The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 17, 2018
Filed:
Dec. 18, 2014
Cirrus Logic International (Uk) Limited, Edinburgh, GB;
Santosh Astgimath, Edinburgh, GB;
Jean Pierre Lasseuguette, Edinburgh, GB;
John Laurence Pennock, Juniper Green, GB;
Cirrus Logic, Inc., Austin, TX (US);
Abstract
Circuitry for biasing a MEMS transducer and associated signal processing circuitry. A reference voltage generator is configured to generate a reference voltage at a reference voltage node. Control circuitry generates a drive signal to control a first current source which is operable to supply a current to the reference voltage generator in response to the drive signal. A switched DC-DC converter, such as a charge pump has a voltage input connected to the reference voltage node and a voltage output for providing a bias voltage for the MEMS transducer. The DC-DC converter cyclically switches in a sequence of states including at least a first state where a first converter capacitance is disconnected from the voltage input followed by a second state where the first converter capacitance is connected to the voltage input. A second current source is operable to supply a bias current in response to a voltage at a bias control node. Switch control circuitry is configured to cyclically open and close a switch connected between the drive node and the bias control node, such that the switch is open during a time window that includes the time at which the switched DC-DC converter switches from the first state to the second state.