JP2019068528A - Booster circuit, power supply circuit, light source drive circuit and distance measurement device - Google Patents

Abstract

To downsize a light source drive part which drives a light source.SOLUTION: A booster circuit comprises: a first power source; an inductive element of which one end is electrically connected with the first power source and which stores a current as magnetic field energy; a switch element which is electrically connected with the other end of the inductive element and applies a voltage to the inductive element; a selection switch which selects a connection destination to be electrically connected with the other end of the inductive element; multiple capacitive elements each of which is electrically connected with the other end of the inductive element by the selection switch and stores electric charge; and a control part which controls the switch element and the selection switch. The inductive element and the switch element are used to charge one capacitive element, among the multiple capacitive elements, which is electrically connected with the inductive element by the selection switch, by boosting a voltage supplied from the first power source.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a booster circuit, a power supply circuit, a light source drive circuit, and a distance measurement device.

  After charging the energy storage element such as a capacitor, the energy storage element is used as a power source, and the switch element such as a transistor is used to discharge the charge stored in the energy storage element, thereby achieving short pulse and high peak drive current. There is known a pulse drive circuit for supplying a load. The energy storage element is charged with a small current value less than 1 [A], and in the discharge by the switch element, the pulse width: several [ns], peak current by instantaneously discharging the charge stored in the capacitor : Several tens to hundreds of [A] of current can be supplied to the load. Such a pulse drive circuit is used to drive a light source in, for example, LiDAR (Light Detection and Ranging) or a laser processing apparatus. Note that LiDAR detects the presence of an object in the scan area by irradiating pulsed light in the scan area and receiving the reflected light from the object present in the scan area. It is an apparatus that measures the distance to an object by measuring the arrival time of reflected light.

  In the present specification, a switch element in a pulse drive circuit used to drive a light source is referred to as a light source drive element.

  In order to pulse drive a plurality of light sources, substrates provided with pulse drive circuits of the respective light sources are separately provided for each light source, or pulse drive circuits for each light source are mounted in parallel on a single substrate. (E.g., Patent Document 1).

  LiDAR has a plurality of (2 to several tens of) light sources for emitting high-output (for example, 70 [W] light quantities) and high-speed (for example, 20 [ns] pulse widths) light emission pulses. By sequentially emitting light from the light source, light scanning of the scanning area is performed. In order to cause the light source to emit light with a light quantity of 70 [W], it is necessary to flow several tens of [A] of current through the light source, and it is necessary to allow this current to drive the light source. Therefore, the size of the light source driving element is about 10 mm square. By reducing the number of light source drive elements, the pulse drive circuit can be miniaturized. As an example, a circuit that drives a plurality of light sources using one light source drive element is known (for example, Patent Document 2).

  Here, in order to reduce the influence of the parasitic inductance or parasitic capacitance of the light source and to improve the rising response of the light source drive element, a high voltage of several tens to several hundreds [V] is applied in pulses to the light source drive element. The way to do it is known. According to this method, the energy storage element is charged so that the potential of the energy storage element of the pulse drive circuit becomes several tens to several hundreds [V] immediately before the light source is pulsed and the light source drive element discharges it. Is realized by

  In patent document 2, in order to make the electric potential of the capacitor | condenser which is an energy storage element into a high voltage, the pressure | voltage rise DCDC circuit is used. Further, in Patent Document 3, the energy storage element is charged by moving the magnetic field energy stored in an inductive element such as a coil to the capacitor which is the energy storage element at once, and the potential of the energy storage element is increased. A boost chopper circuit is used.

There is a demand for miniaturization as to the size of the circuit for driving the light source.
Here, when optically scanning the scan area in LiDAR, it is necessary to repeatedly emit light from the light source at a high frequency of about several hundreds of kHz. In order to repeatedly emit light from the light source at such a high frequency using a pulse drive circuit, it is necessary to charge the energy storage element at a frequency higher than at least the light emission cycle of the light source.

  However, in the method of charging the energy storage element using the step-up DCDC power supply, the inductance of the coil is increased to increase the capacitance of the output capacitor in order to improve the output response of the step-up DCDC circuit (decrease the output impedance). It is necessary to improve the responsiveness to load, for example, by lowering it to increase the amount of allowable current. As a result, the component size of the step-up DCDC circuit becomes large, which is a constraint on downsizing of the circuit scale.

