CN2838192Y - Circuit module of condenser microphone - Google Patents

Abstract

The utility model discloses a circuit module of a condenser microphone, comprising a field effect transistor, a resistor, a diode, at least one capacitor and a package. A source pin, a drain pin and a gate pin are respectively extended from the field effect transistor, two ends of the resistor are respectively connected to the source and gate of the transistor, a cathode and an anode of the diode are respectively connected to the gate and source of the field effect transistor, and the package encapsulates the field effect transistor, the resistor, the diode and the capacitor therein. The utility model is characterized in that one end of the capacitor is connected to the source of the transistor, and an extension pin is extended from the other end, and the gate pin, the source pin, the drain pin and the extension pin are all exposed from the package. By means of the extension pin of the circuit module of the condenser microphone of the utility model, a user can connect the extension pin to an external electronic component or wiring to adjust the electrical characteristics by himself.

Description

Circuit module of condenser microphone

technical field

The utility model relates to a circuit module, in particular to a circuit module of a capacitive microphone which can be added with electronic components to adjust its electrical characteristics.

Background technique

As shown in Figure 1, the circuit design of a general condenser microphone includes a capacitive sensor 7, an impedance converter (Impedance converter) 8 and a filter unit 9, and the capacitive sensor 7 is made of a diaphragm that can perceive sound waves As a result, with the transmission of different sound waves, the degree of vibration of the diaphragm is also different, so different capacitive sensing signals are generated; the design of the impedance converter 8 is mainly based on field effect transistor (FET) components, and its function is to convert the capacitive sensor 7 to amplify the small capacitive sensing signal and convert it into an electrical signal output; the capacitive sensor 7 is extremely sensitive and is easily disturbed by radio frequency or high frequency noise in the environment, so the filter unit 9 is designed to filter out such Radio-frequency or high-frequency noise interference ensures the quality of the output signal of the condenser microphone.

As shown in Figure 2, the aforementioned impedance converter 8 has a field effect transistor 81, a diode 82 and a resistor 83, and the two ends of the resistor 83 are respectively connected to the source and the gate of the field effect transistor 81; The cathode and the anode are respectively connected to the gate and source of the field effect transistor 81 , and their function is to prevent current from being introduced into the source of the field effect transistor 81 .

At present, the condenser microphone tends to be miniaturized. The common impedance converter 8 is designed as an integrated circuit element. In addition, the filter unit 9 is an element connected to the output end of the impedance converter 8. The number of components is large. It seems to take up a lot of space in a limited space. In view of this, there is also a design that directly integrates the impedance converter 8 and the filter unit 9 into an integrated circuit component at present, but since the filter unit 9 is a pre-prepared component, the subsequent It is easy to be restricted in application, for example, when different filtering effects are required, its original characteristics cannot be changed.

Utility model content

Therefore, an object of the present invention is to provide a circuit module of a condenser microphone with external electronic components to adjust its electrical characteristics.

Another object of the present invention is to provide a circuit module of a condenser microphone that can reduce the occupied space.

Therefore, the circuit module of the capacitive microphone of the present invention includes a field effect transistor, a resistor, a diode, at least one capacitor and a package, and a source pin and a drain pin are respectively extended from the field effect transistor. and a gate pin, the two ends of the resistor are respectively connected to the source and gate of the transistor, the cathode and the anode of the diode are respectively connected to the gate and source of the field effect transistor, the package body is the field effect transistor, the resistor , a diode and a capacitor are packaged in it, and it is characterized in that: one end of the capacitor is connected to the source of the transistor, and an expansion pin is extended from the other end, and the gate pin, the source pin, the drain pin and the expansion pin are exposed to the package body.

With the expansion pins of the circuit module of the condenser microphone of the present invention, users can connect the expansion pins to external electronic components or wires to adjust the electrical characteristics by themselves.

