TRANSIMPEDANCE AMPLIFIERS FOR ULTRASONIC SENSING APPLICATIONS
First Claim
1. A transimpedance amplifier (TIA) of an ultrasonic front-end receiver, the TIA configured to convert an input current applied to an input port of the TIA to an output voltage, the input current indicative of a current generated by a piezoelectric transducer (PZT), the TIA comprising:
- a first transistor configured to receive the input current at a source terminal of the first transistor;
a second transistor having a drain terminal coupled to a gate terminal of the first transistor;
a third transistor having a drain terminal coupled to a gate terminal of the second transistor; and
a fourth transistor having a drain terminal coupled to a gate terminal of the third transistor.
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Accused Products
Abstract
Various transimpedance amplifier (TIA) arrangements for ultrasonic front-end receivers used in ultrasonic sensing applications are disclosed. An example TIA includes three common-source gain stages in a feedback loop with a common-gate stage. In some aspects, the TIA may include a level shifter configured to maintain the voltage at the gate of a transistor used to implement the first common-source gain stage of the feedback loop shifted by a certain amount with respect to the voltage at an input port to the TIA. In some aspects, at least portions of the TIA may be biased using bias currents that are configured to be process-, supply voltage-, and/or temperature-dependent. Various embodiments of the TIAs disclosed herein may benefit from one or more of the following advantages: reduced noise, reduced input impedance, reduced temperature coefficient of input impedance, and stability for a wide range of sensor frequencies.
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Citations
20 Claims
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1. A transimpedance amplifier (TIA) of an ultrasonic front-end receiver, the TIA configured to convert an input current applied to an input port of the TIA to an output voltage, the input current indicative of a current generated by a piezoelectric transducer (PZT), the TIA comprising:
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a first transistor configured to receive the input current at a source terminal of the first transistor; a second transistor having a drain terminal coupled to a gate terminal of the first transistor; a third transistor having a drain terminal coupled to a gate terminal of the second transistor; and a fourth transistor having a drain terminal coupled to a gate terminal of the third transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. An ultrasonic sensor system, comprising:
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an ultrasonic receiver, configured to; receive (RX) an RX ultrasonic signal, the RX ultrasonic signal comprising at least a portion of a transmitted (TX) ultrasonic signal that has interacted with an object, where the TX ultrasonic signal is an ultrasonic signal transmitted by an ultrasonic transmitter configured to transmit the TX ultrasonic signal so that the TX ultrasonic signal interacts with the object, and generate a first electrical signal that is indicative of the RX ultrasonic signal; and a transimpedance amplifier (TIA) comprising a plurality of common-source amplifiers in feedback with a common-gate amplifier, configured to convert the first electrical signal generated by the ultrasonic receiver to a second electrical signal. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification