Transmission module and circuit board used therein

A transmission module includes an electrically insulative substrate body, a first card edge connector provided at a first end of the substrate body, a second card edge connector provided at a second end of the substrate body, a circuit element mounted on the substrate body, a control element mounted on the substrate body and provided with a built-in memory which controls the circuit element, a first wiring pattern formed on the substrate body for connecting an electrode of the first card edge connector and the control element together, and a second wiring pattern formed on the substrate body for connecting an electrode of the second card edge connector and the control element together.

The present application is based on Japanese patent application No. 2014-144154 filed on Jul. 14, 2014, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a transmission module with a circuit element and a control element mounted on a circuit board, and a circuit board used therein.

2. Description of the Related Art

In recent years, for a transmission module with a microprocessor having a built-in memory mounted on a circuit board, a firmware has been downloaded into the memory built in the microprocessor prior to factory shipment. The circuit board of the transmission module is provided with a pad for firmware downloading, separately from a card edge connector to be connected to a host, from the point of view of size reduction, cost reduction, etc. A probe is brought into contact with that pad, and the firmware is downloaded via this probe. Also, when the circuit board is mounted with an optical element, work such as alignment and adjustment to the amount of light is needed before factory shipment.

Also, there is a conventional transmission module, which, in order to perform unit verification as to whether or not a microprocessor with a built-in memory is operated as intended, measures voltage of a pad via a probe, compares the measured voltage and an intended voltage, and thereby verifies the operation of the microprocessor (Refer to e.g. JP-A-2007-303859).

Also, conventionally, a circuit board has been suggested that is provided with a card edge connector at opposite ends of a substrate body and that is mounted with electronic components thereon (Refer to e.g. JP-A-2013-171985).

SUMMARY OF THE INVENTION

However, the conventional transmission module has been unable to easily perform work, such as the downloading of the firmware and the verification of the operation of the microprocessor, due to requiring the probe for that work as its dedicated tool.

Accordingly, it is an object of the present invention to provide a transmission module, which is capable of easy work such as firmware downloading, verification with no dedicated tool required, and a circuit board to be used in that transmission module.

(1) According to a first embodiment of the invention, a transmission module comprises:

an electrically insulative substrate body;

a first card edge connector provided at a first end of the substrate body;

a second card edge connector provided at a second end of the substrate body;

a circuit element mounted on the substrate body;

a control element mounted on the substrate body and provided with a built-in memory configured to control the circuit element;

a first wiring pattern formed on the substrate body and configured to connect an electrode of the first card edge connector and the control element together; and

a second wiring pattern formed on the substrate body and configured to connect an electrode of the second card edge connector and the control element together.

In the first embodiment, the following modifications and changes may be made.

(i) The transmission module further includes a third wiring pattern formed on the substrate body and configured to directly connect an electrode of the second card edge connector and the circuit element together.

(ii) The circuit element includes a light emitting element and a driving element configured to drive the light emitting element, or a light receiving element and an amplifying element configured to amplify an output signal of the light receiving element.

(iii) The substrate body is rectangular and is provided with the first and second card edge connectors at both ends opposite each other.

(iv) The first and second card edge connectors are configured to be connectable with the same receptacle connectors.

(2) According to a second embodiment of the invention, a transmission module comprises:

an electrically insulative substrate body;

a card edge connector provided at a first end of the substrate body;

a circuit element mounted on the substrate body;

a control element mounted on the substrate body and provided with a built-in memory configured to control the circuit element;

a first wiring pattern formed on the substrate body and configured to connect an electrode of the card edge connector and the control element together; and

a second wiring pattern formed on the substrate body and extending from the control element to a second end of the substrate body.

In the second embodiment, the following modifications and changes may be made.

The transmission module further includes

a third wiring pattern formed on the substrate body and extending from the circuit element to the second end of the substrate body.

(3) According to a third embodiment of the invention, a circuit board comprises:

an electrically insulative substrate body;

a first card edge connector provided at a first end of the substrate body;

a second card edge connector provided at a second end of the substrate body;

a circuit element mounting area provided on an upper or lower surface of the substrate body, the circuit element mounting area configured to be mounted with a circuit element thereon;

a control element mounting area provided on the upper or lower surface of the substrate body, the control element mounting area configured to be mounted with a control element thereon having a built-in memory configured to control the circuit element;

a first wiring pattern formed on the upper or lower surface of the substrate body and configured to connect an electrode of the first card edge connector and the control element mounting area together; and

a second wiring pattern formed on the upper or lower surface of the substrate body and configured to connect an electrode of the second card edge connector and the control element mounting area together.

(Points of the Invention)

The present invention allows for easy work such as firmware downloading, verification, etc. with no dedicated tool required.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Next, an embodiment according to the invention will be explained in conjunction with the accompanying drawings. It should be noted that in these figures elements having substantially the same functions are given the same numerals respectively, and duplicated descriptions thereof are omitted.

FIG. 1is a plan view showing a schematic configuration example of a transmission module in an embodiment according to the invention.FIG. 2is a front view showing the transmission module shown inFIG. 1.FIG. 3is a plan view showing an essential portion of a second card edge connector and a periphery thereof.

