EP0096778B1 - Microphone - Google Patents

Microphone Download PDF

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Publication number
EP0096778B1
EP0096778B1 EP83105247A EP83105247A EP0096778B1 EP 0096778 B1 EP0096778 B1 EP 0096778B1 EP 83105247 A EP83105247 A EP 83105247A EP 83105247 A EP83105247 A EP 83105247A EP 0096778 B1 EP0096778 B1 EP 0096778B1
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EP
European Patent Office
Prior art keywords
microphone
voltage
amplifier
output
accordance
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Expired
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EP83105247A
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German (de)
French (fr)
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EP0096778A2 (en
EP0096778A3 (en
Inventor
Otmar Dipl.-Ing. Kern
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Georg Neumann GmbH
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Georg Neumann GmbH
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Priority to AT83105247T priority Critical patent/ATE36629T1/en
Publication of EP0096778A2 publication Critical patent/EP0096778A2/en
Publication of EP0096778A3 publication Critical patent/EP0096778A3/en
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    • 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
    • H04R19/00—Electrostatic transducers
    • H04R19/04—Microphones

Definitions

  • the invention relates to a microphone according to the preamble of claim 1.
  • a microphone is known from DE-A-2126 385, Fig. 2 for the case of a 12V phantom power.
  • a phantom circuit is often used to power a microphone, in which the supply voltage is connected to the two wires of the symmetrical LF connection between the microphone and the consumer (impedance) with the same polarity via two resistors of the same size, usually 6.8 kOhm with 48V supply voltage is.
  • the definition of the relatively high supply voltage at 48V had its original meaning in that the necessary microphone capsule voltage should be made available without further voltage transformation.
  • the relatively high internal resistance of the power supply due to the two 6.8 kOhm resistors and the maximum permissible current draw limit the power available to the microphone, with the result that an impedance adjustment to the standardized minimum load resistance of 1 kOhm of the microphone is required .
  • a transformerless power supply for microphones is known as “Tonaderspeisung” also from “Radio Mentor”, vol. 33, no. 7, July 1967, p. 531, fig. 9 and from “Funkschau”, 1969, h. 10, p. 316 .
  • the supply voltage of 12V with opposite polarities is applied to the two wires of the symmetrical LF connection via 180 ohm resistors. This is because of the low internal resistance and the relatively low supply voltage, a sufficient power adjustment of the microphone to the normalized microphone load, but it is necessary in any case to generate the higher microphone capsule voltage of z.
  • B. 50V to use a powerless DC-DC converter.
  • This DC-DC converter simultaneously generates the operating voltage for a preamplifier stage, but not for the power output stage, which receives its operating voltage directly from the tone wires. The need for an impedance matching does not arise for the DC / DC converter.
  • transformerless microphone with phantom power provides the supply of the power amplifier used directly from the tone wires, so that the impedance mismatch described at the outset is accepted, which leads to a restriction of the possible dynamic range.
  • a separate, powerless DC-DC converter is used, similar to the tone wire supply.
  • the object of the invention is to provide a microphone of the type mentioned at the outset which, despite the avoidance of a transformer in the LF signal path, enables impedance matching and thus a significantly higher utilization of the dynamic range.
  • the invention is based on the idea of moving the necessary impedance matching from the LF signal path into the power supply line of the amplifier built into the microphone.
  • an operating voltage adapted to the load for the amplifier is obtained by means of a DC voltage converter.
  • the existing DC-DC converter also allows different voltages to be generated for the microphone capsule, as are required to achieve different directional characteristics.
  • training the DC voltage converters in the form of a flyback converter can be used to achieve two significantly different DC voltages by means of one and the same storage inductance by using a delay device for the time-delayed supply of the voltage occurring in the blocking phase to a rectifier device with particularly high efficiency.
  • the dash-dotted circuit block 1 indicates the microphone and the dash-dotted circuit block 2 the power supply source.
  • the microphone 1 is connected via a 2-wire LF cable 3 to the power supply source 2, which contains the LF consumer Z L as the terminating impedance of the cable 3 and a DC voltage source B of, for example, +48 V, the positive pole of which is connected to each wire of the cable 3 is connected via equally large resistors R (e.g. 6, 8 kOhm).
  • This phantom power supply for the microphone 1 represents the most common case of the power supply for the microphone 1, but the invention is not restricted to this type of power supply.
  • the microphone 1 includes in its LF signal path a microphone capsule 30, which is connected to the input of a microphone amplifier 20 via a series capacitor 40, which is used to separate the DC component in the output current of the capsule 30.
  • a microphone capsule 30 Connected to the output terminals 21, 22 of the amplifier are, on the one hand, the wires of the cable 3 and, on the other hand, the input terminals of a coupling device 50, which couples out the supply voltage fed from the source B via the wires of the cable 3 and feeds it to the input 11 of a DC voltage converter 10.
  • a coupling device 50 which couples out the supply voltage fed from the source B via the wires of the cable 3 and feeds it to the input 11 of a DC voltage converter 10.
  • 2 and 3 DC voltage converter 10 shown in more detail works, for example, as a flyback converter, which has a pulse-width-controlled switching element, in the blocking phase of which the output voltages U B1 and U B2 are generated at the output terminals 13 and 14 of the converter 10.
  • the output voltage U S1 at the output terminal 13 is fed via a series resistor 60 to the capsule 30 for its voltage supply.
  • the output voltage U B2 at the output terminal 14 serves as the operating voltage for the amplifier 20.
  • the generation of the voltages U B1 and UB2 by means of the coupling device 50 and the DC-DC converter 10 allows the microphone 1 to be optimally adapted to the available power of the source B, without the need for a transformer at the microphone output. As a result, the entire dynamic range of the microphone 1 which is possible per se can be used for the first time in the case of a transformerless microphone.
  • the DC-DC converter 10 can preferably be designed as a flyback converter, the primary winding w1 of which is connected to the one winding end at the converter input 11 and to the other winding end via a switching element Tr, in the example shown a switching transistor, with a reference potential (ground) is.
  • the control input of the switching element Tr is connected to the output 17 of a controller 15, the input 16 of which is connected to the output terminal 14 of the converter 10, so that the voltage U B2 is supplied to the controller 15 as an actual value.
  • the controller 15 controls the opening and closing times of the switching element Tr in accordance with a pulse width regulation, so that the energy stored in the primary winding w1 and taken from the secondary windings w21, w22, w23 in each cycle period also in the event of fluctuations in the power supply on the part of source B (FIG. 1 ) is kept at the desired constant value.
  • the primary winding w1 is coupled to two or three secondary windings w21, w22 and w23, each of which feeds an output rectifier D1, C1 or D2, C2 or D3, C3.
  • the output rectifier D1, C1 generates the output voltage U B2 at the output terminal 14, while the output rectifier D2, C2 generates the output voltage U B1 at the output terminal 13.
  • the third output rectifier D3, C3, shown in broken lines in FIG. 2, can be provided, if necessary, for generating a further output voltage U B3 , for example in order to switch the directional characteristic of the microphone capsule 30 (FIG. 1) in a known manner.
  • the time profile of the reverse voltage Usperr shown in solid lines in FIG. 4 is advantageously generated on the secondary windings w21 and w22.
  • the larger output voltage U S1 at the output terminal 13 is obtained from the first voltage peak of the blocking voltage U block before the blocking voltage U block assumes the value U B2 at the output terminal 14.
  • a time window of width AT (FIG. 4) is used to mask out the first voltage peak. used, which is realized by a time delay device arranged between the secondary winding w21 and the output rectifier 01, C1. In the simplest case, this time delay device consists of a series inductance L (FIG. 2).
  • a longitudinal thyristor Th (FIG. 3) can be provided, which is controlled by a comparator 12.
  • the comparator 12 compares the voltage at the anode of the thyristor Th with a reference voltage U ref (corresponds to the amount U B1 in FIG. 3) and blocks, for example, the thyristor Th until the voltage at its anode reaches the value of the reference voltage U ref , that is during a time interval ⁇ T.
  • Both voltages U B1 and U B2 can be obtained both from a common winding w2 and from separate windings w21 and w22.
  • the voltage U B1 is brought to the desired value either by limiting the voltage U s err by the diodes ZD and D4 (FIG. 2) or by comparison with U ref by means of the comparator 12, while the voltage U B2 is brought about in a known manner the effect of the controller 15 is kept constant.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Dc-Dc Converters (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
  • Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
  • Amplifiers (AREA)

