WO2016171551A1 - Alimentation électrique fantôme pour microphone - Google Patents

Alimentation électrique fantôme pour microphone Download PDF

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Publication number
WO2016171551A1
WO2016171551A1 PCT/NL2016/050276 NL2016050276W WO2016171551A1 WO 2016171551 A1 WO2016171551 A1 WO 2016171551A1 NL 2016050276 W NL2016050276 W NL 2016050276W WO 2016171551 A1 WO2016171551 A1 WO 2016171551A1
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WO
WIPO (PCT)
Prior art keywords
resistor
power supply
control circuit
current source
pnp transistor
Prior art date
Application number
PCT/NL2016/050276
Other languages
English (en)
Inventor
Joost Kist
Original Assignee
Joost Kist
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Joost Kist filed Critical Joost Kist
Publication of WO2016171551A1 publication Critical patent/WO2016171551A1/fr

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Classifications

    • 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
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/02—Casings; Cabinets ; Supports therefor; Mountings therein
    • H04R1/04—Structural association of microphone with electric circuitry therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/04—Microphones

Definitions

  • the invention relates to the field of providing phantom power to a microphone, and more specifically to a phantom power supply for phantom powering a microphone.
  • a DC supply voltage which according to the standard may be 12, 24 or 48 V, is applied relative to a ground pin to each signal wire through parallel and equal resistors, wherein for the 48 V supply voltage each resistor has a resistance of 6.8 kQ.
  • FIG. 1 depicts a basic diagram of a phantom power supply 100, indicated by a dashed line, according to the standard. Non-relevant circuit elements have been omitted for clarity.
  • the phantom power supply 100 comprises a DC power supply 105, for example a 12, 24 or 48 V DC power supply.
  • the negative terminal of the DC power supply 105 is connected to ground.
  • the positive terminal of the DC power supply 105 is connected to an
  • first and second standard resistors 1 15, 1 16 may each have a substantially equal resistance value of 6.8 kQ in compliance with said standard.
  • Another node of first resistor 115 is connected to a first internal signal line 120 having a first input terminal 125, and a first signal output terminal 130.
  • Another node of second resistor 116 is connected to a second internal signal line 121 having a second input terminal 126, and a second signal output terminal 131.
  • the phantom power supply 100 has a third input terminal 127 connected to ground.
  • a microphone assembly 150 comprises a microphone 155, sometimes also referred to as a microphone capsule.
  • the microphone 155 is connected to an electronic circuit 156 through a first signal line 160, and a second signal line 161.
  • the electronic circuit 156 has a first output terminal 165, and a second output terminal 166.
  • a third output terminal 167 of the microphone assembly 150 is connected to ground.
  • the first, second and third input terminals 125, 126, 127 of the phantom power supply 100 may be connected to the first, second and third output terminals 165, 166, 167 of the microphone assembly 150 through (long) external lines 170, 171 , 172, respectively, which may be part of one connecting cable.
  • the external lines 170, 171 transfer both power and signals.
  • the first and second signal output terminals 130, 131 may be adapted to be coupled to an input of a pre-amplifier or other microphone signal processing circuit.
  • a technical problem has been recognized in that the electronic circuit 156 in the microphone assembly 150 detects a load in the first and second standard resistors 115, 116 which, from the point of view of the AC microphone signal, are connected to ground. This load causes an unwanted distortion of the microphone signal.
  • the present invention has the object of meeting at least one of such desires, or at least provide an alternative solution to the requirements of the applicable standard.
  • a phantom power supply for a microphone comprises a first DC power supply having an output for supplying a DC voltage, and a pair of signal input terminals adapted to be connected to a pair of signal output terminals of the microphone.
  • the output of the first DC power supply is connected to a first one of the signal input terminals through a series connection of a first current source circuit and a first resistor, wherein the first current source circuit comprises a first current source controlled by a first control circuit.
  • the output of the first DC power supply is further connected to a second one of the signal input terminals through a series connection of a second current source circuit and a second resistor, wherein the second current source circuit comprises a second current source controlled by a second control circuit.
  • the first control circuit and the second control circuit each are adapted to maintain a current source circuit output voltage of the first current source circuit and the second current source circuit, respectively, at a predetermined level.
  • the phantom power supply of the present invention causes power to be supplied to a microphone assembly by a variable current source for each signal line.
  • the current source is voltage controlled by the corresponding control circuit to keep a voltage present at the current source circuit output connected to the corresponding first or second resistor at a
  • a connecting node between the first resistor and the second resistor which may be standard resistors having a value compliant with the above-referenced standard, is absent.
  • a common control circuit is part of the first control circuit and the second control circuit.
  • the common control circuit controls both the first and the second currents sources, thus reducing the common mode rejection ratios of the first and second current sources.
  • the predetermined level equals the DC voltage generated by the first DC power supply to be compliant with the standard.
  • the first resistor and the second resistor have equal resistance values, and/or the first current source has the same structure as the second current source, and/or the first control circuit has the same structure as the second control circuit.
  • At least one of the first current source and the second current source comprises a first PNP transistor.
  • An emitter of the first PNP transistor is connected to a second DC power supply through a third resistor.
  • a collector of the first PNP transistor is connected to a first terminal of the first resistor (in case of the first current source) or the second resistor (in case of the second current source).
  • a base of the first PNP transistor is connected to the second DC power supply through a fourth resistor.
