Classifications

• • 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
  • H03F3/68—Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
• • 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
  • 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
  • H03F2200/432—Two or more amplifiers of different type are coupled in parallel at the input or output, e.g. a class D and a linear amplifier, a class B and a class A amplifier

Definitions

• the present invention relates to a high fidelity audio amplifier with low distortion and high efficiency of the type comprising:
• a reference voltage generator of very high linearity and of low output impedance, able to receive as input the musical signal to be amplified
• a power voltage generator whose output is connected to the output of the reference voltage generator, via a coupling impedance whose module is at least 10 times smaller than the modulus of the impedance of the load specific to be powered by the output of the amplifier;
• Means for inputting the power voltage generator input signal representative of the current output by the reference voltage generator US 6 937 095 describes an amplifier having two voltage generators coupled output. These two generators are voltage generators in that they have a very low output impedance.
• the reference voltage generator behaves as a follower while the power voltage generator supplies, through an impedance, the output current needed to supply the load.
• the reference voltage generator is constructed to have very high linearity and low output impedance so as to obtain low distortion at the output of the amplifier.
• the current consumed by the reference voltage generator is measured and its value is used to control the amplification members of the power voltage generator. Thus, most of the electrical power is supplied by the power voltage generator.
• the reference voltage generator of very high linearity is used to provide the output signal, which affects the accuracy of the amplified output signal.
• the object of the invention is to propose an amplifier having further improved output performance, especially with regard to the distortion rate.
• the subject of the invention is an amplifier of the aforementioned type, characterized in that the means for inputting a signal representative of the current output by the reference voltage generator to the input of the power voltage generator are suitable for provide a linear control of the power voltage generator.
• the amplifier comprises one or more of the following features:
• the means for inputting, at the input of the power voltage generator, a signal representative of the current supplied by the reference voltage generator comprises an integral derivative-proportional regulator (PID);
• PID integral derivative-proportional regulator
• the amplifier comprises means for inputting, at the input of the power voltage generator, a signal representative of the musical signal to be amplified, in addition to the signal representative of the current supplied at the output by the reference voltage generator;
• the output of the reference voltage generator is connected directly to the power supply output of the load without the interposition of an impedance
• the power voltage generator is a class D amplification stage
• the power voltage generator is pulse width modulated or sigma / delta controlled, and the coupling impedance is an inductance, a resistance, or the combination of the two;
• the power voltage generator is an analog class A or AB amplification stage, and the coupling impedance is a resistance, an inductance or a combination of the two;
• said input means of input of the power voltage generator of a signal representative of the current output by the reference voltage generator comprise means for measuring the instantaneous intensity consumed by the reference voltage generator
• said input means of input of the power voltage generator of a signal representative of the current supplied at the output by the reference voltage generator comprise means for measuring the current supplied by the reference voltage generator arranged only upstream the power supply output of the load and the output of the reference voltage generator is connected directly to the coupling point without interposing resistive element therebetween;
• the output impedance of the reference voltage generator is less than 0.2 Ohms.
• the audio amplifier 10 shown in FIG. 1 comprises an input 12 adapted to receive an analog audio signal to be amplified and an output 14 for supplying the amplified signal to which is connected a charge formed by a loudspeaker 16.
• the loudspeaker speaker 16 is connected directly, without other resistive element, between the output 14 of the amplifier and the ground.
• the input 12 of the amplifier is adapted to receive a control voltage whose reference is the ground.
• the amplifier 10 comprises a reference voltage generator 18 of very high linearity and low output impedance and a power voltage generator 20.
• the outputs of the two generators are coupled to each other at the output 14 by a coupling impedance 22.