Abstract

An electroacoustic transducer system comprises a microphone working into a low-frequency amplifier for the energization of an a-c load such as, for example, a loudspeaker or a volume indicator at a control panel. Biasing voltage for the microphone and operating current for the amplifier are derived from a d-c source, via a phantom circuit including the output leads of the amplifier and through a coupler in cascade with a chopper; the latter includes a transistor conducting intermittently under the control of an adjustable pulse generator whose pulse width is varied by negative feedback from the integrated chopper output. An output transformer with a primary in series with the transistor has several secondaries each connected across a storage capacitor through a diode for the generation of a relatively high biasing voltage for the microphone, a relatively low driving voltage for the amplifier and, possibly, a further voltage used to vary the directional pattern of the microphone. To facilitate the establishment of different voltage levels, the development of the lower voltage is delayed-by the combination of a choke with a Zener diode, or by a thyristor-until the higher voltage has been reached by a transient occurring at the beginning of each cutoff phase.

Description

Die Erfindung bezieht sich auf ein Mikrofon gemäß dem Oberbegriff des Patentanspruchs 1. Ein derartiges Mikrofon ist aus der DE-A-2126 385, Fig. 2 für den Fall einer 12V-Phantomspeisung bekannt.The invention relates to a microphone according to the preamble of claim 1. Such a microphone is known from DE-A-2126 385, Fig. 2 for the case of a 12V phantom power.