  Further, the step-up chopper circuit stores the magnetic field energy at a stretch by storing the magnetic field energy in the inductive element that stores the magnetic field energy, the energy storage element to which the magnetic field energy stored in the inductive element is moved, and the inductive element. There are few elements which are comprised by chopper switches, such as a transistor moved to an energy storage element, and comprise one step-up chopper circuit. In patent document 3, one light source is made to emit light using one step-up chopper circuit. The configuration of Patent Document 3 is a configuration of a single inductor single output (SISO) circuit which is one output for one booster coil (inductive element). Therefore, to emit light from a plurality of light sources, the same number of boost chopper circuits as the number of light sources are required. Here, since the inductive element in the step-up chopper circuit requires a large current capacity to store the step-up energy, the inductive element in the step-up chopper circuit is increased in size according to the increase in the voltage boosted by the step-up chopper circuit. Therefore, using the same number of step-up chopper circuits as the number of light sources is a constraint on downsizing of the circuit scale. That is, the configuration of Patent Document 3 has room for improvement in terms of downsizing when trying to emit light from a plurality of light sources.

  An object of the present invention is to miniaturize a light source drive unit for driving a light source.

  Then, in order to solve the above-mentioned subject, a booster circuit is electrically connected with the 1st power supply and one end with the 1st power supply, an inductive element which accumulates an electric current as magnetic field energy, and others of the inductive element A switch element electrically connected to an end to apply a voltage to the inductive element, a selection switch selecting a connection destination electrically connected to the other end of the inductive element, and the inductive switch A plurality of capacitive elements for storing charge, which are electrically connected to the other end of the element, and a control unit for controlling the switch element and the selection switch, the inductive element, and the switch element And boosting the voltage supplied from the first power supply from the capacitive element electrically connected to the inductive element by the selection switch out of the plurality of capacitive elements. To charge.

  The present invention can miniaturize a light source drive unit for driving a light source.

It is a figure which shows the example of a whole structure of the LiDAR apparatus 1000 in embodiment of this invention. It is a figure which shows the example of a circuit structure of the light source drive part 100 in embodiment of this invention. It is a timing chart of light source drive part 100 in an embodiment of the invention. It is a figure which shows the example of another circuit structure of the light source drive part 100 in embodiment of this invention. It is a figure which shows the structural example of the feedback circuit of the light source drive part 100 in embodiment of this invention. It is an output control flowchart of the pressure | voltage rise control part in embodiment of this invention. It is a figure which shows the structural example of the circuit which stabilizes the light source drive part 100 in embodiment of this invention. It is a figure which shows the structural example of the selection switch in embodiment of this invention. It is a figure which shows the structural example of the circuit which integrates the light source drive part 100 in embodiment of this invention. It is a figure which shows the structural example of the light source array as a load in embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described based on the drawings.

  FIG. 1 is a diagram showing an example of the overall configuration of a light detection and ranging (LiDAR) apparatus 1000 according to an embodiment of the present invention. The LiDAR device 1000 detects the presence of an object in the scan area by emitting pulsed light in the scan area and receiving the reflected light from the object present in the scan area. Or, by measuring the arrival time of the reflected light, the distance to the object is measured. The LiDAR device 1000 to which the present invention is applied has a plurality of light sources. By switching a plurality of light sources at a high frequency of several hundreds of kHz and emitting light, high-speed light scanning can be performed, and detection of an object and distance measurement to an object can be performed at high speed. As a result, it is possible to shorten the detection interval of the object and the interval of distance measurement to the object.

  Further, in the LiDAR device 1000, by shortening the pulse width of light emission, the rising edge becomes steep, the timing jitter (error) of time measurement decreases, the heat generation of the light source decreases, and the light source life improves. Heat generation is reduced, and effects such as shortening of the repetition cycle of pulse emission can be achieved.

  As shown in FIG. 1, the LiDAR device 1000 includes a light source drive unit 100, an ECU (Embedded Controller Unit) 201, a measurement control unit 202, an irradiation optical system 203, a light receiving optical system 204, a light receiving element 205, and a light receiving circuit 206. . The light source driving unit 100 includes a boosting circuit 105 which is a power supply circuit for supplying power to the light source, and a light source driving circuit 120 including a light source array 130 which is a light source.