Description of drawings

The circuit module of the capacitive microphone of the present utility model is described in detail below by preferred embodiment and accompanying drawing, in the accompanying drawing:

FIG. 1 is a circuit block diagram illustrating the components included in the circuit design of a general condenser microphone;

FIG. 2 is a circuit diagram illustrating elements of an impedance converter of a general condenser microphone;

Fig. 3 is a circuit block diagram illustrating the components of the first preferred embodiment of the circuit module of the condenser microphone of the present invention;

Fig. 4 is a schematic diagram illustrating the components and assembly methods of the second preferred embodiment of the circuit module of the condenser microphone of the present invention;

Fig. 5 is a circuit block diagram, the circuit module of the capacitive microphone in the first preferred embodiment is externally connected with two inductors so that it has a filtering effect;

FIG. 6 is a schematic diagram of laying the circuit module of the condenser microphone in the second preferred embodiment with two bent lines so as to have a filtering effect.

Detailed ways

The foregoing and other technical content, features and effects of the present invention will be clearly presented in the following detailed descriptions of two preferred embodiments with reference to the drawings. Before the present invention is described in detail, it should be noted that in the following description, similar elements are denoted by the same numerals.

As shown in Figure 3, it is the first preferred embodiment of the circuit module of the condenser microphone of the present invention. In this preferred embodiment, the circuit module 1 of the condenser microphone includes a package body 10, a field effect transistor 11. A resistor 12 , a diode 13 and at least one capacitor 14 . The capacitor 14 can be one or more. For convenience of description, this preferred embodiment is described with two capacitors 141 and 142 .

In this preferred embodiment, the field effect transistor 11 has a source (Source) pole, a drain (Drain) pole and a gate (Gate) pole, a gate pin 111 extending from the gate pole of the field effect transistor 111, drain The pole extension has a drain pin 112 , and the source extension has a source pin 113 .

Two terminals of the resistor 12 are respectively connected to the source and gate of the field effect transistor 11 ; the cathode of the diode 13 is connected to the gate of the field effect transistor 11 , and the anode of the diode 13 is connected to the source of the field effect transistor 11 .

One end of each capacitor 141 , 142 is connected to the source of the field effect transistor 11 , and the other end of each capacitor 141 , 142 is extended with expansion pins 114 , 115 .

The package body 10 is made of epoxy resin material used for sealing, and is used to package the field effect transistor 11, the resistor 12, the diode 13 and the capacitors 141, 142 into an integrated circuit element, and the gate pin 111, The source pin 113, the drain pin 112, and the two expansion pins 114, 115 are all exposed on the package body 10, and the expansion pins 114, 115 are used to add electronic components (such as: inductors) or wiring to increase filtering Effect or reduce electromagnetic wave interference and other applications.

As shown in Figure 4, it is the second preferred embodiment of the circuit module of the condenser microphone of the present invention. Compared with the first preferred embodiment, it is packaged as an integrated circuit element. In this preferred embodiment, the circuit module Group 2 adopts chip direct (Chip on Board; COB) packaging method, the process is to directly stick the bare chip on the printed circuit board, and directly apply the packaging and testing steps of general integrated circuit manufacturing to the assembly of the printed circuit board. The advantage is that it can save space and save test time.

In this preferred embodiment, the circuit module 2 includes a package 20, a bare chip 21, a plurality of metal wires 211-215 and a printed circuit board 22, and the bare chip 21, wires 211-215 and the package 20 It is assembled on the printed circuit board 22 by adopting the aforementioned chip direct packaging method.

Bare chip 21 contains components such as field effect transistor 11, resistor 12, diode 13 and capacitor 141, 142 as described in the first preferred embodiment (see Figure 3), and the functions of described metal wires 211-215 are similar In the first preferred embodiment, the gate pin 111, the drain pin 112, the source pin 113, and the expansion pins 114, 115 (see FIG. 3) are used to electrically connect to the metal on the printed circuit board 22. The layers 221 , 222 and the package body 20 are made of epoxy resin material used for sealing.

