Abstract: A microphone assembly is provided that includes a condenser transducer element having a displaceable diaphragm and a back-plate. The displaceable diaphragm and the back-plate are arranged to form a capacitor in combination. A preamplifier circuit has an input stage, the input stage comprising a P-type field effect transistor. The displaceable diaphragm and the back-plate are operatively connected between a source input and a gate input of the P-type field effect transistor.

Abstract: A microphone assembly is provided that includes a condenser transducer element having a displaceable diaphragm and a back-plate. The displaceable diaphragm and the back-plate are arranged to form a capacitor in combination. A preamplifier circuit has an input stage, the input stage comprising a P-type field effect transistor. The displaceable diaphragm and the back-plate are operatively connected between a source input and a gate input of the P-type field effect transistor.

Abstract: A MEMS microphone comprising a MEMS transducer having a back plate and a diaphragm as well as controllable bias voltage generator providing a DC bias voltage between the back plate and the diaphragm. The microphone also has an amplifier with a controllable gain, and a memory for storing information for determining a bias voltage to be provided by the bias voltage generator and the gain of the amplifier.

Abstract: An amplifier circuit for capacitive transducers, such as miniature electret or condenser microphones, wherein the amplifier circuit comprises bias control means adapted to improve settling of the amplifier circuit. Another aspect of the invention relates to a miniature condenser microphone and a monolithic integrated circuit comprising an amplifier circuit according to the present invention. The present invention provides amplifier circuits of improved performance by resolving traditionally conflicting requirements of maintaining a large input resistance of the amplifier circuit to optimize its noise performance and provide fast settling of the amplifier circuit.

Abstract: A MEMS microphone comprising a MEMS transducer having a back plate and a diaphragm as well as controllable bias voltage generator providing a DC bias voltage between the back plate and the diaphragm. The microphone also has an amplifier with a controllable gain, and a memory for storing information for determining a bias voltage to be provided by the bias voltage generator and the gain of the amplifier.

Abstract: A microphone assembly is provided that includes a condenser transducer element having a displaceable diaphragm and a back-plate. The displaceable diaphragm and the back-plate are arranged to form a capacitor in combination. A preamplifier circuit has an input stage, the input stage comprising a P-type field effect transistor. The displaceable diaphragm and the back-plate are operatively connected between a source input and a gate input of the P-type field effect transistor.

Abstract: An amplifier circuit for capacitive transducers, such as miniature electret or condenser microphones, wherein the amplifier circuit comprises bias control means adapted to improve settling of the amplifier circuit. Another aspect of the invention relates to a miniature condenser microphone and a monolithic integrated circuit comprising an amplifier circuit according to the present invention. The present invention provides amplifier circuits of improved performance by resolving traditionally conflicting requirements of maintaining a large input resistance of the amplifier circuit to optimize its noise performance and provide fast settling of the amplifier circuit.

Abstract: An amplifier circuit for delivering an output signal which varies in amplitude and in phase or frequency, has a power amplifier, an amplitude feedback circuit and a phase or frequency feedback circuit, both constituting closed loops together with said power amplifier, and at least one of said feedback circuits has its gain controllable in dependency of properties of the input or output signals, or both. A radio transmitter includes such an amplifier circuit, and a cellular telephone includes such a radio transmitter. The invention includes a method for controlling an output state in such a radio transmitter.

Abstract: An amplifier circuit for delivering an output signal which varies in amplitude and in phase or frequency, has a power amplifier, an amplitude feedback circuit and a phase or frequency feedback circuit, both constituting closed loops together with said power amplifier, and at least one of said feedback circuits has its gain controllable in dependency of properties of the input or output signals, or both.