Classifications

• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
  • H03F1/08—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements
  • H03F1/083—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements in transistor amplifiers
  • H03F1/086—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements in transistor amplifiers with FET's
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
  • H03F1/08—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements
  • H03F1/14—Modifications of amplifiers to reduce detrimental influences of internal impedances of amplifying elements by use of neutralising means
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F1/00—Details of amplifiers with only discharge tubes, only semiconductor devices or only unspecified devices as amplifying elements
  • H03F1/30—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters
  • H03F1/301—Modifications of amplifiers to reduce influence of variations of temperature or supply voltage or other physical parameters in MOSFET amplifiers
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
  • H03F3/181—Low-frequency amplifiers, e.g. audio preamplifiers
  • H03F3/183—Low-frequency amplifiers, e.g. audio preamplifiers with semiconductor devices only
  • H03F3/185—Low-frequency amplifiers, e.g. audio preamplifiers with semiconductor devices only with field-effect devices
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
  • H03F3/20—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers
  • H03F3/21—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only
  • H03F3/211—Power amplifiers, e.g. Class B amplifiers, Class C amplifiers with semiconductor devices only using a combination of several amplifiers
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
  • H03F3/30—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor
  • H03F3/3001—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor with field-effect transistors
  • H03F3/3033—NMOS SEPP output stages
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
  • H03F3/30—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor
  • H03F3/3001—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor with field-effect transistors
  • H03F3/3061—Bridge type, i.e. two complementary controlled SEPP output stages
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
  • H03F3/30—Single-ended push-pull [SEPP] amplifiers; Phase-splitters therefor
  • H03F3/3081—Duplicated single-ended push-pull arrangements, i.e. bridge circuits
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F3/00—Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
  • H03F3/45—Differential amplifiers
  • H03F3/45071—Differential amplifiers with semiconductor devices only
  • H03F3/45076—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier
  • H03F3/45179—Differential amplifiers with semiconductor devices only characterised by the way of implementation of the active amplifying circuit in the differential amplifier using MOSFET transistors as the active amplifying circuit
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R3/00—Circuits for transducers, loudspeakers or microphones
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/03—Indexing scheme relating to amplifiers the amplifier being designed for audio applications
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/171—A filter circuit coupled to the output of an amplifier
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/267—A capacitor based passive circuit, e.g. filter, being used in an amplifying circuit
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/297—Indexing scheme relating to amplifiers the loading circuit of an amplifying stage comprising a capacitor
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/301—Indexing scheme relating to amplifiers the loading circuit of an amplifying stage comprising a coil
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/309—Indexing scheme relating to amplifiers the loading circuit of an amplifying stage being a series resonance circuit
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/33—Bridge form coupled amplifiers; H-form coupled amplifiers
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/391—Indexing scheme relating to amplifiers the output circuit of an amplifying stage comprising an LC-network
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/393—A measuring circuit being coupled to the output of an amplifier
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/417—A switch coupled in the output circuit of an amplifier being controlled by a circuit
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/459—Ripple reduction circuitry being used in an amplifying circuit
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2200/00—Indexing scheme relating to amplifiers
  • H03F2200/462—Indexing scheme relating to amplifiers the current being sensed
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
  • H03F2203/45—Indexing scheme relating to differential amplifiers
  • H03F2203/45631—Indexing scheme relating to differential amplifiers the LC comprising one or more capacitors, e.g. coupling capacitors
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03F—AMPLIFIERS
  • H03F2203/00—Indexing scheme relating to amplifiers with only discharge tubes or only semiconductor devices as amplifying elements covered by H03F3/00
  • H03F2203/45—Indexing scheme relating to differential amplifiers
  • H03F2203/45638—Indexing scheme relating to differential amplifiers the LC comprising one or more coils

Definitions

• Amplification device comprising a compensation circuit
• the present invention relates to a device for amplifying an input signal comprising:
• each amplification stage comprising:
• a switching circuit the switching circuit being suitable for generating a switched signal having at least two states
• An inductive element connected between the output of the switching circuit and the output of the amplification stage, the inductive element being able to smooth the switched signal generated by the switching circuit to obtain a smoothed signal, the smoothed signal having a useful component and a parasitic component,
• Such an amplification device is, for example, used as an amplifier of the voltage across a load.
• the load is an audio component, such as a loudspeaker
• the high-frequency, triangular-shaped parasitic component generated in the inductive element of the amplification stage is detrimental to the quality of the audio signal output from above. loudspeaker.
• such a parasitic component is at the origin of heating of the amplification device and the load, which induces a loss of output at the output of the amplification device.
