Microphone with slew rate controlled buffer
AssigneeKnowles Electronics, LLC
InventorsSatya Sai Evani, Sudheer Gutta, Sreenath Pariyarath, Gururaj Ghorpade, Sruthi Panangavil
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Abstract
A digital microphone or other sensor assembly includes a transducer and an electrical circuit including a slew-rate controlled output buffer configured to reduce propagation delay and maintain output rise and fall time independent of PVT variation and load capacitance. In some embodiments, the portions of the output buffer are selectably disabled to reduce power consumption without adversely substantially increasing propagation delay.
Claims20
A digital sensor assembly comprising:
- a transducer configured to generate an analog signal responsive to a sensed environmental condition;
- an analog-to-digital converter (ADC) having an input coupled to the transducer;
- and
- a slew-rate controlled output buffer having an input coupled to an output of the ADC, the slew-rate controlled output buffer comprising:
- a first current sink circuit;
- an output driver comprising a first driver coupled to the first current sink circuit;
- and
- a first feedback capacitor selectably coupled between a low impedance node of the first current sink circuit and an output node of the output driver when the first current sink circuit is enabled,
- wherein the first current sink circuit discharges the first driver gate when the first driver needs to be turned ON.
An electrical circuit for a digital sensor assembly, comprising:
- a slew-rate controlled output buffer having an input connectable to a digital circuit of a digital sensor assembly, the slew-rate controlled output buffer comprising:
- a first current sink circuit;
- an output driver comprising a first driver coupled to the first current sink circuit;
- and
- a first feedback capacitor selectably coupled between a low impedance node of the first current sink circuit and an output node of the output driver when the first current sink circuit is enabled,
- wherein the first current sink circuit discharges the first driver gate when the first driver needs to be enabled.
A method of operating a digital sensor assembly having a slew-rate controlled output driver, the method comprising:
- generating an electrical signal representative of a condition sensed by a transducer of the digital sensor assembly;
- providing an output signal, based on the electrical signal, at an output node of slew-rate controlled output driver;
- selectably coupling a feedback capacitor between a low impedance source of a current sink and the output node when the current sink is enabled,
- discharging the output driver gate via a drain of the current sink when the feedback capacitor is coupled between the source of the current sink and the output node.
Dependencies are inferred from the claim text.