JP2016018959A - Power supply device for illumination and overdrive current calculation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an overdrive current calculation method capable of calculating the overdrive current automatically when becoming overdrive voltage, and to provide a power supply device for illumination.SOLUTION: Rated current of rated voltage is probed via probe means. Resistance of the limit resistor of LED lighting is calculated via resistance calculation means. Current value calculation means calculates the overdrive current from a rated voltage to be set, an overdrive voltage to be set, the resistance value of the limit resistor thus calculated, and the rated current thus probed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an illumination power supply device and an overdrive current calculation method.

  When manufacturing a semiconductor device, die bonding for mounting a semiconductor chip (die) on a lead frame as a mounted member is performed. For this die bonding, a die bonder having a collet for adsorbing chips is used.

  As shown in FIG. 11, such a die bonder includes a bonding arm (not shown) having a collet 3 for attracting the semiconductor chip 1 of the supply unit 2 and a confirmation camera (not shown) for observing the semiconductor chip 1 of the supply unit 2. And a confirmation camera (not shown) for observing the island portion 5 of the lead frame 4 at the bonding position.

  The supply unit 2 includes a semiconductor wafer, and the semiconductor wafer is divided into a large number of semiconductor chips 1. Further, the bonding arm holding the collet 3 can be moved between the pickup position and the bonding position via the conveying means.

  Further, the collet 3 is vacuum-sucked through the suction holes opened in the lower end surface thereof, and the chip 1 is adsorbed on the lower end surface of the collet 3. If this vacuum suction (evacuation) is released, the chip 1 is detached from the collet 3.

  Next, a die bonding method using this die bonder will be described. First, the chip 1 to be picked up is observed with a confirmation camera disposed above the supply unit 2, and the collet 3 is positioned above the chip 1 to be picked up, and then the collet 3 as indicated by an arrow A. Is lowered to pick up the chip 1. Thereafter, the collet 3 is raised as shown by the arrow B.

  Next, the island portion 5 of the lead frame 4 to be bonded is observed with a confirmation camera arranged above the bonding position, and the collet 3 is moved in the direction of arrow C, and above the island portion 5. After being positioned, the collet 3 is moved downward as indicated by an arrow D, and the chip 1 is supplied to the island portion 5. In addition, after the chip is supplied to the island portion 5, the collet 3 is raised as indicated by the arrow E and then returned to the standby position above the pip-up position as indicated by the arrow F.

  That is, by moving the collet 3 sequentially as indicated by arrows A, B, C, D, E, and F, the chip 1 positioned based on the observation of the pickup confirmation camera is picked up by the collet 3. The chip 1 is mounted on the island portion 5.

  In such a die bonder, an illumination system is used for image recognition (Patent Document 1). Further, in recent years, LED lighting having excellent characteristics when it consumes less power, has a longer life, and generates less heat than a normal light bulb or fluorescent lamp is used for the lighting system. LED lighting is a lighting fixture using a light emitting diode (LED).

  When the LED illumination is turned on, a strobe power supply 10 has been conventionally used as a power supply as shown in FIG. When the LED lighting (first LED lighting 11 and second LED lighting 11 in the illustrated example) is stroboscopically illuminated, a voltage exceeding the rating (overdrive voltage: hereinafter referred to as Vover) is applied within a limited time (hereinafter referred to as tmax). It can be made brighter than applying a rated voltage (hereinafter referred to as Vnomal).

  A general strobe power supply is a constant voltage power supply as shown in FIG. 12, and a certain Vover value is determined to turn on the strobe. When performing the same operation with a constant current power supply, it is necessary to drive the LED lights 11 and 12 with an overdrive current (hereinafter referred to as Iover) that flows when Vover is applied.

  By the way, when changing the illumination, the same Vover value may be applied if it is a constant voltage power supply. However, in the case of the constant current power supply 13 as shown in FIG. 13, LED illumination (first LED illumination and second LED illumination) is used. Iover is different. For this reason, as shown in FIG. 14, it is necessary to set the Iover individually for the LED lighting (the first LED lighting 14 and the second LED lighting 15) and perform the strobe lighting.

