JP2010045514A - Radio communication device with monitoring function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio communication device with a monitoring function which prevents burning due to overcurrent, using a comparative simple configuration, and at the same time, can solve nonconformities, such as continuing operation of the radio device without noticing abnormal conditions, including inadequate output power, etc. of a power amplifier. <P>SOLUTION: The radio communication device detects currents supplied to a transmission unit or to a receiving unit, discriminates whether the values are within the ranges of upper limit values and lower limit values of the predetermined currents or are out of the ranges, and has a means of reporting this to the user, while the current supplied to the transmission unit or the receiving unit is disconnected , based on the results. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wireless communication device having a monitoring function, and more particularly to a wireless communication device having a function of monitoring and detecting abnormalities in a transmission power amplifier and a receiving unit and promptly notifying a user.

In electronic devices as well as wireless communication devices, in order to prevent excessive current from flowing due to short circuits or abnormalities in electronic components, heat generation, smoke generation, and device burnout are typified. Generally, a protection function such as a current limiting circuit is provided.
As is well known, a fuse is a metal that melts at a relatively low temperature, such as an alloy of lead and tin, shaped into a string or band, and is inserted into a power supply line to an electronic device, and a current exceeding a certain value flows. The power supply to the electronic device is cut off by instantaneously fusing.
FIG. 8 is a block diagram illustrating a main part of a transmission unit of a wireless communication device using a fuse. In FIG. 8, reference numeral 81 denotes a power supply unit, and its output is led to the fuse 83 via the power supply terminal 82 and supplied to the power amplifier 85 via the current detection circuit 84. The current detection circuit 84 generally passes a current to be measured through a circuit (shunt resistor) having a very small resistance value, and calculates a current value that flows based on a voltage (voltage drop value) across the shunt resistor. . In recent years, it is also possible to obtain an integrated circuit that has a very small shunt resistance value, and therefore has little power loss and can accurately detect a current value.
Since the detection signal (voltage or current) corresponding to the detected current value is output from the current detection circuit 84, the detection signal is supplied to the control unit 86, and the power amplifier is set so that the current value becomes constant. The output of 85 is adjusted and guided to the transmission antenna via the output terminal 87 via a transmission filter (not shown). However, even if the output signal of the transmission power is controlled to a constant value in this way, if a failure occurs in the power amplifier 85, an excessive current flows and a burnout accident due to abnormal heat generation occurs. Therefore, the fuse 83 is set to be blown to cut off the supply of current when a current of a certain value or more flows.

In addition, in electronic devices such as portable / portable wireless communication devices, instead of fuses, electronic components (for example, Posister: registered trademark) whose electrical resistance is remarkably increased by heat generated by excessive current may be used. .
Note that, as described in Patent Document 1, in-vehicle wireless communication devices and portable wireless communication devices, the power supply voltage value may differ depending on the use situation. For example, when a portable wireless communication device is used indoors where a commercial power supply (AC power supply) can be used, power is supplied from a stabilized power supply device that converts AC power into a power supply voltage of 12V or a DC voltage of 13.8V. In the case of portable use, the power supply by the built-in battery is often used. However, the battery voltage value may be set to a low value of, for example, about 7.5 V in order to reduce the size. In Patent Document 1, a means for detecting the voltage of the supplied power and a reference for a plurality of power supply voltages so that the wireless communication device can be appropriately operated even when the power supply voltage values are different corresponding to such a situation. There has been proposed a memory device that stores voltage data, reads out the reference voltage data of the memory according to a power supply voltage value supplied thereto, and performs current control based on the reference voltage.
JP 2002-33671 A

However, in the conventional method using the fuse as described above, although a function for limiting excessive current generation is recognized, other power amplifier abnormalities, for example, abnormalities such as a circuit short circuit or a significant decrease in the power amplification function due to defective parts are monitored. There is no function to do. In order to monitor them, another circuit is necessary, which may hinder the cost increase and downsizing of the apparatus. That is, if a means having both an excessive current prevention means and a power amplifier abnormality monitoring function is obtained, it will contribute to both cost reduction and size reduction.
Further, according to the method described in Patent Document 1, it is possible to control the transmission power value to a required value regardless of the selected value of the power supply voltage. However, basically, it is assumed that the power amplifier functions normally. Therefore, in order to detect excessive current detection and power amplification malfunction in those abnormal states, or to actively notify the user of such detection, additional circuits and means are required.
The present invention provides a wireless communication device having a monitoring function capable of detecting abnormalities such as excessive current generation and power amplifier output shortage and reporting the situation to a user with a relatively simple configuration. It is characterized by.