  • a base of the first PNP transistor is connected to an output of the first control circuit (in case of the first current source) or the second control circuit (in case of the second current source) through a fifth resistor.
  • At least one of the first current source and the second current source comprises a series connection of a first PNP transistor and a second PNP transistor.
  • An emitter of the first PNP transistor is connected to a second DC power supply through a third resistor.
  • a base of the first PNP transistor is connected to the second DC power supply through a fourth resistor.
  • a collector of the first PNP transistor is connected to an emitter of the second PNP transistor.
  • a base of the second PNP transistor is connected to an anode of a Zener diode, and a cathode of the Zener diode is connected to the base of the first PNP transistor.
  • a collector of the second PNP transistor is connected to a first terminal of the first resistor (in case of the first current source) or the second resistor (in case of the second current source).
  • the base of the second PNP transistor is connected to an output of the first control circuit (in case of the second current source) or the second control circuit (in case of the second control circuit) through a fifth resistor.
  • At least one of the first control circuit and the second control circuit comprises a second operational amplifier having an inverting amplifier input, a non-inverting amplifier input and an amplifier output.
  • the inverting amplifier input is connected to the first DC power supply through a seventh resistor, and the inverting amplifier input is connected to the amplifier output through a first capacitor.
  • the non-inverting amplifier input is connected to ground through a second capacitor, and the non-inverting amplifier input is connected, through an eighth resistor, to the first terminal of the first resistor (in case of the first control circuit) or the second resistor (in case of the second control circuit).
  • the amplifier output is the output of the first control circuit (in case of the first control circuit) or the output of the second control circuit (in case of the second control circuit).
  • At least one of the first current source and the second current source comprises a third PNP transistor.
  • An emitter of the third PNP transistor is connected to a third DC power supply through a sixth resistor.
  • a collector of the third PNP transistor is connected to a first terminal of the first resistor (in case of the first current source) or the second resistor (in case of the second current source).
  • the at least one of the first current source and the second current source further comprises a first operational amplifier having an inverting amplifier input, a non-inverting amplifier input and an amplifier output.
  • the base of the third PNP transistor is connected to the amplifier output, the inverting amplifier input is connected to the emitter of the third PNP transistor, and the non-inverting amplifier input is connected to an output of the first control circuit (in case of the first current source) or the second control circuit (in case of the second current source).
  • At least one of the first control circuit and the second control circuit comprises a third operational amplifier having an inverting amplifier input, a non- inverting amplifier input and an amplifier output.
  • the inverting amplifier input is connected, through a ninth resistor, to the first terminal of the first resistor (in case of the first control circuit) or the second resistor (in case of the second control circuit).
  • the inverting amplifier input is connected to the amplifier output through a third capacitor.
  • the non-inverting amplifier input is connected to ground through a fourth capacitor.
  • the non-inverting amplifier input is connected to the first DC power supply through a tenth resistor.
  • the amplifier output is the output of the first control circuit (in case of the first control circuit) or the second control circuit (in case of the second control circuit).
  • the present invention relates to a preamplifier, comprising a phantom power supply according to the first aspect of the present invention.
  • the present invention relates to a mixing desk, comprising a phantom power supply according to the first aspect of the present invention, or comprising a preamplifier according to the second aspect of the present invention.
  • the present invention relates to an arrangement comprising a microphone assembly and a phantom power supply according to the first aspect of the present invention.
  • the microphone assembly comprises a condenser microphone.
  • Figure 1 depicts a diagram illustrating a basic diagram of a phantom power supply according to the prior art.
  • Figure 2a depicts a circuit diagram of a phantom power supply according to the present invention, comprising a first current source, a first control circuit, a second current source, and a second control circuit, all schematically shown.
  • Figure 2b depicts a circuit diagram of a phantom power supply according to the present invention, comprising a first current source, a first control circuit, a second current source, and a second control circuit, all schematically shown, wherein a common control circuit is part of the first control circuit and the second control circuit.
  • Figure 3a depicts a circuit diagram of a part of a phantom power supply, configured for one signal line, comprising a first embodiment of a first or second current source and a first embodiment of a first or second control circuit.
  • Figure 3b depicts a circuit diagram of a part of a phantom power supply, configured for two signal lines, comprising the first embodiment of a first and second current source and a further embodiment of a first and second control circuit, wherein a common control circuit is part of the first control circuit and the second control circuit.
  • Figure 3c depicts a circuit diagram of a part of a phantom power supply, configured for one signal line, comprising a second embodiment of a first or second current source and the first embodiment of a first or second control circuit.
  • Figure 3d depicts a circuit diagram of a part of a phantom power supply, configured for two signal lines, comprising the second embodiment of a first and a second current source and a further embodiment of a first and second control circuit, wherein a common control circuit is part of the first control circuit and the second control circuit.
  • Figure 4a depicts a circuit diagram of a part of a phantom power supply, configured for one signal line, comprising a third embodiment of a first or second current source and the first embodiment of a first or second control circuit.
