KR20170100363A - Device for controlling laser diode - Google Patents

Device for controlling laser diode Download PDF

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Publication number
KR20170100363A
KR20170100363A KR1020160022837A KR20160022837A KR20170100363A KR 20170100363 A KR20170100363 A KR 20170100363A KR 1020160022837 A KR1020160022837 A KR 1020160022837A KR 20160022837 A KR20160022837 A KR 20160022837A KR 20170100363 A KR20170100363 A KR 20170100363A
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South Korea
Prior art keywords
laser diode
current
transistors
transistor
voltage
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KR1020160022837A
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Korean (ko)
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KR101825924B1 (en
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정지호
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주식회사 이오테크닉스
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Priority to KR1020160022837A priority Critical patent/KR101825924B1/en
Publication of KR20170100363A publication Critical patent/KR20170100363A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
    • H01S5/042—Electrical excitation ; Circuits therefor

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Semiconductor Lasers (AREA)

Abstract

Disclosed is a laser diode control apparatus. The laser diode control apparatus according to an embodiment of the present invention comprises: a laser diode; a current adjustment part including a plurality of transistors connected in series with the laser diode and controlling currents applied to the laser diode; and a voltage adjustment part including a plurality of voltage driving units adjusting voltages applied to each gate of the plurality of transistors.

Description

[0001] The present invention relates to a device for controlling a laser diode,

The present invention relates to an apparatus for controlling a laser diode, and more particularly, to a technique for controlling a current applied to a laser diode.

A laser diode is a device that generates a laser by using a forward semiconductor junction as an active medium. The laser diode has two electrodes for laser operation and can emit the laser by the forward current of the pn junction.

The optical output power of the laser diode can be adjusted by the magnitude of the forward current applied to the laser diode. Therefore, a circuit configuration for applying a predetermined current to the laser diode is required.

However, if the use time of the laser diode is increased, defects such as a short circuit on a circuit for applying a current to the laser diode, for example, a short circuit may occur. If an overcurrent is applied to the laser diode due to a defect in the circuit, the laser diode is damaged.

According to an exemplary embodiment, a laser diode control apparatus is provided which allows the current applied to the laser diode to be adjusted within a predetermined allowable range.

In one aspect,

Laser diode;

A current regulator including a plurality of transistors connected in series with the laser diode, the current regulator controlling a current applied to the laser diode; And

And a voltage regulating unit including a plurality of voltage driving units for regulating a voltage applied to the gates of the plurality of transistors

A laser diode control device is provided.

Each of the plurality of voltage units may be connected to the gate and drain electrodes of each of the plurality of transistors.

The voltage regulator may adjust a voltage applied to each of the plurality of transistors so that a sum of currents applied to the laser diode by the plurality of transistors of the current regulator does not exceed a predetermined allowable value.

The plurality of transistors may include a field effect transistor.

The laser diode control apparatus may further include a switching unit provided between the current regulating unit and the laser diode and including a plurality of switching elements for switching a current between the plurality of transistors and the laser diode,

Each of the plurality of switching elements may be switched to an off state when a current applied to each of the plurality of switching elements exceeds a predetermined allowable current.

The plurality of switching elements may include a relay switch.

Each of the plurality of switching elements including a coil,

The on / off states of each of the plurality of switching elements can be determined according to the magnitude of the current applied to the coils included in each of the plurality of switching elements by the plurality of voltage driving units.

The laser diode control apparatus further includes a current measuring unit for measuring a current flowing in each of the plurality of transistors,

The plurality of voltage driving units may adjust a magnitude of a current applied to a coil included in each of the plurality of switching elements based on a current value measured by the current measuring unit.

The plurality of voltage driving units may adjust the magnitude of the voltage applied to the gates of the plurality of transistors according to on / off states of the plurality of switching elements, respectively.

According to embodiments, a plurality of transistors for applying current to the laser diode may be provided. By allowing a plurality of transistors to distribute and apply a current to be applied to the laser diode, damage to the transistor can be prevented. Further, by implementing a plurality of transistors as field effect transistors, the magnitude of the current applied by each of the transistors can be easily changed according to the operation of the voltage driving unit. Further, when a part of the transistors is short-circuited, it is possible to prevent an overcurrent from flowing to the laser diode by using the switching element.

