JP2006351710A - Regulation circuit for electrical resistance value - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To regulate electrical resistance value over a wide range and in fine regulation steps. <P>SOLUTION: This electrical resistance value regulating circuit 1 is connected to a regulating object 5 which is required to regulate an electric resistance value among first and second terminals PC1, PC2. Furthermore, the electric resistance value regulating circuit 1 contains a plurality of resistance elements R1 to R6 which are parallel-connected to each other. The resistance elements R2 to R4 of the plurality of resistance elements R1 to R6 are series-connected to short pins 2A to 2D. The desired short pin is short-circuited by soldering or the like, whereby the resistance element is selected which is series-connected to the short-circuited short pin. Thus, since the selected resistance element, the resistance element R1 and the resistance element R6 are parallel-connected to each other, the combined resistance value becomes the combined resistance value of the electrical resistance value regulating circuit 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to adjusting an electric resistance value in, for example, an electric or electronic circuit.

  Variable resistors are used for fine adjustment of current and voltage in electric circuits and electronic circuits. Patent Document 1 discloses a technique for obtaining a desired light emission intensity from a laser diode by finely adjusting a current for driving a laser diode of an optical pickup used in an optical disk device using a variable resistor.

JP 2001-244555 A

  By the way, when the resistance value of the variable resistor is adjusted in a wide range, the adjustment step becomes large, so that fine adjustment is difficult. On the other hand, if the resistance value adjustment step is made fine, the range in which the resistance value can be adjusted becomes narrow.

  Therefore, the present invention solves the above-described problem as an example, and an object thereof is to provide an electric resistance value adjustment circuit capable of adjusting an electric resistance value in a wide range and with fine adjustment steps.

  According to the first aspect of the present invention, the connection portion connected to the adjustment target, the plurality of resistance elements, and the connection portion and at least one of the plurality of resistance elements are short-circuited. And one or a plurality of short-circuit means that conduct.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the best mode for carrying out the invention (hereinafter referred to as an embodiment). In addition, constituent elements in the embodiments described below include those that can be easily assumed by those skilled in the art or those that are substantially the same. The present invention can be applied to all cases where adjustment of the electric resistance value is required.

(Embodiment)
In this embodiment, by short-circuiting the short-circuit means included in the electric resistance value adjusting circuit, by selecting a specific resistance element from a plurality of resistance elements arranged in parallel or in series, the combined resistance of the electric resistance value adjusting circuit It is characterized by changing the value. Next, an electrical resistance value adjusting circuit according to this embodiment will be described.

  FIG. 1 is a conceptual diagram showing an electric circuit including an electric resistance value adjusting circuit according to this embodiment. The electric circuit shown in FIG. 1 shows the configuration of the electric resistance adjustment circuit 1 according to this embodiment. The electric resistance value adjusting circuit 1 is connected to an adjustment target 5 that needs to adjust the electric resistance value. The adjustment target 5 changes the voltage value between the terminals of the adjustment target 5 connected to the electric resistance value adjustment circuit 1 or the current value flowing between the terminals by adjusting the electric resistance value of the electric resistance value adjustment circuit 1. Can be made. Thereby, for example, the frequency of the adjustment target 5, the electric machine output, and other characteristics are adjusted. Examples of the characteristic adjustment target 5 include a drive device for a laser diode used in an optical disk device, a gain adjustment circuit for an amplifier circuit, and the like.

  The connection part of the electrical resistance value adjusting circuit 1 is composed of a first terminal PC1 and a second terminal PC2, and the first terminal PC1 and the second terminal PC2 are connected to the adjustment target 5. When the electric resistance value (hereinafter referred to as resistance value) is adjusted by the electric resistance value adjusting circuit 1, the electric resistance value between the first terminal PC1 and the second terminal PC2 changes, so that the adjustment target 5 is adjusted to a desired resistance value. can do.

  In the electrical resistance adjustment circuit 1 according to this embodiment, a plurality of resistance elements R1 to R6 are connected to the first conductive path 3 and the second conductive path 4. Here, the first conductive passage 3 is connected to the first terminal PC1, and the second conductive passage 4 is connected to the second terminal PC2. In the example shown in FIG. 1, a plurality of resistance elements R1 to R6 are connected in parallel. In the electrical resistance adjustment circuit 1 according to this embodiment, the resistance elements R1 to R6 have different resistance values, but the resistance elements R1 to R6 may have the same resistance value. Two or more resistance elements among the resistance elements R1 to R6 may have the same resistance value. The resistance values of the resistance elements R1 to R6 are appropriately set according to the specifications of the electrical resistance value adjustment circuit 1.