(Entire Configuration of the Transmission Module)

This transmission module100includes a circuit board1, and the circuit board1is mounted with a light emitting element array4configured to output an optical signal, a light receiving element array5configured to receive an optical signal, a driver IC6configured to drive the light emitting element array4, a preamplifier IC7configured to amplify an output signal of the light receiving element array5, a switch8configured to switch a circuit, and a CPU (Central Processing Unit)9to control each circuit element on the circuit board1. Here, the light emitting element array (optical element)4, the light receiving element array (optical element)5, the driver IC (driving element)6, the preamplifier IC (amplifying element)7, and the switch8are examples of the circuit elements. The CPU9is an example of a control element. Herein, the control element is used in the sense of excluding the circuit elements.

(Configuration of the Circuit Board)

As shown inFIG. 1, the circuit board1includes a generally rectangular electrically insulative substrate body2, a first card edge connector3A, which is provided at one end (a first end)2ain a longitudinal direction of the substrate body2, a second card edge connector3B, which is provided at the other end (a second end)2bin the longitudinal direction of the substrate body2. The one end2aand the other end2bare opposite each other. It should be noted that the substrate body2may be a rigid or flexible substrate, or a multilayer substrate.

The substrate body2is formed of an electrically insulative material such as glass epoxy resin. The light emitting element array4and the light receiving element array5are mounted on each circuit element mounting areas, respectively, on a lower surface2cof the substrate body2. The driver IC6, the preamplifier IC7and the switch8are mounted on each circuit element mounting areas, respectively, on an upper surface2dof the substrate body2. The CPU9is mounted on a control element mounting area of the upper surface2dof the substrate body2.

Also, in the lower surface2cand the upper surface2dof the substrate body2(or inside the substrate body2when the circuit board1is formed of a multilayer board), there are formed wiring patterns (seeFIGS. 3 and 5) and through holes (not shown), which connect between electrodes30and31, and the light emitting element array4, the light receiving element array5, the driver IC6, the preamplifier IC7and the switch8(the circuit element mounting areas), and the CPU9(the control element mounting area).

(Configuration of the Card Edge Connector)

The first card edge connector3A is configured in such a manner that a plurality of the electrodes30are formed on both surfaces, respectively, at one end2aof the substrate body2. The second card edge connector3B is configured in such a manner that a plurality of the electrodes31are formed on both surfaces, respectively, at the other end2bof the substrate body2.

The first card edge connector3A is configured to be connectable with a receptacle connector11to be connected with a host side, for example. The second card edge connector3B is also configured to be connectable with a receptacle connector11, which is the same as that connected to the host side. It should be noted that inFIGS. 1 and 2the receptacle connectors11are shown as unconnected.

The receptacle connectors11each include a housing110, which is formed of an electrically insulative resin, a plurality of internal terminals (not shown), which are provided within the housing110, and which are connected to the electrodes30respectively of the first card edge connector3A, or the electrodes31respectively of the second card edge connector3B, and a plurality of external terminals111, which are connected to the internal terminals respectively, and which are exposed from the housing110. The plurality of external terminals111are connected with a cable (not shown).

The first card edge connector3A, the second card edge connector3B and the receptacle connectors11conform to a QSFP (Quad Small Form-factor Pluggable) standard as an optical transceiver standard corresponding to 40 GbE connection. That is, the receptacle connectors11are configured to be able to be connected to the first card edge connector3A and the second card edge connector3B. If the respective standards of the first card edge connector3A at the one end2aand the second card edge connector3B at the other end2bare the same, their standards are not limited to the QSFP standard, but may be another standard. Also, the first card edge connector3A and the second card edge connector3B may conform to different standards respectively. Even in this case, it is possible to perform work before factory shipment with no dedicated tool required.

The light emitting element array4includes a plurality (in the present embodiment four) of light emitting elements arrayed to transmit an optical signal. As the light emitting elements, there are listed, for example, a semiconductor laser element such as a VCSEL (vertical cavity surface emitting laser), an LED (Light Emitting Diode), etc. It should be noted that one light emitting element may be used in place of the light emitting element array4.

The light receiving element array5includes a plurality of light receiving elements arrayed to receive an optical signal. As the light receiving element, there is a photodiode, for example. It should be noted that one light receiving element may be used in place of the light receiving element array5.

The switch8is configured to be able to switch a circuit on the circuit board1, depending on whether a chip resistor is mounted thereon or not, and set whether or not the first card edge connector3A is enabled for firmware writing.

The CPU9has a built-in internal memory9a, and is configured to store a firmware downloaded via the first card edge connector3A or the second card edge connector3B in that internal memory9a. The CPU9performs control based on the firmware stored in that internal memory9a. The CPU9interprets a command transmitted from a host via the first card edge connector3A and a first wiring pattern32a(FIG. 5), and transmits a control signal to the driver IC6and the preamplifier IC7via a fourth wiring pattern32d(FIG. 5).

