High-sensitivity condenser microphone circuit

Abstract

The high-sensitivity condenser microphone circuit comprises a capacitor sound head, a high input impedance circuit, an impedance conversion circuit, a power supply circuit and an output interface, the capacitance sound head outputs a pair of signals through the high input impedance circuit, and the pair of signals are converted into low output impedance signals through the impedance conversion circuit and are output through the output interface; the power supply circuit supplies power to the capacitance sound head, the high input impedance circuit and the impedance conversion circuit. According to the utility model, by arranging the high input impedance circuit and the impedance conversion circuit, the sensitivity of the microphone can be greatly improved, so that the microphone can adapt to an amplifier with smaller driving force.

Description

Technical Field

[0001] The utility model relates to a microphone, in particular to a high-sensitivity capacitor microphone circuit. Background Art

[0002] The sensitivity of existing microphones is generally only about -50dB, so microphone amplifiers with weak driving force cannot drive the microphone. Utility Model Content

[0003] The technical problem to be solved by the present invention is to overcome the above-mentioned deficiencies in the prior art and provide a high-sensitivity condenser microphone circuit, which can improve the sensitivity of the condenser microphone.

[0004] The technical solution adopted by the present invention to solve the above technical problems is:

[0005] A high-sensitivity condenser microphone circuit is characterized in that: it includes a condenser microphone head, a high input impedance circuit, an impedance conversion circuit, a power supply circuit, and an output interface; the condenser microphone head outputs a pair of signals via the high input impedance circuit, and the pair of signals are converted into low output impedance signals via the impedance conversion circuit and output via the output interface; the power supply circuit provides power to the condenser microphone head, the high input impedance circuit, and the impedance conversion circuit.

[0006] Better, the high input impedance circuit includes a capacitor sound head, a field effect transistor Q3, a capacitor C5, a capacitor C3, and a capacitor C4. The capacitor sound head converts the sound signal into an electrical signal, which is then coupled by the capacitor C5 and sent to the G pole of the field effect transistor Q3; the adjustable resistor RP1 and the resistor R7 form a G pole bias voltage adjustment circuit, the resistor R6 is the S pole load resistor, the resistor R5 is a DC negative feedback resistor, and the capacitor C3 and the capacitor C4 are output coupling capacitors.

[0007] Preferably, the impedance conversion circuit includes emitter followers Q1, Q2, resistors R1, R2, R3, R4, and Zener diodes D1, D2, D3, and D4. A pair of signals of equal size and opposite phases output from the S and D poles are coupled through capacitors C3 and C4 and sent to the B poles of emitter followers Q1 and Q2, and then output from the E poles of emitter followers Q1 and Q2, and connected to pins 2 and 3 of the output XLR J2 through resistors R1 and R2.

[0008] Better yet, the power supply circuit includes a power supply that is filtered by capacitor C6, resistor R9, and capacitor C7 and then stabilized by D5 to provide power to Q3; Q4, R11, capacitor C9, capacitor C10, L1, and L2 form an oscillation circuit, the source of the oscillation circuit is filtered by R10 and capacitor C8, and is stabilized by Zener diode D6 and provided; the output of the oscillation circuit passes through a voltage doubling rectifier circuit composed of capacitor C11, capacitor C12, diode D7, and diode D8 to generate a DC voltage of about 60V, which is filtered by resistor R12 and capacitor C13 and then provided to the capacitor sound head.

[0009] Compared with the prior art, the beneficial effect of the present invention is that the present invention can greatly improve the sensitivity of the microphone to about -30dB by providing a high input impedance circuit and an impedance conversion circuit, so that it can adapt to amplifiers with smaller driving force. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a circuit block diagram of a high-sensitivity condenser microphone circuit according to an embodiment of the present invention.

[0011] Figure 2 This is a circuit diagram of a high-sensitivity condenser microphone circuit according to an embodiment of the present invention.

[0012] Figure 3 This is a high input impedance circuit diagram of a high-sensitivity condenser microphone circuit according to an embodiment of the present invention.

[0013] Figure 4 This is an impedance conversion circuit diagram of a high-sensitivity condenser microphone circuit according to an embodiment of the present invention.

[0014] Figure 5 This is a power supply circuit diagram of a high-sensitivity condenser microphone circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0016] like Figure 1 The circuit block diagram of the high-sensitivity condenser microphone circuit shown includes a condenser sound head, a high input impedance circuit, an impedance conversion circuit, a power supply circuit, and an output interface.

[0017] The capacitor sound head outputs a pair of signals via a high input impedance circuit, and the pair of signals are converted into low output impedance signals via an impedance conversion circuit and output via an output interface.

[0018] The power supply circuit provides power to the capacitor sound head, the high input impedance circuit and the impedance conversion circuit.