  As a method of performing strobe lighting, a method of fixing Iover (when the LED illumination to be used is individual), a method of setting from the outside such as manual setting by a switch or a setting of communication, a method of identifying and automatically setting the LED illumination ( For example, there is a method as shown in Patent Document 2.

JP 2001-313303 A JP 2006-351484 A

  In the method of fixing Iover, the LED illumination cannot be changed, and the device design is inferior. Further, in the method of fixing Iover and the method of setting from the outside, it is necessary to examine the value of Iover in advance. Furthermore, in the method of setting from the outside, if the Iover value is set incorrectly, the LED illumination may be damaged. In the method of identifying and automatically setting the LED illumination, an identification circuit is required on the LED illumination side, so that the LED illumination that can be used is limited.

  In view of the above problems, the present invention provides an overdrive current calculation method and an illumination power supply device that can automatically calculate an overdrive current when an overdrive voltage is reached.

  A first illumination power supply device according to the present invention is an illumination power supply device that can be applied with an overdrive voltage higher than a rated voltage by lighting a strobe and has a limiting resistance and a controller serving as a drive source. A constant current supply means capable of applying a lighting current to the LED lighting, a resistance calculating means for calculating a resistance value of a limiting resistance of the LED lighting, a preset overdrive voltage, and a resistance Current value calculation means for calculating an overdrive current when an overdrive voltage is obtained from the resistance value of the limiting resistance of the LED illumination calculated by the calculation means.

  A second illumination power supply device according to the present invention is an illumination power supply device that can be applied with an overdrive voltage higher than a rated voltage by lighting a strobe and has a limiting resistance, and a controller serving as a drive source. A constant current supply means capable of applying a lighting current to the LED lighting, and before the LED lighting is lit at the rated voltage, a search current is applied to the LED lighting from the constant current supply means. Exploring means for exploring a rated current that is a current value necessary for applying the rated voltage, a resistance calculating means for calculating a resistance value of the limiting resistance of the LED lighting, a preset rated voltage, and a preset value The overdrive voltage is obtained from the measured overdrive voltage, the rated current searched by the search means, and the resistance value of the limiting resistance of the LED illumination calculated by the resistance calculation means. It is obtained and a current value calculating means for calculating the Kino overdrive current.

  A general LED illumination includes an LED and a limiting resistor connected in series with the LED. In this case, even if the current flowing through the LED illumination is changed, the change in the forward voltage of the LED is negligibly small. For this reason, the resistance value of LED illumination is substantially equal to the resistance value of the limiting resistor. Thus, in the illumination power supply device of the present invention, the overdrive current is calculated using this limiting resistor.

  That is, according to the first illumination power supply device of the present invention, the resistance value of the limiting resistance of the LED illumination can be calculated via the resistance calculation means. Therefore, the current value calculation means calculates the overdrive current at the overdrive voltage from the preset overdrive voltage and the resistance value of the limiting resistance of the LED illumination calculated by the resistance calculation means. can do.

  Moreover, according to the 2nd power supply apparatus for illumination of this invention, the rated current of a rated voltage can be searched through a search means. Further, the resistance value of the limiting resistance of the LED illumination can be calculated via the resistance calculating means. Therefore, the rated voltage set in advance by the current value calculation means, the preset overdrive voltage, the rated current searched by the search means, and the limiting resistance of the LED lighting calculated by the resistance calculation means The overdrive current at the overdrive voltage can be calculated from the resistance value.

  Thus, if the overdrive current can be calculated, the strobe lighting of the LED illumination can be performed.

When the rated voltage to be set is Vnomal, the overdrive voltage to be set is Vover, the resistance value of the limiting resistor calculated by the resistance calculating means is r, and the rated current searched by the searching means is Inomaal In addition, the overdrive current can be obtained by the following equation (1).

  The power supply device for illumination can be used for illumination for image recognition.

  The overdrive current calculation method of the present invention is an overdrive current calculation method for calculating an overdrive current that becomes an overdrive voltage in LED lighting that can apply an overdrive voltage higher than a rated voltage by lighting a strobe and has a limiting resistance. A resistance calculating step of calculating a resistance value of the limiting resistance of the LED lighting, and applying the exploration current to the LED lighting and applying the rated voltage before the LED lighting is turned on at the rated voltage. From the rated current exploration process for exploring the required rated current value, the preset rated voltage, the preset overdrive voltage, the calculated resistance value of the limiting resistor, and the searched rated current An overdrive current calculating step for calculating a drive current.

  According to the overdrive current calculation method of the present invention, the rated current of the rated voltage can be searched in the searching means step. Further, the resistance value of the limiting resistance of the LED illumination can be calculated in the resistance calculating means step. Then, in the current value calculation means step, the overdrive current is calculated from the preset rated voltage, the preset overdrive voltage, the calculated resistance value of the limiting resistor, and the searched rated current. be able to.

  In the present invention, the overdrive current can be automatically calculated, and it is not necessary to check the overdrive current in advance. In addition, since it is not necessary to set the checked current as an overdrive current, the setting workability for the illumination power supply device is excellent. Moreover, a lighting failure due to an overdrive current setting error is not caused. If it is LED illumination with the same rated voltage, it can be used for various illumination devices. Furthermore, the current value of the overdrive current can be calculated without actually flowing the overdrive current, and the calculation time can be shortened.

  By calculating the overdrive current, the strobe lighting using the overdrive current can be performed.

  If the illumination power supply device of the present invention is used for illumination for image recognition, it is possible to illuminate an object to be recognized with an optimum illuminance for image recognition, and high-accuracy image recognition is possible.

It is a simplified whole block diagram of the power supply device for illumination which shows embodiment of this invention. It is a perspective view of a die bonder. It is a circuit diagram of LED illumination. It is a flowchart figure which shows the usage method of the power supply device for illumination shown in the said FIG. It is a flowchart figure at the time of using the limiting resistance of LED illumination for a judgment element. FIG. 3 is a simplified block diagram illustrating an overdrive current calculation method according to an embodiment of the present invention. It is a graph which shows the relationship between a rated voltage, an overdrive voltage, a rated current, and an overdrive current. It is a graph which shows the electric current and voltage characteristic of LED of LED illumination. It is a graph which shows the electric current and voltage characteristic of the limiting resistance of LED illumination. It is a graph which shows the synthetic | combination voltage of LED and resistance of LED illumination. It is a simplified diagram showing a die bonding process. It is a simplified block diagram of the illumination system using the conventional constant voltage power supply. It is a graph which shows the relationship between a rated current, a rated voltage, an overdrive current, and an overdrive voltage. It is a simplified block diagram of the illumination system using the conventional constant current power supply.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 shows a simplified overall block diagram of an illumination system using the illumination power supply device according to the first embodiment of the present invention. This illumination system is, for example, an image confirmation of a die bonder that is an illuminated device shown in FIG. Used for. The die bonder performs die bonding for mounting the semiconductor chip (die) 21 on the lead frame 24.

  Such a die bonder includes a bonding arm 30 having a collet 23 that adsorbs the semiconductor chip (die) 21 of the supply unit 22, a confirmation camera 26 for observing the semiconductor chip 21 of the supply unit 22, and a lead frame 24 at the bonding position. And a confirmation camera 32 for observing the island portion 25.

  The supply unit 22 includes a semiconductor wafer 28 mounted and supported on a wafer support device 27. The semiconductor wafer 28 is divided into a large number of semiconductor chips 21. The collet 23 is connected to a collet holder 29, and the collet 23, the collet holder 29, and the like constitute a bonding arm 30. The bonding arm 30 can be moved between the pickup position and the bonding position via the conveying means 31. The transport unit 31 can drive the bonding arm 30 in the X, Y, θ, and Z directions.

  Further, the chip 21 is vacuum-sucked through the suction holes opened in the lower end surface of the collet 23, and the chip 21 is adsorbed on the lower end surface of the collet 23. If this vacuum suction (evacuation) is released, the chip 21 is detached from the collet 23.

  Next, a die bonding method using this die bonder will be described. First, the chip 21 to be picked up is observed with the confirmation camera 26 arranged above the supply unit 22, the collet 23 is positioned above the chip 21 to be picked up, and then the collet 23 is lowered. The lever chip 21 is picked up.