In order to solve such a problem, the present invention provides a current supplied to the transmitter or receiver in a wireless communication device including a power supply terminal, a wireless receiver, and a wireless transmitter. Current detection means for detecting current, threshold holding means for holding signals or data indicating upper and lower threshold values corresponding to the upper limit value and lower limit value of the preset current, and the current value detected by the current detection means A current comparing means for comparing with the value of the threshold holding means, a function judging means for judging whether the transmitting section or the receiving section is normal or abnormal based on an output signal of the current comparing means, and a function judging means And switch means for cutting off a current supplied to the transmission unit or the reception unit according to the output signal.
According to a second aspect of the present invention, in the wireless communication device having the monitoring function according to the first aspect, the transmitter or the receiver is either normal or abnormal based on the output signal of the function judging means. It is characterized by comprising display means for displaying.
According to a third aspect of the present invention, in the wireless communication device having the monitoring function according to the second aspect, the display means is any one of an LED, a liquid crystal display, and a voice announcement means.
According to a fourth aspect of the present invention, in the wireless communication device having the monitoring function according to any one of the first to third aspects, a self-check switch is further simulated when the self-check switch is operated. It includes self-checking means for operating the transmitting unit or the receiving unit to determine whether there is an abnormality and displaying the result.
According to a fifth aspect of the present invention, in the wireless communication device having the monitoring function according to any one of the first to fourth aspects, the current comparing means includes a window comparator circuit or a Zener diode.

  As described above, the present invention detects the current supplied to the transmission unit or the reception unit in the wireless communication device, and whether the value is within the range of the upper limit value and the lower limit value of the preset current or out of the range. Because it is configured to determine whether there is a transmission unit, a reception unit, or both transmission / reception units based on the result, whether the transmission unit or the reception unit is normal or abnormal. It is possible to detect abnormalities. Further, in the event of an abnormality, it is possible to prevent burnout due to heat generation by cutting off the current supplied to the respective block portions. Also, if an abnormality is notified by a screen display, blinking of a lamp such as an LED, an announcement voice from a speaker, etc., it is possible to solve the problem of continuing the operation of the wireless device without noticing the abnormality.

Hereinafter, the present invention will be described in detail using the illustrated embodiments. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. . The same parts and the same matters as those already described are denoted by the same reference numerals and numbers, and redundant description is omitted.
FIG. 1 is a block diagram illustrating a part of a transmission unit of a wireless communication device according to the present invention. The circuit shown in this example supplies the output power of the power supply unit 1 to the transmission power amplifier 5 through the power supply terminal 2, the current detection circuit 3, and the control circuit 4. Further, the current detection signal of the current detection circuit 3 is guided to the comparison circuit 6, and the switch means of the control circuit 4 is controlled based on the output signal of the comparison circuit 6. As the power supply unit 1, various cases such as a stabilized power supply that generates a DC power supply from a commercial power supply, an external power supply such as a vehicle battery, or a built-in battery can be considered. In the case of a wireless communication device dedicated for on-vehicle use, the power supply end is merely provided without including a built-in battery.
The comparison circuit 6 includes a lower limit threshold holding circuit 7 which holds a threshold signal corresponding to a lower limit reference value (lower limit threshold), for example, 0.5 A (ampere), and an upper limit reference value (upper limit threshold), for example, 1.0 A (ampere). A signal is supplied from the upper limit threshold holding circuit 8 in which the threshold signal corresponding to is held. The output signal of the comparison circuit 6 is also supplied to the display 9 and displays the state of the power amplifier 5 as described later based on the comparison result in the comparison circuit 6.