As shown in FIG. 5 , two inductors 151 and 152 are externally connected to the circuit module 1 ( FIG. 3 ) of the condenser microphone in the first preferred embodiment, so that the output has a filtering effect. The method is that the source pin 112 of the circuit module 1 of the self-capacitance microphone is used as the input positive voltage (V ₊ ) terminal, and an inductor 151 is connected in series between the source pin 112 and the expansion pin 114, and the expansion pin 114 and the expansion pin 115 are connected in series with an inductor 152. In this way, the inductors 151, 152 are respectively connected in parallel with the capacitors 141, 142. Due to the formation of an inductance-capacitance (LC) filter effect, through the inductor 151, the capacitor 141 , and the signal output from the output voltage (V _out ) end of the connection end 116 of the inductor 152 and the capacitor 142 can achieve the effect of filtering out external radio frequency or high frequency noise interference.

In other embodiments, the circuit module 1 (FIG. 3) of the condenser microphone can still connect resistors in parallel to form a resistance-capacitance (RC) filter effect. Since this is a known technology, the possible changes will not be repeated here. In addition, assuming that the circuit module 1 of the condenser microphone only has a capacitor 141, an inductor 151 can be connected in series between the source pin 112 and the expansion pin 114 to filter out external radio frequency or high frequency noise interference .

As shown in FIG. 6 , the circuit module 2 ( FIG. 4 ) of the condenser microphone in the second preferred embodiment is laid with two bent lines 251 and 252 to have the filtering effect of an inductor. Compared with the second preferred embodiment, the metal layers 221 and 222 also respectively represent the output voltage (V _out ) end and the ground (Ground) end, but a new metal layer 253 represents an input positive voltage (V ₊ ) end, And add a metal wire 216 to form conduction with the bent lines 251, 252 (inductors), similar to the concept in FIG. 5 , and also achieve the effect of filtering out external radio frequency or high frequency noise interference.

To sum up the above, in the first preferred embodiment of the circuit module of the condenser microphone of the present invention, the advantage that the circuit module 1 has the expansion pins 114, 115 is that the user can add suitable electronic components or The wiring is adjusted to the required electrical characteristics without being limited by the electrical characteristics of the components supplied by the original manufacturer, so it can increase its application level.

In addition to the advantages described in the first preferred embodiment, the second embodiment of the circuit module of the capacitive microphone of the present utility model also adopts a chip direct packaging method, because the circuit module 2 of the capacitive microphone is directly applied to the printed circuit board. Assembling the circuit board 22, it can also save space and save test time.

Claims (7)

1. the circuit module of an Electret Condencer Microphone, comprise a field-effect transistor, one resistor, one diode, an at least one capacitor and a packaging body, be extended with the one source pole pin respectively by field-effect transistor, an one drain pin and a gate pin, two ends of resistor are connected to transistorized source electrode and gate, the negative electrode of diode and anode are connected the gate and the source electrode of field-effect transistor respectively, packaging body is with field-effect transistor, resistor, diode and capacitor package are in wherein, it is characterized in that: an end of capacitor is connected in transistorized source electrode, the other end extends one and expands pin, and the gate pin, the source electrode pin, drain pin and expansion pin all expose to packaging body.

2. the circuit module of Electret Condencer Microphone as claimed in claim 1 is characterized in that:

The number of described capacitor is most.

3. the circuit module of Electret Condencer Microphone as claimed in claim 1 is characterized in that:

Described field-effect transistor, resistor, diode and capacitor are to be integrated into a bare chip.

4. the circuit module of Electret Condencer Microphone as claimed in claim 3 is characterized in that:

Described gate pin, source electrode pin, drain pin and expansion pin are plain conductor.

5. the circuit module of Electret Condencer Microphone as claimed in claim 4 is characterized in that:

The circuit module of described Electret Condencer Microphone also comprises a printed circuit board (PCB), and described bare chip, lead and packaging body are to take the direct package method of chip to be assembled on the printed circuit board (PCB).

6. the circuit module of Electret Condencer Microphone as claimed in claim 1 is characterized in that:

Described packaging body is that epoxide resin material is made.

7. the circuit module of Electret Condencer Microphone as claimed in claim 1 is characterized in that:

Also be serially connected with at least one inductor or at least one resistor between described source electrode pin and the expansion pin.

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