• the subject of the invention is an amplification device as described above, in which the amplification device further comprises a compensation circuit, for each amplification stage, capable of generating a signal for amplification. compensation of the parasitic component of the smoothed signal generated in the inductive element of said amplification stage, each compensation circuit being connected to the output of the corresponding amplification stage and to the output of the switching circuit of the other amplification stage, the differences of each smoothed signal and the corresponding compensation signal forming the output signal at the output of the amplification device.
• the amplification device comprises one or more of the following characteristics, taken in isolation or in any technically possible combination:
• each compensation circuit comprises at least one inductive element, the relative difference between the inductance of the inductive element of the compensation circuit and the inductance of the inductive element of the corresponding amplification stage being less than or equal to at 30 percent;
• each compensation circuit comprises a high-pass filter
• the high-pass filter comprises a capacitor
• the input signal is a signal modulated by a carrier frequency, the high-pass filter having a cutoff frequency strictly less than the carrier frequency of the input signal;
• the input signal has a useful frequency, the high-pass filter having a cut-off frequency strictly greater than the useful frequency of the input signal;
• the amplification stages are stages of amplification of a digital signal, the device further comprising at least one analog amplifier connected at the output of one of the amplification stages;
• the or each analog amplifier is an amplifier of class A or AB;
• the device further comprises a device for measuring the output current of each analog amplifier and a control module suitable for receiving at least the measurement of the output current of each analog amplifier, the control module being able to generate the signals at the input of the amplification stages as a function of the output currents measured so that, on the one hand, the signals switched at the output of the switching circuits of said stages are opposite and, on the other hand, that the output current of each of the analog amplifiers is minimized;
• the input signals of each amplification stage are in phase opposition for more than 70 percent of the time.
• the invention also relates to an audio system comprising:
• a loudspeaker connected to the output of each amplification stage.
• FIG. 1 a schematic view of an example of an amplification device according to a first embodiment of the invention
• FIG. 2 an example of a first timing diagram showing the output voltages of the switching circuits of each amplification stage of the amplification device
• FIG. 3 an example of a second chronogram representing the parasitic component of a smoothed signal, the signal of compensation of said parasitic component and the resultant of the two signals, and
• FIG. 4 is a schematic view of an example of an amplification device according to a second embodiment of the invention.
• FIG. 10 An amplification device 10 according to a first embodiment of the invention is illustrated in FIG.
• the amplification device 10 is also known as the "amplification bridge”.
• the amplification device 10 comprises two inputs 10A, 10B receiving signals in opposite phase forming a differential input signal to be amplified and two outputs 20A, 20B for an amplified differential output signal.
• the two inputs 10A, 10B of the amplification device 10 form a differential input.
• the two outputs 20A, 20B of the amplification device 10 form a differential output
• the input signal is, for example, generated by a control module January 1 and an inverter 13 as visible in Figure 1.
• the input signal is a modulated signal, for example, in pulse width, characterized by a carrier frequency and a useful frequency band.
• the useful frequency band is, for example, the interval between 20 Hertz (Hz) and 100 kilohertz (kHz).
• the carrier frequency is, for example, greater than or equal to 400 kHz.
• the input signal is a voltage.
• the signal received by one of the two inputs 10A, 10B of the amplification device is inverted by the inverter 13 so that the signals received by each of the two inputs 10A, 10B are in opposition to each other. phase and form a differential input signal.
• the amplification device 10 further comprises a first amplification stage 12, a second amplification stage 14 and a compensation circuit 16 for each amplification stage 12, 14.
• Each amplification stage 12, 14 comprises an input corresponding to the inputs 10A, 10B of the amplification device 10, an output 20A, 20B corresponding to the outputs 20A, 20B of the amplification device 10, a switching circuit 22 and an element inductive 24.
• the outputs 20A, 20B of each amplification stage 12, 14 are intended to be connected to the same load 26, such as a loudspeaker, to form an audio system.
• the two amplification stages 12, 14 are powered by the same supply voltage V1.
• the supply voltage V1 is, for example, positive.
• Each switching circuit 22 comprises at least two transistors 31, 32 connected in series between the supply voltage V1 and a ground.
• the input of each switching circuit 22 corresponds to the input 10A, 10B of the amplification stage 12, 14 corresponding.
• the output of each switching circuit 22 of the stages 12, 14 is formed by a midpoint 22A, 22B between the two transistors 31, 32 of each of the stages 12, 14.
• the gate of the transistors 31, 32 of each amplification stage 12, 14 is connected to the input of the corresponding switching circuit 22 so as to be powered by the input signal.
• the gate of one of the transistors 31, 32 of each amplification stage 12, 14 being connected to an inverter 34, when one of the transistors 31, 32 is on, the other transistor 31, 32 is blocked.
