JPH09247076A - Radio communication machine provided with power hit detection function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication machine provided with a power hit detection function which can securely detect hit that power voltage does not completely drop. SOLUTION: A low voltage detector 24 outputs a detection signal becoming an 'H' level when power voltage is higher than a threshold which is previously set and becoming a ground terminal level when it is lower than the threshold. A first flip flop 510 and a second flip flop 520 control a capacitor charge/ discharge gate 530 in a period when the detection signal is the 'H' level and charges a capacitor 560. In the period when the detection signal is the ground terminal level, charging is stopped and the charge of the capacitor 560 is discharged through a diode 580 with the output terminal of the low voltage detector 24 becoming the ground terminal level as a route. When power voltage is restored from hit, the voltage detection gate 570 level-judges the charge voltage of the capacitor 560.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication device having a function of detecting an instantaneous interruption of battery voltage, such as a car telephone device.

[0002]

2. Description of the Related Art For example, an automobile telephone device is connected to an on-vehicle battery via a cable to receive power supply, and can be used for a long time. However, the output voltage of the battery temporarily drops (hereinafter, this voltage drop is referred to as a momentary interruption) at the start of electrical components that require a large amount of power, such as the engine and car air-conditioner The supplied voltage may be lower than the proper operating voltage, and the connection with the base station may be disconnected during a call. In addition, in mobile phones, similar problems may occur due to poor battery contact.

In order to solve such a problem, a car phone and a mobile phone are provided with a power interruption detection circuit for detecting an interruption in order to perform an interruption process according to an interruption time. FIG. 4 is a configuration diagram of a main part of a car telephone device including a conventional power interruption detection circuit. This circuit includes a first flip-flop 501 and a second flip-flop 502. These flip-flops 501 and 502
The same clock is input to both of the D-type flip-flops, and data is input to the D terminals of the flip-flops 501 and 502 from a control circuit (not shown). The Q output of the first flip-flop 501 is
The capacitor charge / discharge gate 503 inputs the Q / output of the second flip-flop 502 (the inverted output of the Q output) to the capacitor charge / discharge gate 503 as a gate opening / closing control signal. The same reset signal is inverted and input to each reset terminal.

The capacitor charging / discharging gate 503 opens and closes the gate according to the level of the gate opening / closing control signal (Q / output of the second flip-flop 502), and the gate opening / closing control signal is at "L" level. Sometimes the gate is opened and when it is at "H" level the gate is closed. The Q output of the first flip-flop 501 that has passed through this gate is
It is input to the anode side terminal of the diode 504, one end of the resistor 505, and the voltage detection gate 507, respectively.

A cathode side terminal of the diode 504 is connected to a power source (Vcc) of an automobile telephone or the like. Resistor 5
The other end of 05 is connected to one end of the capacitor 506.
The other end of the capacitor 506 is grounded.

The voltage detection gate 507 determines whether the voltage of the input signal is above or below a predetermined voltage (hereinafter referred to as a momentary interruption detection level). When the voltage is above the momentary interruption detection level, the "H" level is reached. On the other hand, when it is below the instantaneous interruption detection level, the detection signal of "L" level is output to the above-mentioned control circuit. The control circuit executes the instantaneous interruption process when the "L" level detection signal is input.

The instantaneous interruption detection level is set according to the discharge characteristic of the capacitor 506, and serves as a guide for the duration of the instantaneous interruption. For example, the instantaneous interruption time is 200 [m
s], the capacitor 506, which is completely charged with the proper operating voltage of Vcc, is 200 [m] at 0 [V].
After discharging for [s], the voltage of the capacitor is measured. Then, this measurement result is preset as the above-mentioned instantaneous interruption detection level.

Next, the operation of the power interruption detection circuit configured as described above will be described. In the following explanation,
A case where the appropriate voltage of Vcc is 5 [V] and the instantaneous interruption detection level of the voltage detection gate 507 is 2.4 [V] will be described.