  Further, the island portion 25 of the lead frame 24 to be bonded is observed with the confirmation camera 32 disposed above the bonding position, and the collet 23 is moved onto the island portion 25 as indicated by an arrow A1. Thereafter, the collet 23 is lowered and the chip 21 is supplied to the island portion 25.

  When observing with the confirmation camera 26 at the pickup position and when observing with the confirmation camera 32 at the bonding position, an illumination system for illuminating the observation site is required. For this purpose, an illumination system including a controller 41 (hereinafter referred to as a host controller 41) as shown in FIG. 1, an illumination power supply device 42 (hereinafter referred to as a power supply device) of the present invention, and an LED illumination 43 is used. .

  As shown in FIG. 1, the power supply device 42 is connected to a host controller 41 and a plurality of lights 43. In the present embodiment, the illumination 43 is an LED illumination that is driven at a predetermined voltage (for example, 12 V), and the illumination 43 is hereinafter referred to as an LED illumination 43. The host controller 41 is configured by a personal computer, for example.

  The power supply device 42 includes a CPU (central processing unit) 45, a plurality of constant current drive circuits 46, a plurality of voltage measurement circuits 47, and a plurality of ADCs (analog-digital conversion circuits) 48. In this case, a constant current supply circuit (constant current supply means) 50 is formed to apply a current to one LED illumination 43. That is, each constant current supply circuit 50 includes a CPU 45, a constant current drive circuit 46, a voltage measurement circuit 47, an ADC 48, and the like. The constant current supply circuit 50 applies a predetermined current value to the LED illumination 43 by the constant current drive circuit 46 according to an instruction from the CPU 45. Note that the host controller 41 and the CPU 45 are connected via a communication port 51.

By the way, the CPU 45 is provided with exploration means 52 for exploring a current value necessary for applying 12 V to the LED illumination 43 by applying an exploration current before the LED illumination 43 is lit at a predetermined voltage (12 V). ing. That is, when the exploration means 52 instructs to apply the exploration current having a minute current value (for example, 10 mA), the constant current drive circuit 46 of the constant current supply circuit 50 applies a current value of 10 mA to the LED illumination 43. The voltage measuring means 47 measures the output voltage at this time and transmits it to the exploration means 52. The exploration means 52 increases the current value sequentially until 12V is applied to the LED illumination 43 until 12V is applied to the LED illumination 43 (that is, until the voltage measurement value by the voltage measurement means 47 reaches 12V). Apply exploration current. And when 12V is applied to the LED illumination 43, the exploration means 52 uses the current value at that time as a lighting current necessary for lighting the LED illumination 43, and applies the lighting current to light the LED illumination 43.
Thereby, LED43 illumination continues lighting at 12V.

  Incidentally, the LED illumination 43 generally comprises an LED 60 and a limiting resistor 61 connected in series with the LED 60, as shown in FIG. In this case, even if the current flowing through the LED illumination 43 is changed, the change in the forward voltage of the LED is negligibly small. For this reason, the resistance value of the LED illumination 43 is substantially equal to the resistance value of the limiting resistor 61. Thus, in the illumination power supply device of the present invention, the overdrive current is calculated using this limiting resistor. When the current I flowing through the circuit of FIG. 3 is increased by ΔI and the voltage V is increased by ΔV, the resistance value r of the limiting resistor 61 can be obtained by r≈ΔV / ΔI.

  FIG. 8 shows an example of current / voltage characteristics of the LED 60 of the LED illumination 43. In this case, the current I (mA) and the voltage Vf (V) are values shown in Table 1 below. FIG. 9 shows an example of current / voltage characteristics of the limiting resistor 61 of the LED illumination 43. In this case, the current I (mA) and the voltage Vr (V) are the values shown in Table 2 below, and the resistance is as small as 0.1. This corresponds to the case where the limiting resistor 61 is not provided.

このため、図８に示す電流・電圧特性を有すると、図９に示す電流・電圧特性とを合成電圧は図１０に示す特性となる。すなわち、次の表３に示すように、電流Ｉ（ｍＡ）と電圧Ｖ（Ｖ）は、表１の値と表２の値との合成値となる。

Therefore, if the current / voltage characteristics shown in FIG. 8 are provided, the combined voltage of the current / voltage characteristics shown in FIG. 9 becomes the characteristics shown in FIG. That is, as shown in the following Table 3, the current I (mA) and the voltage V (V) are combined values of the values in Table 1 and Table 2.