  • Figure 4b depicts a circuit diagram of a part of a phantom power supply, configured for two signal lines, comprising the third embodiment of a first and a second current source and a further embodiment of a first and second control circuit, wherein a common control circuit is part of the first control circuit and the second control circuit.
  • lines interconnecting circuit components, and crossing each other do not represent an electrical connection at the crossing point. However, if a dot is represented at the crossing point, an electrical connection is intended to be represented at the crossing point.
  • FIG. 1 depicting a basic diagram of a phantom power supply according to the prior art, has been explained above.
  • FIG. 2a depicts a circuit diagram of a phantom power supply 200, indicated by a dashed line, according to the present invention. Circuit components which are not relevant to an understanding of the present invention have been omitted for clarity.
  • the phantom power supply 200 comprises a DC power supply 205 having its negative terminal connected to ground, and its positive terminal connected to an input of first current source circuit 210, and to an input of a second current source circuit 215, both schematically shown, and indicated by a dashed line.
  • the first current source circuit 210 comprises a first current source 21 1 , and a first control circuit 212 controlling the first current source 21 1.
  • the second current source circuit 215 comprises a second current source 216, and a second control circuit 217 controlling the second current source 216.
  • the positive terminal of the DC power supply 205 is connected to an input of the first control circuit 212, and to an input of the second control circuit 217.
  • An output of the first current source circuit 210 or the first current source 21 1 is connected to a first terminal of a first resistor 220.
  • the first resistor 220 is similar to the first standard resistor 115 ( Figure 1) according to the prior art.
  • the second terminal of the first resistor 220 is connected to a first internal signal line 225 having a first input terminal 230 and a first output terminal 235.
  • An output of the second current source circuit 215 or the second current source 216 is connected to a first terminal of a second resistor 221.
  • the second resistor 221 is similar to the second standard resistor 116 ( Figure 1) according to the prior art.
  • the second terminal of the second resistor 221 is connected to a second internal signal line 226 having a second input terminal 231 and a second output terminal 236.
  • the phantom power supply 200 further comprises a third input terminal 232 connected to ground.
  • the first current source 211 and the second current source 216 each provide current to provide power to a microphone assembly, such as a microphone assembly 150 shown in Figure 1 , through the first and second input terminals 230, 231.
  • a voltage of the node connecting the first current source circuit 210 and the first resistor 220, as well as a voltage of the node connecting the second current source circuit 215 and the second resistor 221 are kept at a constant voltage which equals the voltage at the positive terminal of the DC power supply 205 by the first control circuit 212 controlling the first current source 21 1 , and by the second control circuit 217 controlling the second current source 216, respectively.
  • an electronic circuit in a microphone assembly such as electronic circuit 156 in microphone assembly 150 shown in Figure 1
  • an electronic circuit in a microphone assembly coupled to the first and second signal input terminals 230, 231 does not experience the first and second resistors 220, 221 as a load, and as a consequence, a distortion of signals transferred over first internal signal line 225 and second internal signal line 226, respectively, to first and second signal output terminals 235, 236, respectively, is kept to a minimum.
  • FIG. 2b depicts a circuit diagram of a phantom power supply 250, indicated by a dashed line, according to the present invention. Circuit components which are not relevant to an understanding of the present invention have been omitted for clarity.
  • the phantom power supply 250 comprises a DC power supply 255 having its negative terminal connected to ground, and its positive terminal connected to an input of first current source circuit 260, and to an input of a second current source circuit 265, both schematically shown, and indicated by a dashed line.
  • the first current source circuit 260 comprises a first current source 261 , and a common control circuit 262 controlling the first current source 261.
  • the second current source circuit 265 comprises a second current source 266, and the common control circuit 262 controlling the second current source 266.
  • the common control circuit 262 is part of a first control circuit further comprising resistor 270, and of a second control circuit further comprising resistor 271.
  • An output of the first current source circuit 260 or the first current source 261 is connected to a first terminal of a first resistor 220.
  • the first resistor 220 is similar to the first standard resistor 1 15 ( Figure 1) according to the prior art.
  • the second terminal of the first resistor 220 is connected to a first internal signal line 225 having a first input terminal 230 and a first output terminal 235.
  • An output of the second current source circuit 265 or the second current source 266 is connected to a first terminal of a second resistor 221.
  • the second resistor 221 is similar to the second standard resistor 1 16 ( Figure 1) according to the prior art.
  • the second terminal of the second resistor 221 is connected to a second internal signal line 226 having a second input terminal 231 and a second output terminal 236.
  • the phantom power supply 250 further comprises a third input terminal 232 connected to ground.
  • the first current source 261 and the second current source 266 each provide current to provide power to a microphone assembly, such as a microphone assembly 150 shown in Figure 1 , through the first and second input terminals 230, 231.
  • a voltage of the node connecting the first current source circuit 260 and the first resistor 220, as well as a voltage of the node connecting the second current source circuit 265 and the second resistor 221 are kept at a constant voltage which equals the voltage at the positive terminal of the DC power supply 255 by the common control circuit 262 controlling the first current source 261 and the second current source 266.
  • an electronic circuit in a microphone assembly such as electronic circuit 156 in microphone assembly 150 shown in Figure 1 , coupled to the first and second signal input terminals 230, 231 does not experience the first and second resistors 220, 221 as a load, and as a consequence, a distortion of signals transferred over first internal signal line 225 and second internal signal line 226, respectively, to first and second signal output terminals 235, 236, respectively, is kept to a minimum.