1 is a diagram illustrating a laser diode control apparatus according to an exemplary embodiment.
2 is a diagram illustrating a laser diode control apparatus according to another exemplary embodiment.
3 is a diagram exemplifying the configuration of the second switching element.
4 is a diagram showing an example of a relay switch shown in Fig.

In the following drawings, like reference numerals refer to like elements, and the size of each element in the drawings may be exaggerated for clarity and convenience of explanation. On the other hand, the embodiments described below are merely illustrative, and various modifications are possible from these embodiments.

The terms first, second, etc. may be used to describe various elements, but the elements should not be limited by terms. Terms are used only for the purpose of distinguishing one component from another.

The singular expressions include plural expressions unless the context clearly dictates otherwise. Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

Also, the terms " part, " " module, " and the like, which are described in the specification, refer to a unit that processes at least one function or operation.

1 is a diagram illustrating a laser diode control apparatus according to an exemplary embodiment.

1, a laser diode control apparatus according to an exemplary embodiment includes a laser diode 10 and a current controller 300 including a plurality of transistors 310 and 320 connected in series with the laser diode 10 And a voltage regulator 200 including a plurality of voltage driving units 210 and 220 for regulating the voltages applied to the gates G1 and G2 of the plurality of transistors 310 and 320, respectively.

The laser diode 10 may include an active semiconductor layer, and an n-electrode and an n-electrode which are bonded to both surfaces of the active semiconductor layer. The first and second transistors 310 and 320 may apply a forward current to the laser diode 10. The laser output power of the laser diode 10 may be determined by the sum of the currents applied to the laser diode 10 by the first and second transistors 310 and 320.

The current regulating unit 300 may include a plurality of transistors 310 and 320. For example, the current regulator 300 may include a first transistor 310 and a second transistor 320. In FIG. 1, the current regulator 300 includes two transistors 310 and 320. However, the number of transistors included in the current regulator 300 may be greater than two.

Each of the transistors 310 and 320 included in the current regulator 300 may be connected in series with the laser diode 10. For example, the drain electrode D 1 of the first transistor 310 may be connected to the n-electrode of the laser diode 10. Also, the drain electrode D2 of the second transistor 320 may be connected to the n-electrode of the laser diode 10. The source electrodes S1 and S2 of the first and second transistors 310 and 320 are connected to the n electrode of the laser diode 10 so that the first and second transistors 310 and 320 are connected to the laser diode 10 A forward current can be applied.

The transistors 310 and 320 may be field effect transistors (FETs). Unlike the conventional transistor, the field effect transistor can control the drain current according to the magnitude of the voltage applied to the gate. The depletion layer diffusion between the gate and the channel layer may vary depending on the voltage applied to the gate of the field effect transistor. As the diffusion of the depletion layer is changed, the amount of electrons moving from the drain electrode to the source electrode can be varied. As the amount of electrons moving from the drain electrode to the source electrode is changed, the amount of current flowing from the source electrode to the drain electrode can be varied.

When the transistors 310 and 320 are constituted by field effect transistors, the gate current becomes almost zero, and the structure of the transistors 310 and 320 can be easily integrated at higher density than the junction type transistors.

The voltage regulating unit 200 may include a plurality of voltage driving units 210 and 220. For example, the voltage regulator 200 may include a first voltage drive unit 210 and a second voltage drive unit 220. 1 shows an example in which the voltage regulating unit 200 includes two voltage driving units 210 and 220. FIG. However, the number of the voltage driving units 210 and 220 included in the voltage adjusting unit 200 may be more than two. For example, the number of voltage driving units 210 and 220 may correspond to the number of transistors 310 and 320.

The first voltage driving unit 210 may be connected to the drain electrode D1 of the first transistor 310 and the gate G1. The first voltage driving unit 210 controls the magnitude of the current applied to the laser diode 10 by the first transistor 310 by adjusting the magnitude of the voltage applied to the gate G1 of the first transistor 310 . The second voltage driving unit 220 may be connected to the drain electrode D2 and the gate G2 of the second transistor 320. [ The second voltage driving unit 220 controls the magnitude of the current applied to the laser diode 10 by the second transistor 320 by adjusting the magnitude of the voltage applied to the gate G2 of the second transistor 320 .