The current detection circuit 3 in this configuration is the same as that described with reference to FIG. 8 and its description is omitted, but the detection signal is compared with the upper limit reference value and the lower limit reference value in the comparison circuit 6. FIG. 2 is a diagram for explaining the situation, and it is normal that the detected current value is a value between the lower limit reference value corresponding to 0.5 A and the upper limit reference value corresponding to the current value 1.0 A. It is judged as a value, and when it deviates from the range, it is judged as an abnormal state. That is, when the upper limit reference value is exceeded, there is a high risk of burnout due to thermal runaway or the like, so it is regarded as abnormal, and the switch circuit (switch means) provided in the control circuit 4 is opened to supply current to the power amplifier 5. Shut off. Further, when the value is equal to or lower than the lower limit reference value, it is determined that the power amplifier 5 is not operating normally, and the current supply to the power amplifier 5 is similarly stopped.
According to this configuration, it is possible to stop the function of the transmitter not only when an excessive current occurs but also when the transmission power is below a normal value. Usually, when only the output below the specified value can be obtained, many unnecessary frequency signal components are often included in addition to the desired signal component, and there is a high risk of interference with other communication devices. It is desirable to stop the function.

  FIG. 3 is a flowchart showing an example of the above-described processing procedure. Although part of the description is duplicated, an example of processing will be described with reference to FIGS. When the PTT switch is pressed, first, the current detection circuit 3 is activated (S1), the output signal is compared with the lower limit reference value (equivalent to 0.5A) in the comparison circuit 6, and the detected current value I is 0.5A or more. It is determined whether or not there is (S2). As a result, if I ≧ 0.5A, it is determined that the operation is normal (S2, Yes), and then compared with the upper limit reference value. As a result of the comparison, when the current value I is equal to or lower than the upper limit reference value (I ≦ 1.0 A), it is determined that the operation of the power amplifier 5 is normal (S3, Yes), and the “operation” of the power amplifier 5 is performed. , The transmission power is output, and the display 9 displays “normal” (S4). On the other hand, in the comparison with the upper limit reference value and the lower limit reference value in the comparison circuit 6, if the reference value is deviated (S2, S3, No), it is determined as an abnormal state, and the switch means of the control circuit 4 Is controlled to cut off the current supply to the power amplifier 5, thereby stopping the operation of the power amplifier 5 and displaying "abnormal" on the screen of the display 9 (S5).

FIG. 4 is a block diagram showing a modified embodiment of a wireless communication device having the monitoring function of the present invention. In the embodiment shown in this example, processing for comparing the detected current value with a threshold value and processing for determining whether the power amplifier 5 is normal or abnormal based on the comparison result are performed by the microprocessing unit (MPU) 10. Therefore, the upper limit threshold data and the lower limit threshold data are held in the memory (device) 11. Further, the MPU 10 is configured to execute processing such as control of the screen display means 12-1, the alarm output means 12-2 by sound, and the LED lamp blinking means for blinking the LED and the lamp as the notification means 12. .
That is, the screen display unit 12-1 performs the display described in the flow S4 and S5 of FIG. 3 on a display unit (not shown), and the alarm output unit 12-2 by voice, for example, “transmitter abnormality. It is equipped with a voice synthesis IC that generates a voice saying "The current is cut off" and "Transmitter is normal", and the necessary voice output signal is selected by the MPU control, and the speaker provided in the receiver (not shown) Output announcements. In addition, in the control of the LED lamp blinking means for blinking the LED and the lamp, the LED and the lamp are caused to blink in a preset manner corresponding to “overcurrent generation”, “transmission abnormality due to insufficient current”, and “transmission stop”. . Any one of these notification means may be provided, or a plurality of means may be provided simultaneously. The notification by blinking the LED may blink a lamp provided for other purposes such as a power lamp.
In the processing by the MPU 10 as in this example, the upper threshold value and the lower threshold value may be recorded as threshold data at a required address of the memory device and read when necessary, but the present invention is limited to a digital one. Without limitation, for example, the upper and lower thresholds can be set and held as analog signals as will be described below with reference to FIGS. Since the analog system has a relatively simple circuit configuration, the digital system or the analog system can be selected as appropriate in consideration of other controls.