  Among the resistance elements R1 to R6, short-circuit means are connected in series to the resistance elements R2, R3, R4, and R5, respectively. In this embodiment, the short-circuit means is provided between the resistance elements R2, R3, R4, and R5 and the second terminal PC2 constituting the connection portion. And resistance element R2, R3, R4, R5 and 2nd terminal PC2 which comprises a connection part are electrically connected by the conductor. The short-circuit means is connected to the second terminal PC2 via the second conductive passage 4.

  The short-circuit means is normally non-conductive, but electricity can be conducted by soldering or brazing, application of a conductive adhesive, or other means. In this embodiment, the short-circuit means includes a first conductor 2R connected to the resistance elements R2, R3, R4, and R5, and a second conductor 2S connected to the second terminal PC2 via the second conductive path 4. Are short pins 2A to 2B.

  When the short pins 2A to 2D are short-circuited by soldering or brazing, a resistance element connected to the short-circuited short pin can be selected. Thereby, a desired resistance element can be selected from the plurality of resistance elements R2, R3, R4, and R5. Then, the combined resistance value of the electric resistance value adjusting circuit 1 is determined by the selected resistance element.

For example, the first and second conductors 2R and 2S of the short pin 2A are short-circuited by soldering, and the other short pins 2B to 2D are kept non-conductive. In the electrical resistance value adjusting circuit 1 according to this embodiment, since the resistance elements R1 to R6 are connected in parallel, when the short pin 2A is short-circuited, the resistance elements R1, R2, and R6 are connected in parallel. Become. In this case, the reciprocal 1 / R of the combined resistance value R can be obtained by Expression (1).
1 / R = 1 / R1 + 1 / R2 + 1 / R6 (1)

Also, if the first and second conductors 2R, 2S of the short pin 2B are short-circuited by soldering and the other short pins 2A, 2C, 2D are left non-conductive, the combined resistance value R in this case The reciprocal 1 / R can be obtained by equation (2).
1 / R = 1 / R1 + 1 / R3 + 1 / R6 (2)

In general, the reciprocal of the combined resistance value R when n (n is a natural number) resistance elements are connected in parallel is expressed by Expression (3).
1 / R = 1 / R1 + 1 / R2 +... 1 / Rn (3)
The electric resistance adjustment circuit 1 according to this embodiment can select a resistance element corresponding to a short pin to be short-circuited. Therefore, the combined resistance value of the electrical resistance value adjusting circuit 1, that is, the resistance value between the first terminal PC1 and the second terminal PC2 constituting the connection portion, substitutes the resistance value of the selected resistance element into the equation (3). You can ask for it.

  As described above, one of the short pins 2A to 2D can be short-circuited to select one of the plurality of resistance elements R2 to R5, but two or more of the short pins 2A to 2D can be selected. May be short-circuited to select two or more resistance elements from the plurality of resistance elements R2 to R4. By doing in this way, the synthetic | combination resistance value of the electrical resistance value adjustment circuit 1 can be adjusted more finely. Next, a configuration example of the electric resistance value adjusting circuit 1 according to this embodiment will be described.

  FIG. 2 is a plan view showing a configuration example of the electrical resistance value adjusting circuit according to this embodiment. 3 is a cross-sectional view taken along the line XX of FIG. The electric resistance adjustment circuit 1 according to this embodiment is obtained by mounting a chip component of a resistance element on a printed board. In addition, in the electrical resistance value adjustment circuit 1 shown in FIG. 1, six resistance elements R1 to R6 are shown, but some of them are shown in FIG.

  The first conductive path 3, the second conductive path 4, and the first conductor 2 </ b> R constituting the short pins 2 </ b> A, 2 </ b> B, which are short-circuit means, are land portions on the substrate 8 (FIG. 3) of the printed circuit board. Patterned. In this example, the second conductor 2R constituting the short pins 2A, 2B, etc., which are short-circuit means, is patterned integrally with the second conductive path 4.