The voltage regulator 200 may prevent the sum of the currents applied to the laser diode 10 by the transistors 310 and 320 of the current regulator 300 from exceeding a predetermined tolerance. The predetermined allowable value may vary depending on the laser beam output capacity of the laser diode 10. [

The first voltage driving unit 210 of the voltage regulator 200 controls the magnitude of the voltage applied to the gate G1 of the first transistor 310 so that the first transistor 310 is connected to the laser diode 10 So that the applied current can be made smaller than the allowable value. The second voltage driving unit 220 adjusts the voltage applied to the gate G2 of the second transistor 320 so that the current applied to the laser diode 10 by the second transistor 320 is lower than It can be made smaller than the allowable value.

The first transistor 310 and the second transistor 320 can apply a current of the same magnitude to the laser diode 10. As another example, the first transistor 310 and the second transistor 320 may apply currents of different sizes to the laser diode 10, respectively. The voltage applied by the first voltage driving unit 210 to the gate G1 of the first transistor 310 and the voltage applied by the second voltage driving unit 220 to the gate G1 of the second transistor 320 The magnitudes of the voltages may be the same or different.

The first and second voltage driving units 210 and 220 can control the currents applied to the laser diode 10 by controlling the voltages of the gates G1 and G2 of the first and second transistors 310 and 320, The second transistors 310 and 320 can be dispersed. Therefore, the amount of current flowing through each of the first and second transistors 310 and 320 can be reduced. The amount of current flowing through each of the first and second transistors 310 and 320 is reduced, so that the lifetime of the first and second transistors 310 and 320 can be increased.

2 is a diagram illustrating a laser diode control apparatus according to another exemplary embodiment. In the description of the embodiment of FIG. 2, the description overlapping with FIG. 1 is omitted.

2, a laser diode control apparatus according to an exemplary embodiment is provided between a current regulating unit 300 and a laser diode 10 and includes a plurality of transistors 310 and 320 and a laser diode 10 And a switching unit 400 including a plurality of switching devices 410 and 420 for switching the current of the switching device 400. [

The switching unit 400 may include first and second switching devices 410 and 420. Although the switching unit 400 includes two switching devices 410 and 420 in FIG. 2, the present invention is not limited thereto. For example, the number of the switching elements 410 and 420 included in the switching part 400 may vary depending on the number of the transistors 310 and 320 included in the current adjusting part 300.

The first switching device 410 may be connected to the first transistor 310 and the laser diode 10. Also, the second switching device 420 may be connected to the second transistor 320 and the laser diode 10. The ON / OFF state of the first switching device 410 may be changed depending on the magnitude of the current flowing between the first transistor 310 and the laser diode 10. Also, the second switching device 420 may be turned on / off according to the magnitude of the current flowing between the second transistor 320 and the laser diode 10.

For example, if the first transistor 310 is damaged, a short-circuit phenomenon may occur. The impedance of the first transistor 310 is substantially converged to zero and the current between the first transistor 310 and the laser diode 10 increases rapidly to cause damage to the laser diode 10 . When the current between the first transistor 310 and the laser diode 10 becomes larger than a predetermined allowable value, the first switching device 410 switches between the first transistor 310 and the laser diode 10 The circuit of FIG. The predetermined allowable value may vary depending on the maximum optical output value of the laser diode 10. [

Likewise, when the current between the second transistor 320 and the laser diode 10 becomes larger than a predetermined tolerance, the second switching device 420 turns on the circuit between the second transistor 320 and the laser diode 10 Off. The second switching device can prevent the damage of the laser diode 10 by blocking the current between the second transistor 320 and the laser diode 10 when the second transistor 320 is shorted.

The first switching device 410 may be connected to the first voltage driving unit 210. Also, the second switching device 420 may be connected to the second voltage driving unit 220. The ON / OFF state of the first switching device 410 is changed by the first voltage driving unit 210 and the ON / OFF state of the second switching device 420 is changed by the second voltage driving unit 220 .

The first and second switching elements 410 and 420 may include a relay switch. 3 is a diagram illustrating a configuration of the second switching device 420. As shown in FIG.