FIG. 5 is a block diagram showing another embodiment of the present invention, and shows an example in the case where threshold value holding and current value comparison processing are performed as analog signals, unlike the digital method described above.
That is, the comparison circuit 13 shown in FIG. 5 includes, as means for generating an upper limit reference value (upper limit threshold value) and a lower limit reference value (lower limit threshold value), differential amplifiers (op-amps) 14 and 15, an AND gate 16, a Zener diode 17, 18 is characteristic. As is well known, the Zener diode functions so as to have a constant voltage (Zener voltage) with respect to a reverse voltage of a certain value or more, so that the upper reference is applied to the positive electrodes (+) of the differential amplifiers 14 and 15 as shown in the figure. A value having a Zener voltage of 1.5 V is connected as a value, and a value having a Zener voltage of 0.5 V as a lower limit reference value, and the output signal voltage of the current detection circuit 3 is connected to the negative electrode (−) of each differential amplifier. Supply. According to this configuration, only when the detected current value is 0.5 V or more and 1.5 V or less, the switch means of the control circuit 4 is brought into the contact state (ON state) to supply power to the power amplifier 5, otherwise the current is It can be operated to shut off the supply. Note that the polarity (+, −) of the signal supplied to the control circuit 4 can be changed by selecting a Zener diode connection electrode for the differential amplifier or using a NAND gate instead of the AND gate 16. Since it can change, it can select suitably.

FIG. 6 is a circuit diagram showing another embodiment of the comparison circuit used in the present invention. The comparison circuit 20 of this example also belongs to the analog system, but is characterized in that the upper limit reference value and the lower limit reference value are generated by a resistor circuit without using special electronic components such as a Zener diode. . That is, in FIG. 6, reference numerals 21, 22, and 23 are resistors of 10 kΩ, for example, and a resistor network in which they are connected in series is inserted between the power supply line Vcc and the ground (E). Further, two resistance connection points are connected to required input terminals of two differential amplifiers 24 and 25 connected in cascade as shown in the figure, and the output signal of the current detection circuit is supplied as Vin to the remaining input electrodes. The outputs (V ₀₁ , V ₀₂ ) of these two differential amplifiers 24, 25 are configured to be supplied to the control circuit 4 via the AND gate 26.
In this configuration, if the power supply voltage Vcc is 15V, the two divided voltage values of the resistor network are 5V (Vref1) and 10V (Vref2). Therefore, as shown in FIG. 7, the output voltage (Vout) of the AND gate 26 becomes a high potential only in the range where the output voltage of the current detection circuit corresponds to 5V and 10V. Is turned on / off to control the current supplied to the power amplifier.
In FIG. 7, the vertical axis represents the output voltage Vout of the AND gate 26, the horizontal axis represents the output signal (voltage) Vin of the current detection circuit supplied to the differential amplifiers 24 and 25, and the broken line is set to the lower limit reference value 5V. The output voltage V ₀₁ of the differential amplifier 25 and the solid line are the output voltage V ₀₂ of the differential amplifier 24 supplied with the upper limit reference value 10V.

In the embodiment described above, the case where the abnormality of the power amplifier of the transmission unit is monitored has been exemplified. However, the present invention is not limited to this example and can be applied to the case where each unit of the electronic device is similarly monitored. For example, the normality / abnormality is determined by setting the lower limit reference value and the upper limit reference value based on the current value in the normal state of the receiving unit, and similarly detecting the current value of the receiving unit and comparing it with the threshold value. Is possible.
Moreover, when the user operates the self-check switch and the self-check switch, the transmitter or receiver or other circuit parts are operated in a simulated manner so that the user can check the operation of the electronic device as necessary. In addition, it is possible to determine whether there is an abnormality by comparing the flowing current with a threshold value and to include a self-checking means for displaying the result. At that time, if it is necessary to prevent unnecessary transmission signals from being radiated into the air, a dummy resistor with matched impedance is connected to the output terminal of the power amplifier while the self-check switch is pressed. It is also possible to configure such that. In order to further reduce radio waves leaking to the outside, it is effective to configure the dummy resistor as a coaxial type. Furthermore, in order to prevent an increase in the size of the apparatus by incorporating a dummy resistor, a method of connecting an external dummy resistor to the antenna terminal may be used.