  As described above, the CPU 45 includes the resistance calculating unit 63 that calculates the resistance value of the limiting resistor 61 of the LED illumination 43. That is, the CPU 45 includes a calculation unit 62, and the calculation unit 62 includes a resistance calculation unit 63 and a current value calculation unit 64. The current value calculation means 64 includes a preset rated voltage, a preset overdrive voltage, a rated current searched by the search means 52, and a limiting resistance of the LED illumination calculated by the resistance calculation means 63. The overdrive current at the overdrive voltage is calculated from the resistance value of 61.

  Next, a method of using the power supply device shown in FIG. 1 will be described based on the flowchart shown in FIG. In this case, the rated voltage of the LED illumination 43 is 12V, and the overdrive voltage is 18V.

  First, after releasing the connection between the constant voltage power supply and the LED illumination 43 and the host controller 41 (step S1), the power supply device 42 of the present invention is connected to the LED illumination 43 and the host controller 41 (step S2). Configure the lighting system. At this time, the host controller 41 does not need to search for a current value at which a predetermined voltage (12 V) is obtained.

  When the main power supply of the lighting system is turned on and the exploration means 52 instructs the LED illumination 43 to apply a exploration current having a minute current value (for example, 10 mA) (step S3), the constant current of the constant current supply circuit 50 The drive circuit 46 applies an exploration current having a current value of 10 mA to the LED illumination 43 to light the LED illumination 43. The voltage measuring means 47 measures the output voltage at this time (step S4) and transmits it to the exploration means 52.

  At this time, the exploration means 52 determines whether or not the output voltage is smaller than 12V (step S5). If it is smaller than 12V, the exploration means 52 increases the current value until 12V is applied to the LED illumination 43 (that is, until the voltage measurement value by the voltage measurement means 47 reaches 12V) (step S6), and the LED Steps S4 to S6 are repeated until 12V is applied to the illumination 43 to apply the exploration current.

  When the applied voltage of the LED illumination 43 reaches 12V (rated voltage) (step S5), the exploration means 52 sets the current value at that time as a lighting current necessary for lighting the LED illumination 43 (step S7), and thereafter A lighting current is applied to light the LED illumination at 12V. At this time, the exploration current as the lighting current is a rated current and is applied by the constant current supply means 50.

  As described above, after calculating the rated current (Inmal), the overdrive current shifted to step S8 is calculated. As shown in FIG. 6, the calculation process of the overdrive current includes a resistance calculation process 70 for calculating the resistance value of the limiting resistance of the LED lighting, and a rated current for searching for a rated current value necessary for applying the rated voltage. A search step 71 and an overdrive current calculation step 72 for calculating an overdrive current based on the resistance value of the limiting resistor and the like are provided.

  In the resistance calculation step 70, as described above, when the current I flowing through the circuit of FIG. 3 is increased by ΔI and the voltage V is increased by ΔV, the resistance value r of the limiting resistor 61 is r≈ΔV / This is a step for obtaining ΔI. The rated current exploration process 71 is a process up to step S7 in FIG. 4, in which the exploration current is applied to the LED illumination and the rated voltage is applied before the LED illumination is turned on at the rated voltage. This is a process of searching for the required rated current value. Therefore, as the resistance calculation step 70, the resistance value r of the limiting resistor 61 is obtained by Ohm's law from the preset rated voltage (Vnomal) and the calculated calculated rated current (Innomal). There may be. The overdrive current calculating step 72 is a step of calculating an overdrive current from a preset rated voltage, a preset overdrive voltage, a calculated resistance value of the limiting resistor, and a searched rated current. It is.

That is, the rated current, the rated voltage, the overdrive current, and the overdrive voltage have the relationship shown in the graph shown in FIG. Therefore, the preset rated voltage is Vnomal, the preset overdrive voltage is Vover, the limiting resistance calculated by the resistance calculating means is r, and the rated current searched by the searching means is Inomaal. Then, the overdrive current Iover can be obtained by the following formula 2.