Zur Stromversorgung eines Mikrofons wird häufig eine Phantomschaltung verwendet, bei der die Versorgungsspannung über zwei gleich große Widerstände, üblicherweise 6,8 kOhm bei 48V-Speisespannung, auf die beiden Adern der symmetrischen NF-Verbindung zwischen Mikrofon und Verbraucher (Impedanz) mit gleicher Polarität aufgeschaltet ist. Die Festlegung der relativ hohen Versorgungsspannung auf 48V hatte ihre ursprüngliche Bedeutung darin, daß ohne weitere Spannungstransformation die notwendige Mikrofonkapselspannung zur Verfügung gestellt werden sollte. Der durch die beiden 6,8 kOhm - Widerstände bedingte, relativ hohe Innenwiderstand der Stromversorgung sowie die maximal zulässige Stromentnahme begrenzen die dem Mikrofon zur Verfügung stehende Leistung, mit der Folge, daß eine Impedanzanpassung an den standardisierten minimalen Belastungswiderstand von 1 kOhm des Mikrofons erforderlich ist. Diese Impedanzanpassung erfolgt bei einem aus « Radio Mentor », Bd. 33, Nr. 7, Juli 1967, S. 530, Bild 5 bekannten, phantomgespeisten Mikrofon mittels eines Transformators mit einer Untersetzung von 10: 1 im Signalweg des Mikrofons zwischen dessen Verstärker und dem MikrofonAusgang.A phantom circuit is often used to power a microphone, in which the supply voltage is connected to the two wires of the symmetrical LF connection between the microphone and the consumer (impedance) with the same polarity via two resistors of the same size, usually 6.8 kOhm with 48V supply voltage is. The definition of the relatively high supply voltage at 48V had its original meaning in that the necessary microphone capsule voltage should be made available without further voltage transformation. The relatively high internal resistance of the power supply due to the two 6.8 kOhm resistors and the maximum permissible current draw limit the power available to the microphone, with the result that an impedance adjustment to the standardized minimum load resistance of 1 kOhm of the microphone is required . This impedance matching takes place in a phantom-powered microphone known from "Radio Mentor", vol. 33, no. 7, July 1967, p. 530, figure 5 by means of a transformer with a reduction of 10: 1 in the signal path of the microphone between its amplifier and the microphone output.

Eine transformatorlose Stromversorgung von Mikrofonen ist als « Tonaderspeisung » ebenfalls aus « Radio Mentor », Bd. 33, Nr. 7, Juli 1967, S. 531, Bild 9 sowie aus « Funkschau », 1969, H. 10, S. 316 bekannt. Bei dieser Speisetechnik wird im Falle der aus « Radio Mentor bekannten Schaltung die Versorgungsspannung von 12V mit entgegengesetzten Polaritäten auf die beiden Adern der symmetrischem NF-Verbindung über 180 Ohm - Widerstände aufgeschaltet. Hierbei ist zwar wegen des geringen Innenwiderstandes und der relativ niedrigen Versorgungsspannung eine ausreichende Leistungsanpassung des Mikrofons an die normierte Mikrofonbelastung gegeben, doch ist es in jedem Falle erforderlich, zum Erzeugen der höheren Mikrofonkapselspannung von z. B. 50V einen leistungslosen Gleichspannungswandler zu verwenden. Dieser Gleichspannungswandler erzeugt gleichzeitig die Betriebsspannung für eine Vorverstärkerstufe, nicht aber für die Leistungsendstufe, welche ihre Betriebsspannung direkt aus den Tonadern erhält. Die Notwendigkeit einer Impedanzanpassung stellt sich somit für den Gleichspannungswandler nicht.A transformerless power supply for microphones is known as “Tonaderspeisung” also from “Radio Mentor”, vol. 33, no. 7, July 1967, p. 531, fig. 9 and from “Funkschau”, 1969, h. 10, p. 316 . With this supply technology, in the case of the circuit known from «Radio Mentor, the supply voltage of 12V with opposite polarities is applied to the two wires of the symmetrical LF connection via 180 ohm resistors. This is because of the low internal resistance and the relatively low supply voltage, a sufficient power adjustment of the microphone to the normalized microphone load, but it is necessary in any case to generate the higher microphone capsule voltage of z. B. 50V to use a powerless DC-DC converter. This DC-DC converter simultaneously generates the operating voltage for a preamplifier stage, but not for the power output stage, which receives its operating voltage directly from the tone wires. The need for an impedance matching does not arise for the DC / DC converter.