  The ECU 201 transmits a control signal to the measurement control unit 202, and receives measurement data from the measurement control unit 202. The measurement control unit 202 receives a control signal from the ECU 201, and transmits a light source switching signal and a light emission signal to the light source drive unit 100. Further, the measurement control unit 202 receives a light reception signal from the light reception circuit 206, and transmits measurement data to the ECU 201.

  The light source drive unit 100 receives the light source switching signal and the light emission signal output from the measurement control unit 202 by the selective booster unit 110 or the light source drive circuit 120, and generates a current for driving the light source array 130.

  The illumination optical system 203 outputs the light emitted from the light source array 130 as illumination light. The light receiving optical system 204 receives the reflected light and guides it to the light receiving element 205. The light receiving element 205 converts the input reflected light into a signal. The light receiving circuit 206 transmits a light receiving signal to the measurement control unit 202 based on the signal output from the light receiving element 205.

  FIG. 2 is a diagram showing an example of the circuit configuration of the light source drive unit 100 according to the embodiment of the present invention. The booster circuit 105 has one end connected to the main power supply, a coil L (inductive element) for storing energy for boosting, and the other end of the coil L, and stores a magnetic field energy by applying a voltage to the coil L Chopper switch Q1 that supplies the stored magnetic field energy as a current to the other end of coil L, is connected to the other end of coil L, rectifies the current supplied from coil L in one direction, and this current flows It has the rectification switch SCR1-SCR3 which switches the point to either of power supply capacitor C1-C3, and the boost control part 107 which controls switching of rectification switch SCR1-SCR3.

  The boost control unit 107 controls switching on and off of the chopper switch Q1 and connection destinations of the rectifying switches SCR1 to SCR3.

  The rectification switches SCR1 to SCR3 switch the current supplied from the coil L to any of the power supply capacitors C1 to C3 according to a command from the boost control unit 107. One of the power supply capacitors C1 to C3 connected to the other end of the coil L by the rectifying switches SCR1 to SCR3 is charged by the current from the coil L. At this time, the power supply capacitors C1 to C3 selected by the rectification switches SCR1 to SCR3 are charged at a voltage higher than the voltage of the main power supply. The control timing of the boost control unit 107 will be described later.

  The light source drive circuit 120 has a plurality of light sources LD1 to LD3 constituting the light source array 130, light source drive elements Q2 to Q4 for driving the light sources LD1 to LD3 respectively, and a light emission control unit 121 for controlling light emission of the light sources LD1 to LD3. . The light sources LD1 to LD3 emit light using any one of the power supply capacitors C1 to C3 as a power supply. The light emission control unit 121 selects a light source emitting light from the light sources LD1 to LD3.

  That is, the booster circuit 105 constitutes a booster chopper circuit by the coil L, the chopper switch Q1, and any one of the power supply capacitors C1 to C3 connected to the coil L by the rectification switches SCR1 to SCR3. Then, since the charged power supply capacitors C1 to C3 become power supplies of the light sources LD1 to LD3, it is possible to say that the booster circuit 105 is a power supply circuit of the light source drive circuit 120.

  The boost control unit 107 and the light emission control unit 121 each receive an instruction of the light source switching signal and the light emission signal from the measurement control unit 202 and operate. As the operation, the light source emitting light is selected by the light source switching signal, and the light emission timing is controlled by the light emission signal.

  In the LiDAR device 1000, when obtaining a light emission waveform of a short pulse having a short pulse width, the rising speed of the light emission waveform is limited by the parasitic inductance or parasitic capacitance of the light source and the wiring pattern. Therefore, in the LiDAR device 1000, the charging voltage of the power supply capacitor is increased to several tens to several hundreds [V] or more in order to reduce the influence of the parasitic inductance. Also, in order to shorten the light emission cycle, it is effective to increase the amount of current flowing through the capacitor when charging the power supply capacitor.

  Here, in general automotive applications and the like, the power supply voltage is generally at most 48 [V] or less, and in order to obtain a higher voltage than this power supply voltage, a boosted DCDC circuit is generally used. Boost the drive voltage. However, as described above, since there is a trade-off between improvement in output responsiveness of the boost DCDC circuit and miniaturization of the circuit scale, shortening the light emission period using the boost DCDC circuit results in miniaturization. It was difficult.

  In the embodiment of the present invention, miniaturization of the booster circuit for charging the power supply capacitor, which was difficult to realize in the related art by the device of the selective booster unit 110, is realized. It can also be realized by a semiconductor integrated circuit.

