Marvell International Limited

Qualcomm Incorporated

Marvellworld Trade Ltd.

Marvell Asia Pte., Ltd.

Kan Li

Hua Guan

Ngai Yeung Ho

Chi Fan Yung

Sehat Sutardja

Todd Robert Sutton

Poh Boon Leong

Kee Hian Tan

Jize Jiang

Guolei Yu

Xiaodan Zou

An apparatus is disclosed for adaptive switch driving. In an example aspect, the apparatus includes a switching circuit configured to selectively be in a first state that provides an input voltage as an output voltage, be in a second state that provides a ground voltage as the output voltage, or be in a third state that causes the output voltage to change from the input voltage to the ground voltage according to a slew rate. The third state enables the switching circuit to transition from the first state to the second state. The switching circuit is also configured to adjust the slew rate of the output voltage for the third state responsive to at least one of the following: a change in a magnitude of a direct-current supply voltage or a change in a magnitude of an input current.

Adaptive switch driving

According to certain aspects, a driver includes an output transistor coupled between a first rail and an output of the driver, a first current source coupled to a gate of the output transistor, a second current source, and a switch, wherein the switch and the second current source are coupled in series between the gate of the output transistor and a second rail. The driver also includes a current sensor configured to generate a sense current based on an output current of the driver, and a reference current source configured to generate a reference current, wherein the current sensor and the reference current source are coupled to a control input of the switch.

Area efficient slew-rate controlled driver

Certain aspects of the present disclosure generally relate a regulator. For example, the regulator may include a control stage, a sense capacitor having first and second terminals, the first terminal coupled to an output of the voltage regulator, and a current amplifier having an input coupled to the second terminal of the sense capacitor and an output coupled to the control stage. The control stage of the regulator may adjust the output voltage of the regulator based at least in part on a current generated by the current amplifier.

Methods and apparatus for voltage regulation using output sense current

An integrated circuit is disclosed for current-controlled voltage regulation. In an example aspect, the integrated circuit includes a voltage regulator and a current-controlled clamp. The voltage regulator has a regulator output node and produces a regulator current. The voltage regulator includes an error amplifier and an output transistor. The error amplifier has first and second input nodes and an error amplifier output node, with the first input node coupled to a reference voltage. The error amplifier generates an error amplifier output voltage at the output node. The output transistor is coupled between the error amplifier output node and the regulator output node. The output transistor is coupled to the second input node via the regulator output node to establish a feedback path for the voltage regulator. The current-controlled clamp is coupled to the error amplifier output node and clamps the error amplifier output voltage based on the regulator current.

Current-controlled voltage regulation

Certain aspects of the present disclosure generally relate a dual feedback loop regulator. For example, the regulator may include a first amplifier having an output coupled to an output node of the regulator, the output node further coupled to a first feedback path and a second feedback path of the regulator. A first input of a second amplifier may be coupled to the first feedback path and a second input of the second amplifier may be coupled to a reference path. The regulator may also include a transconductance stage having a first transistor and a first current source, the first transistor and the current source coupled to the first feedback path and the second feedback path, and a transimpedance stage coupled to the transconductance stage and an input of the first amplifier.

Fast transient response low-dropout (LDO) regulator

An amplifier circuit amplifies a signal for wireless transmission. A feedback circuit, including a capacitor, is coupled to the amplifier circuit. Components of the feedback circuit are selected based on a feedback factor such that an input impedance to the amplifier circuit has a same impedance characteristic as a feedback circuit impedance of the feedback circuit.

Power amplifier with feedback impedance for stable output

In one embodiment, an apparatus includes an amplifier circuit having a phase shift. The amplifier circuit amplifies a signal for wireless transmission. A feedback circuit is coupled to the amplifier circuit and includes a capacitor. An input impedance to the amplifier circuit has a same impedance characteristic as a feedback circuit impedance of the feedback circuit. A total phase shift of the signal for the amplifier circuit and the feedback circuit is less than a threshold.

A biasing device can supply a bias voltage to bias-able element by coupling a bias circuit to the bias-able element, coupling a state adjusting device to the biasing circuit, configuring the state adjusting device to 1) increase an initial biasing voltage by a first amount when an intermediate voltage threshold exceeds a voltage drop across the bias-able element and 2) increment the increased initial bias voltage by a second amount, where the second amount is a fraction of the first amount, until the voltage drop across the bias-able element substantially equals a predetermined bias voltage. The bias circuit of the biasing device can include a variable resistance, which is controlled by the state adjusting device and configured to vary the biasing voltage, in series with the bias-able element. The variable resistance can include a first variable resistance coupled in series to a first terminal of the bias-able element and a second variable resistance coupled in series to a second terminal of the bias-able element.

Bias setting device

A compensation device that can include a bias-able device, a bias circuit that provides the bias-able device with a bias current, a signal conditioner selectively coupled to the bias-able device, and an emulator. The signal conditioner and emulator can divert current from the bias-able device in an operational and calibration mode, respectively. In calibration mode, the emulator generates a compensation current that is combined with a sense current so that the sense current equals the bias current.

Bias current compensation device and method

A biasing device for a magneto-resistive element, including a first bias supply circuit coupled to the magneto-resistive element; and a first bias control circuit coupled to the first bias supply circuit, the first bias control circuit capable of controlling the first bias supply circuit to provide a first calibration mode bias signal during a calibration mode and a first operating mode bias signal during an operating mode, the first operating mode bias signal having a lower noise level than the first calibration mode bias signal.

Magneto-resistive biasing methods and systems

An RMR is biased with constant power. Voltages are applied across at least two variable resistors, which are coupled on opposing ends of the RMR, to establish a current to the RMR, wherein the current is based on the voltages and on resistance values of the at least two variable resistors. A voltage corresponding to the established current of the RMR is amplified. The amplified voltage is compared to a reference voltage, wherein the reference voltage is based on a target power for the RMR. The resistance values of the at least two variable resistors are modified so that the amplified voltage approaches the reference voltage. Modifying the resistance values of the at least two variable resistors in this manner is seen to bias the RMR with constant power, since the reference voltage is based on a target power for the RMR.

Biasing RMR with constant power

A system for calibrating a magneto-resistive (MR) head includes a biasing circuit and a calibration module. The biasing circuit generates a first current to bias a first head during a calibration mode and a calibrated current to bias the MR head during an operating mode. The calibration module calibrates the first current during the calibration mode by adjusting the first current using nonlinear steps to determine the calibrated current.

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Singapore, Singapore

Kan Li