Abstract: Circuits and methods for controlling electrical coupling by a load switch are disclosed. In an embodiment, the load switch includes a pass element, level-shift circuit and low-resistance active path. The pass element is configured to be coupled to a power supply and a load, and is configured to electrically couple the power supply with the load during ON-state and electrically decouple the power supply from the load during OFF-state. The level-shift circuit includes a first transistor and pull-up resistor and is configured to generate a level-shifted signal in response to an enable signal, and enable the ON-state and the OFF-state of the pass element based on first and second voltages of the level-shifted signal. The low-resistance active path is coupled in parallel with the pull-up resistor for shunting the pull-up resistor in the OFF-state by providing a path for a leakage current of the first transistor in the OFF-state.

Abstract: Circuits and methods for controlling electrical coupling by a load switch are disclosed. In an embodiment, the load switch includes a pass element, level-shift circuit and low-resistance active path. The pass element is configured to be coupled to a power supply and a load, and is configured to electrically couple the power supply with the load during ON-state and electrically decouple the power supply from the load during OFF-state. The level-shift circuit includes a first transistor and pull-up resistor and is configured to generate a level-shifted signal in response to an enable signal, and enable the ON-state and the OFF-state of the pass element based on first and second voltages of the level-shifted signal. The low-resistance active path is coupled in parallel with the pull-up resistor for shunting the pull-up resistor in the OFF-state by providing a path for a leakage current of the first transistor in the OFF-state.

Abstract: A USB host for wakeup from a sleep state includes a hold memory, a USB host controller, and a USB driver. When going to sleep, the USB driver sends a suspend command to the USB host controller in response to receiving a sleep command. The USB driver also reads a controller context from the USB host controller and saves the controller context in the hold memory. Thereafter, the USB driver turns off one or more supply potentials and one or more clocks in the host controller, and returns a sleep acknowledgement. While in sleep, the interface pins are placed in a hold state and notification to the operating system are disabled.

Abstract: A USB host for wakeup from a sleep state includes a hold memory, a USB host controller, and a USB driver. When going to sleep, the USB driver sends a suspend command to the USB host controller in response to receiving a sleep command. The USB driver also reads a controller context from the USB host controller and saves the controller context in the hold memory. Thereafter, the USB driver turns off one or more supply potentials and one or more clocks in the host controller, and returns a sleep acknowledgement. While in sleep, the interface pins are placed in a hold state and notification to the operating system are disabled.

Abstract: Methods and apparatus for proximity detection of hard disk drive read heads are disclosed. A disclosed method comprises forming a first signal having a frequency, a first amplitude, and a first offset voltage, forming a second offset voltage substantially equal to the first offset voltage from the first signal, amplifying the amplitude of the first signal to cause the resonant signal to have a second amplitude greater than the first, and forming a second signal having a frequency indicative of the location of a read head relative to a platter of a hard disk drive.

Abstract: Methods and apparatus for proximity detection of hard disk drive read heads are disclosed. A disclosed method comprises forming a first signal having a frequency, a first amplitude, and a first offset voltage, forming a second offset voltage substantially equal to the first offset voltage from the first signal, amplifying the amplitude of the first signal to cause the resonant signal to have a second amplitude greater than the first, and forming a second signal having a frequency indicative of the location of a read head relative to a platter of a hard disk drive.

Abstract: Methods and apparatus to detect an over-current in switching circuits are described. An example method to detect an over-current in a switching circuit includes randomly selecting a sensor from a plurality of sensors operatively coupled to an output stage of the switching circuit; detecting a first voltage via the randomly selected sensor; and comparing the first voltage to a reference voltage to generate a signal, wherein the signal indicates a status of the output stage of the switching circuit.

Abstract: Circuits and apparatus to reduce transient output noise in an audio amplifier are disclosed. A disclosed example apparatus comprises an amplifier, and an amplifier controller to digitally change a common-mode voltage of the amplifier to reduce an output noise of the amplifier.