Power supply device

Abstract

To disclose a power supply device capable of omitting a power supply line for supplying drive power to a second board, in a communication circuit in which a transmission device provided on a first board to which drive power is provided from a power supply transmits a signal through a signal line to a reception device provided on a second board to which drive power is not provided from the power supply.SOLUTION: A power supply device provides a communication circuit and a power supply circuit. The communication circuit is a circuit providing a transmission device provided on a first board to which drive power is provided from a power supply, a reception device provided on a second board to which drive power is not provided from the power supply, and a termination device, and transmits a signal from the transmission device to the reception device through a signal line. The power supply circuit is a circuit connected to the signal line of the communication circuit in parallel, for generating supply power to be supplied to devices provided on the second board including the reception device based on residual power which is power consumption consumed by the termination device subtracted from output power of the transmission device.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This specification discloses a technique related to a power supply device. [Background technology]

[0002] The bioimplant device described in Patent Document 1 includes an operating unit that operates while implanted in a living body, a power supply unit that outputs a power supply signal to the operating unit, and a cable that electrically connects the operating unit and the power supply unit and transmits the power supply signal. The power supply unit generates a digital signal encoded with a Manchester code as the power supply signal based on control information that controls the operation of the operating unit. The operating unit includes a rectifier circuit that converts the power supply signal into DC power, and a recovery circuit that recovers a clock based on the code superimposed on the power supply signal and uses the clock to extract the control information superimposed as a code on the power supply signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-97942 Summary of the Invention [Problem to be solved by the invention]

[0004] Consider a communication circuit in which a transmitter mounted on a first board that receives drive power from a power source transmits a signal via a signal line to a receiver mounted on a second board that does not receive drive power from the first power source or a different power source. In this case, drive power must be supplied to the second board, and a power line is required in addition to the signal line to supply drive power to the second board. As a result, the number of wires increases.

[0005] In view of these circumstances, this specification discloses a power supply device that can omit the power supply line that supplies drive power to a second board in a communication circuit in which a transmitting device provided on a first board that receives drive power from a power source transmits a signal via a signal line to a receiving device provided on a second board that does not receive drive power from a power source. [Means for solving the problem]

[0006] This specification discloses a power supply device including a communication circuit and a power supply circuit. The communication circuit includes a transmitter provided on a first board that receives drive power from a power supply, a receiver provided on a second board that does not receive drive power from the power supply, and a terminal device, and transmits a signal from the transmitter to the receiver via a signal line. The power supply circuit is connected in parallel to the signal line of the communication circuit and generates supply power to be supplied to a device provided on the second board, including the receiver, based on the remaining power obtained by subtracting the power consumed by the terminal device from the output power of the transmitter. [Effects of the Invention]

[0007] The power supply device includes a power supply circuit, which can supply power to devices mounted on the second board, including the receiving device, and therefore can omit a power line for supplying drive power to the second board. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 10 is a schematic diagram showing an example of wiring of power supply lines and signal lines between a first substrate and a second substrate according to a comparative example. [Figure 2] 10A and 10B are schematic diagrams showing other wiring examples of power supply lines and signal lines between the first substrate and the second substrate according to a comparative example. [Figure 3] FIG. 1 is a schematic diagram illustrating a configuration example of a power supply device. [Figure 4A] 4 is a diagram showing an example of changes over time in input voltages at the non-inverting input terminal and the inverting input terminal of the receiving device of FIG. 3. FIG. [Figure 4B]4 is a diagram showing an example of a change over time in an output voltage at an output terminal of the receiving device of FIG. 3. FIG. [Figure 4C] 4 is a diagram showing an example of a change over time in output voltage at an output terminal of the power supply circuit of FIG. 3. [Figure 4D] 4 is a diagram showing another example of the change over time in the output voltage of the output terminal of the power supply circuit of FIG. 3. FIG. [Figure 5] FIG. 2 is a schematic diagram showing an example of the configuration of a protection device and equipment. [Figure 6] FIG. 10 is a schematic diagram showing another example of the configuration of the power supply device. [Figure 7A] 7 is a diagram showing an example of a change over time in the input voltage of the non-inverting input terminal of the receiving device of FIG. 6. FIG. [Figure 7B] 7 is a diagram showing an example of a change over time in the output voltage of the output terminal of the receiving device of FIG. 6. FIG. [Figure 7C] 7 is a diagram showing an example of a change over time in the output voltage of the output terminal of the power supply circuit of FIG. 6. FIG. [Figure 7D] 7 is a diagram showing another example of the change over time in the output voltage of the output terminal of the power supply circuit of FIG. 6. FIG. [Figure 8] FIG. 10 is a schematic diagram showing another example of the configuration of the power supply device. [Figure 9] FIG. 10 is a schematic diagram showing another example of the configuration of the power supply device. [Figure 10] FIG. 2 is a diagram showing a configuration example of a substrate-related work line; [Figure 11] FIG. 2 is a plan view showing a configuration example of a component mounting machine. [Figure 12] FIG. 12 is a perspective view of the component mounting machine of FIG. [Figure 13] FIG. 1 is a schematic diagram illustrating an example of a display device. DETAILED DESCRIPTION OF THE INVENTION

[0009] 1. Embodiment 1-1. Configuration example of power supply device 10 Assume a communication circuit in which a transmitter 31 provided on a first substrate 21 that receives drive power from a power source 20 transmits a signal via a signal line 30s to a receiver 32 provided on a second substrate 22 that does not receive drive power from a power source (power source 20 or a power source different from power source 20). In this case, drive power needs to be supplied to the second substrate 22.

[0010] 1, driving power is supplied to the first substrate 21 from the power supply 20 using a power supply line 20p and a ground line 30g. Driving power is supplied to the second substrate 22 from the power supply 20 using a power supply line 20p and a ground line 30g different from the power supply line 20p and the ground line 30g described above. Driving power can also be supplied to the second substrate 22 from a power supply different from the power supply 20 using a power supply line 20p and a ground line 30g different from the power supply line 20p and the ground line 30g that supply driving power to the first substrate 21.

[0011] 2, the first substrate 21 is supplied with driving power from the power supply 20 using a power line 20p and a ground line 30g. The second substrate 22 is supplied with driving power from the first substrate 21 using a power line 20p and a ground line 30g that are different from the above-mentioned power line 20p and ground line 30g. In either case, in order to supply driving power to the second substrate 22, a power line 20p is required in addition to the signal line 30s. As a result, the number of wirings increases.