  As described above, in the embodiment of the present invention, the charge capacitors (power supply capacitors in the embodiment of the present invention) in the step-up chopper circuit are selected by the rectifying switches SCR1 to SCR3.

  With this configuration, one coil can charge a plurality of charging capacitors, and the boosted voltage can be supplied to a plurality of loads. That is, the embodiment of the present invention is a SIMO (Single Inductor Multi Output) technology. As described above, the coil in the step-up chopper circuit requires a large current capacity to store the step-up energy, so that the size of the parts becomes large. The fact that only one coil is required is effective for miniaturization. Further, among the components constituting the selective boosting unit 110 in the embodiment of the present invention, all components other than the coil can be components which can be integrated by the semiconductor integration technology. That is, in the embodiment of the present invention, the coil can be used as an external part for the selective booster 110 and can be configured with another integrated circuit, which is also a great advantage for downsizing.

  As a rectifying switch, a diode having a rectifying function may be combined with a switch such as a MOSFET-bipolar transistor, but in the configuration which can be realized in the simplest manner, it is preferable to use a thyristor having a PNPN structure. As a function of the thyristor, once the gate is turned on, the conduction is maintained until the current flows. The gate drive circuit is simplified because the procedure of turning off the thyristor automatically at the timing when the step-up operation is completed is surely performed in the operation of the one-pulse step-up chopper by the function of the thyristor. In addition, since the thyristor has a PNPN structure, it is also advantageous that the integration is easy.

FIG. 3 is a timing chart of the light source drive unit 100 according to the embodiment of the present invention. The operation sequence of the light source driving unit 100 shown in FIG. 2 is as follows.
(1) (t <t1) The boost control unit selects at least one light source to be lit based on the light source switching signal.
(2) (t> t1) The chopper switch Q1 is turned on by the step-up control signal S1, and a current is applied to the step-up coil L. The current rises with the time constant L / R (where R is the on resistance of Q1).
(3) (t = t2) When a predetermined current value Ichg flows in the booster coil L, the booster control unit turns off the chopper switch Q1 and turns on any one of the rectification switches SCR1 to SCR3. Two commutating switches can be turned on at the same time, in which case the charged voltage is halved. Here, the boost control unit sets the switching signal G1 to High to turn on the rectifying switch SCR1.
(4) (t <t3) When the charging is completed, the step-up control unit sets the switching signal G1 to Low to turn off the rectifying switch SCR1.
(5) (t = t3) The light source drive elements Q2 to Q4 corresponding to the light source selected by the light emission signal are turned ON. Here, the light emission control unit turns on Q2 by the light emission signal S2. The charge stored in the drive capacitor flows into the light source to obtain a pulsed light emission waveform. At this time, since the thyristor is off, pulses are emitted until the voltage values of the drive capacitors C1 to C3 disappear.
(6) (t <t4) The boost control unit selects at least one light source to be lit based on the light source switching signal.
(7) (t> t4) The chopper switch Q1 is turned on by the step-up control signal S1, and a current is applied to the step-up coil L. The current rises with the time constant L / R.
(8) (t = t5) When a predetermined current value Ichg flows through the booster coil L, the booster control unit turns off the chopper switch Q1, turns the switching signal G2 to High, and turns on the rectifying switch SCR2.
(9) (t <t6) When the charging is completed, the switching signal G2 is set to Low to turn off the rectifying switch SCR2.
(10) (t> t6) The driving element Q3 corresponding to the light source selected by the light emission signal S3 is turned ON. The charge stored in the drive capacitor flows into the light source to obtain a pulsed light emission waveform. At this time, since the thyristor is off, pulses are emitted until the voltage value of the drive capacitor C2 disappears.
(11) Return to (1).

  FIG. 4 is a diagram showing another circuit configuration example of the light source drive unit 100 according to the embodiment of the present invention. As a modified example of the circuit configuration example of FIG. 2, an example using a transformer instead of an inductor as an inductive element is shown.

  Even when a transformer is used as shown in FIG. 4, the present invention can be realized. In operation, when a current is supplied to the primary side of the transformer M by a chopper switch, an induced current according to the winding ratio flows to the secondary side. The drive capacitors C <b> 1 to C <b> 3 can be selected and boosted by switching the flowing direction of the induced current with the rectification switch.

  FIG. 5 is a diagram showing a configuration example of a feedback circuit of the light source drive unit 100 in the embodiment of the present invention, and some requirements are added.