The present invention can be modified in various ways other than those described above. Further, when the power supply voltage value is configured to be adapted to several different values, as proposed in Patent Document 1, the supply voltage value is detected and various setting values stored in the memory are read out. It is also possible to adopt a method of adjusting the bias value of each part. Further, at that time, the upper limit / lower limit reference value (threshold value) in the present invention is also stored in memory corresponding to the supplied voltage value, and when the power supply voltage is changed, the lower limit / upper limit suitable from the memory is stored. It is also possible to read out threshold data.
Furthermore, it is possible to program a process for realizing a wireless communication apparatus having a monitoring function according to the present invention, for example, the flow shown in FIG. 3 according to an OS that can be controlled by a computer. It is possible to control by the same processing method by installing the program in an apparatus provided with a computer. Since many electronic devices in recent years perform considerable processing by a CPU or MPU, it is relatively easy to implement the present invention simply by reading a program or data necessary for executing the processing described above. It will be possible. As a recording medium for storing such a program, a semiconductor medium (for example, ROM, nonvolatile memory card, etc.), an optical medium (for example, DVD, MO, MD, CD, etc.), a magnetic medium (for example, magnetic tape, flexible disk) Etc.).

The block diagram which shows the example of the principal part structure of the radio | wireless communication apparatus which concerns on this invention. 6 is a current chart for explaining the operation of the comparison circuit used in the present invention. The flowchart which shows the example of control of the radio | wireless communication apparatus which concerns on this invention. The principal part block diagram which shows the other example of the radio | wireless communication apparatus which concerns on this invention. The principal part block diagram which shows the other example of the radio | wireless communication apparatus which concerns on this invention. The circuit diagram which shows the other Example of the comparison circuit used in this invention. The signal waveform diagram for demonstrating operation | movement of the comparison circuit used in this invention. The block diagram of the outline | summary of the radio | wireless communication apparatus using the conventional fuse.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Power supply part, 2 Power input terminal, 3 Current detection circuit, 4 Control circuit (switch means), 5 Power amplifier, 6, 13, 20 Comparison circuit, 7 Lower limit reference value (lower limit threshold), 8 Upper limit reference value (upper limit threshold) ), 9 display, 10 MPU (microprocessing unit), 11 memory (threshold value holding means), 12 notification means, 14, 15, 24, 25 differential amplifier, 16 AND gate, 17, 18 Zener diode, 21 to 23 Resistor

Claims (5)

  In a wireless communication device including a power supply end, a wireless receiver, and a wireless transmitter, current detection means for detecting a current supplied to the transmitter or receiver, and corresponding to an upper limit value and a lower limit value of a preset current Threshold holding means for holding signals or data indicating the upper and lower thresholds, current comparison means for comparing the current value detected by the current detection means with the value of the threshold holding means, and an output signal of the current comparison means Based on the function determination means for determining whether the transmission unit or the reception unit is normal or abnormal, and switch means for cutting off the current supplied to the transmission unit or the reception unit by the output signal of the function determination unit, A wireless communication device equipped with a monitoring function.   2. The radio having a monitoring function according to claim 1, further comprising display means for displaying either normality or abnormality of the transmission section or the reception section based on an output signal of the function determination means. Communication machine.   3. The wireless communication apparatus with a monitoring function according to claim 2, wherein the display means is any one of an LED, a liquid crystal display, and an audio announcement means.   The self-check switch according to any one of claims 1 to 3, and when the self-check switch is operated, the transmitter or the receiver is simulated to determine whether there is an abnormality and the result And a self-checking means for displaying a wireless communication device having a monitoring function.   5. The wireless communication device with a monitoring function according to claim 1, wherein the current comparison unit includes a window comparator circuit or a Zener diode.

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