First, when the automobile telephone or the like is normally energized, the Q output of the first flip-flop 501 is set to the "H" level while the second flip-flop 502 is controlled by the control circuit. The Q / output is at "L" level. Therefore, the capacitor charging / discharging gate 5
03 opens the gate and supplies the "H" level Q output to the capacitor 506. This allows the capacitor 50
6 is charged with an appropriate operating voltage of 5 [V].

After the capacitor 506 is charged in this way, when a momentary interruption occurs in which Vcc becomes 0 [V] as shown in FIG. 5, the capacitor 506 starts discharging via the diode 504.

When Vcc recovers from the momentary interruption, the capacitor 506 stops discharging. At the same time, the control circuit sets the gate opening / closing control signal to the “H” level to close the capacitor charging / discharging gate 503, and the voltage detection gate 50.
The potential at the input end of 7 is stabilized.

When the determination result of the voltage detection gate 507 at this time is "H" level, the control circuit considers that the instantaneous interruption time is the predetermined time or less as described above, and then the mobile telephone. The communication state such as is restored to a state where it can be continued.

On the other hand, when the determination result of the voltage detection gate 507 is the "L" level, the control circuit determines that the instantaneous interruption time is longer than a predetermined time (when the connection with the base station is disconnected during a call). There is a high possibility that it has happened) and it is controlled to return to the initial state. As mentioned above,
According to the power interruption detection circuit, it is possible to detect an interruption for a preset time or longer, and the control circuit can quickly shift to the interruption process.

However, in the conventional power supply interruption detection circuit having the above-mentioned configuration, a problem may occur in the case of an interruption in which Vcc does not drop completely. For example, as shown in FIG.
However, even if the connection with the base station is disconnected due to a momentary interruption for a relatively long time, the capacitor 506 has the same voltage as Vcc (3 [V]). ), The voltage detection gate 507 may not detect a momentary interruption.

In order to solve such a problem, a power supply interruption detection circuit as shown in FIG. 7 has been conventionally considered. The power interruption detection circuit shown in this figure is different from the power interruption detection circuit shown in FIG. 4 in that the reset input is not performed to the second flip-flop 502.

Further, the determination result of the low voltage detector 241 is input to the reset input to the first flip-flop 501. The low voltage detector 241 compares the voltage level of Vcc with a preset determination level, and outputs a determination signal according to the comparison result. The determination level is the instantaneous interruption detection level of the voltage detection gate 507 (2.4
[V]).

For example, when the judgment level is set to 4.5 [V], if the voltage level of Vcc is higher than this level, a signal of "H" level is output, and when the voltage is below the judgment level, "H" level signal is output. An L "level (ground level) signal is output to reset the control circuit and the first flip-flop 501.

According to the power interruption detection circuit having such a configuration, when an interruption which is not detected by the voltage detection gate 507 as shown in FIG. 6 occurs, the low voltage detector 241.
Resets the first flip-flop 501, which causes the Q output of the first flip-flop 501 to be “L”.
Level. On the other hand, since the second flip-flop 502 is not reset, the capacitor charge / discharge gate 503
The gate opening / closing control signal of "L" level is continuously output to open the gate.

Then, since the output end of the capacitor charging / discharging gate 503 is at the ground ("L") level, the capacitor 506 can perform discharging according to the instantaneous interruption time by using this as a discharging path. Therefore, by detecting the voltage level of the capacitor 506 after the Vcc voltage is restored, it is possible to detect an instantaneous interruption for a preset time or longer.

However, in the power interruption detection circuit having such a configuration, the first flip-flop 501 and the second flip-flop 502 do not hold the set value when the voltage supplied to the device is lowered. Since it is not guaranteed, it does not always operate as described above, and there is a problem of lack of reliability.

[0021]

In the power interruption detection function of the conventional wireless communication device, in the case of an interruption in which the power supply voltage does not drop completely, the capacitor discharges only up to the lowered power supply voltage. There was a problem that the interruption time could not be detected. Further, in the conventional countermeasures against this problem, there is a problem that the reliability is lacking because the operation which is out of the operation guaranteed range of the power interruption detection function must be relied upon.