  If the overdrive current can be estimated, the process proceeds to step S9 to determine whether to start the strobe lighting. If not, the process of the overdrive current calculation method is terminated. When the strobe lighting is started in step S9, the process proceeds to step S10 and the strobe lighting is started. That is, it is used for image recognition of a die bonder. Further, if the bonding work of the die bonder is finished, it is determined whether or not the work is finished as shown in step S11, and if the work is finished, the work is finished.

  According to the illumination power supply device, the rated current of the rated voltage can be searched through the searching means 52. Further, the resistance value of the limiting resistance of the LED illumination can be calculated via the resistance calculation means 63. Therefore, from the rated current searched by the searching means 52 by the current value calculating means 64, the resistance value of the limiting resistance of the LED illumination calculated by the resistance calculating means 63, the rated voltage and the overdrive voltage, The overdrive current at the overdrive voltage can be calculated.

  In the present invention, the overdrive current can be automatically calculated, and it is not necessary to check the overdrive current in advance. In addition, since it is not necessary to set the checked current as an overdrive current, the setting workability for the illumination power supply device is excellent. Moreover, a lighting failure due to an overdrive current setting error is not caused. If it is LED illumination 43 with the same rated voltage, it can be used for various illuminating devices. Furthermore, the current value of the overdrive current can be calculated without actually flowing the overdrive current, and the calculation time can be shortened.

  By the way, when the resistance value r of the limiting resistor 61 is low, applying the predetermined voltage (12V) may cause a large current to flow through the LED illumination 43 and cause the LED 60 to fail. For this reason, in this device, when the current is increased until the voltage reaches a certain value (predetermined voltage of 12 V), if the limiting resistor 61 is not included, the increase of the voltage reaches a peak, and the current flows too much It becomes. Note that a small lighting device may fail even in the range H in FIG.

  Therefore, it is preferable to determine whether the connected LED illumination 43 does not include the limiting resistor 61. Next, a determination method in which the resistance value of the limiting resistor 61 is added to the determination element will be described with reference to FIG. In this case, the process starts from step S3 in FIG. In step S21, the resistance value of the limiting resistor 61 is obtained. That is, when the current I is increased by ΔI and the voltage V is increased by ΔV, the resistance value r of the limiting resistor 61 can be obtained by r≈ΔV / ΔI.

  Next, in step S22, it is determined whether the resistance value r is r≈0. If r.apprxeq.0, the limiting resistor 61 is included, and the process returns to step S3 in FIG. If r.apprxeq.0 in step S22, it means that the limiting resistor 61 is not included, and the process proceeds to step S23 to stop lighting and end.

  As described above, when the resistance value of the limiting resistor 61 is set to r, it is possible to prevent the current from flowing excessively to a device that does not have the limiting resistor 61 by determining whether r≈0 or not. Damage to the erroneous LED illumination 43 can be effectively avoided.

  For this reason, the resistance value r of the limiting resistor 61 can be measured without adding remodeling or the like to the commercially available LED lighting in the market, and damage to the LED lighting 43 due to a connection error can be prevented. In addition, the apparatus is not complicated and expensive.

  By the way, in the said embodiment, the rated current in the preset rated voltage is calculated, overdrive current is calculated with this rated voltage, the calculated resistance value of the limiting resistor, and the preset overdrive voltage. However, the overdrive current can be estimated without using the rated current and the rated voltage.

  That is, since the overdrive voltage is known in advance, the overdrive current can be estimated by Ohm's law from the calculated resistance value of the limiting resistor 61 and this overdrive voltage.

  Also in this case, since the overdrive current can be estimated, the same effects as those of the above embodiment can be obtained. Moreover, although the accuracy of the estimated overdrive current value may be somewhat lower than that of the above embodiment, there is an advantage that the time required for the estimation can be greatly shortened.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the number of LED illuminations 43 may be at least one. The lighting system using this power supply device is not limited to a die bonder, and can be used for various devices that require lighting, and is optimal for devices that require lighting that is lit at a preset voltage.

  Further, the current / voltage characteristics of the LED 60 of the LED illumination 43 shown in FIG. 8 and the current / voltage characteristics of the limiting resistor 61 of the LED illumination 43 shown in FIG. 9 are not limited to those in the illustrated example. For this reason, the combined voltage of the LED 60 and the limiting resistor 61 shown in FIG. 10 is not limited to the illustrated example.