Auch bei der Phantomspeisung mehren sich seit einiger Zeit die Bestrebungen, auf Transformatoren in der NF-Signalverarbeitung zu verzichten, beispielsweise, um mögliche Signalverzerrungen zu vermeiden. Ein aus dem Firmensprospekt « Mikrophonverstärker CMC5 der Firma Schalltechnik Dr.-Ing. K. Schoeps vom 27.02.1975 bekanntes, transformatorloses Mikrofon mit Phantomspeisung sieht die Versorgung des verwendeten Endverstärkers unmittelbar aus den Tonadern vor, womit die eingangs beschriebene Impedanzfehlanpassung in Kauf genommen wird, was zu einer Einschränkung des an sich möglichen Dynamikumfangs führt. Für die Erzeugung der höheren Mikrofonkapselspannung von 60V wird ähnlich wie bei der Tonaderspeisung ein gesonderter, leistungsloser Gleichspannungswandler verwendet.In phantom power, too, efforts have been increasing for some time to do without transformers in LF signal processing, for example in order to avoid possible signal distortions. A microphone amplifier CMC5 from Schalltechnik Dr.-Ing. K. Schoeps of February 27, 1975 known, transformerless microphone with phantom power provides the supply of the power amplifier used directly from the tone wires, so that the impedance mismatch described at the outset is accepted, which leads to a restriction of the possible dynamic range. For the generation of the higher microphone capsule voltage of 60V, a separate, powerless DC-DC converter is used, similar to the tone wire supply.

Bei einer weiteren bekannten, wahlweise zwischen 48V-Phantomspeisung, 12V-Phantomspeisung und 12V-Tonaderspeisung umschaltbaren Stromversorgung eines Mikrofons (DE-A-2 126 385) ist im Falle der 48V-Phantomspeisung eine Impedanzanpassung in herkömmlicher Weise entsprechend dem vorstehend erläuterten Stand der Technik mittels Transformator vorgesehen. Für die beiden Fälle der 12V-Speisung werden mittels eines Gleichspannungswandlers die Spannungsverhältnisse der 48V-Phantomspeisung simuliert, so daß in jedem Fall die bereits erwähnten Nachteile des für die Impedanzanpassung nötigen Ausgangstransformators vorhanden sind.In another known, optionally switchable between 48V phantom power, 12V phantom power and 12V tonearm power supply of a microphone (DE-A-2 126 385), in the case of 48V phantom power, impedance matching is conventional in accordance with the prior art explained above provided by transformer. For the two cases of 12V supply, the voltage ratios of the 48V phantom power are simulated by means of a DC voltage converter, so that the disadvantages of the output transformer required for impedance matching are already mentioned in any case.

Die Aufgabe der Erfindung besteht demgegenüber darin, ein Mikrofon der eingangs erwähnten Art zu schaffen, welches trotz Vermeidung eines Transformators im NF-Signalweg eine Impedanzanpassung und damit eine deutlich höhere Ausnutzung des Dynamikumfangs ermöglicht.In contrast, the object of the invention is to provide a microphone of the type mentioned at the outset which, despite the avoidance of a transformer in the LF signal path, enables impedance matching and thus a significantly higher utilization of the dynamic range.

Diese Aufgabe wird erfindungsgemäß durch die kennzeichnenden Merkmale des Patentanspruchs 1 gelöst.This object is achieved by the characterizing features of claim 1.

Vorteilhafte Weiterbildungen und Ausgestaltungen des erfindungsgemäßen Mikrofons ergeben sich aus den Unteransprüchen.Advantageous further developments and refinements of the microphone according to the invention result from the subclaims.

Die Erfindung beruht auf der Überlegung, die nötige Impedanzanpassung aus dem NF-Signalweg in die Stromversorgungszuführung des im Mikrofon eingebauten Verstärkers zu verlegen. Hierzu wird mittels eines Gleichspannungswandlers eine belastungsgerecht angepaßte Betriebsspannung für den Verstärker gewonnen. Auf diese Weise lassen sich im Vergleich zu dem eingangs erwähnten Stand der Technik nicht nur Verbesserungen hinsichtlich der Signalqualität, sondern auch eine Erhöhung der oberen Aussteuerungsgrenze erzielen, da mittels des Gleichspannungswandlers eine annähernd ideale Ausregelung von Schwankungen der Stromversorgung erfolgt und eine optimale Auslegung der im Mikrofon eingebauten Verstärkerschaltungen auf niedrigere Betriebsspannungen möglich ist.The invention is based on the idea of moving the necessary impedance matching from the LF signal path into the power supply line of the amplifier built into the microphone. For this purpose, an operating voltage adapted to the load for the amplifier is obtained by means of a DC voltage converter. In this way, compared to the prior art mentioned at the outset, not only improvements in signal quality, but also an increase in the upper modulation limit can be achieved, since the DC / DC converter provides an almost ideal control of fluctuations in the power supply and an optimal design of the in the microphone built-in amplifier circuits to lower operating voltages is possible.

Der vorhandene Gleichspannungswandler gestattet gleichzeitig die Erzeugung unterschiedlicher Spannungen für die Mikrofonkapsel, wie sie zur Erzielung unterschiedlicher Richtcharakteristiken erforderlich sind. Bei Ausbildung des Gleichspannungswandlers in Form eines Sperrwandlers lassen sich durch Verwendung einer Verzögerungseinrichtung zum zeitverzögerten Zuführen der in der Sperrphase auftretenden Spannung an eine Gleichrichtereinrichtung mit besonders hohem Wirkungsgrad zwei erheblich voneinander abweichende Gleichspannungen mittels ein und derselben Speicherinduktivität erzielen.The existing DC-DC converter also allows different voltages to be generated for the microphone capsule, as are required to achieve different directional characteristics. When training the DC voltage converters in the form of a flyback converter can be used to achieve two significantly different DC voltages by means of one and the same storage inductance by using a delay device for the time-delayed supply of the voltage occurring in the blocking phase to a rectifier device with particularly high efficiency.