As shown inFIG. 3, the second card edge connector3B and a periphery thereof is formed with the plurality of electrodes31, and second and third wiring patterns32band32c, etc. connected to each electrode31on the upper surface2dat the end2bof the substrate body2. The electrodes31and the wiring patterns are formed on the lower surface2cat the end2bof the substrate body2as well, as with the upper surface2d.

(Pin Array of the Second Card Edge Connector)

FIG. 4is a diagram showing a pin array (an array of the electrodes31) of the second card edge connector3B. Pin number8(pin name ModSelL), pin number9(pin name ResetL), and pin number31(pin name LPMode) are provided for firmware downloading to the CPU9.

Pin number11(pin name SCL), and pin number12(pin name SDA) are provided for control signal transmission to the driver IC6and the preamplifier IC7. Pin number28(pin name intL) is provided for RSSI (Received Signal Strength Indicator) signal outputting from the preamplifier IC7.

Also, pin number2(pin name Tx2n), pin number3(pin name Tx2p), pin number5(pin name Tx4n), pin number6(pin name Tx4p), pin number33(pin name Tx3p), pin number34(pin name Tx3n), pin number36(pin name Tx1p), and pin number37(pin name Tx1n) are provided for a signal of the driver IC6.

FIG. 5is a schematic explanatory diagram showing work before factory shipment. The lower surface2cor the upper surface2dof the substrate body2is formed with a first wiring pattern32ato connect the electrodes30of the first card edge connector3A and the CPU9, a second wiring pattern32bto connect the electrodes31of the second card edge connector3B and the CPU9, a third wiring pattern32cto connect the electrodes31of the second card edge connector3B and the driver IC6and the preamplifier IC7, a fourth wiring pattern32dto connect the CPU9and the driver IC6and the preamplifier IC7, a fifth wiring pattern32eto connect the driver IC6and the light emitting element array4, and a sixth wiring pattern32fto connect the light receiving element array5and the preamplifier IC7.

To perform work before factory shipment, the receptacle connector11is connected to the second card edge connector3B (FIG. 1). A firmware is downloaded to the CPU9via the receptacle connector11and the electrodes31corresponding to the pin numbers8,9, and31of the second card edge connector3B, and the second wiring pattern32b. The firmware downloaded is stored in the internal memory9aof the CPU9. It should be noted that verification as to whether or not the CPU9is operated as intended according to the firmware downloaded may be performed via the second card edge connector3B.

Then, a control signal is transmitted directly to the driver IC6and the preamplifier IC7via the receptacle connector11and the electrodes31corresponding to the pin number11(pin name SCL) and the pin number12(pin name SDA) of the second card edge connector3B, and the third wiring pattern32c.

The driver IC6drives the light emitting element array4based on the control signal, and causes the light emitting element array4to output an optical signal. For example, alignment between a light emitting element and an optical component such as a lens, an optical fiber, etc. and adjustment to the amount of light are performed while the amount of light of the optical signal is being observed using an external light receiver.

The preamplifier IC7outputs an RSSI signal as a reception strength signal via the third wiring pattern32c, the electrode31corresponding to the pin number28of the second card edge connector3B and the receptacle connector11, based on the control signal. The RSSI signal has a voltage dependent on the amount of light received in the light receiving element array5. For example, alignment between a light emitting element and an optical component such as a lens, an optical fiber, etc. and adjustment to the amount of light are performed while the voltage of the RSSI signal is being observed.

When the same work as that before factory shipment is performed after factory shipment, the receptacle connector11is connected to the first card edge connector3A, and the switch8switches a circuit on the circuit board1, depending on whether a chip resistor is mounted thereon or not, and enables the first card edge connector3A for firmware writing. Thereafter, in the same manner as before factory shipment, firmware downloading, alignment, adjustment to the amount of light are performed.

FIG. 6is a plan view showing an essential portion of the substrate body2cut at its second card edge connector3B side end2bafter the work before factory shipment has been finished. After the work has been finished before factory shipment, the second card edge connector3B is not needed, and the second card edge connector3B may therefore be cut and separated from the substrate body2, as shown inFIG. 6. By doing so, size reduction of the circuit board1is ensured. The end2b′ of the substrate body2from which the second card edge connector3B is separated becomes the second end.

(Operation and Advantageous Effects of the Present Invention)

The present embodiment has the following operation and advantageous effects.

(1) Since the receptacle connector11for the first card edge connector3A can be connected to the second card edge connector4B, it is possible to, with no such a dedicated tool as a probe required, easily perform firmware downloading, alignment, adjustment to the amount of light, verification, etc., prior to factory shipment.
(2) Since the switch8is provided on the circuit board1, it is possible to perform firmware downloading from the first card edge connector3A.

It should be noted that the invention is not limited to the above described embodiment, but various alterations may be made. For example, although in the above described embodiment the first card edge connector3A and the second card edge connector3B are located at the ends opposite each other of the substrate body2, the first card edge connector3A and the second card edge connector3B may be provided at the same end of the substrate body2, or at ends in directions crossing each other.

Also, although in the above described embodiment the optical elements and the driver IC and the preamplifier IC for the optical elements are mounted on the circuit board, other circuit elements may be mounted on the circuit board without mounting these circuit elements.