  • FIG. 3a depicts a more detailed circuit diagram of a part of an embodiment of a phantom power supply, configured for one internal signal line 375. Circuit components which are not relevant to an understanding of the present invention have been omitted for clarity.
  • a DC power supply 300 for example supplying 48 V, has its negative terminal connected to ground, and has its positive terminal connected to an input of a control circuit 305, indicated by dashed lines.
  • the control circuit 305 comprises an operational amplifier 315 having an inverting amplifier input (marked “-"), a non-inverting amplifier input (marked “+”) and an amplifier output, wherein the inverting amplifier input is connected to the positive terminal of the DC power supply 300 through a resistor 320.
  • the inverting amplifier input further is connected to the amplifier output through a capacitor 325.
  • the non-inverting amplifier input is connected to ground through a capacitor 330.
  • the non-inverting amplifier input further is connected, through a resistor 335, to a first terminal of the first or second resistor 340, respectively, of the phantom power supply.
  • the amplifier output of the operational amplifier 315 is connected to an input of a current source 345, indicated by a dashed line, through a resistor 350.
  • first or second resistor is meant to refer to a first resistor 220 or a second resistor 221 as explained in relation to Figures 2a, 2b.
  • the control circuit 305 is a first control circuit
  • the control circuit 305 is a second control circuit.
  • the current source 345 comprises a PNP transistor 356, wherein an emitter of the PNP transistor 356 is connected to a second DC power supply 301 , for example supplying 60 V, through a resistor 360.
  • a base of the PNP transistor 356 is connected to the second DC power supply 301 through a resistor 361.
  • a collector of the PNP transistor 356 is connected to a first terminal of the first or second resistor 340, respectively.
  • the base of the PNP transistor 356 is connected to an output of the control circuit 305 through resistor 350.
  • the second terminal of the first or second resistor 340 is connected to the internal signal line 375 having a signal input terminal 380 and a signal output terminal 385.
  • circuit diagram of Figure 3a only shows a part of an embodiment of a phantom power supply for one signal line 375.
  • control circuit 305, capacitor 330, current source 345, first or second resistor 340, resistor 350, terminals 380, 385, and their interconnections will be duplicated for two internal signal lines.
  • the current source 345 and another similar current source each provide current to provide power to a microphone assembly through the signal input terminal 380 and another similar signal input terminal.
  • a voltage of the node between the current source 345 and the first or second resistor 340, as well as a voltage of a node between another similar current source and another similar first or second resistor are kept at a constant voltage which equals the voltage at the positive terminal of the DC power supply 300 by the control circuit 305 controlling the current source 345, and by another similar control circuit controlling another similar current source, respectively.
  • an electronic circuit of a microphone assembly coupled to the signal input terminal 380 and another similar signal input terminal does not experience the first and second resistors 340 as a load, and as a consequence, a distortion of signals transferred over internal signal line 375 and another similar internal signal line, respectively, to signal output terminal 385 and another similar signal output terminal, respectively, is kept to a minimum.
  • the term "similar” herein indicates a preference for a component having the same structure and comprising the same elements, in order to obtain a balanced electrical structure having the same or similar electrical characteristics for each internal signal line. However, the same or similar electrical characteristics can also be obtained with different components, having different structure and not comprising the same elements.
  • Figure 3b depicts a more detailed circuit diagram of a part of an embodiment of a phantom power supply, configured for a first internal signal line 375 and a second internal signal line 376. Circuit components which are not relevant to an understanding of the present invention have been omitted for clarity.
  • a DC power supply 300 for example supplying 48 V, has its negative terminal connected to ground, and has its positive terminal connected to an input of a common control circuit 306, indicated by dashed lines.
  • the common control circuit 306 comprises an operational amplifier 315 having an inverting amplifier input (marked “-”), a non-inverting amplifier input (marked “+”) and an amplifier output, wherein the inverting amplifier input is connected to the positive terminal of the DC power supply 300 through a resistor 320.
  • the inverting amplifier input further is connected to the amplifier output through a capacitor 325.
  • the non-inverting amplifier input is connected to ground through a capacitor 330.
  • the non-inverting amplifier input further is connected, through a resistor 335, to a first terminal of the first resistor 340 of the phantom power supply.
  • the non-inverting amplifier input further is connected, through a resistor 336, to a first terminal of the second resistor 341 of the phantom power supply.
  • the amplifier output of the operational amplifier 315 is connected to an input of a first current source 346, indicated by a dashed line, through a resistor 350.
  • the amplifier output of the operational amplifier 315 further is connected to an input of a second current source 347, indicated by a dashed line, through the resistor 350.
  • first or second resistor is meant to refer to a first resistor 220 or a second resistor 221 as explained in relation to Figures 2a, 2b.
  • the common control circuit 306 is part of a first control circuit further comprising resistor 335, and of a second control circuit further comprising resistor 336.
  • the first current source 346 comprises a first PNP transistor 356, wherein an emitter of the PNP transistor 356 is connected to a second DC power supply 301 , for example supplying 60 V, through a resistor 360.
  • a base of the first PNP transistor 356 is connected to the second DC power supply 301 through a resistor 361.
  • a collector of the first PNP transistor 356 is connected to the first terminal of the first resistor 340.
  • the base of the first PNP transistor 356 is connected to an output of the common control circuit 306 through resistor 350.
  • the second current source 347 comprises a second PNP transistor 357, wherein an emitter of the second PNP transistor 357 is connected to the second DC power supply 301 , for example supplying 60 V, through a resistor 360.