  First, a rectifying element D is added to prevent reverse current from flowing to L through the parasitic diode of Q1. Also, the light source drive element is only Q2. Then, the drive current flowing through the light source drive element is rectified to add D1 to D3 for preventing the reverse voltage from being applied to the light sources LD1 to LD3. In addition, level shift circuits connected to the switching signals G1, G2, and G3 are added. The level shift circuit is a circuit for level shifting the voltage so that the gate-cathode voltage does not become a negative voltage when the thyristor is turned on. Generally, a bootstrap circuit or a pulse transformer is used. Furthermore, a feedback circuit for feeding back the boosted voltage value or drive current to the boost control unit 107 is added.

  Regarding the feedback circuit, in the boosting coil L, there are inductance fluctuation factors such as manufacturing variations, temperature characteristics, current characteristics and the like. In the circuit shown in FIG. 5, in order to cancel these fluctuation factors, the boosted voltage value or drive current is fed back to the boost control unit 107 to stabilize the voltage of the power supply capacitor after charging.

  A target to be fed back to the boost control unit 107 is a boosted voltage (charging voltage of a power supply capacitor), a peak value of a pulse current, an optical output of a light source, or the like. In the configuration shown in FIG. 5, the voltage of at least one power supply capacitor (FIG. 5 is C1) is fed back to the boost control unit 107. If C1 = C2 = C3, then by feedback of the voltage of C1, any drive capacitor can be made equal voltage. In fact, since the variation of the capacitance of the drive capacitor is a small variation of several [%] to 10 [%] compared to the coil, it can be regarded as substantially the same. If the post-manufacturing fluctuation (temperature fluctuation etc.) is sufficiently small, the fluctuation factor can be suppressed also by shipping or periodic individual adjustment.

  Further, in the configuration shown in FIG. 5, the peak value (peak current) of the light emission current flowing through the light sources LD1 to LD3 is fed back to the boost control unit 107 by current waveform detection means such as a shunt resistor and a peak hold circuit. As described above, in the light source drive unit 100 of FIG. 5, boost control is performed by using the feedback information acquisition unit as the feedback voltage Vfb for the charging voltage of the power supply capacitor C1 and the feedback current value Ifb for the peak current flowing through the light sources LD1 to LD3. It is fed back to the unit 107.

  As described above, by feeding back the charging voltage of the power supply capacitor C1 and the peak current flowing to the light sources LD1 to LD3 to the boost control unit 107, it is possible to stabilize the amount of light emitted from the light sources LD1 to LD3. Although it is desirable to feed back both the charging voltage of the power supply capacitor C1 and the peak current flowing to the light sources LD1 to LD3, it may be one or the other. Alternatively, it is possible to realize an output light amount control APC (Auto Power Control) that stabilizes the amount of emitted light by monitoring the amount of light emitted from the light source and feeding back a signal obtained by converting the amount of light into voltage or current to the boost control unit 107.

  As output control means performed by the boost control unit 107, pulse width variable control such as PWM is performed. The ON time of the chopper switch Q1 is varied according to the fed back values Vfb and Ifb to control the output.

  FIG. 6 is an output control flowchart of the boost control unit according to the embodiment of the present invention. FIG. 6 shows a feedback control operation of the boost control unit shown in FIG. A general PWM control procedure is shown in which the feedback amount is compared with the target value, and the output is controlled by the pulse width to approach the target value.

  First, in step S10, the voltage Vfb of the power supply capacitor or the peak current value Ifb of the peak-held drive current is AD converted and acquired. Subsequently, after comparing the acquired physical quantity with the target value (S11), the compensation value, that is, the ON time of the boost signal S1 is calculated by calculation (S12). In step S13, since the ON time of the chopper switch Q1 is controlled by the output of the boosting signal S1, the value of the current flowing through the boosting coil can be controlled to control the output voltage.

  For example, when the light emission cycle is variable, the pulse cycle of the ON time of S1 also changes according to the light emission cycle. Therefore, the chopper switch Q1 is turned on / off by pulse width control, that is, pulse width modulation that changes the pulse frequency. OFF control.

  Hereinafter, the reason why the current supplied from the boosting coil L can be controlled by the ON time of the chopper switch Q1 and the reason that the voltage boosted by the current supplied from the boosting coil L can be controlled will be described.

