JP2009130610A - Data transmitter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data transmitter for a module type measuring instrument, capable of transmitting a signal of a gigabit band between printed circuit boards requiring electrical insulation. <P>SOLUTION: The data transmitter for transmitting a signal of a Gbps band between the printed circuit boards includes a pair of connectors which are provided at ends of the printed circuit boards and have an insulating film applied onto the surface, a semiconductor laser provided on one of the pair of connectors, and a photodiode which is provided on the other of the pair of connectors and receives light made incident from the semiconductor laser. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a data transmission device for a modular measuring instrument that transfers data between printed circuit boards, and in particular, a module type capable of transmitting a gigabit second (Gbps) band signal between printed circuit boards that require electrical insulation. The present invention relates to a data transfer device for a measuring instrument.

In module type measuring instruments used for measuring voltage waveforms of high voltage exceeding several hundreds [V] and voltage waveforms of minute voltage less than 1 [mV], printed with electrical parts for acquiring measurement data It is important to electrically insulate the circuit board (measurement module) and the printed circuit board (motherboard) on which electrical components for processing the measurement data are mounted.

  For example, in the measurement of a high voltage waveform, it is possible to secure the protection on the data processing unit side and the safety of the user by insulation.

On the other hand, in the case of a module-type measuring instrument, the measurement module is replaced with an appropriate one depending on the type of object to be measured, and this replacement is performed between the mother board and the motherboard via a connector. Prior art documents of such a data transfer device having an insulated transmission structure include the following.

Japanese Patent Laid-Open No. 2005-18550

FIG. 4 is a block diagram of a conventional modular measuring instrument data transmission apparatus. For example, an electrical component for acquiring measurement data is mounted on the input board 1. An FPGA (Field Programmable Gate Array) 2 outputs a differential signal (eg, 300 Mbps) such as LVDS (Low Voltage Differential Signaling) or a serial bus. Pattern 3 transmits, for example, an operating LVDS signal. The connector 4 is mounted on the end face of the input board 1, and when the signal level is in the Gbps band, the connector itself is also impedance-controlled.

The connector 5 is fitted with the connector 4 and is impedance controlled similarly to the connector 4. The motherboard 6 is mounted with electrical components that perform data processing of data acquired by the input board 1. The FPGA 7 receives data through the pattern 3 and the connectors 4 and 5 and performs data processing.

As described above, the conventional data transmission device of the modular measuring instrument uses the connectors 4 and 5 whose impedances are controlled to transmit signals between the printed circuit boards (the input board 1 and the mother board 6).

  However, when transmitting signals in the Gbps band, the connectors 4 and 5 for connecting the printed circuit boards need expensive impedance-controlled connectors. Moreover, if there are many parallel wirings, the number of pins of the connectors 4 and 5 will increase, and the connectors 4 and 5 will become larger and more expensive.

  In particular, module-type measuring instruments are frequently attached and detached, so when a normal metal connector is used, the contact resistance may increase due to wear or the fitting may deteriorate. In the case of a high frequency band, the contact resistance becomes a noise source.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a data transfer device for a modular measuring instrument that can transmit a gigabit band signal between printed circuit boards that require electrical insulation. And

In order to achieve such a problem, the invention described in claim 1
In a data transmission device that transmits signals in the Gbps band between printed circuit boards,
A pair of connectors provided at an end of the printed circuit board and having an insulating film on the surface;
A semiconductor laser provided on one of the pair of connectors;
A photodiode provided on the other of the pair of connectors and receiving light incident from the semiconductor laser is provided.

According to a second aspect of the present invention, in the data transmission device according to the first aspect,
A driver for driving the laser; and a limiting amplifier for amplifying the voltage output from the photodiode.

The invention according to claim 3 is the data transmission device according to claim 1 or 2,
A lens for condensing the light output from the laser is provided.

Furthermore, the invention according to claim 4 is the data transmission apparatus according to any one of claims 1 to 3,
The laser is a VCSEL array, and the photodiode is a photodiode array.

  The present invention has the following effects. Since data is transferred between printed boards using optical signals, it is possible to provide a data transfer device for a modular measuring instrument that can transmit a gigabit band signal between printed boards that require electrical insulation.

The data transmission apparatus of the present invention will be described below. FIG. 1 shows an example of the configuration of a data transmission device for a modular measuring instrument according to the present invention. The FPGA 10 may be an ASIC, and outputs differential signals such as LVDS, CML (current mode logic), and LVPECL (low-voltage pseudo-emitter-coupled logic) in parallel. Here, these operation signals are assumed to be signals in the Gbps band. The driver IC 20 receives a signal from the FPGA 10 and drives a VCSEL array 31 described later.