Referring to FIG. 3, the second switching device 420 may include a transistor Tr connected to the second voltage driving unit 220, and a relay switch RS. The relay switch RS may be connected to the transistor Tr. The relay switch Rs may be provided between the laser diode 10 and the second transistor 320 to switch the current between the second transistor 320 and the laser diode 10.

The second voltage driving unit 220 can change the gate voltage of the transistor Tr in the second switching device 420 so that the current applied to the relay switch Rs by the transistor Tr have. The relay switch Rs can be switched on / off according to the current supplied from the transistor Tr.

4 is a diagram showing an example of a relay switch shown in Fig.

Referring to FIG. 4, the relay switch RS may include a coil C1 and a switching unit S. The current applied to the coil C1 can be adjusted by the transistor Tr shown in Fig. The first and second voltage driving units 210 and 220 change the gate voltage of the transistor Tr included in each of the first and second switching elements 410 and 420 to change the current flowing through the coil C1 .

When the current flowing through the coil C1 becomes strong, the inside of the coil can magnetize. When the inside of the coil becomes magnetized, the on / off state of the switching unit S can be changed by applying a magnetic force to the switching unit S. With this principle, each of the first and second voltage driving units 210 and 220 changes the magnitude of the current applied to the coil C1 included in each of the first and second switching devices 410 and 420, The ON / OFF states of the first and second switching elements 410 and 420 can be adjusted.

The laser diode control apparatus according to the embodiment may further include a current measuring unit 500 for measuring a current flowing in each of the plurality of transistors 310 and 320. The current measuring unit 500 may include a first current measuring unit 510 and a second current measuring unit 520. The number of current measuring units included in the current measuring unit 500 may vary according to the number of the transistors 310 and 320. The first current measurement unit 510 may be connected in series with the first transistor 310. In addition, the second current measurement unit 520 may be connected in series with the second transistor 320. The first current measuring unit 510 may measure the current flowing to the first transistor 310 and transmit the measurement result to the first voltage driving unit 210. The second current measuring unit 520 may measure the current flowing to the second transistor 320 and may transmit the measurement result to the second voltage driving unit 220.

The first voltage driving unit 210 changes the current applied to the coil C1 of the first switching device 410 when the current value measured by the first current measuring unit 510 exceeds the allowable value, The device 410 can be turned off. The second voltage driving unit 220 changes the current applied to the coil C1 of the second switching device 420 when the current value measured by the second current measuring unit 520 exceeds the allowable value, 2 switching element 420 can be turned off.

When any one of the plurality of switching elements 410 and 420 is turned off, the transistor connected to the turned off switching element can not supply current to the laser diode 10 anymore. Therefore, in order to keep the output amount of the laser diode 10 as predetermined, the amount of current applied to the laser diode 10 by the transistor connected to the ON-state switching element must be increased. A plurality of voltage driving units 210 and 220 may be turned on and off according to the on / off states of the switching devices 410 and 420, respectively, in order to maintain the amount of current supplied to the laser diode 10, 310 and 320 may be adjusted to a different magnitude.

For example, in FIG. 2, when the first transistor 310 is short-circuited by damage, an overcurrent can flow through the first transistor 310. When the overcurrent is detected in the first current measuring unit 510, the first voltage driving unit 210 changes the amount of current applied to the coil C1 of the first switching device 410, 410 are turned off. It is possible to prevent the first transistor 310 from applying the overcurrent to the laser diode 10 as the first switching device 410 is turned off.

When the first switching device 410 is turned off, the first transistor 310 may not be able to apply a current to the laser diode 10. In this case, the second voltage driving unit 220 can make the amount of current applied to the laser diode 10 larger by the second transistor 320 by making the gate G1 voltage of the second transistor 320 larger have. Also, the first voltage driving unit 210 may not apply a voltage to the gate G1 of the first transistor 310, which has lost its function. As described above, according to the ON / OFF states of the switching elements 410 and 420, each of the plurality of voltage driving units 210 and 220 applies a voltage (voltage) applied to the gates G1 and G2 of the plurality of transistors 310 and 320, The optical output power of the laser diode 10 can be maintained at the target output power.