The boost chopper circuit boosts the energy of the boost coil in the process of transferring it to the drive capacitor. The energy amount of the boost coil is defined as WL, and the energy amount of the drive capacitor is defined as WC. When a current is supplied to the booster coil by the chopper switch, the energy amount WL of the booster coil can be expressed by the following equation. I is the current flowing through the coil and L is the coil inductance.
WL = 1/2 * L * I ^ 2
The energy amount WC of the capacitor can be expressed by the following equation. C is a capacitor capacitance, and V is a voltage across the capacitor.
WC = 1/2 * C * V ^ 2
At the same time as the chopper switch Q1 is turned off, the direction of current flow is rectified by the rectifying means to transfer energy to the capacitor. The efficiency at this time is a value close to 100%, and assuming that WL = WC, the voltage V after being boosted can be expressed by the following equation.
V = I * sqrt (L / C)
From the above, it can be seen that the boosted voltage V can be controlled by the current I flowing through the coil.

  FIG. 7 is a diagram showing a configuration example of a circuit that stabilizes the charging voltage of the power supply capacitors C1 to C3 in the light source drive unit 100 according to the embodiment of the present invention. Instead of feeding back the charging voltage of the power supply capacitor, a power supply of the same voltage Vclamp as the boosted voltage is separately prepared, and the charging voltage of the power supply capacitors C1 to C3 is stabilized by clamping the power supply capacitors C1 to C3. Since the current for driving the light sources LD1 to LD3 is supplied from the booster circuit 105, the clamp power supply does not need a current capacity for driving the light sources. There is an effect that all the power supply capacitors C1 to C3 can be made to have a constant voltage regardless of the difference in capacitance of the power supply capacitors C1 to C3. On the other hand, there are disadvantages such as the need for a separate power supply for supplying the stabilized voltage Vclamp and the need to separately consume the clamped power. The clamp power supply may be realized by, for example, a method of adding a boost power supply having another coil, or a method of configuring a SIMO power supply using a C1 boost inductor L shown in FIG.

  FIG. 8 is a diagram showing a configuration example of the selection switch in the embodiment of the present invention. In the embodiment of the present invention, a thyristor capable of realizing the selection switch by a pnpn structure is adopted. The thyristor functions to rectify the current in one direction, and once turned on, has the property of continuing to conduct until the current becomes zero. This property makes it possible to complete the one-pulse boosting operation of the present invention reliably and automatically.

  FIG. 9 is a diagram showing a configuration example of a circuit for integrating the light source driving unit 100 according to the embodiment of the present invention. The boost controller, the selection switch and the rectifying switch can all be integrated by means of semiconductor technology. The plurality of capacitive loads C1 to C3 and the coil L for storing boosted energy have a large capacitance or allowable current and are difficult to integrate, so it is preferable to use external devices. Since the integration can effectively reduce the component area of the drive circuit, the total size of the device can be reduced.

FIG. 10 is a view showing a configuration example of a light source array as a load in the embodiment of the present invention.
A plurality of light sources can be manufactured on one chip by integrating the anode wiring or cathode wiring of the laser diode on the same electrode (common wiring). As an effect, there are cases where multiple light sources can be arranged with accurate position accuracy, and the process of packaging can be reduced.

  Furthermore, in the drive circuit, drive elements with a supply current of several tens of [A] can be reduced rather than simply paralleled, so that the component area of the drive circuit can be reduced.

  As described above, according to the embodiment of the present invention, in the step-up chopper circuit including the coil and the capacitor for driving the light source array, a plurality of capacitors are provided for one coil, and the capacitors forming the step-up circuit are The configuration in which boosting is performed while switching by a switch having a rectifying function enables downsizing, integration, and cost reduction of the boosting circuit. That is, in the light emitting device which emits light from the light source array, the booster power supply unit can be miniaturized.

  In the embodiment of the present invention, the main power supply is an example of the first power supply. The clamp power supply is an example of a second power supply. The boost control unit 107 or the light emission control unit 121 is an example of a control unit. The LiDAR device 1000 is an example of a distance measurement device. The chopper switch is an example of a switch element. The rectifying switch is an example of the selection switch. The power supply capacitor is an example of a capacitive element.

  Although the embodiments of the present invention have been described above in detail, the present invention is not limited to such specific embodiments, and various modifications may be made within the scope of the present invention as set forth in the claims.・ Change is possible.