[0012] Therefore, the power supply device 10 includes a communication circuit 30 and a power supply circuit 40. The power supply device 10 may also include a protection device 50. As shown in FIG. 3 , the power supply device 10 of the embodiment includes a communication circuit 30, a power supply circuit 40, and a protection device 50. The supply power generated by the power supply circuit 40 is supplied to a device 60 provided on the second board 22.

[0013] The communication circuit 30 is a circuit including a transmitter 31 provided on a first substrate 21 to which drive power is supplied from the power source 20, a receiver 32 provided on a second substrate 22 to which drive power is not supplied from a power source (power source 20 or a power source different from power source 20), and a terminal device 33. The communication circuit 30 transmits a signal from the transmitter 31 to the receiver 32 via a signal line 30s.

[0014] As shown in Fig. 3, driving power is supplied to the first substrate 21 from a power supply 20. The power supply 20 may be a DC power supply or an AC power supply. The power supply 20 may be provided outside the first substrate 21 or may be provided on the first substrate 21. The power supply 20 shown in Fig. 3 is a DC power supply and is provided outside the first substrate 21. The power supply 20 shown in Fig. 3 can supply DC power to the first substrate 21 using a power line 20p and a ground line 30g.

[0015] The driving power (DC power or AC power) supplied to the first substrate 21 is supplied to devices provided on the first substrate 21. The devices include a transmitting device 31 and a known control device 21a that controls the transmitting device 31. The first substrate 21 can be equipped with various devices, and the control device 21a can control the various devices. The first substrate 21 can also be equipped with a known power converter. For example, the power converter can increase or decrease the voltage of the DC power supplied to the first substrate 21. The power converter can convert the DC power supplied to the first substrate 21 into AC power, and can also convert the AC power supplied to the first substrate 21 into DC power.

[0016] The transmitting device 31 can transmit a signal to the receiving device 32 via the signal line 30s, and the receiving device 32 can receive the signal, and various configurations are possible. For example, the transmitting device 31 and the receiving device 32 can perform serial communication in accordance with communication standards such as RS422, RS485, and RS232C. The transmitting device 31 and the receiving device 32 can also perform parallel communication. In the embodiment, the transmitting device 31 and the receiving device 32 perform serial communication in accordance with the RS422 communication standard.

[0017] The termination device 33 may take various forms as long as it can stabilize transmission from the transmitter 31 to the receiver 32 (for example, by suppressing signal reflection). The termination device 33 of this embodiment is provided with a resistor on the receiver 32 side. In RS422 communication, balanced transmission is performed using two signal lines 30s for one bit of a signal. In this case, as shown in FIG. 3, the resistor serving as the termination device 33 is connected between the two signal lines 30s. The resistance value of the resistor is set to match the characteristic impedance of the communication cable (signal line 30s and ground line 30g). The communication cable is connected via connectors provided on each of the first board 21 and the second board 22.

[0018] For example, a known comparator can be used for the receiving device 32. The input impedance of the comparator is extremely high, and the output power from the transmitting device 31 is mostly consumed by the terminating device 33 in the communication circuit 30. Therefore, the power supply device 10 utilizes the remaining power obtained by subtracting the power consumed by the terminating device 33 from the output power of the transmitting device 31. Specifically, the power supply device 10 includes a power supply circuit 40.

[0019] The power supply circuit 40 is a circuit connected in parallel to the signal line 30s of the communication circuit 30, and generates supply power to be supplied to the device 60 provided on the second board 22 including the receiving device 32, based on the remaining power obtained by subtracting the power consumed by the terminating device 33 from the output power of the transmitting device 31. The power supply circuit 40 may be provided on the second board 22, or on a board external to the second board 22. The supply power may be DC power or AC power. The power supply circuit 40 shown in FIG. 3 is provided on the second board 22, and supplies DC power to the device 60.

[0020] Specifically, the power supply circuit 40 generates supply power by converting residual AC power into DC power. The power supply circuit 40 can take various forms as long as it can generate supply power. As mentioned above, RS422 communication uses balanced transmission, using two signal lines 30s for one-bit signals. In other words, the signal transmitted by the communication circuit 30 is a differential signal.

[0021] In this embodiment, as shown in FIG. 3, the power supply circuit 40 includes a first diode 41, a second diode 42, and a smoothing capacitor 43. The first diode 41 has an anode 41a connected to one signal line 30s of the differential signal. The second diode 42 has an anode 42a connected to the other signal line 30s of the differential signal. The smoothing capacitor 43 has a positive electrode connected to both the cathode 41k of the first diode 41 and the cathode 42k of the second diode 42, and a negative electrode connected to the ground 20g. The ground 20g is at the same potential as the ground line 30g and is represented by a downward-pointing triangle in the drawing.

[0022] For example, in RS422 and RS485 communications, signals are transmitted at a maximum transmission speed of 10 Mbps. In addition, in RS232C communications, signals are transmitted at a maximum transmission speed of 19.2 kbps. Therefore, first diode 41 and second diode 42 can be made of fast recovery diodes, Schottky barrier diodes, or the like, which are usable in high-frequency circuits in the above frequency bands. Similarly, smoothing capacitor 43 can be made of ceramic capacitors, or the like, which are usable in high-frequency circuits in the above frequency bands. Furthermore, smoothing capacitor 43 can be made of a ceramic capacitor and an electrolytic capacitor connected in parallel, so that both a ceramic capacitor and an electrolytic capacitor can be used.

[0023] The solid broken line L1 in FIG. 4A shows an example of the change over time in the input voltage at the non-inverting input terminal (the + terminal in FIG. 3) of the receiving device 32. The vertical axis in the figure represents the input voltage, and the horizontal axis represents time. The input voltage increases from time T1 to time T2, and is at voltage V1 (high level) from time T2 to time T3. The input voltage decreases from time T3 to time T4, and is at zero voltage (low level) from time T4 to time T5. The input voltage changes in a similar manner from time T5 to time T8, and also changes in a similar manner after time T8.

[0024] The broken line L2 in FIG. 4A shows an example of the change over time in the input voltage at the inverting input terminal (- terminal in FIG. 3) of the receiving device 32. The input voltage decreases from time T1 to time T2, and is at zero voltage (low level) from time T2 to time T3. The input voltage increases from time T3 to time T4, and is at voltage V1 (high level) from time T4 to time T5. The input voltage changes in a similar manner from time T5 to time T8, and also changes in a similar manner after time T8.