• the transistors are, for example, MOSFET transistors.
• the switching circuit 22 of each amplification stage 12, 14 is able to generate a switched signal having at least two states from the input signal 10A, 10B of said amplification stage 12, 14 and the supply voltage V1.
• the supply voltages V1 of the two stages 12, 14 being identical and the input signals 10A, 10B of said stages 12, 14 being in phase opposition, the switched signals at the output 22A, 22B of the switching circuits 22 of each stage 12 , 14 have opposite states.
• the signal switched at the output 22A of the switching circuit 22 of the first amplification stage 12 has a voltage equal to the supply voltage V1, respectively equal to the zero voltage
• the signal switched to the output 22B of the switching circuit 22 of the second amplification stage 12 has a voltage equal to the zero voltage, respectively equal to the supply voltage V1.
• the inductive element 24 is formed, for example, of a coil.
• the inductive element 24 of each amplification stage 12, 14 is connected to the output 22A, 22B of the switching circuit 22 of said stage 12, 14, on the one hand, and the output 20A, 20B of said stage 12, 14, on the other hand.
• the inductive element 24 is able to smooth the switched signal generated by the corresponding switching circuit 22 to obtain a smoothed signal 11, 13.
• the smoothed signal 11, 13 has a useful component and a parasitic component.
• the useful component is low frequency and the parasitic component is high frequency.
• the useful component of the smoothed signal 11, 13 is the component carrying the useful part of the input signal to be amplified.
• the useful component is the music to be amplified, for example the signals of frequency between 20 Hz and 100 kHz.
• the parasitic component of the smoothed signal 11, 13 is a component relative to a triangular wave current generated in the inductive element 24.
• a ripple current is due to a high frequency variation of the voltage at the terminals of the inductive element 24.
• Such a wave current has, for example, a carrier frequency equal to 400 kHz.
• Each compensation circuit 16 is connected, on the one hand, to the output 20A, 20B of the corresponding amplification stage 12, 14 and, on the other hand, to the output 22A, 22B of the switching circuit 22 of the other amplification stage 12, 14.
• the compensation circuit 16 of an amplification stage 12, 14 is connected in parallel with the inductive element 24 and the output 20A, 20B of the other amplification stage 12, 14.
• Each compensation circuit 16 is able to generate a compensation signal 12, 14 of the parasitic component of the smoothed signal 11, 13 generated in the inductive element 24 of the amplification stage 12, 14 corresponding.
• Each compensation circuit 16 comprises at least one inductive element 36 and a high-pass filter 38.
• the relative difference between the inductance of the inductive element 36 of the compensation circuit 16 and the inductance of the inductive element 24 of the corresponding amplification stage 12, 14 is less than or equal to 30 percent (%).
• the relative difference is the ratio of the absolute value of the difference between the inductance of the inductive element 36 of the compensation circuit 16 and the inductance of the inductive element 24 of the stage of amplification 12, 14 corresponding, by the inductance of the inductive element 24 of said amplification stage 12, 14.
• the high-pass filter 38 is formed of a capacitor in its interaction with the inductive element 36 of the corresponding compensation circuit 16.
• the high-pass filter 38 is adapted to allow the passage of the high-frequency spurious component of the smoothed signal 11, 13 into the compensation circuit 16 of said high-pass filter 38.
• the high-pass filter 38 of each compensation circuit 16 has a cutoff frequency strictly lower than the carrier frequency.
• the high-pass filter 38 has a cut-off frequency strictly greater than the useful frequency of the smoothed signal 11, 13.
• the cutoff frequency is, for example, between 100 kHz and 300 kHz.
• Such an amplification device 10 makes it possible, via the compensation signals 12, 14 generated by the compensation circuits 16, to compensate for the high-frequency spurious component of the smoothed signal 11, 13 generated in the inductive element 24 of each stage. amplification 12, 14.
• the compensation signals 12, 14 make it possible to prevent the high-frequency spurious components of the smoothed signals 11, 13 from crossing the load 26.
• the difference of the smoothed signal 11, 13 and the compensation signal 12, 14 of each amplification stage 12, 14 forms the amplified output signal 20A and 20B of the amplification device 10.
• the amplified signal is a current .
• FIG. 2 illustrates in dotted lines the output voltage 22A of the switching circuit 22 of the first amplification stage 12 and in solid lines the output voltage 22B of the switching circuit 22 of the second amplification stage 14.
• FIG. visible in FIG. 2 such voltages have opposite states and switch at 400 kHz between two states of respective voltages equal to 20 volts (V) and 0 V.