  • a base of the second PNP transistor 357 is connected to the second DC power supply 301 through a resistor 362.
  • a collector of the second PNP transistor 357 is connected to the first terminal of the second resistor 341.
  • the base of the second PNP transistor 357 is connected to the output of the common control circuit 306 through resistor 350.
  • the second terminal of the first resistor 340 is connected to the first internal signal line 375 having a signal input terminal 380 and a signal output terminal 385.
  • the second terminal of the second resistor 341 is connected to the second internal signal line 376 having a signal input terminal 381 and a signal output terminal 386.
  • the first current source 346 and the second current source 347 each provide current to provide power to a microphone assembly through the signal input terminals 380, 381.
  • a voltage of the node between the first current source 346 and the first resistor 340, as well as a voltage of a node between the second current source 347 and the second resistor 341 are kept at a constant voltage which equals the voltage at the positive terminal of the DC power supply 301 , by the common control circuit 306 controlling the first and second current sources 345, 346.
  • FIG. 3c depicts a more detailed circuit diagram of a part of an embodiment of a phantom power supply, configured for one signal line 375. Circuit components which are not relevant to an understanding of the present invention have been omitted for clarity.
  • a DC power supply 300 for example supplying 48 V, has its negative terminal connected to ground, and has its positive terminal connected to an input of a control circuit 305, indicated by dashed lines.
  • the control circuit 305 comprises an operational amplifier 315 having an inverting amplifier input (marked “-"), a non-inverting amplifier input (marked “+”) and an amplifier output, wherein the inverting amplifier input is connected to the positive terminal of the DC power supply 300 through a resistor 320.
  • the inverting amplifier input is connected to the amplifier output through a capacitor 325, wherein the non-inverting amplifier input is connected to ground through a capacitor 330.
  • the non-inverting amplifier input is connected, through a resistor 335, to a first terminal of the first or second resistor 340, respectively, of the phantom power supply.
  • the amplifier output of the operational amplifier 315 is connected to an input of a current source 345, indicated by a dashed line, through a resistor 350.
  • first or second resistor is meant to refer to a first resistor 220 or a second resistor 221 as explained in relation to Figures 2a, 2b.
  • the control circuit 305 is a first control circuit
  • the control circuit 305 is a second control circuit.
  • the current source 345 comprises a series connection of a first PNP transistor 355 and a second PNP transistor 356, wherein an emitter of the first PNP transistor 355 is connected to a second DC power supply 301 , for example supplying 60 V, through a resistor 360.
  • a base of the first PNP transistor 355 is connected to the second DC power supply 301 through a resistor 361.
  • a collector of the first PNP transistor 355 is connected to an emitter of the second PNP transistor 356.
  • a base of the second PNP transistor 356 is connected to an anode of a Zener diode 365, and a cathode of the Zener diode 365 is connected to the base of the first PNP transistor 355.
  • the Zener diode 365 functions as a voltage source.
  • a collector of the second PNP transistor 356 is connected to a first terminal of the first or second resistor 340, respectively.
  • the base of the second PNP transistor 356 is connected to an output of the control circuit 305
  • the second terminal of the first or second resistor 340 is connected to an internal signal line 375 having a signal input terminal 380 and a signal output terminal 385.
  • circuit diagram of Figure 3c only shows a part of an embodiment of a phantom power supply for one signal line 375.
  • control circuit 305, capacitor 330, current source 345, first or second resistor 340, resistor 350, terminals 380, 385, and their interconnections will be duplicated for two internal signal lines.
  • the current source 345 and another similar current source each provide current to provide power to a microphone assembly through the signal input terminal 380 and another similar signal input terminal.
  • a voltage of the node between the current source 345 and the first or second resistor 340, as well as a voltage of a node between another similar current source and another similar first or second resistor are kept at a constant voltage which equals the voltage at the positive terminal of the DC power supply 300 by the control circuit 305 controlling the current source 345, and by another similar control circuit controlling another similar current source, respectively.
  • an electronic circuit of a microphone assembly coupled to the signal input terminal 380 and another similar signal input terminal does not experience the first and second resistors 340 as a load, and as a consequence, a distortion of signals transferred over internal signal line 375 and another similar internal signal line, respectively, to signal output terminal 385 and another similar signal output terminal, respectively, is kept to a minimum.
  • FIG. 3d depicts a more detailed circuit diagram of a part of an embodiment of a phantom power supply, configured for a first internal signal line 375 and a second internal signal line 376. Circuit components which are not relevant to an understanding of the present invention have been omitted for clarity.
  • a DC power supply 300 for example supplying 48 V, has its negative terminal connected to ground, and has its positive terminal connected to an input of a common control circuit 306, indicated by dashed lines.
  • the common control circuit 306 comprises an operational amplifier 315 having an inverting amplifier input (marked “-”), a non-inverting amplifier input (marked “+”) and an amplifier output, wherein the inverting amplifier input is connected to the positive terminal of the DC power supply 300 through a resistor 320.
  • the inverting amplifier input is connected to the amplifier output through a capacitor 325, wherein the non-inverting amplifier input is connected to ground through a capacitor 330.
  • the non-inverting amplifier input is connected, through a resistor 335, to a first terminal of the first resistor 340 of the phantom power supply.
  • the non-inverting amplifier input further is connected, through a resistor 336, to a first terminal of the second resistor 341 of the phantom power supply.
  • the amplifier output of the operational amplifier 315 is connected to an input of a first current source 346, indicated by a dashed line, through a resistor 350.