[0025] The solid broken line L3 in Fig. 4B shows an example of the change over time in the output voltage of the output terminal of the receiving device 32. The solid curve L4 in Fig. 4C shows an example of the change over time in the output voltage of the output terminal 40p of the power supply circuit 40. The solid curve L5 in Fig. 4D shows another example of the change over time in the output voltage of the output terminal 40p of the power supply circuit 40. The vertical axes in Figs. 4B to 4D all show output voltage. The horizontal axes in Figs. 4A to 4D show time in the same time period.

[0026] For example, as shown in Fig. 4A, from time T2 to time T3, the input voltage to the non-inverting input terminal (+ terminal in Fig. 3) of the receiving device 32 is voltage V1 (high level), and the input voltage to the inverting input terminal (- terminal in Fig. 3) of the receiving device 32 is zero voltage (low level). Therefore, as shown in Fig. 4B, the output voltage of the output terminal of the receiving device 32 is voltage V1 (= voltage V1 - zero voltage).

[0027] At this time, the potential of the signal line 30s to which the first diode 41 is connected is higher than the potential of the signal line 30s to which the second diode 42 is connected. Therefore, a current flows from the transmitter 31 to the smoothing capacitor 43 via the transmitter 31, the signal line 30s to which the first diode 41 is connected, and the first diode 41, and the smoothing capacitor 43 is charged.

[0028] Conversely, as shown in Fig. 4A, from time T4 to time T5, the input voltage to the non-inverting input terminal (+ terminal in Fig. 3) of the receiving device 32 is zero voltage (low level), and the input voltage to the inverting input terminal (- terminal in Fig. 3) of the receiving device 32 is voltage V1 (high level). Therefore, as shown in Fig. 4B, the output voltage of the output terminal of the receiving device 32 becomes negative voltage V1 (=zero voltage - voltage V1).

[0029] At this time, the potential of the signal line 30s to which the second diode 42 is connected is higher than the potential of the signal line 30s to which the first diode 41 is connected. Therefore, a current flows from the transmitter 31 to the smoothing capacitor 43 via the transmitter 31, the signal line 30s to which the second diode 42 is connected, and the second diode 42, and the smoothing capacitor 43 is charged.

[0030] The same applies to other time periods, and the phenomenon described above for the period from time T2 to time T3 and the phenomenon described above for the period from time T4 to time T5 are repeated in sequence. As a result, as shown by curve L4 in Figure 4C, power supply circuit 40 can output DC power of a substantially constant voltage V2 from output terminal 40p. Output terminal 40p is connected to the positive electrode of smoothing capacitor 43.

[0031] In this way, the transmitting device 31 of the embodiment transmits a differential signal (a signal of opposite phase) for one bit signal via two signal lines 30s, and the receiving device 32 can receive the differential signal. At this time, the power supply circuit 40 converts the remaining AC power, which is obtained by subtracting the power consumed by the termination device 33 from the output power of the transmitting device 31, into DC power, and can generate supply power.

[0032] As shown by curve L5 in FIG. 4D, during the time periods from time T1 to time T2, from time T3 to time T4, from time T5 to time T6, and from time T7 to time T8, the DC power output from output terminal 40p may decrease relative to voltage V2. During these time periods, the input voltage to the non-inverting input terminal (+ terminal in FIG. 3) of receiving device 32 increases, and the input voltage to the inverting input terminal (- terminal in FIG. 3) decreases. Alternatively, during these time periods, the input voltage to the non-inverting input terminal (+ terminal in FIG. 3) of receiving device 32 decreases, and the input voltage to the inverting input terminal (- terminal in FIG. 3) increases.

[0033] The smaller the capacitance of smoothing capacitor 43, the more susceptible it is to fluctuations in the input voltage at the non-inverting input terminal (+ terminal in FIG. 3 ) and the inverting input terminal (− terminal in FIG. 3 ) of receiving device 32, and the more likely the DC power is to contain the above-mentioned ripple. Therefore, it is preferable that the capacitance of smoothing capacitor 43 be set so that the ripple contained in the DC power falls within a predetermined range. The capacitance of smoothing capacitor 43 can be derived by simulation, verification using an actual device, or the like. As a result, as shown by curve L4 in FIG. 4C , power supply circuit 40 can output DC power of a substantially constant voltage V2 from output terminal 40p.

[0034] Furthermore, the higher the voltage of the signal transmitted from the transmitter 31, the longer the input voltage at the non-inverting input terminal (+ terminal in FIG. 3 ) and the input voltage at the inverting input terminal (− terminal in FIG. 3 ) of the receiver 32 fluctuate, making it more likely that the above-mentioned ripple will be present in the DC power. Therefore, the power supply device 10 can set the maximum voltage of the signal transmitted from the transmitter 31 so that the ripple contained in the DC power falls within a predetermined range. The relationship between the maximum voltage of the signal and the ripple can be derived by simulation, verification using an actual device, or the like. This allows the power supply circuit 40 to output DC power of a generally constant voltage V2 from the output terminal 40p, as shown by curve L4 in FIG. 4C .

[0035] Note that if the maximum voltage of the signal transmitted from the transmitter 31 is reduced, the voltage V2 of the DC power output from the output terminal 40p of the power supply circuit 40 will also be reduced in accordance with the voltage of the signal. Therefore, the power supply circuit 40 may also be equipped with a known power converter. The power converter can boost the DC power output from the output terminal 40p of the power supply circuit 40 to a predetermined voltage.

[0036] Regardless of the above-mentioned purpose, the power supply circuit 40 may also include a known power converter. For example, the power converter can step up or step down the DC power output from the output terminal 40p of the power supply circuit 40. The power converter can also convert the DC power output from the output terminal 40p of the power supply circuit 40 into AC power.

[0037] Furthermore, the rated output voltage of the power supply circuit 40 (the rated voltage of the DC power output from the output terminal 40p of the power supply circuit 40) may be determined in accordance with the specifications of the device 60 to which the power generated by the power supply circuit 40 is supplied. In this case, the transmitting device 31 can output a signal with a higher voltage than the voltage obtained by adding the voltage drop caused by the power supply circuit 40 to the rated output voltage of the power supply circuit 40. For example, the voltage drop caused by the power supply circuit 40 shown in FIG. 3 corresponds to the forward voltage of the first diode 41 or the second diode 42.

