JP4878971B2 - Open collector type input / output interface circuit and motor drive device - Google Patents

Description

  The present invention relates to an open collector type input / output interface circuit and a motor driving device used for connection to an external device formed on a motor substrate, for example.

A drive control system such as a general industrial machine or an OA device is provided with an input / output interface circuit for connection to an external device. For example, a motor board provided with a motor drive circuit is provided with a connection terminal (connector) for connecting to an external device and an input / output interface circuit connected to the connector. An input / output terminal of the connector with an external device is required for one input or one output (N interface circuits are required for N inputs / outputs). For example, an open collector (open drain) configuration may be employed as the output terminal specification. That is, the signal is received by connecting the collector (drain) electrode of the switching element (transistor, FET) and the connector. An open collector type interface circuit can be suitably used as a digital output terminal because an output circuit can be connected in parallel to form an OR circuit (a logic operation circuit whose output is turned on when any input is turned on). . Also, the signal level can be freely converted by the pull-up voltage on the external device side.
Japanese Patent Laid-Open No. 2001-100808

In the input / output interface circuit described above, when the number of input / output terminals connected to an external device increases, the number of pins of the connector increases, and an interface circuit corresponding to the increase is required, so that the size of the circuit board increases. For this reason, when the installation space of the circuit board is limited, the function cannot be easily expanded.
Further, by changing the setting of the register for setting the input / output port of the microcomputer (microcomputer), the input / output port of the microcomputer can be used as it is as an input / output interface. However, such a mode is difficult to adopt in consideration of design flexibility such as malfunction due to noise mixing and conversion of signal level with an external device.

  The present invention has been made to solve these problems, and an object of the present invention is to provide an open collector type input / output interface circuit that has a high degree of design freedom for a user even in a small space, and the interface circuit is formed. An object of the present invention is to provide a motor drive device that can be multi-functional even with a small size using a motor substrate.

In order to achieve the above object, the present invention comprises the following arrangement.
A control unit having a plurality of input / output ports for controlling driving of the drive source, a connector terminal for connecting the control unit and an external device, and a base terminal connected to the first input / output port of the control unit via a base resistor A first switching element having a collector terminal connected to the connector terminal via a pull-up resistor, and a first rectifying element and a filter circuit connected between the connector terminal and the second input / output port of the control unit. And a second switching element having a base terminal connected to the third input / output port of the control unit via a base resistor and a collector terminal connected to the connector terminal, and a third input / output port. And a second energization circuit that allows energization from the connector terminal to the second switching element by switching the output level of the first output port. The first switching element is turned ON / OFF by switching the level, the first energizing circuit and the second energizing circuit are switched and energized, and the same connector terminal is used both as an input terminal and an output terminal. To do.
The collector terminal of the first switching element is connected to the anode side of the diode via a pull-up resistor, the collector terminal of the second switching element is connected to the cathode side of the diode, and the cathode terminal of the diode is It is connected to a connector terminal and is connected to an open collector.
When the first switching element is ON, a signal input to the connector terminal through the first energization circuit is read by the second input / output port of the control unit, and the connector terminal is used as the input terminal. When the first switching element is OFF, the control unit outputs the connector terminal through the second energization circuit by setting the output level of the third input / output port to high or low to turn the second switching element ON or OFF. It is used as a terminal.
Further, in the motor drive device, the heat sink is assembled to the second bracket opposite to the first bracket on the motor shaft side, and the open collector type input / output interface for connecting the connector terminal and the control unit described above. A motor board on which a circuit is provided is supported by a heat radiating plate, housed between the second bracket, and assembled in the motor projection area in the axial direction.