  • the amplifier output of the operational amplifier 315 further is connected to an input of a second current source 347, indicated by a dashed line, through the resistor 350.
  • first or second resistor is meant to refer to a first resistor 220 or a second resistor 221 as explained in relation to Figures 2a, 2b.
  • the common control circuit 306 is part of a first control circuit
  • the common control circuit 306 is part of a second control circuit.
  • the first current source 346 comprises a series connection of a first PNP transistor 355 and a second PNP transistor 356, wherein an emitter of the first PNP transistor 355 is connected to a second DC power supply 301 , for example supplying 60 V, through a resistor 360.
  • a base of the first PNP transistor 355 is connected to the second DC power supply 301 through a resistor 361.
  • a collector of the first PNP transistor 355 is connected to an emitter of the second PNP transistor 356.
  • a base of the second PNP transistor 356 is connected to an anode of a Zener diode 365, and a cathode of the Zener diode 365 is connected to the base of the first PNP transistor 355.
  • the Zener diode 365 functions as a voltage source.
  • a collector of the second PNP transistor 356 is connected to the first terminal of the first resistor 340.
  • the base of the second PNP transistor 356 is connected to an output of the common control circuit 306 through resistor 350.
  • the second current source 347 comprises a series connection of a third PNP transistor 357 and a fourth PNP transistor 358, wherein an emitter of the third PNP transistor 357 is connected to the second DC power supply 301 , for example supplying 60 V, through a resistor 362.
  • a base of the third PNP transistor 357 is connected to the second DC power supply 301 through the resistor 361.
  • a collector of the third PNP transistor 357 is connected to an emitter of the fourth PNP transistor 358.
  • a base of the fourth PNP transistor 358 is connected to an anode of the Zener diode 365, and a cathode of the Zener diode 365 is connected to the base of the third PNP transistor 357.
  • the Zener diode 365 functions as a voltage source.
  • a collector of the fourth PNP transistor 358 is connected to the first terminal of the second resistor 341.
  • the base of the fourth PNP transistor 358 is connected to an output of the common control circuit 306 through the resistor 350
  • the second terminal of the first resistor 340 is connected to the first internal signal line 375 having a signal input terminal 380 and a signal output terminal 385.
  • the second terminal of the second resistor 341 is connected to the second internal signal line 376 having a signal input terminal 381 and a signal output terminal 386.
  • the first and second current sources 346, 347 each provide current to provide power to a microphone assembly through the signal input terminals 380, 381.
  • a voltage of the node between the first current source 346 and the first resistor 340, as well as a voltage of the node between the second current source 347 and the second resistor 341 are kept at a constant voltage which equals the voltage at the positive terminal of the DC power supply 300, by the common control circuit 306 controlling the first and second current sources 346, 347.
  • an electronic circuit of a microphone assembly coupled to the signal input terminals 380, 381 does not experience the first and second resistors 340, 341 as a load, and as a consequence, a distortion of signals transferred over the first and second internal signal lines 375, 376 to signal output terminals 385, 386, respectively, is kept to a minimum.
  • the first and second current sources 345, 346, 347 according to Figures 3c, 3d provide a higher resistance experienced by an electronic circuit of a microphone assembly than the first and second current sources 345, 346 according to Figures 3a, 3b.
  • Figure 4a depicts a circuit diagram of a part of a further embodiment of a phantom power supply, configured for one signal line 475. Circuit components which are not relevant to an understanding of the present invention have been omitted for clarity.
  • a DC power supply 400 for example supplying 48 V, has its negative terminal connected to ground, and has its positive terminal connected to an input of a control circuit 405, indicated by dashed lines.
  • the control circuit 405 comprises an operational amplifier 415 having an inverting amplifier input (marked “-"), a non-inverting amplifier input (marked “+”) and an amplifier output, wherein the non-inverting amplifier input is connected to the positive terminal of the DC power supply 400, for example supplying 48 V, through a resistor 435.
  • the inverting amplifier input is connected to the amplifier output through a capacitor 425.
  • the non-inverting amplifier input is connected to ground through a capacitor 430.
  • the inverting amplifier input is connected, through a resistor 420, to a first terminal of the first or second resistor 440, respectively, of the phantom power supply.
  • the amplifier output of the operational amplifier 415 is connected to an input of a current source 445, indicated by a dashed line.
  • first or second resistor is meant to refer to a first resistor 220 or a second resistor 221 as explained in relation to Figures 2a, 2b.
  • the control circuit 405 is a first control circuit
  • the control circuit 405 is a second control circuit.
  • the current source 445 comprises a PNP transistor 450, wherein an emitter of the PNP transistor 450 is connected to a third DC power supply 455, for example supplying 60 V, through a resistor 460, and a collector of the PNP transistor 450 is connected to a first terminal of the first or second resistor 440.
  • the current source 445 further comprises a second operational amplifier 465 having an inverting amplifier input (marked "-"), a non- inverting amplifier input (marked "+”) and an amplifier output.
  • the base of the PNP transistor 450 is connected to the amplifier output of the second operational amplifier 465.
  • the inverting amplifier input of the second operational amplifier 465 is connected to the emitter of the PNP transistor 450, and the non-inverting amplifier input of the second operational amplifier 465 is connected to an output of the control circuit 405, in particular to the amplifier output of the operational amplifier 415.
  • the second terminal of the first or second resistor 440 is connected to a signal line 475 having an input terminal 480 and an output terminal 485.
  • circuit diagram of Figure 4a only shows a part of an embodiment of a phantom power supply for one signal line 475.
  • control circuit 405, capacitor 430, current source 445, first or second resistor 440, terminals 480, 485, and their interconnections will be duplicated for two signal lines.
  • the current source 445 and another similar current source each provide current to provide power to a microphone assembly through the signal input terminal 480 and another similar signal input terminal.
