• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    An electronic circuit comprises at least one radiation emitting element (2), a current regulator (12) with a current generating terminal (O), and a measuring element (14) producing a signal (Vmes) representative of the current crossing it. A switch (6) is controlled by a modulation signal (M) so as to successively open and close an electrical path passing through the current generating terminal (O), the radiation emitting element (2) and the element measuring (14). A conversion circuit (16) is furthermore interposed between the measuring element (14) and the current regulator (12) so as to convert the representative signal (Vmes) into a smoothed signal (S) for a terminal of regulation (Reg). A flight time sensor comprising such an electronic circuit is also proposed.
    公开号:FR3056304A1
    申请号:FR1658704
    申请日:2016-09-16
    公开日:2018-03-23
    发明作者:Jerome Couillault；Peter Gratzl
    申请人:Valeo Comfort and Driving Assistance SAS；
    IPC主号:
    专利说明:

    Holder (s): VALEO COMFORT AND DRIVING ASSISTANCE Simplified joint-stock company.
    Extension request (s)
    Agent (s): VALEO COMFORT AND DRIVING ASSISTANCE.
    104) ELECTRONIC CIRCUIT AND TIME OF FLIGHT SENSOR INCLUDING SUCH AN ELECTRONIC CIRCUIT.
    FR 3 056 304 - A1 (5 /) An electronic circuit comprises at least one radiation emitting element (2), a current regulator (12) with a current production terminal (O), and a measuring element (14 ) producing a signal (V mes ) representative of the current flowing through it.
    A switch (6) is controlled by a modulation signal (M) so as to successively open and close an electrical path passing through the current production terminal (O), the radiation emitting element (2) and the element measuring (14).
    A conversion circuit (16) is also interposed between the measuring element (14) and the current regulator (12) so as to transform the representative signal (V mes ) into a smoothed signal (S) intended for a terminal. regulation.
    A time-of-flight sensor comprising such an electronic circuit is also proposed.

    Electronic circuit and time of flight sensor comprising such an electronic circuit
    Technical field to which the invention relates
    The present invention relates to the supply of radiation emitting elements used for example in time of flight sensors.
    It relates more particularly to an electronic circuit and a time of flight sensor comprising such an electronic circuit.
    The invention applies particularly advantageously in the case where it is desired to obtain good repeatability of the signal emitted by the time of flight sensor.
    TECHNOLOGICAL BACKGROUND
    In time of flight sensors (in English ToF sensot 1 'for Timeof-Flight sensot 1 '), a radiation emitting element, such as a light-emitting diode, emits a given signal, intended to be detected by a receiving element after reflection on an object. It is thus possible to evaluate the distance of the object on the basis of the time elapsed between the emission of the signal and its reception at the level of the receiving element.
    In order to obtain efficient operation, the transmitted signal is modulated at high frequency. The transmitter element must therefore be traversed by a current formed of relatively high frequency high-frequency pulses, with very short rising and falling edges.
    These large variations in high frequency current prevent a priori the use of a current regulator, whose regulation loop has a characteristic time greater than the duration of the aforementioned pulses.
    A voltage-regulated supply and a resistance transforming this voltage into current are therefore frequently used to supply the radiation emitting element.
    This solution however involves heating and a loss of efficiency by the Joule effect in the aforementioned resistor, a current drift linked to the voltage drift of the light-emitting diode with temperature and an imprecision of the current obtained linked to the variability of the voltage. across the light emitting diode from one product to another.
    Object of the invention
    In this context, the present invention provides an electronic circuit comprising at least one radiation emitting element, a current regulator with a regulation terminal and a current production terminal, connected to the radiation emitting element, a measuring element. producing a signal representative of the current flowing through it, a switch controlled by a modulation signal so as to successively open and close an electrical path passing through the current production terminal, the radiation emitting element and the measuring element, and a conversion circuit interposed between the measuring element and the current regulator, and designed to transform the representative signal into a smooth signal (without modulation) intended for the regulation terminal.
    Thanks to the conversion circuit, current regulation at the current regulator will not be disturbed by the current interruptions caused by the switch under the control of the modulation signal.
    Such a circuit thus makes it possible to supply the radiation emitting element with a constant current and to control a modulation of the current in the high frequency emitting element, as is provided for example in a time of flight sensor.
    The emitting element is for example a light-emitting diode; the radiation emitted by the emitting element can be, in this case in particular, infrared radiation.