Die Erfindung wird nachstehend anhand von Ausführungsbeispielen in den Zeichnungen näher erläutert. Es zeigt :

  • Fig. 1 ein elektrisches Prinzipschaltbild eines erfindungsgemäß ausgebildeten Mikrofons mit dessen Stromversorgungsquelle ;
  • Fig. 2 ein elektrisches Schaltbild eines in dem Mikrofon nach Fig. 1 eingebauten Gleichspannungswandlers zum Erzeugen einer belastungsgerecht angepaßten Betriebsspannung für den Mikrofon-Verstärker;
  • Fig. 3 ein elektrisches Schaltbild einer gegenüber Fig. 2 abweichenden Einrichtung zum zeitverzögerten Zuführen der in der Sperrphase des Gleichspannungswandlers nach Fig. 2 auftretenden Spannung an eine Ausgangsgleichrichterschaltung, und
  • Fig. 4 ein Zeitdiagramm für den Verlauf der in der Sperrphase des Gleichspannungswandlers nach Fig. 2 auftretenden Sperrspannung Usperr.
The invention is explained in more detail below on the basis of exemplary embodiments in the drawings. It shows :
  • 1 shows an electrical block diagram of a microphone designed according to the invention with its power supply source;
  • FIG. 2 shows an electrical circuit diagram of a DC-DC converter installed in the microphone according to FIG. 1 for generating an operating voltage adapted to the load for the microphone amplifier;
  • 3 shows an electrical circuit diagram of a device which differs from FIG. 2 for the time-delayed supply of the voltage occurring in the blocking phase of the DC-DC converter according to FIG. 2 to an output rectifier circuit, and
  • FIG. 4 shows a time diagram for the course of the reverse voltage U s p err occurring in the reverse phase of the direct voltage converter according to FIG. 2.

Bei der in Fig. 1 dargestellten elektrischen Prinzipschaltung eines erfindungsgemäßen Mikrofons mit dessen Stromversorgungsquelle sind mit dem strichpunktierten Schaltungsblock 1 das Mikrofon und mit dem strichpunktierten Schaltungsblock 2 die Stromversorgungsquelle angedeutet. Das Mikrofon 1 ist über ein 2-adriges NF-Kabel 3 mit der Stromversorgungsquelle 2 verbunden, welche den NF-Verbraucher ZL als Abschlußimpedanz des Kabels 3 und eine Gleichspannungsquelle B von beispielsweise +48 V enthält, deren Pluspol mit jeder Ader des Kabels 3 über gleich große Widerstände R (z. B. 6, 8 kOhm) verbunden ist. Diese Phantomspeisung des Mikrofons 1 stellt den häufigsten Fall der Stromversorgung für das Mikrofon 1 dar, ohne daß jedoch die Erfindung auf diese Stromversorgungsart beschränkt ist.In the electrical circuit shown in FIG. 1 of a microphone according to the invention with its power supply source, the dash-dotted circuit block 1 indicates the microphone and the dash-dotted circuit block 2 the power supply source. The microphone 1 is connected via a 2-wire LF cable 3 to the power supply source 2, which contains the LF consumer Z L as the terminating impedance of the cable 3 and a DC voltage source B of, for example, +48 V, the positive pole of which is connected to each wire of the cable 3 is connected via equally large resistors R (e.g. 6, 8 kOhm). This phantom power supply for the microphone 1 represents the most common case of the power supply for the microphone 1, but the invention is not restricted to this type of power supply.

Das Mikrofon 1 umfaßt in seinem NF-Signalweg eine Mikrofonkapsel 30, die über einen Längskondensator 40, der zur Abtrennung des Gleichstromanteils im Ausgangsstrom der Kapsel 30 dient, mit dem Eingang eines Mikrofonv erstärkers 20 verbunden ist. An die Ausgangsklemmen 21, 22 des Verstärkers sind einerseits die Adern des Kabels 3 und andererseits die Eingangsklemmen einer Koppeleinrichtung 50 angeschlossen, welche die von der Quelle B über die Adern des Kabels 3 eingespeiste Versorgungsspannung auskoppelt und dem Eingang 11 eines Gleichspannungswandlers 10 zuführt. Der in den Fign. 2 und 3 näher dargestellte Gleichspannungswandler 10 arbeitet beispielsweise als Sperrwandler, welcher ein impulsbreitengeregeltes Schaltglied aufweist, in dessen Sperrphase die Ausgangsspannungen UB1 und UB2 an den Ausgangsklemmen 13 bzw. 14 des Wandlers 10 erzeugt werden. Die Ausgangsspannung US1 an der Ausgangsklemme 13 wird über einen Längswiderstand 60 der Kapsel 30 zu deren Spannungsversorgung zugeführt. Die Ausgangsspannung UB2 an der Ausgangsklemme 14 dient als Betriebsspannung für den Verstärker 20.The microphone 1 includes in its LF signal path a microphone capsule 30, which is connected to the input of a microphone amplifier 20 via a series capacitor 40, which is used to separate the DC component in the output current of the capsule 30. Connected to the output terminals 21, 22 of the amplifier are, on the one hand, the wires of the cable 3 and, on the other hand, the input terminals of a coupling device 50, which couples out the supply voltage fed from the source B via the wires of the cable 3 and feeds it to the input 11 of a DC voltage converter 10. The in the Figs. 2 and 3 DC voltage converter 10 shown in more detail works, for example, as a flyback converter, which has a pulse-width-controlled switching element, in the blocking phase of which the output voltages U B1 and U B2 are generated at the output terminals 13 and 14 of the converter 10. The output voltage U S1 at the output terminal 13 is fed via a series resistor 60 to the capsule 30 for its voltage supply. The output voltage U B2 at the output terminal 14 serves as the operating voltage for the amplifier 20.

