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US 9,644,961 B2Granted
Drive circuit for a MEMS resonator
AssigneeMurata Manufacturing Co., Ltd.
InventorLasse Aaltonen
Life of this patent
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Abstract
A drive loop circuit for a MEMS resonator. The circuit comprises a closed loop circuit to detect and amplify a signal of the MEMS resonator, a phase shifting circuit to phase shift the detected and amplified signal, and a feedback circuit to feed the detected, amplified and phase shifted signal as a feedback signal back to the MEMS resonator. The phase shifting circuit can include a low pass filter of at least 2nd order.
Claims19
A drive circuit for a MEMS resonator, said drive circuit comprising;
- a drive loop circuit configured to detect and amplify a signal;
- a phase shifting circuit configured to phase shift the detected and amplified signal;
- and
- a feedback circuit configured to feed the detected, amplified and phase shifted signal as a feedback signal back to the MEMS resonator,
- wherein the phase shifting circuit is a low pass filter of at least 2nd order having a continuous time low pass filter architecture, and
- wherein a 90 degree phase shift target frequency of the low pass filter is equal to the mechanical resonance frequency of the MEMS resonator.
3 more elements
A method for driving a MEMS resonator, the method comprising:
- detecting and amplifying a signal of the MEMS resonator;
- phase shifting the detected and amplified signal;
- and
- feeding the detected, amplified and phase shifted signal as a feedback signal back to the MEMS resonator,
- wherein the phase shifting the detected and amplified signal is effected with a low pass filter of at least 2nd order having a continuous time low pass filter architecture, and
- wherein a 90 degree phase shift frequency of the low pass filter is set equal to the mechanical resonance frequency of the MEMS resonator.
3 more elements
Dependencies are inferred from the claim text.