Overload recovery optimization in microelectromechanical system application specific integrated circuit
AssigneeApple Inc.
InventorEddie L. Ng
Life of this patent
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Abstract
Disclosed herein is a MEMS ASIC. In some examples, the MEMS ASIC can include a MEMS, an analog front end (AFE) amplifier, an analog-to-digital converter (ADC), an overload detector, and a high-ohmic (HO) block. The HO block and the MEMS can form a high-pass filter (HPF). The impedance of the HO block can be related to the DC operating level of the AFE amplifier and the cutoff frequency of the HPF. In some examples, an overload event can occur, and the overload detector can be configured to adjust the impedance of the HO block to reduce the settling time of the MEMS ASIC. Methods of using the MEMS ASIC to reduce the settling time of the MEMS ASIC due to an overload event are disclosed herein.
Claims21
A circuit comprising:
- a microelectromechanical system (MEMS) component;
- an analog front end (AFE) amplifier including an input coupled to the MEMS component and an output;
- an overload detector coupled to the input of the AFE amplifier;
- and
- a set of high-ohmic (HO) blocks comprising a first HO block coupled to the input of the AFE amplifier and the overload detector, wherein a resistance of the first HO block is variable and is capable of being adjusted to a first resistance or a second resistance by the overload detector, and wherein the second resistance is lower than the first resistance;
- and
- logic coupled to the overload detector and configured to:
- determine whether an overload event at the input of the AFE amplifier has occurred;
- and
- in accordance with the determination that the overload event has occurred, cause the overload detector to change the resistance of the first HO block from the first resistance to the second resistance.
A circuit comprising:
- a microelectromechanical system (MEMS) component;
- an analog front end (AFE) amplifier comprising a first input coupled to the MEMS component, a second input, and an output;
- an overload detector coupled to at least one or more of:
- the first and second inputs of the AFE amplifier and the output of the AFE amplifier;
- and
- a set of high-ohmic (HO) blocks comprising:
- a first HO block coupled to the first input of the AFE amplifier and the overload detector;
- a second HO block coupled to the second input of the AFE amplifier and the overload detector, wherein respective resistances of the first and second HO blocks are variable and are capable of being adjusted to a first resistance or a second resistance by the overload detector, and wherein the second resistance is lower than the first resistance;
- and
- logic coupled to the overload detector and configured to:
- determine whether an overload event has occurred at any of the first and second inputs of the AFE amplifier, and the output of the AFE amplifier;
- and
- in accordance with the determination that the overload event has occurred, cause the overload detector to selectively change, based on the determination, the resistance of the first and second HO blocks from the first resistance to the second resistance.
A method of operating a microelectromechanical system (MEMS) circuitry, comprising:
- sensing, using an overload detector, a signal at an input of an analog front end (AFE) amplifier, wherein:
- the input of the AFE amplifier is coupled to a MEMS component, and
- the overload detector is coupled to the input of the AFE amplifier;
- and
- determining, using the overload detector, whether an overload event at the input of the AFE amplifier has occurred;
- and
- in accordance with the determination that the overload event has occurred, causing the overload detector to change a resistance of a first high-ohmic (HO) block of a set of HO blocks from a first resistance to a second resistance, wherein:
- the first HO block is coupled to the overload detector,
- the resistance of the first HO block is variable and is capable of being adjusted to the first resistance or the second resistance by the overload detector, and
- the second resistance is lower than the first resistance.
Dependencies are inferred from the claim text.