[0038] The transmitting device 31 must output a signal within a voltage range that complies with the communication standard. For example, in RS422 communication, the transmitting device 31 must output a signal with a maximum voltage (corresponding to the voltage V1 described above) in the range of 2V to 6V. In this case, for example, the transmitting device 31 can output a signal with a maximum voltage (voltage V1) in the range of 5V to 6V. Assuming that the forward voltage of the first diode 41 or the second diode 42 is approximately 0.7V, the power supply circuit 40 can output DC power with a rated output voltage of approximately 4V to 5V from the output terminal 40p.

[0039] The power supply device 10 includes a communication circuit 30 and a power supply circuit 40. Therefore, there is concern about the influence of noise from the power supply circuit 40. However, the signal transmitted by the communication circuit 30 of this embodiment is a differential signal. That is, the transmitter 31 transmits a differential signal (a signal with an opposite phase) for a one-bit signal via two signal lines 30s, and the receiver 32 receives the differential signal. Therefore, the influence of common mode noise applied between the ground 20g and the signal line 30s is reduced compared to the case of a single-ended signal, which will be described later.

[0040] Furthermore, in the power supply circuit 40 of the embodiment, the smoothing capacitor 43 is connected to one signal line 30s of the differential signal via a first diode 41, and is connected to the other signal line 30s of the differential signal via a second diode 42. Therefore, normal mode noise applied between the two signal lines 30s is reduced by the smoothing capacitor 43. Note that what has been described above regarding normal mode noise also applies to the case of a single-ended signal, which will be described later.

[0041] Furthermore, the power supply device 10 can use a twisted pair cable for the signal line 30s as needed. Also, the power supply device 10 can use a shielded cable for the communication cable (signal line 30s and ground line 30g) as needed. Furthermore, the power supply device 10 can include a known noise suppression device such as a choke coil in the communication circuit 30 as needed.

[0042] The power supply device 10 can be equipped with various protection devices 50. For example, the power supply device 10 can be equipped with at least one protection device 50 selected from a current limiting device 51, an overload protection device 52, and an overload guidance device 53. The current limiting device 51 regulates the output of the power supply circuit 40 when the supply current supplied from the power supply circuit 40 to the device 60 exceeds an allowable value. For example, the current limiting device 51 can be a fuse. When the supply current supplied to the device 60 exceeds an allowable value, the fuse blows, regulating the output of the power supply circuit 40.

[0043] 5, the current limiting device 51 may also include, for example, a power supply monitoring device 50a and a current detector 51a. The power supply monitoring device 50a may be configured to monitor the state of the power supplied from the power supply circuit 40, and a known integrated circuit for power supply monitoring may be used. The current detector 51a may be configured to detect the supply current, and a known current detector may be used. The current detector 51a of the embodiment detects the current of the DC power (direct current) output from the output terminal 40p. When the current value detected by the current detector 51a exceeds an allowable value, the power supply monitoring device 50a stops the supply of power to the device 60 and regulates the output of the power supply circuit 40.

[0044] The overload protection device 52 regulates the output of the power supply circuit 40 when the output voltage of the power supply circuit 40 falls below an allowable value. The overload protection device 52 may take various forms as long as it can regulate the output of the power supply circuit 40 when the output voltage of the power supply circuit 40 falls below an allowable value. As shown in Fig. 5, the overload protection device 52 may include, for example, a power supply monitoring device 50a and voltage dividers 52a and 52b.

[0045] In this embodiment, the voltage dividers 52a and 52b are resistors that divide the voltage of the DC power (DC voltage) output from the output terminal 40p. The DC voltage divided by the voltage dividers 52a and 52b decreases as the load increases. Therefore, when the DC voltage divided by the voltage dividers 52a and 52b falls below a predetermined voltage value, the power supply monitoring device 50a determines that the output voltage of the power supply circuit 40 is below the allowable value and is in an overload state. In this case, the power supply monitoring device 50a stops the supply of power to the device 60 and regulates the output of the power supply circuit 40.

[0046] The overload guidance device 53 notifies an overload when the output voltage of the power supply circuit 40 falls below an allowable value. The overload guidance device 53 may take various forms as long as it can notify an overload when the output voltage of the power supply circuit 40 falls below an allowable value. As shown in Fig. 5, the overload guidance device 53 may include, for example, a power supply monitoring device 50a, voltage dividers 52a and 52b, a resistor 53a, a light-emitting diode 53b, a transistor 53c, a resistor 53d, and a resistor 53e.

[0047] The resistor 53a, the light-emitting diode 53b, and the transistor 53c are connected in series in this order from the positive side between the positive side (the side of the output terminal 40p) and the negative side (the side of the ground 20g) of the DC power output from the output terminal 40p. The resistor 53d is provided between the output port of the power supply monitoring device 50a and the base terminal of the transistor 53c. The resistor 53e is provided between the base terminal and the emitter terminal of the transistor 53c.

[0048] When the power supply monitoring device 50a determines that the output voltage of the power supply circuit 40 is below the allowable value and is in an overload state, it changes the output port from low to high. This controls the transistor 53c from an open state to a closed state, causing the light-emitting diode 53b to emit light. This allows, for example, an operator to visually recognize the overload. Note that the power supply device 10 can be equipped with various other protective devices 50 in addition to those described above. For example, the power supply device 10 can also be equipped with protective devices 50 that perform overvoltage protection, overheat protection of circuit elements, etc.

[0049] The device 60 is not limited to any particular type of device, as long as it consumes less power than the power supplied by the power supply circuit 40 (which is roughly equivalent to the remaining power obtained by subtracting the power consumed by the terminal device 33 from the output power of the transmitter 31). The device 60 may be, for example, a sensor. As shown in FIG. 5, the device 60 may also be, for example, a display device. Each of at least one device 60 (three in this figure) shown in FIG. 5 includes a resistor 60a, a light-emitting diode 60b, a transistor 60c, a resistor 60d, and a resistor 60e.

[0050] The resistor 60a, the light-emitting diode 60b, and the transistor 60c are connected in series in this order from the positive side between the positive side (the side of the output terminal 40p) and the negative side (the side of the ground 20g) of the DC power output from the output terminal 40p. The resistor 60d is provided between the output port of the control device 22a and the base terminal of the transistor 60c. The resistor 60e is provided between the base terminal and the emitter terminal of the transistor 60c.