A part of the plurality of transistors 310 and 320 included in the current regulating unit 300 may perform the function of a spare transistor. For example, the second switching device 320 may remain off while the first switching device 310 is on. Also, the second voltage driving unit 220 may not apply the voltage to the second transistor 320. Accordingly, the second transistor 320 may not operate while the first transistor 310 is normally operating as a spare transistor.

However, if the first transistor 310 generates a short circuit due to breakage, the first switch 410 may be turned off. When the first switch 410 is turned off, the second voltage driving unit 220 may change the second switch 420 to the on state and apply the driving voltage to the second transistor 320. That is, if the first transistor 310 is damaged, the second transistor 320 may perform the function of supplying the current to the laser diode 10.

The laser diode control apparatus according to the exemplary embodiments has been described above with reference to Figs. 1 to 3. Fig. According to the embodiments, a plurality of transistors for applying current to the laser diode 10 may be provided. It is also possible to prevent the transistors 310 and 320 from being damaged by allowing the plurality of transistors 310 and 320 to distribute the current applied to the laser diode 10. [ By implementing the plurality of transistors 310 and 320 as the field effect transistors, the magnitude of the current applied by each of the transistors 310 and 320 can be easily changed according to the operation of the voltage driving units 210 and 220 . Further, when a part of the transistors is short-circuited, the switching elements 410 and 420 can be used to prevent an overcurrent from flowing to the laser diode 10

While a number of embodiments have been described in detail above, they should be construed as examples of preferred embodiments rather than limiting the scope of the invention. Therefore, the scope of the present invention should not be limited by the described embodiments but should be determined by the technical idea described in the claims.

10: Laser diode
200:
300:
400:
500: current measuring unit
210 and 220: first and second voltage driving units
310, 320: first and second transistors
410, 420: first and second switching elements
510, 520: first and second current measuring units

Claims (10)

Laser diode;
A current regulator including a plurality of transistors connected in series with the laser diode, the current regulator controlling a current applied to the laser diode; And
And a voltage regulating unit including a plurality of voltage driving units for regulating a voltage applied to the gates of the plurality of transistors
Laser diode control device. The method according to claim 1,
Wherein each of the plurality of voltage units is connected to gate and drain electrodes of each of the plurality of transistors. The method according to claim 1,
Wherein the voltage regulator adjusts a voltage applied to each of the plurality of transistors so that a sum of currents applied to the laser diode by the plurality of transistors of the current regulator does not exceed a predetermined tolerance. The method according to claim 1,
Wherein the plurality of transistors comprise field effect transistors. The method according to claim 1,
A laser diode disposed between the current regulator and the laser diode,
And a switching unit including a plurality of switching elements for switching a current between the plurality of transistors and the laser diode,
Wherein each of the plurality of switching elements switches to an OFF state when a current applied to each of the plurality of switching elements exceeds a predetermined allowable current. 6. The method of claim 5,
Wherein the plurality of switching elements includes a relay switch. The method according to claim 6,
Each of the plurality of switching elements including a coil,
Wherein the on / off states of each of the plurality of switching elements are determined according to a magnitude of a current applied to the coils included in each of the plurality of switching elements by the plurality of voltage driving units. 8. The method of claim 7,
And a current measuring unit for measuring a current flowing in each of the plurality of transistors,
Wherein the plurality of voltage driving units adjust a magnitude of a current applied to a coil included in each of the plurality of switching elements based on a current value measured by the current measuring unit. 9. The method of claim 8,
Wherein the plurality of voltage driving units differently adjust the magnitude of a voltage applied to the gate of each of the plurality of transistors in accordance with ON / OFF states of the plurality of switching elements. 6. The method of claim 5,
Wherein the plurality of transistors includes a first transistor for applying a current to the laser diode and a second transistor for replacing the function of the first transistor when the first transistor is damaged,
Wherein the plurality of switching elements includes a first switching element connected to the first transistor and a second switching element connected to the second transistor, and the second switching element is turned on when the first switching element is turned off To the laser diode control device.
KR1020160022837A 2016-02-25 2016-02-25 Device for controlling laser diode KR101825924B1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20190036020A (en) 2017-09-27 2019-04-04 최환용 Apparatus for controlling multichannel laser diodes light source and controlling method thereof

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20190036020A (en) 2017-09-27 2019-04-04 최환용 Apparatus for controlling multichannel laser diodes light source and controlling method thereof

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