If the above-described open collector type input / output interface circuit is used, the first switching element is turned ON / OFF by switching the output level of the first input / output port by the control unit, and the first energizing circuit and the second By switching the energization circuit and energizing, the same connector terminal can be used both as an input terminal and an output terminal. Therefore, the same connector terminal can be used as an input terminal or output terminal according to the specifications of the external device, and even if the number of connector terminals is limited in a limited installation space, the degree of freedom in design is ensured as much as possible. be able to.
The collector terminal of the first switching element is connected to the anode side of the diode via a pull-up resistor, the collector terminal of the second switching element is connected to the cathode side of the diode, and the cathode terminal of the diode is the connector terminal If a high voltage is applied to the connector terminal, the diode is blocked from energizing the first energizing circuit, so that the second input / output port may be damaged. Absent.
Further, when the first switching element is ON, a signal input to the connector terminal through the first energization circuit is read from the second input / output port of the control unit and the connector terminal is used as the input terminal.
Further, when the first switching element is OFF, the output level of the third input / output port of the control unit is set to high or low so that the second switching element is turned ON or OFF, thereby connecting the same connector terminal to the output terminal. Use as
In this way, by simply switching the input / output port setting and output level of the control unit, the first and second energization circuits can be switched to use the same connector terminal as the input / output terminal. It is possible to provide an input / output interface circuit that can meet design needs and has a high degree of design freedom even in a space-saving manner.
In the motor drive device, the motor board provided with the open collector type input / output interface circuit for connecting the connector terminal and the control unit described above is supported by the heat radiating plate and housed between the bracket and the motor is projected in the axial direction. When assembled within the area, it is possible to provide a motor drive device that has a high degree of design freedom and can be multifunctional even if it is small.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of an open collector interface circuit according to the invention will be described with reference to the accompanying drawings. As an example, the open collector type interface circuit in the present embodiment will be described in a case where it is provided in a motor driving device of a stepping motor. The open collector type interface circuit is provided on the motor board that connects the motor driving device and the external device. Hereinafter, a schematic configuration of the motor drive device will be described.

With reference to FIG.5 and FIG.6, the schematic structure of the motor drive device using a stepping motor as an example is demonstrated.
A rotor core (not shown) is provided with a rotor core having rotor teeth, and rotates together with a rotating shaft 11 made of a nonmagnetic material. The stator is provided with the rotor surrounded by the stator core 12. The stator core 12 is provided with a pole having stator small teeth opposed to the rotor small teeth provided on the rotor core, and a magnet wire is wound around the pole via an insulator (not shown). ) By switching the excitation phase to the magnet wire wound around the pole of the stator core 12 and energizing it, the rotor small teeth of the rotor core rotate to a position that is magnetically stable to the stator small teeth facing the stator small teeth. It is supposed to be.

  5X, Y, and Z, the rotor is supported by a pair of brackets 13 and 14 via bearings. The stator core 12 is sandwiched between the pair of brackets 13 and 14 on both sides in the axial direction and fixed with screws. The rotating shaft 11 is provided so as to protrude outward through the first bracket 13 on the motor shaft side. Further, a heat radiating plate 15 is assembled to the second bracket 14 on the side opposite to the first bracket 13. In FIG. 6, the board | substrate recessed part 17 is formed in the inner surface side of the heat sink 15, and the fin 18 is formed in the outer surface side. The motor substrate 16 is supported by the substrate recess 17 of the heat radiating plate 15 and accommodated between the second bracket 14 and assembled in the motor projection area in the axial direction.

  In FIG. 6, an open collector type interface circuit for connecting the control unit 1 and the connector terminal 2 is formed on the motor board 16. Specifically, on the upper surface side (motor side) of the motor board 16, the connector terminals 2 and electronic components (chip resistor, chip capacitor, etc.) 19 with a relatively small amount of heat generation are mounted on the board. In addition, on the lower surface side (heat radiating plate side) of the motor substrate 16, an electrolytic capacitor 20, an IC 21, and a control unit (microcomputer) 1 that generate a relatively large amount of heat are mounted on the substrate. The motor board 16 is connected to the motor by a wiring cable (FFC, FPC, cable, etc.) 22. As will be described later, a single connector terminal 2 serves as both an input terminal and an output terminal by setting the control unit 1.

