicating that it is time to replace battery B. In addition to being able to know that a message has arrived, there is no particular problem in data transmission.

However, the same effect can be achieved by using a timer TM that counts clock pulses with a counter, and the set time of the timer TM and the predetermined value of the battery voltage V _B may be determined according to the conditions.
In addition to the light emitting diode LD for power indication, similar results can be obtained by installing a dedicated alarm indicator DP, and the configuration of each part can be freely selected according to the situation, allowing for various modifications. be.

As is clear from the above explanation, according to the present invention, the time for battery replacement is notified and there is no risk of data transmission being interrupted, so that great effects can be obtained in various battery-operated acoustic couplers. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a circuit diagram showing a specific example of the configuration. B...Battery, VD...Voltage detection circuit, TM...
Timer, SW...switch circuit, SP...speaker, DP...alarm indicator.

Claims (1)

[Scope of utility model registration request] In an acoustic coupling device using a battery power source, a voltage detection circuit detects that the battery voltage has decreased below a predetermined value, an alarm indicator responds to the detection output of the voltage detection circuit, and the detection output of the voltage detection circuit 1. An acoustic coupling device comprising: a timer that is activated and stops the operation of the acoustic coupling transmission speaker when time-up occurs.