TWI692210B - Communication device - Google Patents

Abstract

A communication device is provided. The communication device includes a receiving unit and a transmitting unit. Receiving unit generates a step-down communication command according to a first communication command from another communication device, and generates a PWM signal according to the step-down communication command, and decodes the PWM signal to generate a decoded signal. The transmitting unit includes an operational amplifier and a switch circuit. The operational amplifier generates a turn-on signal according to a voltage signal. The operational amplifier includes a positive terminal, a negative terminal, and an output terminal coupled to the negative terminal. The switch circuit is coupled between the negative terminal and the output terminal. The switch circuit is turned on according to the turn-on signal and when the switch circuit is turned on, the switch circuit generates a current signal as a second communication command according to the voltage signal.

Description

Communication device

The invention relates to a communication device, and particularly a communication device suitable for a fire protection system.

Traditionally, communication devices often use capacitors to convert voltages to decode communication commands received by the communication devices. However, using capacitors to convert voltages is prone to unstable voltages after conversion, resulting in decoding failures and communication failures. In addition, communication devices usually only have the function of receiving and sending signals but no other functions. The communication device has a single function and it is difficult to support different product applications. Furthermore, the conventional communication devices often use many components, which causes complicated components. When the communication device fails, it is difficult for the maintenance personnel to detect the cause of the failure.

The invention provides a communication device including a receiving unit and a sending unit. The receiving unit is used for receiving a first communication command from another communication device and generating the first communication command after the voltage reduction, and generating a pulse width modulation signal according to the first communication command after the voltage reduction, and adjusting according to the pulse width The pulse width of the variable signal at the high level and the pulse width at the low level decode the pulse width modulation signal to generate a decoded signal. The sending unit includes an operational amplifier and a switching circuit. The operational amplifier is used to generate a pilot signal according to the voltage signal. The operational amplifier includes a positive input terminal, a negative input terminal, and an output terminal coupled to the negative input terminal. The positive input terminal receives the aforementioned voltage signal, and the output terminal outputs the aforementioned pilot signal. The switch circuit is coupled to the negative input terminal of the operational amplifier and the input Between the output terminals, the switch circuit is turned on according to the conduction signal and generates a current signal according to the voltage signal when turned on as a second communication command to output to another communication device.

The invention provides a receiving unit, which includes a voltage divider circuit, a digital analog converter, a comparison circuit and a calculation circuit. The voltage dividing circuit is used to receive the communication command from the communication device, and perform voltage division conversion on the communication command to generate the communication command after the voltage reduction. The digital-to-analog converter is used to generate a reference voltage according to a digital signal. The comparison circuit is used to compare the reference voltage and the communication command after step-down to generate a pulse width modulation signal. The calculation circuit is used to calculate the pulse width of the pulse width modulation signal at the high level and the pulse width of the pulse width modulation signal at the low level to generate the decoded signal.

The invention provides a transmission unit, which includes a digital analog converter, an operational amplifier and a switch circuit. The digital-to-analog converter is used to generate a voltage signal according to a digital signal. The operational amplifier is used to generate a pilot signal according to the voltage signal. The operational amplifier includes a positive input terminal, a negative input terminal, and an output terminal. The positive input terminal receives the aforementioned voltage signal, the output terminal is coupled to the negative input terminal, and the output terminal outputs the aforementioned pilot signal. The switch circuit is coupled between the negative input terminal and the output terminal to form a negative feedback line. The switch circuit is turned on according to the conduction signal and generates a current signal according to the voltage signal during the conduction as a communication command and output to the communication device.

1: communication device

11: receiving unit

111: voltage divider circuit

C: connection point

R1: first resistance

R2: second resistance

112: The first digital analog converter

113: Comparison circuit

114: Computing circuit

12: sending unit

121: Operational amplifier

1211: Positive input

1212: Negative input

1213: output

122: switch circuit

G: gate extreme

D: Ji extreme

S: source extreme

123: Second digital analog converter

124: The first multiplexer

125: second multiplexer

126: Switch

127: load

128: Analog to digital converter

13: input and output lines

15: Controller

2: Communication device

3: Power line

4: Ground line

C: connection point

C1: Control signal

C2: Control signal

C3: Control signal

D1: the first digital signal

D2: Second digital signal

V1: voltage signal

V2: reference voltage

S1: The first communication command

S2: Second communication instruction

S3: PWM signal

S4: Decode the signal

S5: guide communication number

Fig. 1 is a block diagram of an embodiment of a communication device according to this case.

