TRANSCEIVER CIRCUIT FOR FILM BULK ACOUSTIC RESONATOR (FBAR) TRANSDUCERS

• US 20090273256A1
• Filed: 04/30/2008
• Published: 11/05/2009
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies Wireless IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Martin, Steven, Buccafusca, Osvaldo
• Granted Patent: US 7,732,977 B2
• Time in Patent Office: Days
• US Class Current: 310/318
• CPC Class Codes: H03H 9/545 including active elements

Abstract

A piezoelectric transducer device includes a receive signal path, a transistor and a piezoelectric transducer connected to a first terminal of the transistor. The device also includes a switch connected to a second terminal of the transistor, wherein the switch is adapted to selectively connect the second terminal of the transistor to a transmit signal or to a bias voltage; an output connected to a third terminal of the transistor, and adapted to receive a signal from the transducer when the switch is connected to the bias voltage, wherein the switch is not in the receive signal.

Claims

1. A piezoelectric transducer device, comprising:

a receive signal path;

a transistor;

a piezoelectric transducer connected to a first terminal of the transistor;

a switch connected to a second terminal of the transistor, wherein the switch is adapted to selectively connect the second terminal of the transistor to a transmit signal or to a bias voltage; and

an output connected to a third terminal of the transistor, and adapted to receive a signal from the transducer when the switch is connected to the bias voltage, wherein the switch is not in the receive signal.

2. A transducer device as claimed in claim 1, wherein the transistor is a field effect transistor (FET), the first terminal is a source, the second terminal is a gate and the third terminal is a drain.

3. A transducer device as claimed in claim 2, wherein the transistor is a metal oxide semiconductor field effect transistor (MOSFET).

4. A transducer device as claimed in claim 1, wherein the transistor is a bipolar transistor.

5. A transducer device as claimed in claim 1, wherein the switch is one of:

an optocoupler;

a field effect transistor;

or an electromechanical switch.

6. A transducer device as claimed in claim 1, wherein the piezoelectric transducer is a film bulk acoustic resonator (FBAR) transducer.

7. A sensor, comprising:

piezoelectric transducer device, comprising;

a transistor;

a piezoelectric transducer connected to a first terminal of the transistor;

a switch connected to a second terminal of the transistor, wherein the switch is adapted to selectively connect the second terminal of the transistor to a transmit signal or to a bias voltage; and

an output connected to a third terminal of the transistor, and adapted to receive a signal from the transducer when the switch is connected to the bias voltage.

8. A sensor as claimed in claim 7, wherein the transistor is a field effect transistor (FET), the first terminal is a source, the second terminal is a gate and the third terminal is a drain.

9. A sensor as claimed in claim 8, wherein the transistor is a metal oxide semiconductor field effect transistor (MOSFET).

10. A sensor as claimed in claim 7, wherein the transistor is a bipolar transistor.

11. A sensor as claimed in claim 7, wherein the switch is one of:

an optocoupler;

a field effect transistor;

or an electromechanical switch.