Abstract:
A low-power receiver architecture of use in direct sequence spread spectrum communications system receivers, such as in a code division multiple access system, is provided. The receiver employs analog correlation, wherein its analog-digital, converters are able to operate at the system symbol rate, and the requirement for finite impulse response filters is obviated. The low-power receiver architecture is also applicable as a front-end structure for multiple-mode receivers.
Abstract:
A method of transferring sets of video line data and macroblock data, comprising the steps of determining a macroblock period and a video line period longer than the macroblock period, dividing each set of video line data to be transferred within the video line period into two or more portions according to the difference between the determined macroblock period and video line period, aligning a burst transfer of each of the portions of the divided set of video line data and each set of macroblock data to the macroblock period, and initiating the burst transfer of the sets of video line data and macroblock data at macroblock period intervals.
Abstract:
In accordance with an embodiment, a method of operating a piezoelectric transducer configured to transduce mechanical vibrations into transduced electrical signals at a pair of sensor electrodes includes stimulating a resonant oscillation of the piezoelectric transducer by applying at least one pulse electrical stimulation signal to the pair of sensor electrodes; detecting, at the pair of sensor electrodes, at least one electrical signal resulting from the stimulated resonant oscillation, wherein the at least one electrical signal resulting from the stimulated resonant oscillation oscillates at a resonance frequency of the piezoelectric transducer; measuring a frequency of oscillation of the at least one electrical signal resulting from the stimulated resonant oscillation to obtain a measured resonance frequency of the piezoelectric transducer; and tuning a stopband frequency of a notch filter coupled to the piezoelectric transducer to match the measured resonance frequency of the piezoelectric transducer.
Abstract:
A wireless power receiver includes a rectifier with first and second inputs coupled to first and second terminals of a receiver coil, and having a first output coupled to ground and a second output at which a rectified voltage is produced. A first switch is coupled between the second input and ground, and is controlled by a first gate voltage generated at a first node. A second switch is coupled between the first node and ground, and is controlled by a second gate voltage. The first gate voltage closes the first switch to couple the second input to ground when the rectified voltage is less than a threshold voltage, boosting the rectified voltage. The second gate voltage closes the second switch to cause the second gate voltage to be pulled to ground when the rectified voltage is greater than the threshold voltage, limiting the boosting of the rectified voltage.
Abstract:
An over-voltage protection circuit and methods of operation are provided. In one embodiment, a method includes monitoring a voltage at an output of a rectifier, a voltage at an output of a voltage regulator, or a combination thereof. The method further includes determining the over-voltage condition based on the monitoring; and in response to determining the over-voltage condition, regulating the voltage at the output of the rectifier in accordance with a voltage difference between the voltage at the output of the rectifier and the voltage at the output of the voltage regulator.
Abstract:
A bridge rectifier and associated control circuitry collectively form a “regtifier” which rectifies an input time varying voltage and regulates the rectified output voltage produced without the use of a traditional voltage regulator. To accomplish this, the gate voltages of transistors of the bridge rectifier that are on during a given phase may be modulated via analog control (to increase the on-resistance of those transistors) or via pulse width modulation (to turn off those transistors prior to the end of the phase). The transistors of the bridge rectifier that would otherwise be off during a given phase may be turned on to help dissipate excess power and thereby regulate the output voltage. This modulation is based upon both a voltage feedback signal and a current feedback signal.
Abstract:
A wireless power-reception system has a bridge rectifier with two high-side and two low-side transistors, linked to input-nodes and sense-resistors. During a first phase, a control circuit activates certain transistors for rectification, producing an output voltage, while modulating a gate voltage of a non-activated low-side transistor to dissipate excess power and regulate the output voltage. During a first given number of occurrences of the first phase, the control circuit determines the current through the low-side transistor having its gate voltage modulated based upon a voltage across a first sense resistor coupled between that low-side transistor and ground. During a second given number of occurrences of the first phase, the control circuit determines the current delivered to the load based upon a voltage across the first sense resistor and a voltage across a second sense resistor coupled between the other low-side transistor and ground.
Abstract:
A method for operating a wireless power transmitter includes: receiving a power control command from a wireless power receiver; computing a potential voltage change for a transmitter voltage of the wireless power transmitter in accordance with a target transmitter power and a present value of a transmitter current of the wireless power transmitter; comparing the potential voltage change with a discrete step size of a supply voltage; and in response to determining that the magnitude of the potential voltage change is equal to or larger than the discrete step size of the supply voltage, adjusting the transmitter power by: adjusting the supply voltage by one or more discrete steps; and controlling a power conversion circuit of the wireless power transmitter using a target current value computed in accordance with the target transmitter power and the adjusted supply voltage.
Abstract:
A method for operating an electronic device includes a touchscreen controller determining based on a frequency of a vertical synchronization signal (Vsync), whether a first display frame includes an idle time, the idle time being a duration of time remaining in the first display frame after an image displayed on a display of the electronic device is updated during the first display frame. The method further includes in response to determining that the first display frame includes the idle time, the touchscreen controller transmitting an uplink signal in the first display frame, the uplink signal being transmitted during the idle time of the first display frame.
Abstract:
A device includes an analog to digital converter configured to convert voltages into a digital signal by sampling the voltages at a fixed sampling time; a first multiplier configured to multiply the digital signal with in-phase coefficients, the in-phase coefficients generated to produce a demodulated in-phase signal at a demodulation signal frequency; a first adder configured accumulate the demodulated in-phase signal to output in-phase magnitude values; a second multiplier configured to multiply the digital signal with quadrature coefficients, the quadrature coefficients generated to produce a demodulated quadrature signal at the demodulation signal frequency; and a second adder configured to accumulate the demodulated quadrature signal to output quadrature magnitude values.