Figure 2, as shown in FIG. 3, the first conductive path 3, between the first conductor 2R constituting short pin 2A, and 2B, etc., resistor chips ₆₁ through ₃ is mounted as a chip component The The resistor chips 6 _{1 to} 6 ₃ correspond to the resistor elements R2 to R3 in FIG. The resistor chips 6 _{1 to} 6 ₃ are attached to the first conductive path 3 and the first conductor 2R by solder 9.

As shown in FIGS. 2 and 3, the first conductor 2R and the second conductor 2S constituting the short pins 2A, 2B and the like are provided at a predetermined interval. As a result, the short pins 2A, 2B, etc., which are short-circuit means, are normally non-conductive unless short-circuited with solder or the like. On first conductor 2R, solder 9 is riding when mounting the resistor chip ₆₁ and the like. In the manufacturing process of the electric resistance adjustment circuit 1, the solder 9 is also placed on the second conductor 2S. This is to facilitate soldering when the first conductor 2R and the second conductor 2S are short-circuited. Note that the solder 9 placed on the first conductor 2R or the second conductor 2S may be a reflow solder when mounting components.

  When adjusting the combined resistance value of the electric resistance value adjusting circuit 1, the first conductor 2R and the second conductor 2S that constitute the short pins 2A, 2B, etc. are short-circuited by soldering to obtain a desired value. The resistor chip (resistive element) is selected. That is, as shown in FIG. 3, the solder 10 is placed between the first conductor 2 </ b> R and the second conductor 2 </ b> S using the soldering iron 11, and both are soldered.

  In the electric resistance adjustment circuit 1 according to this embodiment, the constricted portion 7 is provided between the second conductors 2 </ b> S provided in the second conductive passage 4 in a plan view. Thereby, in the second conductive passage 4 which is a conductor, the cross-sectional area between the second conductors 2S constituting the short-circuit means is smaller than the cross-sectional area of the second conductor 2S constituting the short-circuit means. As a result, when soldering between the first conductor 2R and the second conductor 2S, the heat transmitted to the adjacent resistor chip can be reduced, so that the influence of heat during soldering can be reduced.

  Here, the cross-sectional area refers to a cross-sectional area through which current flows. In this example, the cross-sectional area refers to a cross-sectional area in a plane orthogonal to the base material 8 of the printed board. Moreover, planar view means the state seen from the direction orthogonal to the surface where a several short circuit means is arranged. For example, in this embodiment, since a plurality of short-circuit means are arranged on the surface of the base material 8 of the printed board, the state viewed from the direction orthogonal to the surface of the base material 8 corresponds to a plan view. .

  The electrical resistance adjustment circuit 1 according to this embodiment selects a desired resistance element from a plurality of resistance elements R2 to R5 connected in parallel by short-circuiting the short-circuit means by soldering, brazing, or other means. Thus, the combined resistance value of the electric resistance value adjusting circuit 1 is changed. Thereby, the electrical resistance value adjusting circuit 1 can surely obtain a desired combined resistance value. In addition, since the resistance elements R2 to R5 that can be selected by the short pins 2A to 2D that are short-circuiting means are connected in parallel, variations of combinations of resistance elements to be selected can be increased. As a result, the combined resistance value of the electric resistance value adjusting circuit 1 can be changed in fine steps.

  In particular, when the resistance value is adjusted by a variable resistor, the adjusted resistance value may be shifted due to a mechanical shift. However, the electrical resistance value adjusting circuit 1 does not cause a mechanical shift, so that the combined resistance value hardly shifts after the combined resistance value of the electrical resistance value adjusting circuit 1 is adjusted. Thereby, the inspection after adjusting the combined resistance value can be omitted. In addition, since the electric resistance adjustment circuit 1 does not include a movable part, the reliability is also improved.

  When a variable resistor is used, the resistance value cannot be finely adjusted if the resistance value adjustment range is increased, and the resistance value adjustment range cannot be increased if the resistance value is finely adjusted. That is, in the variable resistor, it is almost impossible to achieve both the adjustment range of the resistance value and the adjustment step of the resistance value. The electrical resistance value adjustment circuit 1 according to this embodiment changes a combined resistance value of the electrical resistance value adjustment circuit 1 by selecting a desired resistance element from a plurality of resistance elements by a short-circuit means. For this reason, the combined resistance value adjustment step can be finely set while increasing the combined resistance value adjustment range by the combination of the resistance elements constituting the electrical resistance value adjusting circuit 1. In this case, the combined resistance value of the electric resistance value adjusting circuit 1 can be adjusted with a larger adjustment range and a finer adjustment step by selecting the resistance value and number of the resistance elements, or by selecting a combination of the resistance elements to be selected. .

