System and method for transducer biasing and shock protection
AssigneeInfineon Technologies AG
InventorsChristian Jenkner, Richard Gaggl, Benno Muehlbacher
Life of this patent
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Abstract
In accordance with an embodiment, an interface circuit includes an amplifier configured to be coupled to a transducer, a first bypass circuit coupled to a first voltage reference and the amplifier, a second bypass circuit coupled to the first voltage reference and the amplifier, and a control circuit coupled to the second bypass circuit. The first bypass circuit conducts a current when an input signal amplitude greater than a first threshold is applied to the transducer and the control circuit causes the second bypass circuit to conduct a current for a first time period after the first bypass circuit conducts a current.
Claims22
An interface circuit comprising:
- an amplifier configured to be coupled to a transducer;
- a first bypass circuit coupled to a first voltage reference and the amplifier, wherein the first bypass circuit is configured to conduct a first current when an input signal amplitude greater than a first threshold is applied to the transducer;
- a second bypass circuit coupled to the first voltage reference and the amplifier;
- and
- a control circuit coupled to the second bypass circuit and configured to cause the second bypass circuit to conduct a second current for a first time period after the first bypass circuit conducts the first current.
A method of operating a transducer comprising:
- conducting a current from the transducer when an input signal having an amplitude greater in magnitude than a threshold value is input to the transducer;
- detecting the current from the transducer;
- and
- reducing an impedance between the transducer and a voltage source after detecting the current.
A microphone system comprising:
- a capacitive microelectromechanical system (MEMS) microphone;
- an amplifier coupled to a first capacitive plate of the MEMS microphone;
- and
- a charge control circuit coupled to the amplifier, wherein the charge control circuit comprises:
- a first diode coupled to the amplifier;
- a bypass switch coupled to the amplifier and in parallel with the first diode;
- a current detection circuit coupled to the first diode and the bypass switch and configured to detect a current in the first diode;
- and
- a switch control circuit coupled to the current detection circuit and configured to control the bypass switch based on information received from the current detection circuit.
A microphone system comprising:
- a capacitive microelectromechanical system (MEMS) microphone;
- an amplifier coupled to a first capacitive plate of the MEMS microphone;
- and
- a charge control circuit coupled to the amplifier, wherein the charge control circuit comprises:
- a first diode coupled to the amplifier;
- a bypass switch coupled to the amplifier and in parallel with the first diode;
- a current detection circuit coupled to the first diode and the bypass switch;
- and
- a switch control circuit coupled to the current detection circuit and configured to control the bypass switch;
- a second diode coupled to the amplifier;
- and
- an additional current detection circuit coupled to the second diode and to the switch control circuit.
A microphone system comprising:
- a capacitive microelectromechanical system (MEMS) microphone;
- an amplifier coupled to a first capacitive plate of the MEMS microphone;
- and a charge control circuit coupled to the amplifier, wherein the charge control circuit comprises:
- a first diode coupled to the amplifier;
- a bypass switch coupled to the amplifier and in parallel with the first diode;
- a current detection circuit coupled to the first diode and the bypass switch;
- and a switch control circuit coupled to the current detection circuit and configured to
- control the bypass switch;
- and
- a second diode coupled in parallel with the first diode, wherein an anode of the first diode is coupled to a cathode of the second diode.
Dependencies are inferred from the claim text.