  By the way, in the lighting power supply apparatus according to the present invention, the calculation of the overdrive current does not actually flow the overdrive current, so the calculated (estimated) current value may differ from the actual current value of the overdrive current. There is sex. If this calculated (estimated) current value is larger than the actual overdrive current, the LED illumination 43 used may be damaged. Therefore, from the viewpoint of protecting the LED illumination 43, the overdrive current may be obtained by multiplying the calculated (estimated) current value by, for example, about 0.8.

  In the embodiment, the CPU 45 is provided with the calculating means 62 having the resistance calculating means 63 and the current value calculating means 64. However, the calculating means 62 is provided outside the CPU 45 and further in the casing in which the CPU 45 is accommodated. It may be provided outside. In the illustrated example, the resistance calculating unit 63 and the current value calculating unit 64 are integrally provided, but the resistance calculating unit 63 and the current value calculating unit 64 may be separately disposed. For this reason, only one of the resistance calculation means 63 and the current value calculation means 64 may be provided outside the CPU 45 and further outside the casing in which the CPU 45 is housed. In addition, when the resistance calculation means 63 and the current value calculation means 64 are provided outside, they can be configured by a personal computer (personal computer) or the like.

50 Constant current supply circuit (Constant current supply means)
52 exploration means 61 limiting resistance 63 resistance calculation means 64 current value calculation means 70 resistance calculation step 71 rated current exploration step 72 overdrive current calculation step

Claims (6)

An illumination power supply device connected to an LED illumination capable of applying an overdrive voltage higher than a rated voltage by lighting a strobe and having a limiting resistance, and a controller serving as a drive source,
A constant current supply means capable of applying a lighting current to the LED illumination;
Resistance calculating means for calculating a resistance value of the limiting resistance of the LED illumination;
Current value calculation means for calculating an overdrive current when the overdrive voltage is obtained from a preset overdrive voltage and the resistance value of the limiting resistance of the LED illumination calculated by the resistance calculation means A power supply device for lighting. An illumination power supply device connected to an LED illumination capable of applying an overdrive voltage higher than a rated voltage by lighting a strobe and having a limiting resistance, and a controller serving as a drive source,
A constant current supply means capable of applying a lighting current to the LED illumination;
Exploring means for exploring a rated current, which is a current value necessary for applying the rated voltage by applying an exploration current from a constant current supply means to the LED illumination before lighting the LED illumination at the rated voltage; ,
Resistance calculating means for calculating a resistance value of the limiting resistance of the LED illumination;
The overdrive voltage based on the preset rated voltage, the preset overdrive voltage, the rated current searched for by the searching means, and the resistance value of the limiting resistance of the LED illumination calculated by the resistance calculating means A lighting power supply device comprising: current value calculating means for calculating an overdrive current at the time.   The lighting power supply device according to claim 1 or 2, wherein the LED lighting is stroboscopically turned on with an overdrive current calculated by a current value calculation means. When the rated voltage to be set is Vnomal, the overdrive voltage to be set is Vover, the resistance value of the limiting resistor calculated by the resistance calculating means is r, and the rated current searched by the searching means is Inomaal 4. The illumination power supply device according to claim 2, wherein Iover, which is an overdrive current, is obtained by the following equation (1).

  The illumination power supply device according to any one of claims 1 to 4, wherein the illumination power supply device is used for illumination for image recognition. An overdrive current calculation method for calculating an overdrive current that is an overdrive voltage in LED lighting that can be applied with an overdrive voltage higher than a rated voltage by lighting a strobe and has a limiting resistance,
A resistance calculating step of calculating a resistance value of the limiting resistance of the LED illumination;
Before turning on the LED illumination at the rated voltage, a rated current exploration step of exploring a rated current value required to apply the exploration current to the LED illumination and apply the rated voltage;
An overdrive current calculating step for calculating an overdrive current from a preset rated voltage, a preset overdrive voltage, a calculated resistance value of the limiting resistor, and a searched rated current; An overdrive current calculation method characterized by the above.

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