  Furthermore, the electrical resistance value adjusting circuit 1 according to this embodiment can adjust the combined resistance value only by short-circuiting the short-circuit means. For this reason, the electrical resistance value adjusting circuit 1 according to this embodiment can greatly reduce the labor of changing the resistance element compared to the case where the resistance value is adjusted by changing the resistance element, thereby improving workability. To do. In addition, a decrease in the durability of the substrate or the like accompanying the replacement of the resistance element can be suppressed very slightly. Furthermore, since the resistance element can be constituted by a resistance chip, space can be saved as compared with the case where the resistance element is replaced or a variable resistor is used. In addition, since the unit price of the resistor chip is lower than that of the variable resistor, the manufacturing cost of the electrical resistance value adjusting circuit 1 can be reduced.

(First modification)
The electrical resistance value adjustment circuit according to Modification 1 has substantially the same configuration as the electrical resistance value adjustment circuit according to the above embodiment, except that at least the short-circuiting means are arranged non-parallel in plan view. Other configurations are the same as in the above embodiment. FIGS. 4-1 and FIGS. 4-2 are top views which show the electrical resistance value adjustment circuit which concerns on the 1st modification of this embodiment.

  The electric resistance value adjusting circuit 1b shown in FIG. 4A includes a short pin (which is a short-circuit means) 2A in which the resistance elements R2 to R4 are arranged in parallel and connected in series to each other in plan view. ˜2C are arranged non-parallel in plan view. That is, in the plan view, the short pin 2A is disposed to be inclined with respect to the short pin 2B (inclination angle β), and the short pin 2C is disposed to be inclined with respect to the short pin 2B (inclination angle α). . The short pin 2A is arranged with an inclination angle (α + β) with respect to the short pin 2C.

  In the electric resistance value adjusting circuit 1c shown in FIG. 4B, the resistance elements R2 to R4 connected in series with the short pins 2A to 2C are also arranged non-parallel in plan view. That is, in a plan view, the short pin 2A and the resistance element R2 are arranged to be inclined with respect to the short pin 2B and the resistance element R3 (inclination angle β), and the short pin 2C and the resistance element R4 are the short pin 2B and the resistance element R4. Inclined with respect to the element R3 (inclination angle α). The short pin 2A and the resistance element R2 are arranged with an inclination angle (α + β) with respect to the short pin 2C and the resistance element R4.

  By configuring in this way, even when the resistance elements R2 to R4 are arranged close to each other, the distance between the short pins 2A to 2C as the short-circuit means can be increased, so that the short pins 2A to 2C are short-circuited. The soldering work becomes easier. As a result, the working efficiency is improved and a short circuit can be more reliably performed.

(Second modification)
The second modification of this embodiment has substantially the same configuration as that of the above embodiment, except that a plurality of resistance elements are connected in series. Other configurations are the same as in the above embodiment. FIG. 5 is a conceptual diagram showing an electric circuit including the electric resistance value adjusting circuit according to this embodiment. The electric circuit shown in FIG. 5 shows the configuration of an electric resistance value adjusting circuit 1a according to this modification. The electrical resistance value adjusting circuit 1a is connected to an adjustment target 5 that needs to adjust the electrical resistance value.

  The connection part of the electrical resistance adjustment circuit 1a is composed of a first terminal PC1 and a second terminal PC2, and the first terminal PC1 and the second terminal PC2 are connected to the adjustment target 5. In the electrical resistance value adjusting circuit 1a according to this modification, a plurality of resistance elements R1 to R5 are connected in series. The resistive element R1 is connected to the first terminal PC1 via the first conductive path 3, and the resistive element R5 is connected to the second terminal PC2 via the second conductive path 4.