Next, an open collector type interface circuit formed on the motor substrate 16 will be described with reference to FIG.
The control unit 1 is a microcomputer and includes control elements such as an MPU and a CPU. The microcomputer 1 includes a plurality of input / output ports P1, P2, P3... And controls driving of a motor (not shown). In the microcomputer 1, the ports P1, P2, P3... Can be set to either input terminals or output terminals. The connector terminal 2 is provided in the motor drive circuit together with the microcomputer 1 and connects the microcomputer 1 and an external device.

  The first port P1 of the microcomputer 1 is used as a first input / output port. A first transistor (PNP transistor; first switching element) 3 is connected between the first port P1 and the anode of the diode D via a pull-up resistor R2. Specifically, the base terminal of the first transistor 3 is connected to the first port P1. A DC voltage of DC 5 V is supplied to the emitter terminal of the first transistor 3. The collector terminal of the first transistor 3 is connected to the anode terminal of the diode D via the pull-up resistor R2. The cathode terminal of the diode D is connected to the connector terminal 2. A pull-down resistor R1 is connected to the base terminal of the first transistor 3.

The second port P2 of the microcomputer 1 is used as a second input / output port. As an example, a filter circuit 5 diode D composed of a resistor R3 and a capacitor C1 is connected in series between the second port P2 and the connector terminal 2 to form a first energization circuit A. In addition, although the filter circuit 5 illustrated the passive filter which combined resistance R3 and the capacitor | condenser C1, the passive filter comprised by the combination of other passive components or an active filter may be sufficient.
When a signal is input to the connector terminal 2 when the first transistor 3 is ON, a current flows toward the external connection device via the pull-up resistor R2, the diode D, and the connector terminal 2 connected to the DC power supply (DC5V). As a result, the voltage level of the connector terminal 2 changes. At this time, the change in the voltage level of the connector terminal 2 is read by the second port P2 after removing noise by the filter circuit 5.

  The third port P3 of the microcomputer 1 is used as a third input / output port. A second transistor (NPN type transistor; second switching element) 4 is connected between the third port P 3 and the cathode of the diode D. Specifically, the base terminal of the second transistor 4 is connected to the third port P3. The collector terminal of the second transistor 4 is connected to the connector terminal 2 (on the cathode terminal side of the diode D). The emitter terminal of the second transistor 4 is connected to the ground (GND) side.

  A second energization circuit B that allows energization to the ground from the connector terminal 2 to the collector-emitter of the second transistor 4 is formed. Here, when an input voltage unacceptable by the microcomputer 1 is supplied to the connector terminal 2, the second input / output port P2 is not destroyed because it is blocked by the diode D.

  That is, the first transistor 3 is turned on / off by switching the output level of the first port P1 by the microcomputer 1, and the first energizing circuit A and the second energizing circuit B are switched to be energized to be the same. The connector terminal 2 is used as both an input terminal and an output terminal. Hereinafter, a specific description will be given using an equivalent circuit.

  In FIG. 1, when the microcomputer 1 sets the output level of the first port P1 to L (low), the first transistor 3 is turned on and the pull-up resistor R2 is connected to the DC power supply (DC5V). The third port P3 is set as an output port and fixed at a low level. At this time, the interface circuit of FIG. 1 can be equivalently expressed as a first energization circuit A as shown in FIG. That is, when a signal is input to the connector terminal 2 when the first transistor 3 is ON, the signal goes to the external connection device via the pull-up resistor R2, the diode D, and the connector terminal 2 connected to the DC power supply (DC5V). Current flows, and the voltage level of the connector terminal 2 changes. The change in the voltage level of the connector terminal 2 is read by the second input port P2 after removing noise by the filter circuit 5. At this time, the connector terminal 2 is used as an input terminal of the motor drive device.

  Next, in FIG. 3, when the microcomputer 1 sets the output level of the first port P1 to H (high), the first transistor 3 is turned off, and the pull-up resistors R2 and R3 are connected to the DC power supply (DC5V). Disconnected state. Here, the second port P2 sets the input / output setting to output. At this time, the interface circuit of FIG. 3 can be equivalently expressed as a second energization circuit B as shown in FIG. That is, when the first transistor 3 is OFF, the output level of the third port P3 of the microcomputer 1 is set to high or low, and the second transistor 4 is turned ON or OFF. Thus, for example, if 24 V or 12 V DC power is supplied from the connector terminal 2 through the pull-up resistor R on the external device side, the input signal to the connector terminal 2 is sent to the second transistor 4 (second energization). Output to ground through circuit B). At this time, the same connector terminal 2 is used as an output terminal of the motor drive device.

