Abstract: Aspects of the subject technology relate to control circuitry for light-emitting diodes. The control circuitry may include a feedforward loop and a feedback loop for a power supply for the light-emitting diodes. The light-emitting diodes may be arranged in strings that are individually controllable by a current control transistor on the string. The feedforward loop may determine a total upcoming load current for the power supply based on reference voltages for controlling each of the current control transistors. The output of the power supply may be modified based on a combination of a current from the feedforward loop and a current from the feedback loop.

Abstract: Aspects of the subject technology relate to control circuitry for light-emitting diodes. The control circuitry may operate a light-emitting diode using a multi-peak pulse-width-modulation signal. The control circuitry may include a multi-stage driver having a relatively larger driver stage for providing a direct current through a light-emitting diode and a relatively smaller driver stage configured to cooperate with a pulse-width-modulation controller to pulse-width-modulate a current through the light-emitting diode.

Abstract: Embodiments of end-to-end deep learning systems and methods are disclosed to recognize speech of vastly different languages, such as English or Mandarin Chinese. In embodiments, the entire pipelines of hand-engineered components are replaced with neural networks, and the end-to-end learning allows handling a diverse variety of speech including noisy environments, accents, and different languages. Using a trained embodiment and an embodiment of a batch dispatch technique with GPUs in a data center, an end-to-end deep learning system can be inexpensively deployed in an online setting, delivering low latency when serving users at scale.

Abstract: Embodiments of end-to-end deep learning systems and methods are disclosed to recognize speech of vastly different languages, such as English or Mandarin Chinese. In embodiments, the entire pipelines of hand-engineered components are replaced with neural networks, and the end-to-end learning allows handling a diverse variety of speech including noisy environments, accents, and different languages. Using a trained embodiment and an embodiment of a batch dispatch technique with GPUs in a data center, an end-to-end deep learning system can be inexpensively deployed in an online setting, delivering low latency when serving users at scale.

Abstract: Aspects of the subject technology relate to display of an electronic device. The display includes a backlight unit having a voltage source, a string of light-emitting diodes and a bypass switch for each light-emitting diode in the string. The string of light-emitting diodes can receive, at a first end, a supply voltage from the voltage source. The bypass switch for each light-emitting diode is controllable to pulse-width-modulate that light-emitting diode. The headroom voltage feedback circuit is coupled to a second end of the string.

Abstract: Aspects of the subject technology relate to control circuitry for operating light-emitting diodes (LEDs). The control circuitry may include a pulse-width-modulation (PWM) driver for the LEDs and headroom voltage control circuitry. The PWM driver may adjust a rising edge or a trailing edge of the PWM cycles for various LEDs to ensure a headroom voltage detection window for the headroom voltage control circuitry to sample the headroom voltage of those LEDs without being affected by the rising edge of the PWM cycle for LED or the falling edge of the PWM cycle for another LED.

Abstract: Aspects of the subject technology relate to control circuitry for light-emitting diodes. The control circuitry may operate a light-emitting diode using a multi-peak pulse-width-modulation signal. The control circuitry may include a multi-stage driver having a relatively larger driver stage for providing a direct current through a light-emitting diode and a relatively smaller driver stage configured to cooperate with a pulse-width-modulation controller to pulse-width-modulate a current through the light-emitting diode.

Abstract: A multi-ringed differential microphone array includes a first number of microphones situated along a first substantial circle having a first radius, a second number of microphones situated along a second substantial circle having a second radius, and a processing device, communicatively coupled to the first number microphones and the second number of microphones, to receive a plurality of electronic signals generated by the first number of microphones and the second number of microphones, determine a differential order (N) based on the second number, and execute an N-th order minimum-norm beamformer to calculate an estimate of the sound source based on the plurality of electronic signals.

Abstract: Aspects of the subject technology relate to control circuitry for light-emitting diodes. The control circuitry may operate a light-emitting diode using a multi-peak pulse-width-modulation signal. The control circuitry may include a multi-stage driver having a relatively larger driver stage for providing a direct current through a light-emitting diode and a relatively smaller driver stage configured to cooperate with a pulse-width-modulation controller to pulse-width-modulate a current through the light-emitting diode.

Abstract: Aspects of the subject technology relate to control circuitry for light-emitting diodes. The control circuitry may include a feedforward loop and a feedback loop for a power supply for the light-emitting diodes. The light-emitting diodes may be arranged in strings that are individually controllable by a current control transistor on the string. The feedforward loop may determine a total upcoming load current for the power supply based on reference voltages for controlling each of the current control transistors. The output of the power supply may be modified based on a combination of a current from the feedforward loop and a current from the feedback loop.

Abstract: Aspects of the subject technology relate to control circuitry for light-emitting diodes. The control circuitry includes a two-dimensional light-emitting diode (LED) array. The control circuitry may include a single LED array operable by a common driver or multiple LED arrays each operable by a dedicated LED matrix driver. Each matrix driver may receive a synchronization signal from a common controller and may include a programmable phase lock loop (PLL) to synchronize each matrix driver to the synchronization signal. The LED array may include multiple strings of LEDs mounted in series along the string. Each LED in each string may include a bypass switch operable to modify the current through that LED by pulse-width modulation.