[FIG. 2] It is a circuit diagram of one embodiment of the two communication devices of FIG.

[FIG. 3] A schematic diagram of signal flow when the communication device of FIG. 1 operates in the second operation mode.

FIG. 4 is a block schematic diagram of an embodiment of a sending unit of the communication device of FIG. 1.

[FIG. 5] A schematic diagram of an embodiment in which the two communication devices of FIG. 1 are applied to a fire fighting system.

FIG. 1 is a block diagram of an embodiment of a communication device 1 according to this case. Please refer to FIG. 1. The communication device 1 can bidirectionally communicate with another communication device 2. The communication device 1 can receive the communication command S1 (hereinafter referred to as the first communication command S1) from the communication device 2 and decode the first communication command S1 (hereinafter referred to as the command receiving program), and the communication device 1 can generate another A communication command (hereinafter referred to as a second communication command S2) is sent to the communication device 2 (hereinafter referred to as a command sending program) to establish two-way communication between the communication device 1 and the communication device 2. In one embodiment, the first communication command S1 is a voltage modulation signal.

Taking the communication device 1 including a group of receiving units 11 and a sending unit 12 as an example, as shown in FIG. 1, the communication device 1 includes a receiving unit 11, a sending unit 12 and an input/output line 13. In the command receiving process, the I/O line 13 receives the first communication command S1 from the communication device 2, the I/O line 13 transmits the first communication command S1 to the receiving unit 11, and the receiving unit 11 performs the step-down processing on the first communication command S1 In order to generate the first communication command S1 after voltage reduction, the receiving unit 11 then generates a pulse width modulation (PWM) signal S3 according to the first communication command S1 after voltage reduction, and the receiving unit 11 calculates the PWM signal S3 in The pulse width of the high level (hereinafter referred to as the first width) and the pulse width of the PWM signal S3 at the low level (hereinafter referred to as the second width), the receiving unit 11 then decodes the PWM signal S3 according to the first width and the second width to generate A decoding signal S4. For example, if the pulse width at the high bit is twice the pulse width at the low bit, the logic "1" is represented and the pulse width at the low bit is twice the pulse width at the high bit, representing a logic "0". For example, when the receiving unit 11 calculates that the aforementioned first width is twice the second width, the receiving unit 11 generates a decoding including logic "1" For the signal S4, when the receiving unit 11 calculates that the second width is twice the first width, the receiving unit 11 generates a decoded signal S4 including logic "0".

On the other hand, in the instruction sending program, the sending unit 12 generates the second communication instruction S2 and sends the second communication instruction S2 to the communication device 2. The transmission unit 12 includes an operational amplifier 121 and a switching circuit 122. The operational amplifier 121 includes a positive input 1211, a negative input 1212, and an output 1213. The positive input terminal 1211 receives a voltage signal V1. The voltage signal V1 includes different voltage levels that are switched between a high level and a low level; the negative input terminal 1212 is coupled to the output terminal 1213 via the switch circuit 122 (ie, the switch circuit 122 is coupled to the negative Between the input terminal 1212 and the output terminal 1213), the operational amplifier 121 has a negative feed-back line.

Here, the operational amplifier 121 generates a pilot communication signal S5 according to the voltage signal V1 received by the positive input terminal 1211 at a high level, and the switch circuit 122 receives the pilot communication signal S5 and conducts according to the pilot communication signal S5; and, according to the negative feedback line of the operational amplifier 121, The negative input terminal 1212 of the operational amplifier 121 generates the voltage level of the voltage signal V1 according to the voltage signal received by the positive input terminal 1211. The switch circuit 122 receives the voltage level of the voltage signal V1 generated by the negative input terminal 1212. When conducting, a current signal is generated according to the voltage level of the voltage signal V1. The current signal is used as the second communication command S2 to output the second communication command S2 to the communication device 2 via the output/input line 13 of the communication device 1. Based on this, the switching circuit 122 generates a current signal according to the voltage signal from the operational amplifier 121 with a stable and accurate voltage level, and the current signal generated by the switching circuit 122 is also more stable and accurate, thereby improving the communication device 1 and the communication device 2 The quality of communication between.