The connector 30 is used by being fitted to a connector 40 described later, and an insulating film is applied to the end surface. A VCSEL array 31 (Vertical Cavity Surface Emitting LASER) (vertical cavity surface emitting laser) is a kind of semiconductor laser, and can be manufactured at a relatively low cost as compared with other semiconductor lasers. The lens array 32 is a condensing lens, and condenses and outputs the light output from the VCSEL array 31.

Note that at least as many combinations of these lasers and lenses as the number of signal lines are required. The printed circuit board on which the FPGA 10, the driver IC 20, and the connector 30 are mounted is not shown.

The connector 40 is used by being fitted to the connector 30, and an end surface is provided with an insulating film. The PD array 41 (Photodiode) generates a voltage when light is incident thereon. Here, since the signal transfer between the PD array 41 and the VCSEL is performed by an optical signal, the connector 30 and the connector 40 are not electrically connected and insulation is maintained.

The limiting amplifier 50 is a logarithmic amplifier and amplifies the voltage output from the PD array 41. The FPGA 60 may be an ASIC, and receives differential signals in parallel and performs data processing. The printed circuit board on which the connector 40, the limiting amplifier 50, and the FPGA 60 are mounted is not shown.

In this way, the connectors 30 and 40 having the insulating film are connected to each other, and the signal is transferred between the printed circuit boards via the VCSEL array 31 and the PD array 41, so that the insulation between the printed circuit boards is maintained. Band signals can be transmitted.

Further, since signals are transferred using these components, it is not necessary to use an expensive connector corresponding to the Gbps band, and a data transmission apparatus can be configured at a low cost. Further, since the attenuation amount of the signal in the Gbps band can be reduced at the connector portion, an improvement in the opening degree of the differential signal eye pattern can be expected.

Furthermore, even if the attachment and detachment is performed frequently, the contact resistance does not increase, so that noise in the high frequency band is reduced.

Note that the present invention can be applied to configurations other than those shown in FIG. 1 as long as electrical insulation is required and high-speed serial transmission is performed. Moreover, when electrical insulation is not required, it can be used as a substitute for a high frequency connector.

Next, application examples of the present invention will be described. FIG. 2 shows an application example of the present invention. A differential signal such as LVDS, CML, and LVPECL is input to the connector 70, and an insulating film is applied to the end face. The laser driver 71 is prepared for the signal line, and is provided in the connector 70 unlike FIG. The laser 72 is also required for the signal lines, and a VCSEL is used as in FIG. Although a condenser lens is also required on the output side of the laser 72, the illustration is omitted.

As described above, the laser driver 71 can be provided inside the connector 70 and the photodiode 81 can be provided inside the connector 80.

Next, another application example of the present invention will be described. FIG. 3 shows another application example of the present invention. The connector 100 includes an LD unit 101, a PD unit 102, a normal pin 103, a PD unit 104, and an LD unit 105. On the other hand, the connector 110 includes a PD unit 111, an LD unit 112, a normal pin 113, an LD unit 114, and a PD unit 115. In this way, bidirectional communication can also be performed.

Next, the connection relationship of each component will be described. The optical signal output from the LD unit 101 is received by the PD unit 111. The optical signal output from the LD unit 112 is received by the PD unit 102. Signals using these optical elements are in the Gbps band.

On the other hand, the normal pins 103 are connected to the normal pins 113. The signals used for these pins are signals having a speed of 100 Mbps or less in addition to the power line. The optical signal output from the LD unit 114 is received by the PD unit 104, and the optical signal output from the LD unit 105 is received by the PD unit 115.

As described above, since high-speed serial transmission uses light and uses a normal pin for power lines and transmissions of 100 Mbps or less, it includes a laser driver and an amplifier not shown. Even if the parts around the connector are arranged, the data transmission device can be configured at a lower cost than the connector corresponding to the Gbps band.

It is a structural example of the data transmission apparatus of the module type measuring device by this invention. It is an application example of the present invention. It is another application example of the present invention. It is a block diagram of the data transmission apparatus of the conventional module type measuring device.

Explanation of symbols

10 FPGA
20 Driver IC
30 Connector 31 VCSEL Array 32 Lens Array 40 Connector 41 PD Array 50 Limiting Amplifier 60 FPGA
70 Connector 71 Laser 80 Connector 81 Photodiode 82 Limiting Amplifier

Claims (4)

In a data transmission device that transmits signals in the Gbps band between printed circuit boards,
A pair of connectors provided at an end of the printed circuit board and having an insulating film on the surface;
A semiconductor laser provided on one of the pair of connectors;
A data transmission device comprising a photodiode provided on the other of the pair of connectors and receiving light incident from the semiconductor laser. The data transmission apparatus according to claim 1, further comprising: a driver that drives the laser; and a limiting amplifier that amplifies the voltage output from the photodiode. 3. A data transmission apparatus according to claim 1, further comprising a lens for condensing light output from the laser. 4. The data transmission apparatus according to claim 1, wherein the laser is a VCSEL array, and the photodiode is a photodiode array.

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