The present invention has been made to solve the above problems, and provides a wireless communication device having a power interruption detection function capable of reliably detecting even an interruption in which the power supply voltage does not drop completely. The purpose is to provide.

[0023]

In order to achieve the above object, a wireless communication device having a power interruption detection function according to the present invention includes a capacitor circuit charged by a power supply voltage via a gate circuit, A low-voltage detection circuit that outputs a detection signal to the detection signal line, which becomes the H level when the power supply voltage is higher than a preset threshold value and becomes the ground terminal level when it is below the threshold value, and the low voltage detection circuit. While the detection signal of the circuit is input and the H-level detection signal is output from the low-voltage detection circuit, the gate circuit is turned on to charge the capacitor circuit, and the low-voltage detection circuit outputs the detection signal of the ground terminal level. The gate control circuit that sets the gate circuit to the non-conducting state during the output period to stop the charging of the capacitor circuit and the charging voltage of the capacitor circuit during the charging stop period is low. The discharge circuit for discharging to the ground terminal through the detection signal line of the pressure detection circuit, and the non-conduction state of the gate circuit for a predetermined measurement period from the time when the detection signal of the low voltage detection circuit returns from the ground terminal level to the H level. A circuit for holding the charging circuit and a circuit for measuring the charging voltage value of the capacitor circuit during the period when the gate circuit is held in the non-conducting state by this circuit and determining the instantaneous interruption period of the power supply voltage based on the measured value I configured it.

In the wireless communication device having the power interruption detection function configured as described above, the gate control circuit charges the capacitor circuit while the interruption occurs and the power supply voltage is equal to or lower than the preset threshold value. To stop. Then, during this charging stop period, the discharging circuit discharges the charging voltage of the capacitor circuit to the ground terminal through the detection signal line of the low voltage detecting circuit, and then measures the charging voltage value of the capacitor circuit after discharging. Based on the measured value, the instantaneous interruption period of the power supply voltage is obtained.

Therefore, according to the wireless communication device having the power interruption detection function, even an interruption in which the power supply voltage does not drop completely can be reliably detected and the interruption process can be started.

[0026]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a wireless communication device having a power interruption detection function according to the first embodiment of the present invention.

A radio communication signal sent from a base station (not shown) via a radio communication channel is input to a receiving circuit (RX) 3 via an antenna 1 and an antenna duplexer (DUP) 2, where a frequency synthesizer ( SYN) 4 and the received local oscillation signal are combined and converted into an intermediate frequency signal.

The received intermediate frequency signal is A / D
After being sampled by the converter (A / D) 7, it is input to the digital demodulation circuit (DEM) 6, and the demodulation circuit 6 carries out frame synchronization and bit synchronization and then digitally demodulates it. The synchronization signal obtained by the frame synchronization and the bit synchronization is the control circuit (CONT) 20.
Is supplied to.

The digital demodulation signal output from the digital demodulation circuit 6 includes a digital speech signal and a digital control signal, of which the digital control signal is supplied to the control circuit 20 for identification. On the other hand, the digital speech signal has an error correction decoding circuit (CH-D
The error correction decoding is performed in EC) 8.

The error-correction-decoded digital speech signal is subjected to a decoding process, which will be described later, by a voice decoding circuit (SP-DEC) 9, and further, a D / A converter (D / A).
In A) 10, the analog call signal is returned to the analog call signal, which is then supplied to the speaker 11 and output from the speaker 11.

On the other hand, the transmission signal input from the microphone 12 is sampled by the A / D converter (A / D) 13 and then transmitted through the acoustic echo canceller (AEC) 14 to the voice coding circuit (SP-COD). ) 15 is entered,
It is encoded here.

The encoded digital transmission signal obtained by this encoding is combined with the digital control signal output from the control circuit 20 and the error correction code circuit (CH-COD) 1
After being subjected to error correction coding in 6, it is input to a digital modulation circuit (MOD) 18.

The digital modulation circuit 18 generates a modulation signal corresponding to the coded digital transmission signal, and the modulation signal is converted into an analog signal by the D / A converter (D / A) 17 and then the transmission circuit. (TX) 5 is input.

