System and Method for Controlling Resonance Frequency of Film Bulk Acoustic Resonator Devices

• US 20090039981A1
• Filed: 08/09/2007
• Published: 02/12/2009
• Est. Priority Date: 08/09/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Ravi, Ashoke, Ito, Hiroyuki, Lakdawala, Hasnain, Soumyanath, Krishnamurthy
• Granted Patent: US 7,719,389 B2
• Time in Patent Office: Days
• US Class Current: 333/188
• CPC Class Codes: H03H 19/004 Switched capacitor networks
• CPC Class Codes: H03H 2009/02204 operating on an additional circuit element, e.g. applying a tuning DC voltage to a passive circuit element connected to the resonator
• CPC Class Codes: H03H 9/02007 of bulk acoustic wave devices

Abstract

Disclosed is a system and method for controlling a resonance frequency of a Film Bulk Acoustic Resonator (FBAR) device. The system includes at least one switching capacitor coupled to the FBAR device and a modulator. The at least one switching capacitor includes at least one capacitor and a switch configuration disposed in series with the FBAR device and the at least one capacitor, which is switch configuration capable of opening and closing connection of the at least one capacitor with the FBAR device. The modulator is coupled to the switch configuration, which generates a switching condition signal based on the manufacturing variation in the FBAR device and the environmental effects on the FBAR device. The switch configuration performs opening and closing of the connection of the at least one capacitor and the FBAR device based on the switching condition signal.

Claims

1. A system for controlling a resonance frequency of a Film Bulk Acoustic Resonator (FBAR) device, the system comprising:

at least one switched capacitor coupled to the FBAR device, the switched capacitor capable of connecting with and disconnecting from the FBAR device; and

a modulator operably coupled to the at least one switched capacitor, the modulator configured to generate a switching condition signal based on at least one of manufacturing variations of the FBAR device and environmental effects thereon;

wherein the at least one switched capacitor connects with and disconnects from the FBAR device based on the switching condition signal.

2. The system of claim 1, wherein the at least one switched capacitor comprises

at least one capacitor;

and

a switch configuration for connecting and disconnecting the at least one capacitor with the FBAR device based on the switching condition signal, wherein the switch configuration is disposed in series with the at least one capacitor and the FBAR device.

3. The system of claim 1, wherein the modulator is a sigma-delta modulator.

4. A method for controlling a resonant frequency of a Film Bulk Acoustic Resonator (FBAR) device, the method comprising:

generating a switching condition signal based on at least one of manufacturing variations in the FBAR device and environmental effects thereon; and

modifying a circuit of the FBAR device by one of making and breaking a connection of at least one capacitive load in the circuit of the FBAR device for controlling the resonant frequency of the FBAR device, wherein the making and breaking of the connection is performed based on the switching condition signal.

5. The method of claim 4, wherein the switching condition signal is generated by a sigma-delta modulator.