Abstract: Aspects of the subject technology relate to control circuitry for light-emitting diodes. The control circuitry includes a two-dimensional light-emitting diode (LED) array. The control circuitry may include a single LED array operable by a common driver or multiple LED arrays each operable by a dedicated LED matrix driver. Each matrix driver may receive a synchronization signal from a common controller and may include a programmable phase lock loop (PLL) to synchronize each matrix driver to the synchronization signal. The LED array may include multiple strings of LEDs mounted in series along the string. Each LED in each string may include a bypass switch operable to modify the current through that LED by pulse-width modulation.

Abstract: Aspects of the subject technology relate to display circuitry such as backlight control circuitry for operating parallel strings of light-emitting diodes (LEDs). A voltage supply circuit of the backlight control circuitry provides a common supply voltage to the strings of LEDs. Headroom control circuitry samples a residual voltage at the end of each string, determines a minimum of the residual voltages, and provides feedback, based on the determined minimum voltage, to the voltage supply circuit. A headroom control feedback loop may be provided including sampling lines coupled to the second end of each string of LEDs for sampling a residual voltage of each string. Headroom control circuitry may modify the supply voltage based on the minimum residual voltage. Sample-and-hold circuitry may be provided that holds the sampled residual voltages until the voltage supply circuit is ready for an update.

Abstract: Aspects of the subject technology relate to control circuitry for operating light-emitting diodes (LEDs). The control circuitry may include a pulse-width-modulation (PWM) driver for the LEDs and headroom voltage control circuitry. The PWM driver may adjust a rising edge or a trailing edge of the PWM cycles for various LEDs to ensure a headroom voltage detection window for the headroom voltage control circuitry to sample the headroom voltage of those LEDs without being affected by the rising edge of the PWM cycle for LED or the falling edge of the PWM cycle for another LED.

Abstract: Aspects of the subject technology relate to display circuitry such as backlight control circuitry for operating light-emitting diodes (LEDs). The backlight control circuitry may include a pulse-width-modulation (PWM) transistor and a current regulation transistor coupled in series with at least one LED. The current regulation transistor may have a gate terminal that receives a feedback-controlled gate voltage. The backlight control circuitry may include a gate clamp circuit coupled to the gate terminal of the current regulation transistor that clamps the gate voltage during a portion of a PWM on pulse.

Abstract: Aspects of the subject technology relate to display circuitry such as backlight control circuitry for operating light-emitting diodes (LEDs). The backlight control circuitry may include a pulse-width-modulation (PWM) transistor and a current regulation transistor coupled in series with at least one LED. The current regulation transistor may have a gate terminal that receives a feedback-controlled gate voltage. The backlight control circuitry may include a gate clamp circuit coupled to the gate terminal of the current regulation transistor that clamps the gate voltage during a portion of a PWM on pulse.

Abstract: A backlight driver chip for an electronic device includes an input that receives data corresponding to a brightness of a backlight device. The backlight driver chip also includes correction circuitry that determines an amplitude correction factor based at least in part on the data and the brightness of the backlight device. The correction circuitry also determines a corrected brightness based at least in part on the amplitude correction factor. The backlight driver chip further includes an output that provides a current signal that drives the backlight device, wherein the current signal is based at least in part on the corrected brightness.

Abstract: This application relates to systems, methods, and apparatus for controlling a switching frequency of a boost or flyback converter to be above an audible frequency range when operating the boost or flyback converter in a pulse frequency modulation (PFM) mode. The boost or flyback converter uses one or more switches for converting power for a display panel. In order to boost the switching frequency when operating in the PFM mode, the boost or flyback converter can selectively implement certain current and/or voltage limits for pulses that are generated as a result of the switching. The current and/or voltage limits can be set according to a load of the boost or flyback converter, and a correspondence between the current and/or voltage limits and the loads can be stored in a lookup table accessible to the boost or flyback converter.

Abstract: A differential microphone array includes a plurality of microphones situated on a substantially planar platform, the plurality of microphones including a total number (M) of microphones and at least two subsets of the plurality of microphones situated along at least two substantially concentric ellipses with respect to a center, and a processing device, communicatively coupled to the plurality of microphones, to receive a plurality of electronic signals generated by the plurality of microphones responsive to a sound source and execute a minimum-norm beamformer to calculate an estimate of the sound source based on the plurality of electronic signals, in which the minimum-norm beamformer has a differential order (N), and wherein M>N+1.

Abstract: Devices and methods for controlling brightness of a display backlight are provided. A display backlight controller may control the brightness of the display backlight by changing a duty cycle of a PWM signal that drives the LED current. However, because of LED efficacy and response time, the final output brightness (NITS) may not be linear between 0% to 100%. The disclosed methods may be used to correct the brightness using a predetermined correction factor. Further, the minimum and maximum duty cycle of the output dimming duty cycle may be limited or corrected. In one example, a backlight controller receives an input duty cycle and determines a product of the input duty cycle and a maximum duty cycle to produce a reduced duty cycle. Moreover, the backlight driver may determine a corrected duty cycle using the correction factor. The final output duty cycle and LED current may then be determined.