  • a voltage of the node between the current source 445 and the first or second resistor 440, as well as a voltage of a node between another similar current source and another similar first or second resistor are kept at a constant voltage which equals the voltage at the positive terminal of the DC power supply 400 by the control circuit 405 controlling the current source 445, and by another similar control circuit controlling another similar current source, respectively.
  • an electronic circuit of a microphone assembly coupled to the signal input terminal 480 and another similar signal input terminal does not experience the first and second resistors 440 as a load, and as a consequence, a distortion of signals transferred over internal signal line 475 and another similar internal signal line, respectively, to signal output terminal 485 and another similar signal output terminal, respectively, is kept to a minimum.
  • Figure 4b depicts a circuit diagram of a part of a further embodiment of a phantom power supply, configured for a first internal signal line 475 and a second internal signal line 476. Circuit components which are not relevant to an understanding of the present invention have been omitted for clarity.
  • a DC power supply 400 for example supplying 48 V, has its negative terminal connected to ground, and has its positive terminal connected to an input of a common control circuit 406, indicated by dashed lines.
  • the common control circuit 406 comprises a first operational amplifier 415 having an inverting amplifier input (marked “-"), a non-inverting amplifier input (marked “+”) and an amplifier output, wherein the non-inverting amplifier input is connected to the positive terminal of the DC power supply 400, for example supplying 48 V, through a resistor 435.
  • the inverting amplifier input is connected to the amplifier output through a capacitor 425.
  • the non- inverting amplifier input is connected to ground through a capacitor 430.
  • the inverting amplifier input is connected, through a resistor 420, to a first terminal of the first resistor 440 of the phantom power supply.
  • the inverting amplifier input further is connected, through a resistor 421 , to a first terminal of the second resistor 441 of the phantom power supply.
  • the amplifier output of the first operational amplifier 415 is connected to an input of a first current source 445, indicated by a dashed line.
  • the amplifier output of the first operational amplifier 415 further is connected to an input of a second current source 446, indicated by a dashed line.
  • first or second resistor is meant to refer to a first resistor 220 or a second resistor 221 as explained in relation to Figures 2a, 2b.
  • the common control circuit 406 is part of a first control circuit
  • the resistor 441 being the second resistor
  • the common control circuit 406 is part of a second control circuit.
  • the first current source 445 comprises a first PNP transistor 450, wherein an emitter of the first PNP transistor 450 is connected to a third DC power supply 455, for example supplying 60 V, through a resistor 460, and a collector of the first PNP transistor 450 is connected to a first terminal of the first resistor 440.
  • the first current source 445 further comprises a second operational amplifier 465 having an inverting amplifier input (marked "-"), a non-inverting amplifier input (marked "+”) and an amplifier output.
  • the base of the first PNP transistor 450 is connected to the amplifier output of the second operational amplifier 465.
  • the inverting amplifier input of the second operational amplifier 465 is connected to the emitter of the first PNP transistor 450, and the non-inverting amplifier input of the second operational amplifier 465 is connected to an output of the common control circuit 406, in particular to the amplifier output of the operational amplifier 415.
  • the second current source 446 comprises a second PNP transistor 451 , wherein an emitter of the second PNP transistor 451 is connected to the third DC power supply 455, for example supplying 60 V, through a resistor 461 , and a collector of the second PNP transistor 451 is connected to a first terminal of the second resistor 441.
  • the second current source 446 further comprises a third operational amplifier 466 having an inverting amplifier input (marked "-"), a non-inverting amplifier input (marked "+”) and an amplifier output.
  • the base of the second PNP transistor 451 is connected to the amplifier output of the third operational amplifier 466.
  • the inverting amplifier input of the third operational amplifier 466 is connected to the emitter of the PNP transistor 451 , and the non-inverting amplifier input of the third operational amplifier 466 is connected to an output of the common control circuit 406, in particular to the amplifier output of the first operational amplifier 415.
  • the second terminal of the first resistor 440 is connected to the first internal signal line 475 having an input terminal 480 and an output terminal 485.
  • the second terminal of the second resistor 441 is connected to the second internal signal line 476 having an input terminal 481 and an output terminal 486.
  • the first current source 445 and second current source 446 each provide current to provide power to a microphone assembly through the signal input terminals 480, 481.
  • a voltage of the node between the first current source 445 and the first resistor 440, as well as a voltage of a node between the second current source 446 and the second resistor 441 are kept at a constant voltage which equals the voltage at the positive terminal of the DC power supply 400 by the common control circuit 406 controlling the first and second current sources 445, 446.
  • an electronic circuit of a microphone assembly coupled to the signal input terminals 480, 481 does not experience the first and second resistors 440, 441 as a load, and as a consequence, a distortion of signals transferred over the first and second internal signal lines 475, 476 to the signal output terminals 485, 486, respectively, is kept to a minimum.
  • a phantom power supply for a microphone comprises a first DC power supply having an output for supplying a DC voltage, and signal input terminals adapted to be connected to signal output terminals of the microphone.
  • the output of the first DC power supply is connected to each one of the signal input terminals through a respective series connection of a current source circuit and a resistor, wherein each current source circuit comprises a current source controlled by a control circuit.
  • Each control circuit is adapted to maintain a current source circuit output voltage of the corresponding current source circuit at a predetermined level.
  • Coupled is defined as connected, although not necessarily directly, and not necessarily mechanically, and possibly wirelessly.