[0051] The control device 22a can control the receiving device 32 and various devices 60 provided on the second board 22. The control device 22a can also obtain the status of the power supply provided by the power supply circuit 40 from the power supply monitoring device 50a. The control device 22a changes the output port connected to the device 60 that lights up the light-emitting diode 60b from low to high. This controls the transistor 60c from an open state to a closed state, causing the light-emitting diode 60b to emit light. Therefore, for example, an operator can visually recognize the guidance provided by the light-emitting diode 60b.

[0052] 1-2. Other Configuration Examples of the Power Supply Device 10 The power supply device 10 can take various forms. In the drawings, common parts in each form are assigned common reference numerals, and duplicated explanations are omitted in this specification. For example, the transmitter 31 and receiver 32 can perform serial communication in accordance with the RS232C communication standard. In RS232C communication, unbalanced transmission is performed using one signal line 30s for one bit signal. In other words, the signal transmitted by the communication circuit 30 is a single-ended signal.

[0053] As shown in FIG. 6, the power supply circuit 40 also includes a first diode 41, a second diode 42, and a smoothing capacitor 43. However, the anode 41a of the first diode 41 is connected to the signal line 30s. The anode 42a of the second diode 42 is connected to the ground 20g (ground line 30g). The positive electrode of the smoothing capacitor 43 is connected to both the cathode 41k of the first diode 41 and the cathode 42k of the second diode 42, and the negative electrode is connected to the ground 20g. The ground 20g is at the same potential as the ground line 30g and is represented by a downward-pointing triangle in the drawing. In addition, in this embodiment, a resistor serving as a termination device 33 is connected between the signal line 30s and the ground 20g (ground line 30g).

[0054] The solid broken line L6 in Fig. 7A shows an example of the change over time in the input voltage of the non-inverting input terminal (+ terminal in Fig. 6) of the receiving device 32. The vertical axis of the figure represents the input voltage, and the horizontal axis represents time. The inverting input terminal (- terminal in Fig. 6) of the receiving device 32 is connected to the ground 20g (ground line 30g) and is at zero voltage (low level).

[0055] As shown in Fig. 7A, the input voltage at the non-inverting input terminal (the + terminal in Fig. 6) of receiving device 32 alternates between voltage V1 and negative (negative) voltage V1. Specifically, the input voltage increases from time T1 to time T2, and remains at voltage V1 from time T2 to time T3. The input voltage decreases from time T3 to time T4, and remains at negative (negative) voltage V1 from time T4 to time T5. The input voltage also changes similarly from time T5 to time T8, and continues to change similarly after time T8.

[0056] The solid broken line L7 in Fig. 7B shows an example of the change over time in the output voltage of the output terminal of the receiving device 32. The solid curve L8 in Fig. 7C shows an example of the change over time in the output voltage of the output terminal 40p of the power supply circuit 40. The solid curve L9 in Fig. 7D shows another example of the change over time in the output voltage of the output terminal 40p of the power supply circuit 40. The vertical axes in Figs. 7B to 7D all show output voltage. The horizontal axes in Figs. 7A to 7D show time in the same time period.

[0057] For example, as shown in Fig. 7A, from time T2 to time T3, the input voltage to the non-inverting input terminal (+ terminal in Fig. 6) of the receiving device 32 is voltage V1, and the input voltage to the inverting input terminal (- terminal in Fig. 6) of the receiving device 32 is zero voltage (low level). Therefore, as shown in Fig. 7B, the output voltage of the output terminal of the receiving device 32 is voltage V1 (= voltage V1 - zero voltage).

[0058] At this time, the potential of the signal line 30s to which the first diode 41 is connected is higher than the potential of the ground 20g (ground line 30g) to which the second diode 42 is connected. Therefore, a current flows from the transmitter 31 to the smoothing capacitor 43 via the transmitter 31, the signal line 30s to which the first diode 41 is connected, and the first diode 41, and the smoothing capacitor 43 is charged.

[0059] Conversely, as shown in Fig. 7A, from time T4 to time T5, the input voltage to the non-inverting input terminal (the + terminal in Fig. 6) of the receiving device 32 is a negative voltage V1, and the input voltage to the inverting input terminal (the - terminal in Fig. 6) of the receiving device 32 is zero voltage (low level). Therefore, as shown in Fig. 7B, the output voltage of the output terminal of the receiving device 32 is a negative voltage V1 (= negative voltage V1 - zero voltage).

[0060] At this time, the potential of the ground 20g (ground line 30g) to which the second diode 42 is connected is higher than the potential of the signal line 30s to which the first diode 41 is connected. Therefore, a current flows from the transmitter 31 to the smoothing capacitor 43 via the transmitter 31, the ground 20g (ground line 30g) to which the second diode 42 is connected, and the second diode 42, and the smoothing capacitor 43 is charged.

[0061] The same applies to other time periods, and the phenomenon described above for the period from time T2 to time T3 and the phenomenon described above for the period from time T4 to time T5 are repeated in sequence. As a result, as shown by curve L8 in Figure 7C, power supply circuit 40 can output DC power of a substantially constant voltage V2 from output terminal 40p. Output terminal 40p is connected to the positive electrode of smoothing capacitor 43.

[0062] In this way, even when the signal transmitted in the communication circuit 30 is a single-ended signal, the power supply circuit 40 can generate supply power in the same way as in the case of a differential signal. Also, even when the signal transmitted in the communication circuit 30 is a single-ended signal, the power supply circuit 40 can generate supply power by converting remaining AC power into DC power in the same way as in the case of a differential signal.

[0063] As shown by curve L9 in Fig. 7D, a phenomenon may occur in which the DC power output from output terminal 40p drops relative to voltage V2, as in the case of a differential signal. Therefore, it is preferable that smoothing capacitor 43 has a capacitance set so that the ripple contained in the DC power falls within a predetermined range. Furthermore, power supply device 10 can also set the maximum voltage of the signal transmitted from transmitter 31 so that the ripple contained in the DC power falls within a predetermined range.

[0064] Furthermore, the transmitting device 31 can output a signal with a voltage higher than the voltage obtained by adding the voltage drop caused by the power supply circuit 40 to the rated output voltage of the power supply circuit 40. In the power supply circuit 40 shown in FIG. 6, the voltage drop caused by the power supply circuit 40 also corresponds to the forward voltage of the first diode 41 or the second diode 42. Thus, what has been described above about the power supply device 10 shown in FIG. 3 can also be said about the power supply device 10 shown in FIG. 6.