Die Gewinnung der Spannungen UB1 und UB2 mittels der Koppeleinrichtung 50 und des Gleichspannungswandlers 10 gestattet die optimale Anpassung des Mikrofons 1 an die zur Verfügung stehende Leistung der Quelle B, ohne daß ein Transformator am Mikrofonausgang erforderlich ist. Hierdurch kann erstmals bei einem transformatorlosen Mikrofon der gesamte, an sich mögliche Dynamikumfang des Mikrofons 1 genutzt werden.The generation of the voltages U B1 and UB2 by means of the coupling device 50 and the DC-DC converter 10 allows the microphone 1 to be optimally adapted to the available power of the source B, without the need for a transformer at the microphone output. As a result, the entire dynamic range of the microphone 1 which is possible per se can be used for the first time in the case of a transformerless microphone.

Der Gleichspannungswandler 10 kann gemäß Fig. 2 in bevorzugter Weise als Sperrwandler ausgebildet sein, dessen Primärwicklung w1 mit dem einen Wicklungsende an den Wandlereingang 11 und mit dem anderen Wicklungsende über ein Schaltglied Tr, im dargestellten Beispielsfall ein Schalttransistor, mit einem Bezugspotential (Masse) verbunden ist. Der Steuereingang des Schaltgliedes Tr ist mit dem Ausgang 17 eines Reglers 15 verbunden, dessen Eingang 16 mit der Ausgangsklemme 14 des Wandlers 10 verbunden ist, so daß die Spannung UB2 dem Regler 15 als Istwert zugeführt wird. Der Regler 15 steuert die Öffnungs- und Schließzeiten des Schaltgliedes Tr entsprechend einer Impulsbreitenregelung, so daß die in jeder Taktperiode in die Primärwicklung w1 eingespeicherte und den Sekundärwicklungen w21, w22, w23 entnommene Energie auch bei Schwankungen der Stromversorgung seitens der Quelle B (Fig. 1) auf dem gewünschten konstanten Wert gehalten wird.2, the DC-DC converter 10 can preferably be designed as a flyback converter, the primary winding w1 of which is connected to the one winding end at the converter input 11 and to the other winding end via a switching element Tr, in the example shown a switching transistor, with a reference potential (ground) is. The control input of the switching element Tr is connected to the output 17 of a controller 15, the input 16 of which is connected to the output terminal 14 of the converter 10, so that the voltage U B2 is supplied to the controller 15 as an actual value. The controller 15 controls the opening and closing times of the switching element Tr in accordance with a pulse width regulation, so that the energy stored in the primary winding w1 and taken from the secondary windings w21, w22, w23 in each cycle period also in the event of fluctuations in the power supply on the part of source B (FIG. 1 ) is kept at the desired constant value.

Die Primärwicklung w1 ist mit zwei bzw. drei Sekundärwicklungen w21, w22 und w23 gekoppelt, die jeweils einen Ausgangsgleichrichter D1, C1 bzw. D2, C2 bzw. D3, C3 speisen. Der Ausgangsgleichrichter D1, C1 erzeugt die Ausgangsspannung UB2 an der Ausgangsklemme 14, während der Ausgangsgleichrichter D2, C2 die Ausgangsspannung UB1 an der Ausgangsklemme 13 erzeugt. Der in Fig. 2 gestrichelt gezeichnete, dritte Ausgangsgleichrichter D3, C3 kann bei Bedarf zur Erzeugung einer weiteren Ausgangsspannung UB3 vorgesehen werden, beispielsweise, um die Richtcharakteristik der Mikrofonkapsel 30 (Fig. 1) in bekannter Weise umzuschalten.The primary winding w1 is coupled to two or three secondary windings w21, w22 and w23, each of which feeds an output rectifier D1, C1 or D2, C2 or D3, C3. The output rectifier D1, C1 generates the output voltage U B2 at the output terminal 14, while the output rectifier D2, C2 generates the output voltage U B1 at the output terminal 13. The third output rectifier D3, C3, shown in broken lines in FIG. 2, can be provided, if necessary, for generating a further output voltage U B3 , for example in order to switch the directional characteristic of the microphone capsule 30 (FIG. 1) in a known manner.