    In certain embodiments, such as that described below, a plurality of transmitter elements mounted in series on the electrical path can be provided.
    The measuring element can in practice be a resistor, in which case the signal representative of the current is the voltage across this resistor.
    The conversion circuit is for example a low-pass filter. In this case, such a low-pass filter may have a cutoff frequency lower than the frequency of the modulation signal.
    As a variant, the conversion circuit could be a peak detector (in English peak detectot 1 '), or an assembly formed by an analog-digital converter and a processor.
    Such a modulation signal is for example a periodic signal, here with a period of less than 100 ns.
    The invention also provides a time-of-flight sensor comprising an electronic circuit as proposed above.
    Such a time-of-flight sensor may further include a receiving element, such as a reception matrix (comprising a plurality of pixels). The receiving element can then be designed to receive, after reflection, the radiation emitted by the radiation emitting element. Such a time-of-flight sensor forms a three-dimensional camera.
    Detailed description of an exemplary embodiment
    The description which follows with reference to the accompanying drawings, given by way of nonlimiting examples, will make it clear what the invention consists of and how it can be carried out.
    In the attached drawings:
    - Figure 1 shows an electronic circuit of a time of flight sensor;
    - Figure 2 shows a first electrical signal used in the electronic circuit of Figure 1; and
    - Figure 3 shows a second electrical signal used in the electronic circuit of Figure 1.
    A time-of-flight sensor, such as a three-dimensional camera based on the time-of-flight principle (in English ToF 3D camera for Time of Flight 3D camera), comprises at least one element emitting electromagnetic radiation 2 (typically one or more light emitting diode (s) emitting in the infrared) and an electromagnetic radiation receiving element 4, such as a reception matrix formed of pixels.
    The radiation E emitted by the emitting element 2 (generally through an optical emission system not shown in FIG. 1) is reflected towards the receiving element 4 (reference R in FIG. 1) by the first object encountered on the radiation path E.
    By measuring the time between the emission of a signal given by the transmitter element 2 and the reception of a corresponding signal by the receiver element 4, we can assess the distance from the first object encountered above.
    In the case already mentioned where the receiving element 4 is a reception matrix, an optical receiving system (such as a lens) is placed opposite the receiving element 4 so that each pixel of the receiving element 4 receives the reflected signal R coming from a particular direction of the solid angle analyzed by the time of flight sensor.
    As visible in FIG. 1, a control unit 5 (for example a microcontroller) controls the emission of radiation E by the emitting element 2, as described below, then analyzes the signals L, measured by the receiving element 4 (here for the different pixels of the matrix) so as to determine the distance d, from the first object encountered (here for a plurality of directions of space facing the time-of-flight sensor) according to the principle recalled above.
    This distance d, (or these distances d,) is (are) transmitted (s) by the control unit 5 to another electronic system (not shown) for use by the latter.
    For example, in the automotive field, the time of flight sensor can be placed at the front of the vehicle in order to construct a map of the environment before the vehicle and / or detect an obstacle and / or assess the speed from another vehicle located at the front (by derivation of the distance d,).
    According to another conceivable possibility, the time of flight sensor can be placed in the passenger compartment of the vehicle (for example facing the driver of the vehicle) and the distances d, determined by the control unit 5 can be used within a gesture recognition algorithm.
    As shown in FIG. 1, the transmitter element 2 is supplied (with electric current) by a supply circuit 10.
    A controlled switch 6 is also mounted in series with the supply circuit 10 and the transmitter element 2 in order to be able to generate (under the control of a modulation signal M produced by the control unit 5 and shown in FIG. 3) a modulation of the radiation E emitted by the emitting element 2. Such a modulation is used in the context of the operation of the time of flight sensor in order to emit a signal recognizable by the receiving element 4 (after reflection on the first object encountered).
    The supply circuit 10 includes a current regulator 12, a measurement element 14 and a conversion circuit, here a low-pass filter 16.
    The current regulator 12 comprises a supply terminal V a iim connected to a terminal of the vehicle battery 8, an activation terminal Enbl, a regulation terminal Reg and an output terminal O where the current I produced is delivered by the current regulator 12.
    Current regulator 12 is designed to deliver to the output terminal
    O, when a predetermined voltage is present on the Enbl activation terminal, a current I regulated as a function of the voltage present on the regulation terminal
    Reg.