In the transmission circuit 5, the modulated signal is combined with the transmission local oscillation signal output from the frequency synthesizer 4, converted into a transmission radio frequency signal, and further amplified by the transmission power amplifier. The radio frequency signal output from the transmission circuit 5 is transmitted from the antenna 1 to the base station (not shown) via the antenna duplexer 2.

Reference numeral 21 denotes a console unit (CU) in which a key switch group such as a transmission key, an end key, a dial key and various function keys, a liquid crystal display and the like are arranged.
Reference numeral 2 is a power supply circuit (POW) that generates a desired operating voltage Vcc based on the output voltage of the power supply 23 (such as a vehicle-mounted battery).

The low voltage detector (DET) 24 monitors the voltage level of Vcc and outputs a determination signal according to the voltage level. In addition, the power interruption detection circuit 25 is
It is intended to detect a momentary interruption of power supply from 2.

Hereinafter, referring to FIG. 2, the low voltage detector 24
The power interruption detection circuit 25 will be described in detail.
FIG. 2 is a diagram showing a configuration of the power supply interruption detection circuit 25. The power supply interruption detection circuit 25 includes a first flip-flop 510 and a second flip-flop 520. These flip-flops 510 and 520 are both D-type flip-flops, which hold data input from the control circuit 20 and output it at clock timing.

Further, the Q of the first flip-flop 510 is
The output is input to the capacitor charge / discharge gate 530, and the Q / output of the second flip-flop 520 (the inverted output of the Q output) is input to the capacitor charge / discharge gate 530 as a gate opening / closing control signal. It should be noted that each reset terminal receives a determination signal of a low voltage detector 24, which will be described later, inverted and is connected to a cathode side terminal of a diode 580, which will be described later.

The capacitor charging / discharging gate 530 opens and closes the gate according to the level of the gate opening / closing control signal (Q / output of the second flip-flop 520). When the gate is "L" level, the gate is opened and closed. The gate is closed at "H" level. The Q output of the first flip-flop 510 that has passed through this gate is connected to the anode side terminal of the diode 540, one end of the resistor 550, the voltage detection gate 5
70 and the anode of the diode 580, respectively.

The diode 540 has a cathode side terminal connected to Vcc generated by the power supply circuit 22. The output of the capacitor charging / discharging gate 530 is input to one end of the resistor 550 as described above, while the other end is connected to the capacitor 5
It is connected to one end of 60. The other end of the capacitor 560 is grounded.

The voltage detection gate 570 determines whether the voltage of the input signal is above or below a preset voltage level (hereinafter referred to as an instantaneous interruption detection level). On the other hand, when the detection signal is at "L" level or lower, the detection signal at "L" level is output to the control circuit 20, respectively. On the other hand, the control circuit 20 executes a predetermined instantaneous interruption process when the "L" level detection signal is input.

The instantaneous interruption detection level is set in advance according to the discharge characteristic of the capacitor 560, as in the case of the voltage detection gate 507 described above. Diode 580
As described above, the cathode side terminal is connected to the output terminal of the capacitor charge / discharge gate 530, the anode side terminal is the reset terminal of the first flip-flop 510 and the second flip-flop 520, and the low voltage detector described later. 24
Are connected to the judgment signal output terminals of.

The low voltage detector 24 monitors the voltage level of Vcc, and outputs a determination signal of "H" level (voltage level of Vcc) when the voltage level is higher than a preset determination level and is below the determination level. At the time of, the determination signal of "L" level (ground level) is output. This determination signal is input as a reset signal for the control circuit 20 and the first flip-flop 510 and the second flip-flop 520. The first flip-flop 510 and the second flip-flop 520 are reset by the “L” level determination signal.

Next, the operation of the power interruption detection circuit 25 configured as described above will be described. In the following description, the proper voltage of Vcc is 5 [V], the voltage detection gate 57
The instantaneous interruption detection level of 0 is 2.4 [V], and the low voltage detector 24
The case in which the determination level is 4.5 [V] will be described.

