公开(公告)号：US20220130327A1

公开(公告)日：2022-04-28

申请号：US17507717

申请日：2021-10-21

Applicant: APPLE INC.

Inventor： Mohammad J. Navabi-Shirazi ,  Ming Gu ,  Alejandro Lara Ascorra ,  James E. Brown

IPC: G09G3/32 ,  G09G5/10

Abstract: Light emitting diode display panels with an open loop amplifier resulting in better brightness accuracy and matching between multiple light emitting diode strings.

公开(公告)号：US10750595B1

公开(公告)日：2020-08-18

申请号：US16427865

申请日：2019-05-31

Applicant: Apple Inc.

Inventor： Erhan Ozalevli ,  Evaldo M. Miranda, Jr. ,  Mohammad J. Navabi-Shirazi

IPC: H05B45/37 ,  H02M1/08 ,  H03L7/183 ,  H05B45/00 ,  H05B45/44

Abstract: LED backlight circuits for a display and methods for operating the circuits are disclosed. The LED backlight circuit includes a set of drivers and a set of LED strings. A driver can control a light output level of the LED strings. The LED strings can be controlled by a mixed-mode LED driver that utilizes a PWM control signal over a first range of light output levels and an analog control signal over a second range of light output levels. Clock signals used for PWM control and for frequency-to-current or frequency-to-voltage conversion for analog control can both be generated from a phase locked loop (PLL).

公开(公告)号：US10678092B2

公开(公告)日：2020-06-09

申请号：US15711932

申请日：2017-09-21

Applicant: Apple Inc.

Inventor： Ji Yeoul Ryoo ,  Asif Hussain ,  Jingdong Chen ,  Mohammad J. Navabi-Shirazi ,  Yanhui Xie

IPC: G06F5/00 ,  G02F1/13357 ,  G09G3/34 ,  G09G3/36 ,  H05B45/00 ,  H05B45/37 ,  H05B45/46 ,  H05B47/10 ,  G02F1/1335 ,  G06F3/041

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.

公开(公告)号：US10009968B2

公开(公告)日：2018-06-26

申请号：US15069724

申请日：2016-03-14

Applicant: Apple Inc.

Inventor： Jingdong Chen ,  Asif Hussain ,  Behzad Mohtashemi ,  Manisha P. Pandya ,  Mohammad J. Navabi-Shirazi

IPC: H05B33/08 ,  G09G3/34

CPC classification number: H05B33/0815 ,  G09G3/3406 ,  G09G2330/06 ,  H05B33/086

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.

公开(公告)号：US09673701B2

公开(公告)日：2017-06-06

申请号：US15050152

申请日：2016-02-22

Applicant: Apple Inc.

Inventor： Behzad Mohtashemi ,  Asif Hussain ,  Manisha P. Pandya ,  Mohammad J. Navabi-Shirazi ,  Nileshbhai J. Shah

IPC: H02M3/156

CPC classification number: H02M3/156 ,  H02M2003/1566

Abstract: A power conversion circuit, such as a buck converter/regulator, includes a feedback loop operatively coupling the output voltage to the controller for the switching mechanism. The feedback loop includes an analog error amplifier that sources current to the controller when the output voltage falls below a predetermined reference voltage and sinks current from the controller when the output voltage rises above a predetermined reference voltage. The feedback loop further includes at least one of a sinking boost circuit that sinks additional current from the controller when the output voltage falls below a low voltage threshold or a sourcing boost circuit that sources additional current to the controller when the output voltage rises above a high voltage threshold. The boost circuits can include analog amplifiers, digital comparators, or a combination thereof.

公开(公告)号：US20140176352A1

公开(公告)日：2014-06-26

申请号：US14029534

申请日：2013-09-17

Applicant: APPLE INC.

Inventor： Asif Hussain ,  Mohammad J. Navabi-Shirazi ,  Jingdong Chen ,  Manisha P. Pandya

IPC: H01H13/83

CPC classification number: H01H13/83 ,  G06F3/0202

Abstract: Systems, devices, and methods for a shared matrix of shared row pins and/or column pins between a first array of keys and a second array of lights of a keyboard. A keyboard controller addresses the first array of keys and the second array of lights during a scanning period using the shared row pins and/or column pins. Each key is backlit by one or more lights of the second array of lights that may be individually controlled. The keyboard controller may drive the desired lights of a respective row while detecting key presses of the same row during the row interval using the shared row pins and/or column pins. In some embodiments, the keyboard controller may drive the desired lights of a row during driving interval of the row interval, and scan the keys of the row separately during a sensing interval of the row interval.

Abstract translation: 用于共享行引脚和/或列引脚的共享矩阵在键的第一阵列与键盘的第二阵列之间的系统，设备和方法。 键盘控制器在扫描周期期间使用共享行引脚和/或列引脚来寻址第一阵列的键和第二阵列的光。 每个键都可以由可以单独控制的第二阵列灯的一个或多个灯背光。 键盘控制器可以在使用共享的行引脚和/或列引脚的行间隔期间检测同一行的按键时驱动相应行的期望的光。 在一些实施例中，键盘控制器可以在行间隔的驱动间隔期间驱动行的期望光，并且在行间隔的感测间隔期间单独扫描行的键。