Um mit besonders hohem Wirkungsgrad zwei unterschiedliche Ausgangsspannungen UB1 und UB2 erzielen zu können, wird in vorteilhafter Weise der in Fig. 4 mit durchgezogener Linie dargestellte Zeitverlauf der Sperrspannung Usperr an den Sekundärwicklungen w21 und w22 erzeugt. Hierbei wird aus der ersten Spannungsspitze der Sperrspannung Usperr die größere Ausgangsspannung US1 an der Ausgangsklemme 13 gewonnen, bevor die Sperrspannung Usperr den Wert UB2 an der Ausgangsklemme 14 annimmt. Zur Ausblendung der ersten Spannungsspitze wird ein Zeitfenster der Breite AT (Fig. 4) verwendet, das durch eine zwischen der Sekundärwicklung w21 und dem Ausgangsgleichrichter 01, C1 angeordnete Zeitverzögerungseinrichtung realisiert wird. Im einfachsten Falle besteht diese Zeitverzögerungseinrichtung aus einer Längsinduktivität L (Fig. 2). Alternativ kann auch ein Längsthyristor Th (Fig. 3) vorgesehen werden, der von einem Vergleicher 12 gesteuert wird. Der Vergleicher 12 vergleicht die Spannung an der Anode des Thyristors Th mit einer Referenzspannung Uref (entspricht betragsmäßig UB1 in Fig. 3) und sperrt beispielsweise den Thyristor Th solange, bis die Spannung an dessen Anode den Wert der Referenzspannung Uref erreicht, also während eines Zeitintervalls ΔT.In order to be able to achieve two different output voltages U B1 and U B2 with a particularly high degree of efficiency, the time profile of the reverse voltage Usperr shown in solid lines in FIG. 4 is advantageously generated on the secondary windings w21 and w22. Here, the larger output voltage U S1 at the output terminal 13 is obtained from the first voltage peak of the blocking voltage U block before the blocking voltage U block assumes the value U B2 at the output terminal 14. A time window of width AT (FIG. 4) is used to mask out the first voltage peak. used, which is realized by a time delay device arranged between the secondary winding w21 and the output rectifier 01, C1. In the simplest case, this time delay device consists of a series inductance L (FIG. 2). Alternatively, a longitudinal thyristor Th (FIG. 3) can be provided, which is controlled by a comparator 12. The comparator 12 compares the voltage at the anode of the thyristor Th with a reference voltage U ref (corresponds to the amount U B1 in FIG. 3) and blocks, for example, the thyristor Th until the voltage at its anode reaches the value of the reference voltage U ref , that is during a time interval ΔT.

Beide Spannungen UB1 und UB2 können sowohl aus einer gemeinsamen Wicklung w2 als auch aus getrennten Wicklungen w21 und w22 gewonnen werden. Die Spannung UB1 wird entweder durch Begrenzung der Spannung Usperr durch die Dioden ZD und D4 (Fig. 2) oder durch Vergleich mit Uref mittels des Vergleichers 12 auf den gewünschten Wert gebracht, während die Spannung UB2 in bekannter Weise durch die Wirkung des Reglers 15 konstant gehalten wird.Both voltages U B1 and U B2 can be obtained both from a common winding w2 and from separate windings w21 and w22. The voltage U B1 is brought to the desired value either by limiting the voltage U s err by the diodes ZD and D4 (FIG. 2) or by comparison with U ref by means of the comparator 12, while the voltage U B2 is brought about in a known manner the effect of the controller 15 is kept constant.

Claims (7)

1. A microphone which is supplied by a power source (2) in a standardized way of a phantom circuit, comprising
a transmitter unit (30),
an amplifier (20) connected in series to the transmitter unit for driving an impedance (ZJ loading the microphone output,
a coupling device (50) for disconnecting the power supplied by the phantom power source (B), and
a direct-voltage converter (10), arranged between the coupling device and the amplifier, for generating the operating voltage of the amplifier, characterized in that the amplifier output (21, 22) is connected without interconnection of a transformer to the microphone output or the impedance load (ZJ. respectively, and that the direct-voltage converter (10) is formed such as to convert the power supplied by the phantom power source (B) with respect to the ratio between voltage and current in a way so as to provide an optimum ratio of operating voltage and current for the amplifier (20) with respect to the impedance load (ZJ at the microphone output.
2. A microphone in accordance with claim 1, characterized in that the direct-voltage converter (10) is formed as inverse converter circuit.
3. A microphone in accordance with claim 2, in which the output voltage of the direct-voltage converter is generated during the blocking phase of an pulsewidth regulated contact member, characterized by a device (L ; 12, Th) for time- delayed supply of the voltage appearing during the blocking phase to an output rectifier circuit (D1, C1), such as to limit through time delay the inverse voltage to the inverse value (US2) generated by the rectifier circuit.
4. A microphone in accordance with claim 3, characterized in that a longitudinal inductance (L) is provided as time delaying device.
5. A microphone in accordance with claim 3, characterized in that a longitudinal thyristor (Th) controlled by a comparator (12) is provided as time-delaying device.
6. A microphone in accordance with claims 3 or 5, characterized by a device (ZD, D4) for limiting the voltage value (UB1) of the inverse voltage (Usperr) occurring during the time delay (AT).
7. A microphone in accordance with claim 6, characterized in that the limiting device (ZD, D4) is composed of a series circuit of a Zener diode (ZD) and a diode (D4) arranged in parallel to the delay device (L).
EP83105247A 1982-06-14 1983-05-26 Microphone Expired EP0096778B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83105247T ATE36629T1 (en) 1982-06-14 1983-05-26 MICROPHONE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3222295 1982-06-14
DE3222295 1982-06-14