In one embodiment, as shown in FIG. 1, the sending unit 12 further includes a load 127 coupled between the switch circuit 122 and the ground. The load 127 may be a fixed resistance value. Resistance, the switching circuit 122 is based on the voltage level of the voltage signal V1 and the load 127 generates a second communication command S2 of a constant current signal, the current magnitude of the constant current signal is more stable, and the communication between the communication device 1 and the communication device 2 is improved Communication quality.

Furthermore, as shown in FIG. 1, the receiving unit 11 includes a voltage divider circuit 111, a digital analog converter 112 (hereinafter referred to as a first digital analog converter 112 ), a comparison circuit 113, and a calculation circuit 114. The voltage dividing circuit 111 is coupled between the input/output line 13 and the comparison circuit 113. The comparison circuit 113 is coupled between the voltage dividing circuit 111 and the calculation circuit 114, and the comparison circuit 113 is coupled between the first digital-to-analog converter 112 and the calculation circuit 114. In one embodiment, the first communication command S1 has a voltage level of 30-40V, and the voltage dividing circuit 111 receives the first communication command S1 from the I/O line 13 and generates the divided voltage conversion of the first communication command S1 The first communication command S1 after the voltage reduction, the first communication command S1 after the voltage reduction may have a voltage level of 6V or 3.3V. The first digital-to-analog converter 112 generates a reference voltage V2 according to a digital signal (hereinafter referred to as the first digital signal D1). The two input terminals of the comparison circuit 113 are respectively coupled to the output terminals of the voltage dividing circuit 111 and the first digital analog converter 112. The comparison circuit 113 receives the first communication command S1 after the voltage reduction from the voltage dividing circuit 111 and from the first digital The analog converter 112 receives the reference voltage V2, and the comparison circuit 113 compares the reference voltage V2 with the first communication command S1 after the step-down. When the voltage level of the first communication command S1 after the step-down is greater than the reference voltage V2, the comparison circuit 113 The high level is output. When the voltage level of the first communication command S1 after the step-down is lower than the reference voltage V2, the comparison circuit 113 outputs a low level. Therefore, the comparison circuit 113 is based on the first communication command S1 and the reference voltage V2 after the step-down The PWM signal S3 is generated, the calculation circuit 114 receives the PWM signal S3 from the comparison circuit 113, and the calculation circuit 114 calculates the first width and the second width of the PWM signal S3 to decode the PWM signal S3 to generate the decoded signal S4.

In one embodiment, the first communication command S1 is a multi-segment voltage signal. The receiving unit 11 may include a complex first digital analog converter 112, a complex comparison circuit 113, and a complex calculation circuit 114. The complex first digital analog converter 112 generates different reference voltages V2, respectively, and the complex comparison circuit 113 at different time points The first communication command S1 after the step-down is compared with a different reference voltage V2, so that the complex calculation circuit 114 generates a plurality of decoded signals S4 corresponding to the first communication command S1 of the multi-segment voltage signals.

In one embodiment, please refer to FIGS. 1 and 2 together. The voltage divider circuit 111 includes two series-connected resistors R1 and R2 (hereinafter referred to as first resistor R1 and second resistor R2). The first resistor R1 is coupled for communication The input/output line 13 of the device 1 is connected to the second resistor R2. The second resistor R2 is coupled to the first resistor R1 and the ground, and the resistance value of the second resistor R2 is greater than the resistance value of the first resistor R1. Therefore, according to the resistance values of the first resistor R1 and the second resistor R2, the voltage dividing circuit 111 converts the voltage of the first communication instruction S1 to generate the first communication instruction S1 after voltage reduction, one of the comparison circuits 113 The input terminal is coupled to the connection point C between the first resistor R1 and the second resistor R2, and the comparison circuit 113 generates the PWM signal S3 according to the first communication command S1 and the reference voltage V2 after the step-down received from the connection point C.