• FIG. 3 illustrates in fine lines the high-frequency triangular parasitic component of the smoothed signal 11 of the first amplification stage 12; in dotted lines the compensation signal 12 of said parasitic component; and in full bold lines the output signal obtained by the difference between the smoothed signal 11 and the compensation signal 12.
• the smoothed signal 11 is a current of amplitude equal to plus or minus 0.4 amperes at a frequency of 400 kHz.
• the output signal 15 is freed from the high-frequency triangular parasitic component of the smoothed signal 11 and comprises only the low-frequency part of the signal, that is to say the useful component.
• each compensation circuit 16 is supplied directly by the switching circuit 22 of the other stage of the stage. 12, 14. No additional power supply is required or any other active component, such as a transistor for example.
• FIG. 4 An amplification device 10 according to a second embodiment is illustrated in FIG. 4.
• the amplification device 10 according to the second embodiment comprises the same elements as the first embodiment. These elements are therefore not described again.
• the amplification device 10 further comprises at least one analog amplifier 40. In FIG. 4, two analog amplifiers 40 are shown.
• Each analog amplifier 40 is connected to the output 20A, 20B of one of the amplification stages 12, 14.
• one of the amplifiers 40 illustrated in FIG. 4 is connected to the output 20A of the first stage 12 and the other amplifier 40 is connected to the output 20B of the second amplification stage 14.
• Each amplifier 40 is, for example, a class A or class AB amplifier.
• a class A amplifier is an amplifier having a very high linearity and a low output impedance. Preferably, the output impedance of a Class A amplifier is less than 0.2 ohms.
• a class B amplifier is an amplifier having amplification elements that operate in linear mode for only half the time and are substantially off the other half of the time.
• a class AB amplifier is an amplifier capable of switching from a state to a blocked state so that the amplifier is class A for low power, and class B for higher power.
• the signal to be amplified 41 is inverted by a gain amplifier 43 to give an intermediate signal 44.
• the signal to be amplified 41 and the intermediate signal 44 therefore constitute a differential signal.
• a reference voltage Vcom is added to each of the signal to be amplified 41 and the intermediate signal 44 via adders 45 so as to form the respective input signals 46A and 46B of each of the amplifiers 40.
• the reference voltage Vcom is between the supply voltage V1 and the ground.
• the reference voltage Vcom is equal to half of the supply voltage V1.
• the input signals 46A and 46B of the amplifiers 40 are voltages.
• the input signals 46A and 46B of the amplifiers 40 have the same DC component Vcom and opposite alternatives.
• a measuring device 47 is able to measure the output current of each of the amplifiers 40 and to provide the measurements made to the control module 11.
• the measuring device 47 comprises a Hall effect sensor capable of measuring the output currents via the difference of the supply currents of each of the amplifiers 40.
• the control module 1 1 is able to control each of the amplification stages 12, 14 so that the input signals 10A, 10B of the amplification stages 12, 14 are opposite (so that the switched signals at the output 22A, 22B switching circuits 22 of said stages 12, 14 are opposed), while minimizing the current supplied by each of the amplifiers 40.
• the weak dispersions of the values of these components less than 30%, ensure that the input signals 10A, 10B of the amplification stages 12, 14 are in phase opposition for more than 70% of the time.
• the amplification device 10 makes it possible to perform both an analog amplification and a digital amplification of an analog signal to amplify 41.
• the amplification device 10 has a linearity at least equal to that of the analog amplifiers 40 used in the system and an energy efficiency very close to that of the digital amplification stages 12, 14 used, insofar as the analog amplifiers 40 consume very little power, so very little power.
• the amplifiers 40 provide less than 1% of the current supplied to the load 26.
• such an amplification device 10 is adapted to amplify audio signals, for example, intended for a loudspeaker, with a very high frequency. high linearity and a very high energy efficiency.
• the compensation circuits 16 make it possible to prevent the high-frequency triangular parasitic components of the smoothed signals from being absorbed in the analog amplifiers 40, which would have the consequence of causing them to overheat and to deteriorate the quality of the output signal and the performance of such amplifiers 40.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Multimedia (AREA)
• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Amplifiers (AREA)

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• 2016
  • 2016-08-22 FR FR1657841A patent/FR3055173B1/fr active Active
• 2017
  • 2017-08-21 WO PCT/EP2017/071051 patent/WO2018036974A1/fr active Application Filing
  • 2017-08-21 KR KR1020197008425A patent/KR102526738B1/ko active IP Right Grant
  • 2017-08-21 JP JP2019510653A patent/JP2019528637A/ja active Pending
  • 2017-08-21 CN CN201780056999.3A patent/CN109716647B/zh active Active
  • 2017-08-21 US US16/327,235 patent/US10797654B2/en active Active
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