Publications (3)

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EP0096778A2 EP0096778A2 (en) 1983-12-28
EP0096778A3 EP0096778A3 (en) 1985-12-04
EP0096778B1 true EP0096778B1 (en) 1988-08-17

Family

ID=6166020

Family Applications (1)

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EP83105247A Expired EP0096778B1 (en) 1982-06-14 1983-05-26 Microphone

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US (1) US4541112A (en)
EP (1) EP0096778B1 (en)
AT (1) ATE36629T1 (en)
DE (1) DE3377765D1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010054895A1 (en) * 2010-12-17 2012-06-21 Austriamicrosystems Ag microphone amplifier

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2734265B2 (en) * 1991-12-12 1998-03-30 日本電気株式会社 Amplifier circuit for electret condenser microphone
US5377273A (en) * 1992-03-26 1994-12-27 Hewlett-Packard Company Batteryless power supply for transducers
ES2158368T3 (en) 1996-12-11 2001-09-01 Gn Netcom As POWER CIRCUIT FOR MICROPHONE.
JP3890301B2 (en) * 2003-01-15 2007-03-07 株式会社オーディオテクニカ Condenser microphone
EP1690332A1 (en) 2003-12-01 2006-08-16 Audioasics A/S Microphone with voltage pump
EP1585360B1 (en) * 2004-03-30 2017-05-10 AKG Acoustics GmbH Power supply of phantom power supplied microphones
EP1585359B1 (en) * 2004-03-30 2017-10-04 AKG Acoustics GmbH Remote control of phantom power supplied microphones
US7356151B2 (en) 2004-03-30 2008-04-08 Akg Acoustic Gmbh Microphone system
EP1585365B1 (en) * 2004-03-30 2011-08-10 AKG Acoustics GmbH Polarization voltage setting of microphones
JP4304118B2 (en) * 2004-04-22 2009-07-29 株式会社オーディオテクニカ Microphone output connector
JP4579778B2 (en) * 2004-08-17 2010-11-10 ルネサスエレクトロニクス株式会社 Sensor power supply circuit and microphone unit using the same
DE102005007623A1 (en) * 2005-02-18 2006-08-31 Robert Bosch Gmbh microphone
DE102008022588A1 (en) 2007-05-09 2008-11-27 Henrik Blanchard Externally polarized condenser microphone i.e. high-quality sound receiver, for use in e.g. professional studio technology, has control amplifier separated from buffer amplifier to compare capsule voltage with preset reference value
DE102010000686B4 (en) * 2010-01-05 2018-05-09 Sennheiser Electronic Gmbh & Co. Kg condenser microphone
US9544027B2 (en) * 2014-02-19 2017-01-10 Texas Instruments Incorporated Loop powered transmitter with a single tap data isolation transformer and unipolar voltage converters
US10412477B2 (en) 2016-09-19 2019-09-10 Wade Goeke High fidelity, professional grade microphone system for direct coupling to recording components
CN112217482B (en) * 2020-08-31 2024-02-13 湖南大学 Electroacoustic transduction system and impedance matching control method thereof
CN114040301B (en) * 2021-11-15 2024-02-27 歌尔微电子股份有限公司 Microphone quick start circuit, microphone chip and microphone

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1240128B (en) * 1964-08-01 1967-05-11 Sennheiser Electronic High-frequency capacitor microphone with an oscillator and a coupled resonant circuit that is tuned to its frequency and whose capacitance is formed by the transducer element
AT298583B (en) * 1970-06-08 1972-05-10 Akg Akustische Kino Geraete Capacitive sound receiver Capacitive sound receiver
US4122514A (en) * 1976-11-01 1978-10-24 Hewlett-Packard Company Direct current power supply

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102010054895A1 (en) * 2010-12-17 2012-06-21 Austriamicrosystems Ag microphone amplifier
DE102010054895B4 (en) 2010-12-17 2018-10-31 Austriamicrosystems Ag microphone amplifier

Also Published As

Publication number Publication date
ATE36629T1 (en) 1988-09-15
DE3377765D1 (en) 1988-09-22
US4541112A (en) 1985-09-10
EP0096778A2 (en) 1983-12-28
EP0096778A3 (en) 1985-12-04

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