In an embodiment, please refer to FIG. 1 and FIG. 2 together. The sending unit 12 includes a digital analog converter 123 (hereinafter referred to as a second digital analog converter 123). The output of the second digital analog converter 123 is coupled to the operation At the positive input terminal 1211 of the amplifier 121, the second digital analog converter 123 generates a voltage signal V1 according to a digital signal (hereinafter referred to as the second digital signal D2), and the second digital analog converter 123 sends the voltage signal V1 to the operational amplifier 121 The positive input terminal 1211 enables the operational amplifier 121 to generate the pilot signal S5, and the negative input terminal 1212 of the operational amplifier 121 generates the voltage level of the voltage signal V1.

Furthermore, as shown in FIG. 2, the switching circuit 122 includes a transistor, such as a metal oxide semiconductor field effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor; MOSFET), and the switching circuit 122 includes a gate terminal G and a source terminal S and Ji extreme D. The gate terminal G is coupled to the output terminal 1213 of the operational amplifier 121, the source terminal S is coupled to the first resistor R1 of the voltage dividing circuit 111 and the input/output line 13, and the drain terminal D is coupled to the negative input terminal 1212 of the operational amplifier 121 and the load 127 The gate terminal G is coupled to the output terminal 1213 of the operational amplifier 121. Based on this, when the operational amplifier 121 outputs the conductive communication signal S5 according to the voltage signal V1 at the high level, the gate terminal G receives the conductive communication signal S5 from the output terminal 1213 of the operational amplifier 121 to turn on the switching circuit 122, and then the switching circuit 122 turns on according to The voltage level of the voltage signal V1 generated by the negative input terminal 1212 of the operational amplifier 121 generates a current signal as the second communication command S2. On the other hand, when the voltage signal V1 is at a low level, the operational amplifier 121 outputs a low level but does not output the pilot signal S5. At this time, the gate terminal G receives the low level, and the ground terminal to which the drain terminal D is coupled according to the load 127 also has a low level. At this time, the switch circuit 122 is cut-off, and the switch circuit 122 stops generating current signals. Based on this, according to the high level and the low level of the voltage signal V1, the switch circuit 122 generates a corresponding current modulation signal to generate different commands to communicate with the communication device 2.

In an embodiment, as shown in FIG. 1, the communication device 1 further includes a controller 15. The controller 15 may be a microcontroller (MCU). The controller 15 is coupled to the calculation circuit 114 and the second digital analog converter 123. The controller 15 receives the decoded signal S4 from the calculation circuit 114. The controller 15 generates a corresponding second digital signal D2 according to different decoded signals S4, so that The digital-to-analog converter 123 performs digital-to-analog conversion according to different second digital signals D2 to generate a corresponding voltage signal V1, and the switch circuit 122 generates a current signal corresponding to the voltage signal V1. Here, according to different first communication commands S1, the sending unit 12 can generate corresponding second communication commands S2, In response to the first communication command S1 sent by the communication device 2.

In other embodiments, the controller 15 may generate different second digital signals D2 by default or according to the settings of the designer of the communication device 1, so that the second digital analog converter 123 performs corresponding digital analog conversion to generate corresponding The voltage signal V1 causes the switch circuit 122 to generate different current signals correspondingly. Based on this, the communication device 1 can generate the corresponding second communication command S2 according to different communication protocols of the communication device 2 of different models/specifications, and the communication device 1 has better compatibility.

In an embodiment, the communication device 1 has a first operation mode and a second operation mode. When the communication device 1 is in the first operation mode, the sending unit 12 generates and sends a second communication command S2. When the communication device 1 is in the first In the two operation modes, the sending unit 12 supports the function of voltage detection. The sending unit 12 does not generate and does not send the second communication command S2. In the second operation mode, the sending unit 12 receives the first communication command S1 after the step-down and detects the voltage level of the first communication command S1 after the step-down. In detail, please refer to FIGS. 2 and 3 together. The sending unit 12 further includes two multiplexers 124 and 125 (hereinafter referred to as a first multiplexer 124 and a second multiplexer 125) and a switch 126, respectively. Among them, the first multiplexer 124 and the second multiplexer 125 are two-to-one multiplexers (2-to-1 mux). The two input terminals of the first multiplexer 124 are respectively coupled to the second digital analog converter 123 and the connection point C. The output terminal of the first multiplexer 124 is coupled to the positive input terminal 1211 of the operational amplifier 121. The two input terminals of the second multiplexer 125 are respectively coupled to the output terminal 1213 and the drain terminal D of the operational amplifier 121. The output terminal of the second multiplexer 125 is coupled to the negative input terminal 1212 of the operational amplifier 121. The switch 126 is coupled between the gate terminal G and the output terminal 1213 of the operational amplifier 121.