  In the electrical resistance value adjusting circuit 1a according to this modification, the resistance elements R1 to R5 have different resistance values, but the resistance elements R1 to R5 may have the same resistance value. Two or more resistance elements among the resistance elements R1 to R5 may have the same resistance value. The resistance values of the resistance elements R1 to R5 are appropriately set according to the specifications of the electric resistance value adjusting circuit 1a.

  In the electrical resistance value adjusting circuit 1 a according to this modification, short pins 2 </ b> A to 2 </ b> D, which are short-circuiting means, are provided between the resistance elements and the second conductive path 4. In this modification, between the resistance elements R1 and R2 and the second conductive path 4, between the resistance elements R2 and R3 and the second conductive path 4, between the resistance elements R3 and R4, and the second conductive path 4 In the meantime, short pins 2 </ b> A to 2 </ b> D, which are short-circuit means, are provided between the resistance elements R <b> 4 to R <b> 5 and the second conductive path 4.

  Prior to short-circuiting the short pins 2A to 2D, which are short-circuiting means, all the short pins 2A to 2D are non-conductive, so that the current flowing through the electric resistance adjustment circuit 1a flows from the first terminal PC1 to the first conductive path 3, resistance It flows to the second terminal PC2 through the elements R1 to R5 and the second conductive path 4. When the short pins 2A to 2D are short-circuited by soldering or brazing, the current flowing through the electric resistance adjustment circuit 1a passes through the short-circuited short pins. For this reason, a connecting portion, that is, a resistance element on the first and second terminals PC1 and PC2 side is selected from the shorted short pin, and a resistance circuit is configured in which these resistance elements are connected in series.

For example, the first and second conductors 2R and 2S of the short pin 2A are short-circuited by soldering, and the other short pins 2B to 2D are kept non-conductive. In this state, the resistance element R1 is selected. The combined resistance value R of the electric resistance value adjusting circuit 1a at this time can be obtained by Expression (4).
R = R1 (4)

If the first and second conductors 2R, 2S of the short pin 2B are short-circuited by soldering and the other short pins 2A, 2C, 2D are left non-conductive, the resistance elements R1, R2 are selected. The Since the resistance elements R1 and R2 are connected in series, the combined resistance value R of the electrical resistance value adjusting circuit 1a at this time can be obtained by Expression (5).
R = R1 + R2 (5)

Moreover, when not short-circuiting all the short pins 2A-2D, all the resistance elements R1-R5 with which this electrical resistance value adjustment circuit 1a is provided are selected. Since all the resistance elements R1 to R5 are connected in series, the combined resistance value R of the electrical resistance value adjusting circuit 1a at this time can be obtained by Expression (6).
R = R1 + R2 + R3 + R4 + R5 (6)

  Thus, the electrical resistance value adjusting circuit 1a according to this modification forms a resistance circuit in which the resistance elements are connected in series by short-circuiting the short pin, and the electrical resistance is provided by the resistance element included in the resistance circuit. The combined resistance value of the value adjustment circuit 1a is determined. Then, by selecting a short pin to be short-circuited, the combined resistance value of the electric resistance value adjusting circuit 1a can be adjusted.

  As described above, in this embodiment and the modification thereof, the connection portion (first and second terminals PC1, PC2) connected to the adjustment target 5 whose electric resistance value needs to be adjusted, and the connection portion are electrically connected by the conductor. A plurality of resistive elements R2 to R5 connected to each other, provided between the connecting portion and the resistive element, and the connecting portion and the resistive element are electrically connected by a conductor, And a plurality of short-circuit means (short pins 2A to 2D) for selecting a desired resistance element from the plurality of resistance elements by short-circuiting. Thereby, an electrical resistance value can be adjusted with a fine adjustment step in a wide range.

  Next, as an example, the case of adjusting the characteristics of the LD driver of the optical pickup provided in the optical disc apparatus will be described. In addition, you may apply to adjustment of the emitted light intensity of a semiconductor laser diode, etc. FIG. 6 is a block diagram illustrating a configuration example of an optical pickup driving device of an optical disk drive. The optical pickup driving device shown in FIG. 6 includes an optical pickup that includes a light source and a driver that is a light source driving unit. The optical pickup 20 is provided in a CD (Compact Disc) player or a DVD (Digital Video Disk or Digital Versatile Disk) player (optical disk device), reads information from a CD or DVD (optical disk), or reads information from a CD or DVD. Or record.