1000 LiDAR device 100 light source drive unit 105 boost circuit 107 boost control unit 110 selective boost unit 120 light source drive circuit 121 light emission control unit 130 light source array 201 ECU
202 measurement control unit 203 irradiation optical system 204 light receiving optical system 205 light receiving element 206 light receiving circuit

Patent No. 3975669 gazette JP, 2009-170870, A JP, 2016-152336, A

Claims (14)

The first power supply,
An inductive element, one end of which is electrically connected to the first power supply, for storing current as magnetic field energy;
A switch element electrically connected to the other end of the inductive element to apply a voltage to the inductive element;
A selection switch for selecting a connection destination electrically connected to the other end of the inductive element;
A plurality of capacitive elements for storing charge, which are electrically connected to the other end of the inductive element by the selection switch;
A control unit that controls the switch element and the selection switch;
Have
The capacitive element electrically connected to the inductive element by the selection switch out of the plurality of capacitive elements using the inductive element and the switch element, the first power supply A booster circuit that boosts and charges the voltage supplied from the The control unit is configured to select, from among the plurality of capacitive elements, a voltage value of the capacitive element electrically connected to the other end of the inductive element by the selection switch, and a current value flowing to a load of the booster circuit. Get at least one of
The booster circuit according to claim 1, wherein the on-time of the switch element is changed according to the acquired voltage value or current value.   The booster circuit according to claim 1, further comprising a second power supply that applies a predetermined voltage to the plurality of capacitive elements. The selection switch is a plurality of thyristors connected to each of the plurality of capacitive elements,
The control unit controls the on / off operation of the plurality of thyristors according to the on / off timing of the switch element, and a capacitor electrically connected to the other end of the inductive element among the plurality of capacitive elements. The booster circuit according to any one of claims 1 to 3, wherein a sexing element is selected. The booster circuit according to any one of claims 1 to 4, wherein the control unit and the selection switch are disposed on a semiconductor integrated circuit.
Boost circuit.   A power supply circuit for supplying power from the capacitive element charged by the booster circuit according to any one of claims 1 to 5. The first power supply,
An inductive element, one end of which is electrically connected to the first power supply, for storing current as magnetic field energy;
A switch element electrically connected to the other end of the inductive element to apply a voltage to the inductive element;
A selection switch for selecting a connection destination electrically connected to the other end of the inductive element;
A plurality of capacitive elements for storing charge, which are electrically connected to the other end of the inductive element by the selection switch;
A control unit that controls the switch element and the selection switch;
A plurality of light sources electrically connected to each of the plurality of capacitive elements;
Have
The capacitive element electrically connected to the inductive element by the selection switch out of the plurality of capacitive elements using the inductive element and the switch element, the first power supply Boost the voltage supplied from the
A light source drive circuit configured to emit a light source electrically connected to the charged capacitive element among the plurality of light sources using the charged capacitive element as a power source; The control unit controls the voltage value of the capacitive element electrically connected to the other end of the inductive element by the selection switch among the plurality of capacitive elements, and the current flowing to the load of the light source drive circuit Get at least one of the values,
The light source drive circuit according to claim 7, wherein the on time of the switch element is changed according to the acquired voltage value or current value.   9. The light source drive circuit according to claim 7, further comprising a second power supply that applies a predetermined voltage to the plurality of capacitive elements. The selection switch is a plurality of thyristors connected to each of the plurality of capacitive elements,
The control unit controls the on / off operation of the plurality of thyristors according to the on / off timing of the switch element, and a capacitor electrically connected to the other end of the inductive element among the plurality of capacitive elements. The light source driving circuit according to any one of claims 7 to 9, wherein the light emitting element is selected.   The light source drive circuit according to any one of claims 7 to 10, wherein the control unit and the selection switch are disposed on the same semiconductor integrated circuit.   The light source drive circuit according to any one of claims 7 to 11, wherein the light source is a semiconductor laser.   The light source drive circuit according to any one of claims 7 to 11, wherein the light source is a semiconductor laser, and the semiconductor laser is a laser light source array in which an anode or a cathode is wired by a common electrode. A distance measuring device using the light source drive circuit according to any one of claims 7 to 13, wherein
A light emitter for irradiating the object with light from the light source;
A light receiving unit that receives the reflected light from the target and acquires a light reception timing;
A distance measurement device comprising: a time measurement unit that measures an arrival time of the light from a time difference between the light emission timing of the light and the light reception timing.

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