  When the connector terminal 2 is used as an open collector output terminal as shown in FIG. 4, even if an input voltage unacceptable by the microcomputer 1 is supplied to the connector terminal 2, the diode D leads the first energizing circuit A side. Therefore, there is no problem that the second input / output port P2 is destroyed.

  As described above, the same connector terminal can also be used as the input / output terminal by switching to the first energization circuit A or the second energization circuit B simply by switching the setting and output level of the input / output port of the microcomputer 1. As a result, it is possible to provide an input / output interface circuit that can meet a wide range of user customization design needs and has a high degree of design freedom even in a small space.

  In the above embodiment, transistors are used as the first and second switching elements, but other switching elements such as FETs may be used. In this case, the open drain type is used instead of the open collector type, but the effect is the same. Moreover, although the step motor was illustrated as a drive source, other motor drive devices, such as a DC brush motor and a DC brushless motor, may be used.

It is explanatory drawing of the open collector type input / output interface circuit in the case of using a connector terminal as an output terminal. It is explanatory drawing of the equivalent circuit of FIG. It is explanatory drawing of an open collector type input / output interface circuit in the case of using a connector terminal as an input terminal. It is explanatory drawing of the equivalent circuit of FIG. It is the front view, upper view, and lower view of a motor drive device. It is a partially exploded front view of a motor drive device.

Explanation of symbols

A 1st energization circuit B 2nd energization circuit 1 Microcomputer 2 Connector terminal 3 1st transistor circuit 4 2nd transistor circuit 5 Filter circuit 11 Rotating shaft 12 Stator core 13, 14 Bracket 15 Heat sink 16 Motor board 17 Recess for substrate 18 Fin 19 Electronic component 20 Electrolytic capacitor 21 IC
22 Wiring cable

Claims (4)

A control unit that includes a plurality of input / output ports and controls driving of the driving source;
A connector terminal for connecting the control unit and an external device;
A first switching element having a base terminal connected to the first input / output port of the control unit via a base resistor and a collector terminal connected to the connector terminal via a pull-up resistor;
A first energization circuit in which a rectifying element and a filter circuit are connected between the connector terminal and a second input / output port of the control unit;
A second switching element having a base terminal connected to the third input / output port of the control unit via a base resistor and a collector terminal connected to the connector terminal is provided, and the output level of the third input / output port is switched. A second energization circuit that allows energization from the connector terminal to the second switching element,
By switching the output level of the first input / output port by the control unit, the first switching element is turned on / off, the first energizing circuit and the second energizing circuit are switched and energized to the same connector terminal. An open collector type input / output interface circuit characterized by having both an input terminal and an output terminal.   The collector terminal of the first switching element is connected to the anode side of the diode via a pull-up resistor, the collector terminal of the second switching element is connected to the cathode side of the diode, and the cathode terminal of the diode is the connector terminal 2. The open collector type input / output interface circuit according to claim 1, wherein the open collector type input / output interface circuit is connected to an open collector.   When the first switching element is ON, a signal input to the connector terminal through the first energization circuit is read by the second input / output port of the control unit, and the connector terminal is used as the input terminal. When the switching element is OFF, the control unit sets the output level of the third input / output port as high or low and turns the second switching element ON or OFF, thereby using the connector terminal as an output terminal through the second energization circuit. 2. The open collector type input / output interface circuit according to claim 1, which is used.   4. The open collector type according to claim 1, wherein a heat radiating plate is assembled to the second bracket opposite to the first bracket on the motor shaft side, and the connector terminal and the control unit are connected. A motor drive device, wherein a motor board on which an input / output interface circuit is provided is supported by a heat radiating plate and housed between a second bracket and assembled in a motor projection area in an axial direction.

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