[0065] However, when the signal transmitted in the communication circuit 30 is a single-ended signal, it is more susceptible to the influence of common-mode noise than when it is a differential signal. Therefore, the power supply device 10 can use a twisted pair cable for the communication cable (signal line 30s and ground line 30g) as needed. Also, the power supply device 10 can use a shielded cable for the communication cable (signal line 30s and ground line 30g) as needed. Furthermore, the power supply device 10 can include a known noise suppression device such as a choke coil in the communication circuit 30 as needed.

[0066] The communication circuit 30 described above is a unidirectional circuit that transmits a signal from the transmitting device 31 provided on the first board 21 to the receiving device 32 provided on the second board 22. However, as shown in FIG. 8, the communication circuit 30 may further include a circuit that transmits a signal from the transmitting device 31 provided on the second board 22 to the receiving device 32 provided on the first board 21. In this case, the communication circuit 30 can perform full-duplex communication between the first board 21 and the second board 22 using different signal lines 30s. Note that although the communication circuit 30 shown in FIG. 8 is the communication circuit 30 shown in FIG. 3 to which the above-mentioned circuits have been added, the communication circuit 30 shown in FIG. 6 to which the above-mentioned circuits have been added may also be used.

[0067] 9, the communication circuit 30 may further include a transmitter 31 provided on the second board 22 and a receiver 32 provided on the first board 21. In this case, the communication circuit 30 can perform half-duplex communication between the first board 21 and the second board 22 using the same signal line 30s.

[0068] Specifically, when transmitting a signal from the transmitting device 31 provided on the first board 21 to the receiving device 32 provided on the second board 22, the control device 21a provided on the first board 21 connects the communication cable (signal line 30s and ground line 30g) to the side of the transmitting device 31. The control device 22a provided on the second board 22 connects the communication cable (signal line 30s and ground line 30g) to the side of the receiving device 32. At this time, the receiving device 32 provided on the first board 21 and the transmitting device 31 provided on the second board 22 are disconnected from the circuit.

[0069] Conversely, when transmitting a signal from the transmitting device 31 provided on the second board 22 to the receiving device 32 provided on the first board 21, the control device 21a provided on the first board 21 connects the communication cable (signal line 30s and ground line 30g) to the side of the receiving device 32. The control device 22a provided on the second board 22 connects the communication cable (signal line 30s and ground line 30g) to the side of the transmitting device 31. At this time, the transmitting device 31 provided on the first board 21 and the receiving device 32 provided on the second board 22 are disconnected from the circuit.

[0070] Furthermore, transmission of a signal from the transmitter 31 provided on the second board 22 to the receiver 32 provided on the first board 21 can be performed while the power supply circuit 40 is able to supply power. Therefore, for example, a signal transmitted from the transmitter 31 provided on the second board 22 to the receiver 32 provided on the first board 21 is expected to be a response to a signal transmitted from the transmitter 31 provided on the first board 21 to the receiver 32 provided on the second board 22. Note that although the communication circuit 30 shown in FIG. 9 is the communication circuit 30 shown in FIG. 3 to which the transmitter 31 and receiver 32 have been added, the communication circuit 30 shown in FIG. 6 to which the transmitter 31 and receiver 32 have been added may also be used.

[0071] 1-3. Example of the configuration of the substrate work line WL0 In the substrate-related work line WL0, substrate-related work machines WM0 perform predetermined substrate-related work on substrates 90. There are no limitations on the types and number of substrate-related work machines WM0 that make up the substrate-related work line WL0. As shown in Fig. 10, the substrate-related work line WL0 of this embodiment is equipped with multiple substrate-related work machines WM0, including a printer WM1, a print inspection machine WM2, a component mounting machine WM3, a reflow furnace WM4, and a visual inspection machine WM5, and the substrates 90 are transported in the above order by a substrate transport device.

[0072] The printer WM1 prints solder at the mounting positions of multiple components 91 on the board 90. The print inspection machine WM2 inspects the printing condition of the solder printed by the printer WM1. As shown in FIG. 11, the component mounting machine WM3 mounts multiple components 91 on the board 90 on which solder has been printed by the printer WM1. There may be one or more component mounting machines WM3. When multiple component mounting machines WM3 are provided, the multiple component mounting machines WM3 can share the mounting work of multiple components 91.

[0073] The reflow furnace WM4 heats the board 90 on which multiple components 91 have been mounted by the component mounting machine WM3, melting the solder and performing soldering. The visual inspection machine WM5 inspects the mounting state of the multiple components 91 mounted by the component mounting machine WM3. In this way, the board-related work line WL0 uses multiple board-related work machines WM0 to sequentially transport the boards 90 and perform production processes including inspection processes to produce board products 900. Note that the board-related work line WL0 can also be equipped with board-related work machines WM0 such as a function inspection machine, a buffer device, a board supply device, a board inverting device, a shield mounting device, an adhesive application device, and an ultraviolet irradiation device as needed.

[0074] The substrate-related performing machines WM0 and the line management device LC0 that make up the substrate-related performing line WL0 are communicatively connected by a communication unit. The line management device LC0 and the management device HC0 are communicatively connected by the communication unit. The communication unit can communicatively connect them by wire or wirelessly, and various communication methods can be used.

[0075] In the embodiment, a local area network (LAN) is configured by the plurality of substrate-related performing machines WM0, the line management device LC0, and the management device HC0. Therefore, the plurality of substrate-related performing machines WM0 can communicate with each other via the communication unit. Furthermore, the plurality of substrate-related performing machines WM0 can communicate with the line management device LC0 via the communication unit. Furthermore, the line management device LC0 and the management device HC0 can communicate with each other via the communication unit.

[0076] The line management device LC0 controls the multiple substrate-related performing machines WM0 that make up the substrate-related performing line WL0 and monitors the operating status of the substrate-related performing line WL0. The line management device LC0 stores various control data for controlling the multiple substrate-related performing machines WM0. The line management device LC0 transmits the control data to each of the multiple substrate-related performing machines WM0. Furthermore, each of the multiple substrate-related performing machines WM0 transmits its operating status and production status to the line management device LC0.