First, when Vcc is at an appropriate voltage and the car telephone or the like is normally energized, the control circuit 20
Control the Q output of the first flip-flop 510 to the “H” level, while the second flip-flop 52
The 0 / Q output is "L" level. Therefore, the capacitor charging / discharging gate 530 opens the gate to supply the “H” level Q output to the capacitor 560. This allows the capacitor 560 to operate at the proper operating voltage 5
It is charged with [V].

After the capacitor 560 is charged in this way, when Vcc drops below 4.5 [V] due to the occurrence of a momentary interruption as shown in FIG. 5 or 6, the low voltage detector 24 outputs " The L "level determination signal is output to reset the first flip-flop 510 and the second flip-flop 520. As a result, the Q / output of the second flip-flop 520 becomes "H" level, the capacitor charging / discharging gate 530 is closed, and the output end of the gate becomes high impedance.

On the other hand, at this time, the capacitor 560 discharges through the diode 580 whose anode terminal is at the ground level according to the "L" level determination signal of the low voltage detector 24 as a path. This discharge has a Vcc of 4.5
This is performed while [V] or less (the determination signal of the low voltage detector 24 is at "L" level).

When Vcc recovers from the instantaneous interruption, the determination signal of the low voltage detector 24 becomes "H" level. On the other hand, the control circuit 20 controls the second flip-flop 520
Is controlled to bring the Q / output to the “H” level, and the output end of the capacitor charge / discharge gate 530 is kept at high impedance for a certain period of time. This stabilizes the potential at the input end of the voltage detection gate 570.

At this time, the potential of the capacitor 560 is determined by the voltage detection gate 570, and when the determination result is "H" level (the potential of the capacitor 560 is larger than 2.4 [V]). Is the control circuit 2
0 is regarded as the momentary interruption time being the predetermined time or less as described above, and the communication state of the car telephone or the like is returned to the state in which the communication state can be continued.

On the other hand, the determination result of the voltage detection gate 570 is "L" level (the potential of the capacitor 560 is 2.
4 [V] or less), the control circuit 20 determines that the instantaneous interruption time is longer than or equal to a predetermined time (there is a high possibility that the connection with the base station has been disconnected during a call). It is considered and controlled to return to the initial state.

As described above, in the power interruption detection circuit, V
Even if there is a momentary interruption such that cc does not fall completely, the reset input from the low voltage detector 24 is used as a path to discharge the capacitor 560 according to the momentary interruption time. Therefore, it is possible to reliably detect even a momentary interruption in which Vcc does not drop completely and continues for a preset time or longer.

Further, the low voltage detector 24 is provided with, for example, a backup function to cope with a decrease in operating voltage, so that it is possible to accurately determine the level. Therefore, it is possible to detect an instantaneous interruption even outside the operation guarantee range of the instantaneous power interruption detection circuit 25.

The present invention is not limited to the above embodiment. For example, the object can also be achieved by the power supply interruption detection circuit 26 using one flip-flop as shown in FIG. 3 instead of the power supply interruption detection circuit 25 described above.

Hereinafter, referring to FIG. 3, the power interruption detection circuit 2
6 will be described. The flip-flop 620 is a D-type flip-flop, which holds the data input from the control circuit 20 at the D terminal, and outputs this data as Q / output at the clock timing. This Q / output is input to the capacitor charge / discharge gate 630 as a gate opening / closing control signal. The reset terminal receives the determination signal of the low voltage detector 24 inverted and also receives a diode 680 described later.
Connected to the cathode side terminal of. Note that the flip-flop 620 is reset by the "L" level determination signal from the low voltage detector 24, like the second flip-flop 620 described above.

Vcc is input to the capacitor charging / discharging gate 630, and a gate opening / closing control signal (flip-flop 62
The gate is opened / closed according to the level of 0 / output), and the gate is opened at the time of “L” level and “H”.
Close the gate when level. V passed through this gate
The cc output is the voltage detection gate 670 at one end of the resistor 650.
And to the anode side terminal of the diode 680, respectively.

The output of the capacitor charging / discharging gate 630 is input to one end of the resistor 650 as described above, while
The other end is connected to one end of the capacitor 660. The other end of the capacitor 660 is grounded.

