Qualcomm Incorporated

Sean Baker

Dinesh Jagannath Alladi

Balasubramanian Sivakumar

Kentaro Yamamoto

Liang Zhao

Wei Huang

Dan Yuan

An apparatus for generating a substantially constant DC reference voltage. The apparatus includes a reference voltage generator configured to generate a substantially constant direct current (DC) reference voltage based on a voltage on a data signal transmission line, wherein the voltage is based on a bandgap reference voltage. In one implementation, the data signal transmission line is a differential signal transmission line and the voltage is a common mode voltage. In another implementation, the data signal transmission line is an I-data signal transmission line and a Q-data signal transmission line, and the voltage is an average or weighted-average of the common mode voltages of the I- and Q-differential signals. In another implementation, the reference voltage is based on a single-ended (e.g., positive- and/or negative)-component or vice-versa of I- and Q-data signals, respectively.

Apparatus and method for generating reference DC voltage from bandgap-based voltage on data signal transmission line

An example apparatus is disclosed for alias rejection through charge sharing. The apparatus includes a filter-sampling network, a digital-to-analog converter, and a charge-sharing switch. The filter-sampling network includes a capacitor and a first switch, which is coupled between an input node and the capacitor. The filter-sampling network is configured to connect or disconnect the capacitor to or from the input node via the first switch. The digital-to-analog converter includes a capacitor array and a second switch, which is coupled between the input node and the capacitor array. The capacitor array is coupled between the second switch and a charge-sharing node. The digital-to-analog converter is configured to connect or disconnect the capacitor array to or from the input node via the second switch. The charge-sharing switch is coupled between the charge-sharing node and the capacitor and is configured to connect or disconnect the capacitor to or from the digital-to-analog converter.

Alias rejection through charge sharing

In one embodiment, a circuit includes a first input of a comparator for an analog to digital converter (ADC). The first input is coupled to a first capacitive network. The circuit further includes a second input of the comparator for the ADC. The second input is coupled to a second capacitive network. The first capacitive network includes a first set of capacitors where a first plate of the first set of capacitors is selectively coupled to an input signal. The second capacitive network includes a second set of capacitors where a second plate of the first set of capacitors is selectively coupled to the input signal. The first plate and the second plate are opposite plates of the first set of capacitors and the second set of capacitors.

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San Diego, CA, United States of America

Sean Baker