  The optical pickup 20 includes a light source having a structure in which a semiconductor laser diode (hereinafter referred to as LD) 21 as a light source and a photodiode (hereinafter referred to as PD) 22 as a light detection element are integrally provided in a package. Then, by irradiating light emitted from the LD 21 to the CD or DVD, information is written to or read from these.

  The LD 21 is connected to the LD driver 30. The LD driver 30 drives the LD 21 based on the LD drive signal sent from the controller 14. The controller 14 is composed of, for example, a microcomputer. A memory 15 is connected to the controller 14. The memory 15 stores a control program necessary for controlling the LD driver 30, a control program necessary for processing the read information or recording information, and the like.

  The optical pickup 20 is provided with a temperature detector 23 for monitoring the operating environment temperature of the LD 21. The output of the temperature detector 23 is converted into a digital signal by an A / D (Analog / Digital) converter 13 and taken into the controller 14. The output of the PD 22 is processed by the inverter (I / V) 11, converted into a digital signal by the A / D converter 12, and taken into the controller 14.

  The PD 22 detects part of the light emitted from the LD 21. The controller 14 takes in the value of the photocurrent generated thereby, and calculates a current difference value between the photocurrent and the reference current value. The power calibration unit 17 keeps the light emission intensity of the LD 21 constant by performing feedback control of the DC bias current (drive current) of the LD 21 so that the current difference value is always equal to or less than a certain value. The disc discriminating unit 16 connected to the controller 14 acquires the output value from the optical pickup 20 via the controller 14 and discriminates the presence / absence of the optical disc, the type of the optical disc, and the like.

  The LD driver 30 provided in the optical pickup driving device shown in FIG. 6 drives the LD 21 at a predetermined driving frequency. For this reason, radiation is generated according to the magnitude of the drive frequency. This radiation is preferably as small as possible in driving the LD 21, and ideally it should not occur. In this example, in order to suppress the radiation (hereinafter referred to as unnecessary radiation) generated by the LD driver 30 of the optical pickup driving device to a value smaller than a predetermined value, the electric resistance value adjusting circuit 1 (FIG. 1) is used (see FIG. 6). In this embodiment, the electric resistance value adjusting circuit 1 is used, but electric resistance value adjusting circuits 1a, 1b and the like according to the modification may be used.

  FIG. 7 is an explanatory diagram showing a state in which an electric resistance value adjusting circuit is connected to the LD driver. As shown in FIG. 7, the LD driver 30 and the electrical resistance value adjustment circuit 1 are electrically connected by connection portions (first and second terminals PCa and PCb) of the electrical resistance value adjustment circuit 1. Next, a procedure for adjusting unnecessary radiation of the LD driver 30 will be described.

  FIG. 8 is a flowchart showing a procedure for adjusting unnecessary radiation of the LD driver. FIG. 9 is an explanatory diagram showing an example of a table describing a short pin to be short-circuited used when adjusting unnecessary radiation of the LD driver. In adjusting the unwanted radiation of the LD driver 30, first, components are mounted on the optical pickup driving device (step S11).

  Next, the optical pickup driving device on which the component is mounted is simply driven (step S12), and the driving frequency (LDD driving frequency) of the LD driver 30 is measured (step S13). If the measured LDD driving frequency is within the allowable range, the unnecessary radiation adjustment process is terminated and the process proceeds to a subsequent process (step S14: Yes). When the measured LDD drive frequency is outside the allowable range (step S14: No), a desired one of the short pins 2A to 2D provided in the electric resistance adjustment circuit 1 is short-circuited by soldering (step S15). As a result, the combined resistance value of the electric resistance value adjusting circuit 1 is adjusted so that the unnecessary radiation of the LD driver 30 falls within an allowable range.

  Here, since there is a correlation between the LDD driving frequency and unnecessary radiation, it is possible to estimate how much unnecessary radiation is generated by measuring the LDD driving frequency. Then, by adjusting the combined resistance value of the electric resistance value adjusting circuit 1 connected to the LD driver 30 according to the value of unnecessary radiation, unnecessary radiation can be kept within an allowable range. The relationship between the value of unnecessary radiation, that is, the LDD driving frequency and the adjustment amount of the combined resistance value of the electric resistance value adjusting circuit 1 can be obtained in advance. FIG. 9 shows an example of a table in which this relationship is obtained in advance and the adjustment amount of the combined resistance value of the electric resistance value adjusting circuit 1 with respect to the LDD driving frequency, that is, a short pin that short-circuits the electric resistance value adjusting circuit 1 is described. It is a table. In this table, the LDD drive frequency is shown as a non-dimensional relative value.