The voltage detection gate 670 determines whether the voltage of the input signal is above or below the instantaneous interruption detection level as in the case of the voltage detection gate 570 described above. When the detection signal of 1 is below the instantaneous interruption detection level, the detection signal of "L" level is output to the control circuit 20 described above. The instantaneous interruption detection level is set in the same manner as in the case of the voltage detection gate 570 described above.

Next, the operation of the power interruption detection circuit 26 configured as described above will be described. As in the first embodiment described above, the proper voltage of Vcc is 5 [V], the instantaneous interruption detection level of the voltage detection gate 670 is 2.4 [V],
A case where the determination level of the low voltage detector 24 is 4.5 [V] will be described.

First, when Vcc is at an appropriate voltage and the automobile telephone or the like is normally energized, the capacitor charging / discharging gate 630 causes the flip-flop 620 to "L".
It is opened by the level gate opening / closing control signal, and Vcc is supplied to the capacitor 660. This allows the condenser 6
60 is charged.

After the capacitor 660 is charged in this way, when Vcc falls below 4.5 [V] due to the occurrence of the instantaneous interruption as shown in FIG. 5 or 6, the low voltage detector 24 outputs " The determination signal of L ″ level is input to the flip-flop 620 and reset. As a result, the Q / output of the flip-flop 620 becomes the “H” level, the capacitor charging / discharging gate 630 is closed, and the output end of the gate becomes high impedance.

On the other hand, the capacitor 660 discharges through the diode 680 whose anode terminal is at the ground level according to the "L" level determination signal of the low voltage detector 24 as a path. This discharge is performed while Vcc is 4.5 [V] or less (the determination signal of the low voltage detector 24 is "L" level).

When Vcc recovers from the instantaneous interruption, the determination signal of the low voltage detector 24 becomes "H" level. On the other hand, the control circuit 20 controls the flip-flop 620 to set the Q / output to the “H” level and keeps the output end of the capacitor charge / discharge gate 630 at high impedance for a certain period of time. This stabilizes the potential at the input end of the voltage detection gate 670.

At this time, the voltage detection gate 670 determines the potential of the capacitor 660, and the determination result is the "H" level (the potential of the capacitor 660 is larger than 2.4 [V]). The control circuit 2
0 is regarded as the momentary interruption time being the predetermined time or less as described above, and the communication state of the car telephone or the like is returned to the state in which the communication state can be continued.

On the other hand, the determination result of the voltage detection gate 670 is "L" level (the potential of the capacitor 660 is 2.
4 [V] or less), the control circuit 20 determines that the instantaneous interruption time is longer than or equal to a predetermined time (there is a high possibility that the connection with the base station has been disconnected during a call). It is considered and controlled to return to the initial state.

Therefore, as in the first embodiment described above, in the power interruption detection circuit 26, the reset input from the low voltage detector 24 is applied even if the interruption is such that Vcc does not drop completely. The capacitor 660 is discharged according to the instantaneous disconnection time through the path. Therefore, it is possible to reliably detect even a momentary interruption in which Vcc does not drop completely and continues for a preset time or longer.

Further, the low voltage detector 24 is provided with, for example, a backup function to cope with a decrease in operating voltage, so that accurate level determination can be performed. Therefore, it is possible to detect an instantaneous interruption even outside the operation guarantee range of the instantaneous power interruption detection circuit 26.

Further, when Vcc recovers from the momentary interruption, the output terminal of the capacitor charging / discharging gate 630 is kept at a high impedance for a certain period of time to stabilize the potential of the input terminal of the voltage detection gate 670, thereby determining the potential of the capacitor 660. The accuracy is improved.

In the above description, the automobile telephone device has been described as an example, but the present invention is not limited to the automobile telephone device and the portable telephone device, and is applicable to other wireless communication devices. Needless to say. Further, the present invention can be similarly implemented even if various modifications are made without departing from the gist of the invention.