• the input of the reference voltage generator 18 is connected directly, without the interposition of an impedance at the input 12 of the amplifier while the output of the reference voltage amplifier 18 is connected directly to the output 14 without interposition of any resistive, capacitive or inductive element.
• the outputs of the voltage generators 18 and 20 are connected at a coupling point 24, the coupling impedance 22 being arranged between the output of the power voltage generator 20 and the coupling point 24.
• the reference voltage generator 18 comprises a voltage amplification stage 26 schematized by a differential amplifier whose non-inverting input is connected directly to the input 12 and whose inverting input is connected to a feedback loop 27 is connected directly to the output of the differential amplifier 26.
• the voltage amplification stage is formed, for example, of an operational amplifier mounted as a voltage follower.
• the reference voltage generator 18 is a class A amplifier having a very high linearity and a low output impedance.
• the output impedance of the reference voltage generator is less than 0.2 ohms.
• the differential amplifier 26 is powered by two direct voltages V + and V and consumes a current respectively noted and l 2 on each of these supply inputs.
• Means for measuring the current consumed 28A, 28B are provided on each of the supply inputs of the differential amplifier 26.
• These means are formed, for example, of current detectors as described in document US Pat. No. 6,937,095. They are capable of supplying information representative of the current output by the reference voltage generator, the current supplied by the generator 18 being directly connected. aware that it consumes.
• the outputs of the current sensors 28A, 28B are connected to an adder 30 forming the input of a PID linear regulator 32 having a linear amplification stage 34, a bypass stage 36 and an integration stage 38 each connected in parallel and receiving as input a value representative of the sum of the currents consumed by the reference voltage generator 18.
• the outputs of the 34, 36 and 38 are connected to an adder 40.
• the PID regulator 32 is able to provide at the output a signal representative of the current output by the reference generator 18.
• the summator 40 is connected by another input to the input 12, via a linear amplification stage 42 to receive the musical signal to be amplified.
• the power voltage generator 20 is formed in the example considered of a differential amplifier 50 mounted as a follower, and whose inverting input is connected directly to the output by a feedback loop 51 while the input not Inverter is connected to the output of summator 40.
• the power voltage generator 20 is adapted to receive as input a combination of the audio signal to be amplified from the input 12 and a value representative of the current consumed by the reference voltage generator.
• the differential amplifier 50 consists of a class D amplifier, that is to say an amplifier of the "push / pull" type comprising, according to its amplifier branch, two transistors. MOSFET “mounted anti-series, these two transistors being driven according to a pulse width modulation law.
• the impedance 22 consists of an inductance, a resistance or a combination of both.
• the two transistors are controlled according to a sigma / delta law.
• the power voltage generator 20 consists of a class A or class AB amplifier.
• the coupling impedance 22 consists of an inductance, a resistance or a combination of both.
• the coupling impedance 22, whether it is a coil or a resistor has a module less than ten times the load module, namely the loudspeaker 16, in the frequency range useful.
• the resistor 22 used in the case of a class AB amplifier to form the power voltage generator 20 is less than 0.4 ohms.
• the inductance of the coil forming the coupling impedance is less than 100 ⁇ .
• the value representative of the current supplied by the reference voltage generator introduced into the PID regulator 32 is given by the difference of the potentials measured across the impedance 22 and a complementary resistor disposed between the coupling point 24 and the output 14 according to the assembly described in the document FR 2 873 872.

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• Power Engineering (AREA)
• Multimedia (AREA)
• Amplifiers (AREA)

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• 2010
  • 2010-03-16 US US13/582,327 patent/US20140050335A1/en not_active Abandoned
  • 2010-03-16 WO PCT/FR2010/050469 patent/WO2011107669A1/fr active Application Filing
  • 2010-03-16 KR KR1020127025630A patent/KR101438464B1/ko active IP Right Grant
  • 2010-03-16 JP JP2012555460A patent/JP5503027B2/ja active Active
  • 2010-03-16 BR BR112012022177A patent/BR112012022177A2/pt not_active Application Discontinuation
  • 2010-03-16 CN CN2010800665698A patent/CN103004083A/zh active Pending
  • 2010-03-16 EP EP10716396A patent/EP2543142A1/fr active Pending

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