  As shown in FIG. 9, for example, when the LDD drive frequency is in the range of 1 to 2 as a result of measuring the LDD drive frequency, the short pin 2A (A) is short-circuited by soldering. When the LDD drive frequency is in the range of 3.1 to 12, the short pin 2C (C) is short-circuited by soldering. Thereby, unnecessary radiation can be kept within an allowable range.

  The operation of short-circuiting the short pin of the electric resistance adjustment circuit 1 by soldering is easier than the operation of replacing the resistance element, and it is not necessary to remove and re-install the resistance element many times. There is almost no decrease in durability of the part. In addition, unlike the variable resistor, the electrical resistance value adjustment circuit 1 can adjust the combined resistance value with a wide adjustment range and fine adjustment steps, so that the resistance adjustment work is easy. As described above, the electric resistance value adjusting circuit 1 is effective in adjusting unnecessary radiation of the LD driver 30.

  Furthermore, since the variable resistor is generally composed of a plurality of resistors, the temperature dependence of the resistance value is relatively large. However, since the electric resistance value adjusting circuit 1 is composed of a resistor element, The temperature dependence of the value is smaller than the variable resistor. In particular, since the LD driver 30 and the LD 21 are used in an environment having a large temperature change, the electric resistance value adjusting circuit 1 is advantageous.

  Further, since the electric resistance value adjusting circuit 1 has no movable part, the resistance value does not change due to disturbance such as vibration. In this respect, the electric resistance value adjusting circuit 1 is advantageous as compared with the variable resistor. In particular, the LD driver 30 is used in an optical disc apparatus that handles a rotating optical disc. That is, the LD driver 30 is used in an apparatus having a vibration source. The electrical resistance value adjusting circuit 1 is preferably used even in an apparatus having a vibration source because the electrical resistance value is not affected by vibration or the like.

It is a conceptual diagram which shows the electric circuit containing the electrical resistance value adjustment circuit which concerns on this embodiment. It is a top view which shows the structural example of the electrical resistance value adjustment circuit which concerns on this embodiment. It is XX sectional drawing of FIG. It is a top view which shows the electrical resistance value adjustment circuit which concerns on the 1st modification of this embodiment. It is a top view which shows the electrical resistance value adjustment circuit which concerns on the 1st modification of this embodiment. It is a conceptual diagram which shows the electric circuit containing the electrical resistance value adjustment circuit which concerns on this embodiment. It is a block diagram which shows the structural example of the optical pick-up drive apparatus of an optical disk drive. It is explanatory drawing which shows the state which connected the electrical resistance value adjustment circuit to LD driver. It is a flowchart which shows the procedure which adjusts the unnecessary radiation of LD driver. It is explanatory drawing which shows an example of the table which described the short pin used to short-circuit used when adjusting the unnecessary radiation of LD driver.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c Electrical resistance value adjustment circuit 2A, 2B, 2C, 2D Short pin 2R 1st conductor 2S 2nd conductor 3 1st conductive path 4 2nd conductive path 5 Adjustment object 6 ₁ , 6 ₂ , 6 ₃ , 6 ₄ Resistive chip 7 Constriction 9, 10 Solder 20 Optical pickup 30 LD driver

Claims (4)

A connection to be connected to the adjustment target;
A plurality of resistance elements;
One or a plurality of short-circuit means for conducting the connection portion and at least one of the plurality of resistance elements by being short-circuited;
An electric resistance value adjusting circuit comprising: The short-circuit means and the connection portion are connected by a conductor,
The conductor is
The electrical resistance value adjusting circuit according to claim 1, wherein a cross-sectional area between the short-circuit means is smaller than a cross-sectional area of the short-circuit means.   The electrical resistance value adjusting circuit according to claim 1, wherein at least the plurality of short-circuiting means are arranged non-parallel.   4. The electrical resistance value adjusting circuit according to claim 1, wherein the short-circuit unit is provided between the connection portion and the resistance element. 5.

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