Cirrus Logic Inc.

At&t Intellectual Property I, L.p.

Nishant Jain

Vamsikrishna Parupalli

Tejasvi Das

Xiaofan Fei

Xin Zhao

Lei Zhu

Eric B Smith

Ku He

Adam Klein

Mengde Wang

Stewart G Kenly

James Bert Grantges

Hunter Sinclair

John Crane

Yoklim Law

Nicholas Macron

David Richard

Techniques for reducing electromagnetic interference (EMI) in a switching amplifier circuit, control edge-rate with reduced sensitivity to process and temperature variations and that is reduced with increasing power supply voltage. The techniques control current levels in a pre-driver stage that drives an output driver of a switching amplifier circuit, according to a bias control. A first slope of a variation of the bias control with respect to a power supply voltage of the switching amplifier circuit over a first portion of a range of variation of the power supply voltage has a direction opposite a second slope of the variation of the reference output current with respect to the power supply voltage over a second portion of the range of variation of the power supply voltage. The resulting operation reduces electromagnetic interference generated by the driver over the second portion of the range of variation of the power supply voltage.

Parametric-insensitive edge rate control in switched-power circuits with tailored power supply voltage sensitivity

An electronic control system provides selectable linear and pulse-width modulated (PWM) operation with reduced disruption when changing from PWM operation to linear operation. The system includes an output stage that has a push-pull driver coupled to the load, which may be a motor, a haptic device, or other device requiring current-mode control. The system also includes a pulse-width modulated (PWM) driver for providing pulse-width modulated drive signals to gates of the transistors of the output stage when a pulse-width modulated mode is selected, and a linear amplifier stage that provides a linear analog signal to the gates of the transistors when a linear mode is selected. A pre-charging circuit pre-charges the gates during a pre-charge cycle that is initiated when the operating mode changes from the PWM operating more to the linear operating mode.

Pre-biased mode switching in system having selectable pulse-width modulated (PWM) and linear operation

An electronic control system provides selectable path operation, such as linear and pulse-width modulated (PWM) operation and provides path transition management to improve operation. The system supplies a current or a voltage to a load in response to an input signal or value and includes an output driver, and multiple selectable control paths. The system includes a control circuit that selects between the first control path and the second control path in response to a path selection indication to drive the output driver. The system may include an evaluator that determines the path selection indication in conformity with an amplitude and a slew rate of the input. One or all of the control paths may have a response time to changes in the input signal or value, and the control circuit may delay switching from the second control path to the first control path to compensate for the response time.

Management of path selection in a multi-path control system

A system may include a plurality of playback paths comprising an open-loop playback path configured to drive an output load and a closed-loop playback path. The closed-loop playback path may include an outer feedback loop comprising one or more integrators, a quantizer, and an output driver for driving the output load, the outer feedback loop having an outer loop feedback gain and an inner feedback loop comprising the one or more integrators and the quantizer and excluding the output driver, wherein the inner feedback loop has a variable inner loop feedback gain which is adjustable to match the outer loop feedback gain.

Cross-fading in dual-path pulse width modulation system

The disclosure is directed to a connection manager that includes a dialer configured to interact with a modem to provide a connection to a service provider. The connection manager includes a graphical user interface and an advice window. The graphical user interface is configured to manipulate parameters associated with the connection. The graphical user interface includes a form component. The advice window is responsive to user actions associated with the form component.

Connection manager and methods of connection management

Growing community of inventors

Austin, TX, United States of America

Nishant Jain