[0069]

As described above, according to the present invention, a low voltage detection circuit, a gate control circuit, and a discharge circuit are newly provided, and an instantaneous interruption occurs and the power supply voltage is set to a preset threshold value. While the voltage is below, discharge the charging voltage of the capacitor circuit to the ground terminal through the detection signal line of the low voltage detection circuit, and then find the power supply voltage interruption period from the charging voltage value of the capacitor circuit after discharging. I am trying.

Further, a circuit for holding the non-conduction state of the gate circuit for a predetermined measurement period from the time when the detection signal of the low voltage detection circuit returns from the ground terminal level to the H level is provided to change the charging voltage value of the capacitor circuit. By detecting in a stable state, the accuracy of detection of instantaneous interruption of the power supply voltage is improved.

Therefore, according to the present invention, it is possible to provide a power interruption detection circuit capable of reliably detecting an interruption even when the power supply voltage does not drop completely and shifting to the interruption processing.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a configuration of a first embodiment of a wireless communication device having a power interruption detection function according to the present invention.

FIG. 2 is a circuit block diagram showing a configuration of a power supply interruption detection circuit shown in FIG.

FIG. 3 is a circuit block diagram showing a configuration of a modified example of the power interruption detection circuit shown in FIG.

FIG. 4 is a circuit block diagram showing a configuration of a conventional power interruption detection circuit of a wireless communication device having a power interruption detection function.

FIG. 5 is a waveform diagram showing a change in power supply voltage when a momentary interruption that completely falls occurs.

FIG. 6 is a waveform diagram showing a change in power supply voltage when a momentary interruption that does not completely fall occurs.

7 is a circuit block diagram showing a configuration of a conventional power supply interruption detection circuit which is an improvement of the power supply interruption detection circuit shown in FIG.

[Explanation of symbols]

 1 ... Antenna 2 ... Antenna duplexer (DUP) 3 ... Reception circuit (RX) 4 ... Frequency synthesizer (SYN) 5 ... Transmission circuit (TX) 6 ... Digital demodulation circuit (DEM) 7 ... A / D converter (A / D) 8 ... Correction decoding circuit (CH-DEC) 9 ... Speech decoding circuit (SP-DEC) 10 ... D / A converter (D / A) 11 ... Speaker 12 ... Microphone 13 ... A / D converter (A / D) 14 ... Acoustic echo canceller (AEC) 15 ... Voice coding circuit (SP-COD) 16 ... Error correction coding circuit (CH-COD) 17 ... D / A converter (D / A) 18 ... Digital modulation circuit (MOD) ) 20 ... Control circuit (CONT) 21 ... Console unit (CU) 22 ... Power supply circuit (POW) 23 ... Power supply 24 ... Low voltage detector (DET) 25, 26 ... Power supply interruption detection circuit 510 ... No. Flip-flop 520 ... second flip-flop 530, 630 ... capacitor charging and discharging the gate 540,580,680 ... diodes 550, 650 ... resistor 560,660 ... capacitor 570,670 ... voltage detection gate 620 ... flip-flop

Claims (1)

[Claims] 1. A capacitor circuit charged by a power supply voltage via a gate circuit, and H when the power supply voltage is higher than a preset threshold value.
A low voltage detection circuit that outputs a detection signal that becomes the ground terminal level to the detection signal line when the level is lower than or equal to the threshold value, and the detection signal of the low voltage detection circuit is input, and the low voltage detection circuit outputs the H level signal. The gate circuit is turned on to charge the capacitor circuit while the detection signal is being output, and the gate circuit is turned off while the ground terminal level detection signal is being output from the low voltage detection circuit. A gate control circuit which is set to a state to stop charging to the capacitor circuit; and a discharge circuit which discharges a charging voltage of the capacitor circuit to a ground terminal via a detection signal line of the low voltage detection circuit during the charging stop period. , The detection signal of the low voltage detection circuit changes from the ground terminal level to H
A circuit that holds the non-conduction state of the gate circuit for a predetermined measurement period from the time when the level is returned to the level, and the charging voltage value of the capacitor circuit is measured by this circuit while the gate circuit is kept non-conduction state. And a circuit for determining the instantaneous interruption period of the power source voltage based on the measured value.