Qualcomm Incorporated

Hanil Lee

Chulmin Jung

Li-chung Chang

Xiao Chen

Jung Pill Kim

Vijayakumar Dhanasekaran

Venugopal Boynapalli

Ravi Sridhara

Shih-Hsin Jason Hu

Harshat Pant

Maulin Pareshbhai Bhagat

Ramkumar Sivakumar

Dongyang Tang

Pradeep Charles Silva

Xinwang Zhang

Qubo Zhou

Seohee Kim

Christol Barnes

Li-Chung Chang

Maulin P Bhagat

A system includes a comparator having a first input, a second input, and an output. The system also includes a first voltage divider having an input and an output, wherein the input of the first voltage divider is coupled to a first power rail, and the output of the first voltage divider is coupled to the first input of the comparator. The system also includes a second voltage divider having an input and an output, wherein the input of the second voltage divider is coupled to a second power rail, and the output of the second voltage divider is coupled to the second input of the comparator. The system further includes a power multiplexer coupled to the first power rail, the second power rail, and a first circuit, and a control circuit coupled to the output of the comparator and the power multiplexer.

Power multiplexer

An integrated circuit is disclosed that includes a power supply multiplexer for selecting between a first power supply voltage and a second power supply voltage to provide a selected power supply voltage to a memory. A controller includes a comparator stage having a comparator with switchable inputs so that the comparator stage may control a binary state of a first output signal responsive to whether the first power supply voltage is greater than the second power supply voltage plus a voltage offset of the comparator. Similarly, the comparator stage may control a binary state of a second output signal responsive to whether the first power supply voltage is greater than the second power supply voltage minus the voltage offset. The controller controls the selection by the power supply multiplexer responsive to the binary states of the first and second output signals.

Power level comparator with switching input

A power amplifier provides reduction of click and pop in audio applications. The power amplifier includes a first amplifier and an auxiliary amplifier. The auxiliary amplifier is used to ramp the power amplifier output from ground to an offset voltage to reduce the 'click and pop' sound. The first amplifier and the auxiliary amplifier having a shared feedback loop. An output of the first amplifier and an output of the auxiliary amplifier may be switchably coupled to the shared feedback loop. A wave generator controls a switch to couple the first amplifier output or the auxiliary amplifier output to the shared feedback loop.

Audio power amplifier for reduced click and pop (CnP)

Amplifiers with improved linearity and noise performance are described. In an exemplary design, an apparatus includes first through sixth transistors. The first transistor receives an input signal and provides an amplified signal. The second transistor receives the amplified signal and provides signal drive for an output signal. The third transistor receives the input signal and provides an intermediate signal. The fourth transistor provides bias for the third transistor in a high linearity mode. The fifth transistor receives the intermediate signal and provides signal drive for the output signal in a low linearity mode. The third and fourth transistors form a deboost path that is enabled in the high linearity mode to improve linearity. The third and fifth transistors form a cascode path that is enabled in the low linearity mode to improve gain and noise performance. The sixth transistor generates distortion component used to cancel distortion component from the first transistor.

Amplifiers with improved linearity and noise performance

A receiver with a balanced I/Q transformer is described. In an exemplary design, the receiver includes an LNA that amplifies a received RF signal and provides a single-ended RF signal to the balanced I/Q transformer. The balanced I/Q transformer includes at least one primary coil and first and second secondary coils. The first secondary coil is magnetically coupled to the at least one primary coil and provides a first differential RF signal to a first mixer. The second secondary coil is magnetically coupled to the at least one primary coil and provides a second differential RF signal to a second mixer. The first and second mixers downconvert the first and second differential RF signals with I and Q LO signals, respectively, and provide differential I and Q downconverted signals. The primary and secondary coils may be fabricated on two conductive layers of an integrated circuit.

Receiver with balanced I/Q transformer

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San Diego, CA, United States of America

Hanil Lee