[0077] The management device HC0 manages at least one line management device LC0. For example, the operating status and production status of the substrate-related performing machine WM0 acquired by the line management device LC0 are transmitted to the management device HC0 as necessary. The management device HC0 is provided with a storage device. The storage device can store various acquired data acquired by the substrate-related performing machine WM0. For example, various image data captured by the substrate-related performing machine WM0 is included in the acquired data. A record (log data) of the operating status acquired by the substrate-related performing machine WM0 is also included in the acquired data. The storage device can also store various production information related to the production of the board products 900.

[0078] 1-4. Example of component placement machine WM3 configuration 11, the component mounting machine WM3 mounts a plurality of components 91 on a board 90. As shown in FIG. 11, the component mounting machine WM3 includes a board transport device 811, a component supply device 812, a component transfer device 813, a component camera 814, a board camera 815, and a control device 816.

[0079] The board transport device 811 is configured, for example, by a belt conveyor or the like, and transports the board 90 in a transport direction (X-axis direction). The board 90 is a circuit board on which electronic circuits, electric circuits, magnetic circuits, etc. are formed. The board transport device 811 transports the board 90 into the component mounting machine WM3 and positions the board 90 at a predetermined position within the machine. After the component mounting machine WM3 has completed the mounting process of multiple components 91, the board transport device 811 transports the board 90 out of the component mounting machine WM3.

[0080] The component supply device 812 supplies a plurality of components 91 to be mounted on the board 90. The component supply device 812 is equipped with a plurality of feeders 812a arranged along the transport direction (X-axis direction) of the board 90. Each of the plurality of feeders 812a is equipped with a reel. A carrier tape storing a plurality of components 91 is wound around the reel. The feeder 812a feeds the carrier tape by a pitch to supply the components 91 so that they can be picked up at a supply position located at the tip side of the feeder 812a. The component supply device 812 can also supply electronic components (e.g., lead components) that are relatively large compared to chip components and the like, arranged on a tray.

[0081] The component transfer device 813 includes a head drive device 813a and a movable table 813b. The head drive device 813a is configured to be able to move the movable table 813b in the X-axis direction and the Y-axis direction (directions perpendicular to the X-axis direction in a horizontal plane) using a linear motion mechanism. A mounting head 820 is detachably (replaceably) attached to the movable table 813b using a clamp member. The mounting head 820 uses at least one holding member 830 to pick up and hold components 91 supplied by the component supply device 812, and mounts the components 91 on the board 90 positioned by the board transport device 811. The holding member 830 can be, for example, a suction nozzle or a chuck.

[0082] The component camera 814 and the board camera 815 may be well-known imaging devices. The component camera 814 is fixed to a base of the component mounting machine WM3 so that its optical axis faces upward in the vertical direction (the Z-axis direction, which is perpendicular to the X-axis and Y-axis directions). The component camera 814 can capture images of components 91 and the like held by the holding member 830 from below. The board camera 815 is mounted on the movable stage 813b of the component transfer device 813 so that its optical axis faces downward in the vertical direction (the Z-axis direction). The board camera 815 can capture images of boards 90 and the like from above. The component camera 814 and the board camera 815 capture images based on control signals sent from the control device 816. Image data of the images captured by the component camera 814 and the board camera 815 is sent to the control device 816.

[0083] The control device 816 includes a known arithmetic unit and memory device, and forms a control circuit. Information output from various sensors provided in the component mounting machine WM3, image data, etc. are input to the control device 816. The control device 816 sends control signals to each device based on a control program and predetermined mounting conditions that have been set in advance.

[0084] For example, the control device 816 causes the board camera 815 to capture an image of the board 90 positioned by the board transport device 811. The control device 816 processes the image captured by the board camera 815 to recognize the positioning state of the board 90. The control device 816 also causes the holding member 830 to pick up and hold the component 91 supplied by the component supply device 812, and causes the component camera 814 to capture an image of the component 91 held by the holding member 830. The control device 816 processes the image captured by the component camera 814 to recognize the orientation of the component 91.

[0085] The control device 816 moves the holding member 830 toward above the intended placement position that is set in advance by a control program or the like. The control device 816 also corrects the intended placement position based on the positioning state of the board 90, the attitude of the component 91, and the like, and sets the placement position where the component 91 will actually be placed. The intended placement position and the placement position include a rotation angle in addition to the position (X-axis coordinate and Y-axis coordinate).

[0086] The control device 816 corrects the target position (X-axis coordinate and Y-axis coordinate) and rotation angle of the holding member 830 to match the placement position. The control device 816 lowers the holding member 830 at the corrected rotation angle in the corrected target position to place the component 91 on the board 90. The control device 816 repeats the above pick-and-place cycle to perform the placement process of placing multiple components 91 on the board 90.

[0087] 1-5. Configuration example of display device 70 As described above, the device 60 is not limited as long as it consumes less power than the power supplied by the power supply circuit 40 (roughly equivalent to the remaining power obtained by subtracting the power consumed by the termination device 33 from the output power of the transmission device 31). For example, the device 60 includes a display device 70 that displays information about the device DD0 that is equipped on the substrate-related operation machine WM0 that performs a predetermined substrate-related operation on the board 90. The display device 70 may take various forms as long as it can display information about the device DD0.

[0088] For example, if the substrate-related operation operation machine WM0 is the component mounting machine WM3, the device DD0 includes a feeder 812a. The feeder 812a is installed in one of the multiple slots of the component supply device 812. As shown in FIG. 12, the display device 70 is disposed in a position (e.g., the front) of the substrate-related operation operation machine WM0 (component mounting machine WM3) that is easily visible to the operator. Also, as shown in FIG. 13, the display device 70 has individual display units 71 at positions corresponding to the multiple slots. A plurality of individual display units 71 are provided, one for each slot.

[0089] Each of the multiple individual display units 71 can display the status of the feeder 812a installed in the slot. Note that numbers or the like indicating slot numbers that identify the multiple slots are provided near each of the multiple individual display units 71. The status of the feeder 812a displayed by the individual display unit 71 includes, but is not limited to, a normal status, an abnormal status, a warning status, and the like. The normal status indicates that the feeder 812a is properly installed in the slot and is operable.

[0090] The abnormal state includes a state in which the feeder 812a is properly installed in the slot but an abnormality such as a component shortage, a component supply failure, a collection error, an image processing error, or a communication error has occurred. The abnormal state also includes a state in which the feeder 812a is not properly installed in the slot. The warning state includes a state in which the feeder 812a is properly installed in the slot but, for example, communication is in progress between the feeder 812a and the control device 816, and a warning is issued to the operator to remove the feeder 812a.

[0091] Each of the plurality of individual display units 71 is provided with a plurality of types of light sources (for example, three types: red, green, and yellow). The light sources may be, for example, the light-emitting diodes 60b shown in FIG. 5 described above. Each of the plurality of individual display units 71 lights up the light source according to the state of the feeder 812a installed in the slot.

[0092] For example, each of the multiple individual display units 71 lights up a green light-emitting diode 60b when the feeder 812a installed in the slot is in a normal state. Each of the multiple individual display units 71 lights up a red light-emitting diode 60b when the feeder 812a installed in the slot is in an abnormal state. Each of the multiple individual display units 71 lights up a yellow light-emitting diode 60b when the feeder 812a installed in the slot is in a warning state. In this way, each of the multiple individual display units 71 can indicate the state of the feeder 812a installed in the slot by emitting light from the light-emitting diode 60b of a single color. Also, each of the multiple individual display units 71 can indicate the state of the feeder 812a installed in the slot by emitting light from the light-emitting diode 60b of multiple colors.

[0093] 2. Examples of Effects of the Embodiments The power supply device 10 includes the power supply circuit 40, and therefore can supply power to the device 60 provided on the second board 22, including the receiving device 32. Therefore, the power supply device 10 can omit the power line 20p that supplies drive power to the second board 22. [Explanation of symbols]

[0094] 10: power supply device, 20: power supply, 20g: ground, 21: first substrate, 22: second board, 30: communication circuit, 30s: signal line, 31: transmitting device, 32: receiving device, 33: Termination device, 40: Power supply circuit, 41: First diode, 41a: Anode, 41k: cathode, 42: second diode, 42a: anode, 42k: cathode, 43: smoothing capacitor, 51: current limiting device, 52: overload protection device, 53: Overload guide device, 60: Equipment, 70: Display device, 90: Board, DD0: Device, WM0: Substrate work machine.

Claims

1. a communication circuit including a transmitter provided on a first board to which drive power is supplied from a power supply, a receiver provided on a second board not to which drive power is supplied from the power supply, and a termination device, the communication circuit transmitting a signal from the transmitter to the receiver via a signal line; a power supply circuit that is connected in parallel to the signal line of the communication circuit and converts the remaining power of the signal to generate supply power to be supplied to devices provided on the second board including the receiving device based on the remaining power obtained by subtracting the power consumed by the terminating device from the output power of the signal transmitted by the transmitting device; and A power supply device comprising:

2. A circuit comprising a transmitter provided on a first board to which drive power is supplied from a power source, a receiver provided on a second board not supplied with drive power from a power source, and a terminal device, wherein the circuit comprises a communication circuit for transmitting a signal from the transmitter to the receiver via a signal line; a power supply circuit connected in parallel to the signal line of the communication circuit, the power supply circuit generating power to be supplied to devices provided on the second board including the receiving device based on the remaining power obtained by subtracting the power consumed by the terminating device from the output power of the transmitting device; Equipped with The transmitter is a power supply device that outputs a signal with a voltage higher than the rated output voltage of the power supply circuit plus a voltage drop caused by the power supply circuit.

3. A circuit comprising a transmitter provided on a first board to which drive power is supplied from a power source, a receiver provided on a second board to which drive power is not supplied from a power source, and a terminal device, wherein the circuit comprises a communication circuit for transmitting a signal from the transmitter to the receiver via a signal line; a power supply circuit connected in parallel to the signal line of the communication circuit, the power supply circuit generating power to be supplied to devices provided on the second board including the receiving device based on the remaining power obtained by subtracting the power consumed by the terminating device from the output power of the transmitting device; an overload guidance device that provides overload guidance when the output voltage of the power supply circuit falls below an allowable value; A power supply device comprising:

4. A circuit comprising a transmitter provided on a first board to which drive power is supplied from a power source, a receiver provided on a second board to which drive power is not supplied from a power source, and a terminal device, wherein the circuit comprises a communication circuit for transmitting a signal from the transmitter to the receiver via a signal line; a power supply circuit connected in parallel to the signal line of the communication circuit, the power supply circuit generating power to be supplied to devices provided on the second board including the receiving device based on the remaining power obtained by subtracting the power consumed by the terminating device from the output power of the transmitting device; Equipped with The power supply device includes a display device that displays information about a device installed in a substrate-related operation machine that performs a predetermined substrate-related operation on a substrate.

5. 5. The power supply device according to claim 1, wherein the power supply circuit converts the remaining AC power into DC power to generate the supply power.

6. the signal transmitted in the communication circuit is a differential signal, The power supply circuit includes: a first diode having an anode connected to one of the signal lines of the differential signals; a second diode having an anode connected to the other signal line of the differential signal; a smoothing capacitor having a positive electrode connected to both the cathode of the first diode and the cathode of the second diode and a negative electrode connected to ground; The power supply device according to claim 5 , comprising:

7. the signal transmitted in the communication circuit is a single-ended signal; The power supply circuit includes: a first diode having an anode connected to the signal line; a second diode having an anode connected to ground; a smoothing capacitor having a positive electrode connected to both the cathode of the first diode and the cathode of the second diode and a negative electrode connected to the ground; The power supply device according to claim 5 , comprising:

8. 8. The power supply device according to claim 6, wherein the smoothing capacitor has a capacitance set so that a ripple contained in the DC power falls within a predetermined range.

9. The power supply device according to any one of claims 1 to 8, further comprising a current limiting device that limits the output of the power supply circuit when the supply current supplied from the power supply circuit to the device exceeds an allowable value.

10. 10. The power supply device according to claim 1, further comprising an overload protection device that limits the output of the power supply circuit when the output voltage of the power supply circuit falls below an allowable value.

11. The power supply device according to any one of claims 1 to 10, wherein the communication circuit further includes a circuit for transmitting a signal from a transmitting device provided on the second board to a receiving device provided on the first board, and full-duplex communication is performed between the first board and the second board using different signal lines.

12. The power supply device according to any one of claims 1 to 11, wherein the communication circuit further comprises a transmitting device provided on the second board and a receiving device provided on the first board, and half-duplex communication is performed between the first board and the second board using the same signal line.

Images