Qualcomm Incorporated

ChienChung Yang

Sherif Galal

Dongyang Tang

Xinwang Zhang

Vijayakumar Dhanasekaran

Subbarao Surendra Chakkirala

Khaled Mahmoud Abdelfattah Aly

Earl Schreyer

Yuhua Guo

Pradeep Charles Silva

Chieh-Yu Hsieh

Xiaopeng Zhong

A wireless device may include a plug that is shared by high speed data, analog audio signals, and power. Switches may be included on wires between the plug and the circuits that provide the high-speed data, analog audio signals and power to isolate those circuits from overvoltage conditions. Linearizer circuits may be included to provide gate driving signals to the switches, e.g., during transmission of analog audio signals. The linearizer circuits may include digital-to-analog converters to apply a gain factor to analog audio signals.

Linearizer circuits and methods for audio switches

A sigma-delta analog-to-digital converter is provided that includes an initial continuous-time integration stage having a variable input resistor and an integration capacitor. A switched-capacitor circuit charges and discharges a replica capacitor to a reference voltage to generate a bias current. A SAR-based tuning circuit includes a variable tuning resistor that generates a tuning voltage while conducting a mirrored version of the bias current. A resistance of the variable input resistor is adjusted responsive to a tuning code from the SAR-based tuning circuit.

Analog-to-digital converter having time-constant tuning with pulse-width-based reference current and resistance searching

Aspects of the present disclosure relate to apparatus and methods for dynamically adjusting the common-mode input signal of a power amplifier, such as a class-D power amplifier. One example power amplifier circuit generally includes a first amplifier having a signal input and a power input; and a common-mode adjustment circuit having a first input coupled to the power input of the first amplifier, having an output coupled to the signal input of the first amplifier, and being configured to generate a common-mode signal to apply to the signal input of the first amplifier, based on a power supply voltage on the power input of the first amplifier.

Dynamic common-mode adjustment for power amplifiers

A class-D amplifier including a pulse width modulator including an input configured to receive a first signal based on an input signal, and an output configured to generate a pulse width modulated (PWM) signal; an H-bridge including an input coupled to an output of the pulse width modulator and an output coupled to a load, wherein the H-bridge is configured to generate an output signal across the load based on the PWM signal; and a deadtime compensation circuit coupled to the H-bridge, wherein the deadtime compensation circuit is configured to compensate for deadtime distortion in the output signal. The deadtime compensation circuit may be a feedback circuit between an output of the H-bridge and an input of the pulse width modulator, a pulse modification circuit at the output of the pulse width modulator, or an offset signal generating circuit providing an offset signal to the pulse width modulator.

Class-D amplifier with deadtime distortion compensation

Growing community of inventors

San Diego, CA, United States of America

ChienChung Yang