    The measuring element 14, here a resistor, is mounted in series with the emitting element 2 and the controlled switch 6 between the output terminal (or current production terminal) O and the earth of the electronic circuit (connected as to it at the other terminal of the vehicle battery 8 as shown in Figure 1).
    The measuring element 14 thus provides a signal (here the voltage V mes across the terminals of the measuring element 14) representative of the current passing through this measuring element 4.
    This signal V mes is transmitted to the regulation terminal Reg of the current regulator 12 through the conversion circuit, that is to say here through the low-pass filter 16. Thus, the low-pass filter 16 transmits on the regulation terminal Reg a smoothed signal S, here limited to the low-frequency components of the representative signal V mes .
    Alternatively, the conversion circuit 16 could be a peak detector. Such a peak detector also makes it possible to transmit to the regulation terminal Reg a smoothed signal S, free from the variations present in the signal Vmes due to the modulation of the current I by the controlled switch 6 under the control of the modulation signal. Mr.
    According to yet another variant, the conversion circuit 16 could include an analog-digital converter (capable of converting the signal V me s into a data sequence) and a processor (capable of generating, on one of its output terminals, a smooth signal S produced by digital processing on the basis of the aforementioned data sequence).
    The measuring element 14, the conversion circuit 16 and the regulation terminal Reg form a regulation loop, or feedback loop, of the current regulator 12 making it possible to obtain a predetermined current I on the output terminal O.
    The operation of the electronic circuit which has just been described is presented below.
    In order to emit a burst of radiation E by the emitting element 2, the control unit 5 controls periodically (with a period TO the activation of the current regulator 2 for a predetermined duration t 0 , here by applying to the terminal activation Enbl of the current regulator 12 a corresponding signal B (formed as shown in FIG. 2 of a periodic voltage step of duration t 0 and period T-ι) .Therefore we have t 0 <T-ι.
    During these periods of activation of the current regulator 12, the control unit 5 also transmits the modulation signal M already mentioned, intended for a control terminal of the controlled switch 6 in order to allow (successively and in a manner repeated) the opening and closing of the controlled switch 6 in accordance with the modulation signal M (an example of which is shown in FIG. 3).
    The modulation signal M is for example a periodic square signal of period T 2 , with in general T 2 <0.11 t 0 (and consequently T 2 <0.11.T-ι). It should be noted in this regard that FIG. 3 is purely illustrative and does not represent the case which has just been described (where each burst of duration to includes at least 10 pulses of the modulation signal M).
    In practice, the duration t 0 is for example between 50 ps and 600 ps. The period Τί can for its part be between 1 ms and 4 ms, while the period T 2 is for example between 20 ns and 100 ns.
    Due to the command of the switch controlled 6 by the modulation signal M, the current I (produced by the current generator 12) only flows in the emitting element 2 (or the emitting elements) at times when the modulation signal M is at the high level (that is to say during the pulses formed in this modulation signal M).
    In order to obtain particularly efficient operation, the rising and falling edges of the modulation signal M are of short duration.
    This gives the radiation E required to operate the time-of-flight sensor as explained above.
    However, thanks to the low-pass filter 16, the signal S received on the regulation terminal Reg of the current regulator 12 does not include the sudden variations present in the representative signal V me s and due to the interruption of the current I at the frequency of the modulation signal M.
    In this regard, the low-pass filter 16 typically has a cutoff frequency of between 1 / t 0 and 1 / T 2 (i.e. less than the frequency 1 / T 2 of the modulation signal), for example between 20 kHz and 50 MHz.
    Thus, the regulation of the current I by the current regulator 12 (by means of the regulation loop, or feedback loop, comprising the measuring element 14, the low-pass filter 16 and the regulation terminal Reg) functions correctly. despite the rapid variations in current intensity in the emitting element 2 caused by the controlled switch 6 for the modulation necessary for the operation of the flight time sensor.
    It is noted that in nominal operation (the current I having reached the setpoint), the signal S at the output of the low pass filter corresponds to only a proportion of the representative signal V me s when the current I flows in the measuring element 14 ( the representative signal V me s being zero the rest of the time). This situation is taken into account when defining the regulation loop (by increasing, for example in proportion, the value of the resistance forming the measuring element 14) in order to obtain the setpoint current I at the output of the current regulator. 12 in the presence of predetermined interruptions of this current I during a burst.