[0019] like Figure 2 、 3As shown, the high-input impedance circuit includes a capacitor head, field-effect transistor (FET) Q3, capacitors C5, C3, and C4. The capacitor head converts the sound signal into an electrical signal, which is then coupled by capacitor C5 to the G terminal of FET Q3. Adjustable resistor RP1 and resistor R7 form the G terminal bias voltage adjustment circuit, resistor R6 serves as the S terminal load resistor, resistor R5 serves as the DC negative feedback resistor, and capacitors C3 and C4 serve as output coupling capacitors. Due to the extremely high input impedance of FET Q3, when a signal is input to the G terminal of FET Q3, the S and D terminals can output a pair of equal and opposite signals.

[0020] like Figure 2 、 4 As shown, the impedance conversion circuit includes emitter followers Q1, Q2, resistors R1, R2, R3, R4, and Zener diodes D1, D2, D3, and D4. A pair of signals of equal size and opposite phases output from the S pole and the D pole are coupled through capacitors C3 and C4 and sent to the B pole of the emitter follower Q1 and the emitter follower Q2, and then output from the E pole of the emitter follower Q1 and the emitter follower Q2, and connected to pins 2 and 3 of the output XLR J2 through resistors R1 and R2.

[0021] The output XLR J2 is connected to a 48V phantom power supply, so there is a 48V DC power supply on pins 2 and 3 of XLR J2. The 48V can provide power to emitter followers Q1 and Q2. Resistors R3 and R4 are bias resistors of emitter followers Q1 and Q2. Capacitors C1 and C2 are filter capacitors. D1, D2, D3, and D4 are Zener diodes. The emitter followers Q1 and Q2 in this circuit work as an emitter follower, which can effectively reduce the output impedance and provide the microphone with better load capacity.

[0022] like Figure 2 、 5 As shown, the power supply circuit includes a power supply that is filtered by capacitor C6, resistor R9, and capacitor C7 and then stabilized by D5 to provide power to Q3. Q4, R11, capacitor C9, capacitor C10, L1, and L2 form an oscillation circuit. The source of the oscillation circuit is filtered by R10 and capacitor C8 and stabilized by Zener diode D6. The output of the oscillation circuit passes through a voltage doubling rectifier circuit composed of capacitor C11, capacitor C12, diode D7, and diode D8 to generate a DC voltage of about 60V, which is filtered by resistor R12 and capacitor C13 to provide voltage to the capacitor sound head.

Claims

1. High-sensitivity condenser microphone circuit, characterized by: It includes a capacitor sound head, a high input impedance circuit, an impedance conversion circuit, a power supply circuit, and an output interface; the capacitor sound head outputs a pair of signals via the high input impedance circuit, and the pair of signals are converted into low output impedance signals via the impedance conversion circuit and output via the output interface; the power supply circuit provides power to the capacitor sound head, the high input impedance circuit, and the impedance conversion circuit.

2. The high-sensitivity condenser microphone circuit according to claim 1, characterized in that The high input impedance circuit includes a capacitor sound head, a field effect transistor Q3, a capacitor C5, a capacitor C3, and a capacitor C4. The capacitor sound head converts the sound signal into an electrical signal, which is then coupled by the capacitor C5 and sent to the G pole of the field effect transistor Q3; the adjustable resistor RP1 and the resistor R7 form a G pole bias voltage adjustment circuit, the resistor R6 is the S pole load resistor, the resistor R5 is a DC negative feedback resistor, and the capacitor C3 and the capacitor C4 are output coupling capacitors.

3. The high-sensitivity condenser microphone circuit according to claim 1, characterized in that The impedance conversion circuit includes emitter followers Q1, Q2, resistors R1, R2, R3, R4, and Zener diodes D1, D2, D3, and D4. A pair of signals of equal size and opposite phases output from the S and D poles of the field effect transistor G are coupled through capacitors C3 and C4 and sent to the B poles of the emitter followers Q1 and Q2, and then output from the E poles of the emitter followers Q1 and Q2, and connected to pins 2 and 3 of the output XLR J2 through resistors R1 and R2.

4. The high-sensitivity condenser microphone circuit according to claim 1, characterized in that The power supply circuit includes: the power supply is filtered by capacitor C6, resistor R9, and capacitor C7, and then stabilized by D5 to provide power to Q3; the transistor Q4, resistor R11, capacitor C9, capacitor C10, inductors L1 and L2 form an oscillation circuit; the source of the oscillation circuit is filtered by R10 and capacitor C8, and is stabilized by Zener diode D6; the output of the oscillation circuit passes through a voltage doubling rectifier circuit composed of capacitor C11, capacitor C12, diode D7, and diode D8 to generate a DC voltage of about 60V, which is filtered by resistor R12 and capacitor C13 to provide voltage to the capacitor sound head.

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