Interface circuit for connecting a microphone circuit to a preamplifier.

Abstract

An interface circuit (INT C ) is disclosed, adapted to connect a microphone circuit (MC D ) to a preamplifier (P A ), the microphone circuit (MC D ) comprising a microphone (3) and at least an output node (M O , M O ') and the preamplifier (P A ) comprising at least an input node (10, 10') adapted to be connected to said output node (M O , M O ') through said interface circuit (INT C ). The interface circuit (INT C ) comprises at least a decoupling capacitor (C DEC ) for DC decoupling said input node (10, 10') from said output node (M O , M O '), the decoupling capacitor (C DEC ) having a first end connected / connectable to said input node (10, 10') and a second end connected / connectable to said output node (M O , M O '). The interface circuit (INT C ) comprises at least one active circuit (UG AMP , UG AMP ') connected to the first end of the decoupling capacitor (C DEC ), adapted to operatively act as a resistance multiplier and having an equivalent resistance that together with the decoupling capacitor (C DEC ) defines a high-pass filter operatively connected / connectable between the microphone (3) and the preamplifier (P A ) .

Description

technical field [0001] The invention relates to an interface circuit for connecting a microphone circuit to a preamplifier. Background technique [0002] One of the main aspects taken into consideration in the development of electronic devices, especially mobile devices, is footprint. In the field of mobile devices such as mobile phones, one of the keys to creating a phone with more functionality without changing the size of the phone is reducing the footprint on a printed circuit board (PCB). For many years, the focus has been on integrating as much as possible on-chip all those passive components that represent the main limitation of area reduction, such as resistors, capacitors and inductors. In older generation phones, this component was an SMD (Surface Mount Device) mounted directly on the motherboard. Later, due to advances in technology, these devices were located inside the chip package, known as the PDI (Passive Device Integration) approach, and in some cases dire...

AI Technical Summary

Problems solved by technology

[0009] In view of the above limitations of prior art interface circuits between a microphone circuit and a preamplifier, it is an object of the present invention to provide an interface circuit for connecting a microphone circuit to a preamplifier, which is adapted to address the above Shown about the inability to reduce the footprint below the desired value due to the presence of one or more decoupling capacitors that cannot be integrated on a chip

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