    权利要求:
    Claims (12)
    [1" id="c-fr-0001]
    1. Electronic circuit comprising at least one radiation emitting element (2), characterized by:
    - a current regulator (12) with a regulation terminal (Reg) and a current production terminal (O) connected to the radiation emitting element (2);
    - a measuring element (14) producing a signal (V me s) representative of the current flowing through it;
    - a switch (6) controlled by a modulation signal (M) so as to successively open and close an electrical path passing through the current production terminal (O), the radiation emitting element (2) and the element measuring (14), and
    - a conversion circuit (16) interposed between the measuring element (14) and the current regulator (12), and designed to transform the representative signal (Vmes) into a smoothed signal (S) intended for the regulation terminal (Reg).
    [2" id="c-fr-0002]
    2. The electronic circuit as claimed in claim 1, in which the emitting element is a light-emitting diode (2).
    [3" id="c-fr-0003]
    3. Electronic circuit according to claim 1 or 2, wherein the radiation emitted by the emitting element (2) is infrared radiation.
    [4" id="c-fr-0004]
    4. Electronic circuit according to one of claims 1 to 3, comprising a plurality of transmitter elements connected in series on the electrical path.
    [5" id="c-fr-0005]
    5. Electronic circuit according to one of claims 1 to 4, wherein the measuring element is a resistor (14).
    [6" id="c-fr-0006]
    6. Electronic circuit according to one of claims 1 to 5, wherein the conversion circuit is a low-pass filter (16).
    [7" id="c-fr-0007]
    7. The electronic circuit as claimed in claim 6, in which the low-pass filter (16) has a cutoff frequency lower than the frequency of the modulation signal (Μ).
    [8" id="c-fr-0008]
    8. Electronic circuit according to one of claims 1 to 5, wherein the conversion circuit is a peak detector.
    [9" id="c-fr-0009]
    9. Electronic circuit according to one of claims 1 to 8, in which the modulation signal (M) is periodic with a period of less than 100 ns.
    [10" id="c-fr-0010]
    10. Time-of-flight sensor comprising an electronic circuit according to one of claims 1 to 9.
    [11" id="c-fr-0011]
    11. Time-of-flight sensor according to claim 10, comprising a receiving element (4) designed to receive, after reflection, the radiation emitted by the radiation emitting element (2).
    [12" id="c-fr-0012]
    12. Time-of-flight sensor according to claim 11, in which the receiving element (4) is a reception matrix.
    1/1
    B
    Τι
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
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    US20140293038A1|2013-03-28|2014-10-02|General Electric Company|Methods and devices for adjusting brightness of a light source|WO2020120128A1|2018-12-14|2020-06-18|Valeo Comfort And Driving Assistance|Flight time sensor and surveillance system comprising such a sensor|
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    法律状态:
    2017-09-29| PLFP| Fee payment|Year of fee payment: 2 |
    2018-03-23| PLSC| Publication of the preliminary search report|Effective date: 20180323 |
    2018-09-28| PLFP| Fee payment|Year of fee payment: 3 |
    2019-09-30| PLFP| Fee payment|Year of fee payment: 4 |
    2020-09-30| PLFP| Fee payment|Year of fee payment: 5 |
    2021-09-30| PLFP| Fee payment|Year of fee payment: 6 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1658704|2016-09-16|
    FR1658704A|FR3056304B1|2016-09-16|2016-09-16|ELECTRONIC CIRCUIT AND TIME-OF-FLIGHT SENSOR COMPRISING SUCH AN ELECTRONIC CIRCUIT|FR1658704A| FR3056304B1|2016-09-16|2016-09-16|ELECTRONIC CIRCUIT AND TIME-OF-FLIGHT SENSOR COMPRISING SUCH AN ELECTRONIC CIRCUIT|
    PCT/EP2017/073512| WO2018050897A1|2016-09-16|2017-09-18|Electronic circuit and time-of-flight sensor comprising such an electronic circuit|
    CN201780067432.6A| CN109964539B|2016-09-16|2017-09-18|Electronic circuit and time-of-flight sensor comprising such an electronic circuit|
    US16/338,670| US20190227146A1|2016-09-16|2017-09-18|Electronic circuit and time-of-flight sensor comprising such an electronic circuit|
    EP17776967.6A| EP3513628A1|2016-09-16|2017-09-18|Electronic circuit and time-of-flight sensor comprising such an electronic circuit|
    JP2019524053A| JP6907311B2|2016-09-16|2017-09-18|Electronic circuits and flight time sensors with such electronic circuits|
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