Nuvoton Technology Corporation

Rfstream Corporation

Lance Wong

Vincent Mui

Aditya Raina

A feedback amplifier includes an operational amplifier having an input end and an output end. A first resistor is coupled with the input end of the operational amplifier. A second resistor has a first end coupled with the input end of the operational amplifier and a second end coupled with the output end of the amplifier. A voltage divider has a first end being operably coupled with the output end of the operational amplifier and a second end being analog grounded. In an embodiment, the feedback amplifier further includes a first switch coupled to the first end of the voltage divider and the output end of the operational amplifier, and a second switch coupled to an internal node of the voltage divider. In an embodiment, the feedback amplifier is configured to provide attenuation when the first switch is open and second switch is closed.

Feedback amplifier and audio system thererof

An amplifier circuit includes a first circuit and a second circuit connected in series. The first circuit has a first terminal coupled to a first power supply terminal, a second terminal coupled to an output node, and a control terminal for receiving a first signal for controlling a current flow. The second circuit has a first terminal coupled to the output node, a second terminal couple to a second power supply terminal, and a control terminal for receiving a second signal controlling a current flow in the first circuit. A bias circuit is coupled to the third terminal of the first circuit and is configured to limit a current flow in the first circuit when a voltage at the output node is outside a predetermined voltage range. In an embodiment, the bias circuit includes a plurality of diode devices connected in series and a switch device coupled to the diode devices.

Method and apparatus for output amplifier protection

A method for tuning a filter to a desired frequency using successive approximation. Elements of the filter are selected according to a control code used to vary the filter's oscillation frequency. The control code is set to the middle of the control code range and resulting oscillation frequency is compared to the desired frequency. If the control code needs to be increased, the control code is set to &#xbe; of the control code range. If the control code needs to be decreased, the control code is set to &#xbc; of the control code range. The method continues using successive approximation to determine the value of each bit of the control code. Thus, successive approximation is used to converge on the value of the control code that produces an oscillation frequency of the filter that is closest to the desired frequency (with a maximum error of 1 least significant bit).

Growing community of inventors

San Francisco, CA, United States of America

Lance Wong