The first multiplexer 124, the second multiplexer 125 and the switch 126 are controlled by the controller 15. When the communication device 1 is in the first operation mode, as shown in FIG. 2, the controller 15 generates control The signal C1 controls the output of the first multiplexer 124 to be coupled to the second digital-to-analog converter 123, and the controller 15 generates a control signal C2 to control the output of the second multiplexer 125 to be coupled to the drain terminal D, and the controller 15 The control signal C3 is generated to control the switch 126 to be turned on. Here, the output terminal 1213 of the operational amplifier 121 is coupled to the negative input terminal 1212 through the switch 126, the switch circuit 122, and the second multiplexer 125 to form the aforementioned negative feedback line, and the positive input terminal 1211 of the operational amplifier 121 is A multiplexer 124 is coupled to the second digital-to-analog converter 123. The operational amplifier 121 generates a current signal based on the voltage signal V1 and the aforementioned negative feedback line control switch circuit 122.

On the other hand, when the communication device 1 is in the second operation mode, as shown in FIGS. 3 and 4, the controller 15 generates a control signal C1 to control the output end of the first multiplexer 124 to be coupled to the connection point C, the controller 15 The generation control signal C3 controls the switch 126 to be turned off, and the generation control signal C2 controls the output terminal of the second multiplexer 125 to be coupled to the output terminal 1213 of the operational amplifier 121. Here, the line between the output terminal 1213 of the operational amplifier 121 and the gate terminal G is open, and the output terminal 1213 of the operational amplifier 121 is coupled to the negative input terminal 1212 via the second multiplexer 125 to form a single gain ( uni-gain), and the positive input terminal 1211 of the operational amplifier 121 is coupled to the voltage divider circuit 111. The positive input terminal 1211 of the operational amplifier 121 receives the stepped-down first communication command S1 from the connection point C via the first multiplexer 124, and based on the aforementioned single-gain feedback line, the output terminal 1213 of the operational amplifier 121 outputs the step-down After the voltage level of the first communication command S1, the output terminal 1213 of the operational amplifier 121 can be further coupled to the analog-to-digital converter 128 to convert the voltage level of the first communication command S1 after the step-down to a digital signal, As other applications.

In an embodiment, please refer to FIG. 5, the communication devices 1 and 2 are used in a fire fighting system. The communication device 1 may be a smoke detection device or a manual alarm device, and the communication device 2 may be a fire fighting host. The communication device 2 which is a fire fighting host can be coupled to at least one communication device 1 (FIG. 4 is a communication device Set 2 to be coupled to three communication devices 1 as an example, but this case is not limited to this). The communication device 2 is coupled to the communication device 1 via the power line 3 and the ground line 4. The communication device 2 sends a power signal via the power line 3 to supply power to the communication device 1, and the communication device 2 sends the aforementioned first communication command S1 to the communication device 1 via the power line 3 to communicate with the communication device 1. Moreover, the communication device 1 also sends a second communication command S2 to the communication device 2 via the power line 3 to communicate with the communication device 2. When the communication device 2 detects that the current value on the power line 3 changes, the communication device 2 can learn that the communication device 1 sends the second communication command S2. For example, when the communication device 1 does not send the second communication command S2, the current value on the power line 3 is 2mA, and when the communication device 1 sends the second communication command S2 with 50mA, the current value on the power line 3 The change is 52 mA. At this time, the communication device 2 further decodes the second communication command S2 to complete the communication between the communication device 1 and the communication device 2.

In summary, according to one embodiment of the communication device, the receiving unit and the sending unit of the present case, the communication device supports the function of voltage detection, and the sending unit of the communication device generates a constant current signal as a communication command, and the constant current signal Can improve communication quality. Furthermore, the sending unit and the receiving unit include a digital analog converter. The digital analog converter generates an adjustable voltage signal according to the adjustable digital signal, so that the sending unit and the receiving unit can be flexibly designed according to the communication specifications of different fire engines and send The unit and the receiving unit can operate flexibly, thereby improving the performance and compatibility of the product.

Although the case has been disclosed by the examples as above, it is not used to limit the case. Anyone with ordinary knowledge in the technical field of the subject can make some changes and modifications within the spirit and scope of the case, so the scope of protection of the case The scope defined in the attached patent application scope shall prevail.

1: communication device

11: receiving unit

111: voltage divider circuit

112: The first digital analog converter

113: Comparison circuit

114: Computing circuit

12: sending unit

121: Operational amplifier

1211: Positive input

1212: Negative input

1213: output

122: switch circuit

123: Second digital analog converter

127: load

13: input and output lines

15: Controller

2: Communication device

D2: Second digital signal

V1: voltage signal

V2: reference voltage

S1: The first communication command

S2: Second communication instruction

S3: PWM signal

S4: Decode the signal

S5: guide communication number

Claims (7)

A communication device suitable for a fire fighting system includes: a receiving unit for receiving a first communication command from another communication device and generating the first communication command after voltage reduction, and according to the first A communication command generates a pulse width modulation signal, and decodes the pulse width modulation signal according to the pulse width of the pulse width modulation signal at the high level and the pulse width at the low level to generate a decoded signal; a controller, coupled Connected to the receiving unit to generate a corresponding second digital signal according to the decoded signal; and a transmitting unit, coupled to the controller, including: a second digital analog converter to generate a voltage according to the second digital signal Signal; an operational amplifier for generating a pilot signal according to the voltage signal, including: a positive input terminal, coupled to the second digital-to-analog converter, for receiving the voltage signal; a negative input terminal; and an output terminal , Which is coupled to the negative input terminal for outputting the pilot signal; and a switch circuit, coupled between the negative input terminal and the output terminal, for conducting according to the pilot signal and generating according to the voltage signal when conducting A current signal is output to the other communication device as a second communication command. The communication device according to claim 1, wherein the receiving unit includes: a voltage divider circuit that performs voltage division conversion on the first communication instruction to generate the first communication instruction after voltage reduction; a first digital analog conversion The generator generates a reference voltage according to a first digital signal; A comparison circuit that compares the reference voltage with the first communication command after the step-down to generate the pulse width modulation signal; and a calculation circuit that calculates the pulse width of the pulse width modulation signal at a high level and the pulse width modulation The pulse width of the low signal is changed to generate the decoded signal. The communication device according to claim 2, wherein the voltage dividing circuit includes a first resistor and a second resistor connected to each other, and a voltage drop occurs at a connection point between the first resistor and the second resistor The first communication instruction. The communication device according to claim 2, wherein the positive input terminal of the operational amplifier further receives the first communication command after voltage reduction, and the operational amplifier generates a voltage level according to the first communication command after voltage reduction And the output terminal outputs the voltage level. The communication device according to claim 4, wherein the sending unit further includes a switch, a first multiplexer, and a second multiplexer. The communication device has a first operation mode and a second operation mode. When the communication device is in the first operation mode, the switch is turned on and coupled to a control terminal and the output terminal of the switch circuit, and the first multiplexer is coupled to the second digital analog conversion circuit and the positive input terminal , And the second multiplexer is coupled to a drain terminal of the switch circuit and the negative input terminal, the operational amplifier generates the pilot signal according to the voltage signal in the first operation mode; when the communication device is in the first In the two operation modes, the switch is turned off to cause an open circuit between the control terminal and the output terminal, and the first multiplexer is coupled to the positive input terminal and the voltage divider circuit, and the second multiplexer is coupled Connected to the negative input terminal and the output terminal, the operational amplifier generates and outputs the voltage level according to the first communication command after the voltage reduction in the second operation mode. The communication device according to claim 1, wherein the first communication instruction is a voltage modulation signal, and the input terminal further receives a power signal through a power line, and the power line The communication device is coupled to the other communication device, and the first communication command comes from the power line. The communication device according to claim 1, wherein the sending unit further includes a load having a resistance value coupled between the switch circuit and the ground terminal, the switch circuit is generated according to the voltage level of the voltage signal and the load The current signal for constant current.

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