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

Abstract

Selon l'invention, une alimentation électrique fantôme pour un microphone comprend une première alimentation électrique CC comportant une sortie permettant de fournir une tension CC, et des bornes d'entrée de signal conçues pour être connectées à des bornes de sortie de signal du microphone. La sortie de la première alimentation électrique CC est connectée à chacune des bornes d'entrée de signal par une connexion en série respective d'un circuit source de courant et d'une résistance, où chaque circuit source de courant comprend une source de courant commandée par un circuit de commande. Chaque circuit de commande est conçu pour maintenir une tension de sortie de circuit source de courant du circuit source de courant correspondant à un niveau prédéterminé.
PCT/NL2016/050276 2015-04-20 2016-04-20 Alimentation électrique fantôme pour microphone WO2016171551A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL2014677A NL2014677B1 (en) 2015-04-20 2015-04-20 Phantom power supply for microphone.
NL2014677 2015-04-20

Publications (1)

Publication Number Publication Date
WO2016171551A1 true WO2016171551A1 (fr) 2016-10-27

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NL (1) NL2014677B1 (fr)
WO (1) WO2016171551A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10312649B2 (en) 2017-03-30 2019-06-04 Pcb Piezotronics, Inc. Phantom powered preamp converter

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3933870A1 (de) * 1989-10-11 1991-04-18 Neumann Gmbh Georg Verfahren und schaltungsanordnung zum steuern von mikrofonen
EP1585360A1 (fr) * 2004-03-30 2005-10-12 AKG Acoustics GmbH Dispositif d'alimentation de microphones à alimentation fantôme

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3933870A1 (de) * 1989-10-11 1991-04-18 Neumann Gmbh Georg Verfahren und schaltungsanordnung zum steuern von mikrofonen
EP1585360A1 (fr) * 2004-03-30 2005-10-12 AKG Acoustics GmbH Dispositif d'alimentation de microphones à alimentation fantôme

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10312649B2 (en) 2017-03-30 2019-06-04 Pcb Piezotronics, Inc. Phantom powered preamp converter

Also Published As

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NL2014677A (en) 2016-10-24
NL2014677B1 (en) 2017-01-20

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