公开(公告)号：US11689094B2

公开(公告)日：2023-06-27

申请号：US17324307

申请日：2021-05-19

Applicant: Apple Inc.

Inventor： Zhiyuan Hu ,  Jingdong Chen ,  Yanhui Xie ,  Asif Hussain

IPC: H02M3/07 ,  H02M1/00 ,  H02M7/483

CPC classification number: H02M1/0095 ,  H02M3/07 ,  H02M7/4837

Abstract: Power converters can include a plurality of switching devices and a combination of one or more inductors and one or more flying capacitors. Both boost and buck converters may employ such topologies, and can achieve high efficiency and small size in at least some applications, including those with high conversion ratios. A control circuit can generate a first pair of complementary gate drive signals to drive a first complementary switch pairs and a second pair of complementary gate drive signals to drive a second complementary switch pair. The control circuit can vary a phase shift between the first pair of complementary gate drive signals and the second pair of complementary gate drive signals to regulate the flying capacitor voltage.

公开(公告)号：US20230100812A1

公开(公告)日：2023-03-30

申请号：US17870576

申请日：2022-07-21

Applicant: Apple Inc.

Inventor： Behzad Mohtashemi ,  Mohammad J Navabi-Shirazi ,  Feng Guo ,  Omar Alnaggar ,  Venkataraman V Iyer ,  Jingdong Chen ,  Yang Zhang ,  Ming Gu ,  Asif Hussain

IPC: G09G3/34

Abstract: Systems and methods for preserving a pulse width modulation (PWM) resolution while increasing the frequency of a pulse width modulation (PWM) clock are provided. An electronic display backlight system may include a backlight element and backlight dimming circuitry. The backlight element may be driven according to a pulse width modulation (PWM) signal over a PWM clock cycle equal to a multiple M of a baseline PWM clock frequency associated with a baseline PWM resolution. The backlight dimming circuitry may receive a brightness code of the baseline PWM resolution and generate the PWM signal at least in part by dividing the brightness code by M.

公开(公告)号：US20220061135A1

公开(公告)日：2022-02-24

申请号：US17238851

申请日：2021-04-23

Applicant: Apple Inc.

Inventor： Ming Gu ,  Yanhui Xie ,  Jingdong Chen ,  Asif Hussain ,  Behzad Mohtashemi ,  Mohammad Jafar Navabi-Shirazi ,  Linda A. Kamas ,  Alejandro Lara Ascorra

IPC: H05B45/14 ,  H05B45/325 ,  G09G3/34

Abstract: Aspects of the subject technology relate to electronic devices having a display. The display includes a channel of light emitting diodes (LEDs) having controllable brightness levels and control circuitry coupled to the channel of LEDs. The control circuitry provides a pulse width modulated (PWM) signal having a duty cycle to control the brightness levels. An adaptive headroom control circuitry is configured to sense a headroom voltage signal for the channel of LEDs and apply a first time period for blanking the headroom voltage signal during the first time period that is associated with a settling time for the headroom voltage signal.

公开(公告)号：US20210364855A1

公开(公告)日：2021-11-25

申请号：US17203340

申请日：2021-03-16

Applicant: Apple Inc.

Inventor： Mingxia Gu ,  Jun Qi ,  Yanming Li ,  Jingdong Chen

IPC: G02F1/13357 ,  G09G3/34

Abstract: A pixel array may be illuminated with backlight illumination from a backlight. The backlight may include a two-dimensional array of light-emitting diodes, with each light-emitting diode being placed in a respective cell. Different light-emitting diodes may have unique brightness magnitudes based on the content of the given display frame. Driver integrated circuits may control one or more associated light-emitting diodes to have a desired brightness level. The driver integrated circuits may be formed in an active area of the backlight. The driver integrated circuits may be arranged in groups that are daisy chained together. A digital signal (that includes information such as addressing information) may be propagated through the group of driver integrated circuits. To manage thermal performance of the backlight, the backlight may include a thermally conductive layer and/or a heat sink structure. To increase the efficiency of the backlight, the backlight may include one or more reflective layers.

公开(公告)号：US10383186B2

公开(公告)日：2019-08-13

申请号：US15785082

申请日：2017-10-16

Applicant: Apple Inc.

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

IPC: H05B33/08 ,  G02F1/13357 ,  G02F1/1335

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.

公开(公告)号：US20190215924A1

公开(公告)日：2019-07-11

申请号：US16353896

申请日：2019-03-14

Applicant: Apple Inc.

Inventor： Mohammad J. Navabi-Shirazi ,  Alejandro Lara Ascorra ,  Asif Hussain ,  Ji Yeoul Ryoo ,  Jingdong Chen ,  Jun Qi ,  Manisha P. Pandya ,  Yanhui Xie

IPC: H05B33/08 ,  G09G3/34

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.

公开(公告)号：US20140210697A1

公开(公告)日：2014-07-31

申请号：US13756259

申请日：2013-01-31

Applicant: APPLE INC.

Inventor： Asif Hussain ,  Jingdong Chen ,  Mohammad Jafar Navabi-Shirazi ,  Manisha Pandya ,  Alejandro L. Ascorra

IPC: G09G5/10

CPC classification number: G09G5/10 ,  G09G3/3406 ,  G09G2320/0261 ,  G09G2320/064 ,  G09G2320/0646 ,  G09G2320/10 ,  G09G2330/021 ,  G09G2354/00 ,  G09G2360/144 ,  G09G2360/16

Abstract: A system may include a processor, a graphics controller, and a display. The graphics controller may generate video data to be presented on the display. The display may include a display panel, a backlight unit for providing the display panel with backlight, and a display timing controller for communicating with the graphics controller. The display may be used in non-movie mode and movie mode. The backlight unit may be operated in fixed backlight mode during the non-movie display mode and may be operated in dynamic pixel backlight (DPB) mode during the movie display mode. Backlight level adjustments may be sloped only during the non-movie mode. Backlight level sloping can be handled internally within the backlight unit, can be controlled using pulse width modulation with the display timing controller, and implemented using incremental backlight level adjustments with the processor.

Abstract translation: 系统可以包括处理器，图形控制器和显示器。 图形控制器可以生成要呈现在显示器上的视频数据。 显示器可以包括显示面板，用于向显示面板提供背光的背光单元，以及用于与图形控制器通信的显示定时控制器。 显示器可以用于非电影模式和短片模式。 背光单元可以在非电影显示模式期间以固定背光模式操作，并且可以在动画显示模式期间以动态像素背光（DPB）模式操作。 仅在非电影模式期间，背光级别调整可能会倾斜。 背光水平倾斜可以在背光单元内部处理，可以使用显示定时控制器的脉冲宽度调制进行控制，并使用处理器进行增量背光级调整。

公开(公告)号：US20140139143A1

公开(公告)日：2014-05-22

申请号：US13940181

申请日：2013-07-11

Applicant: Apple Inc.

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

IPC: H05B33/08

CPC classification number: H05B33/0887 ,  G06F1/26 ,  H02M3/156 ,  H02M2001/0025 ,  H05B33/0815 ,  H05B33/0884 ,  Y02B20/341

Abstract: A measured voltage drop across a power-line transistor is used as a sensing element to measure the current and detect an over-current condition for an LED backlight system. An over-current or short condition is detected when the measured voltage drop exceeds a threshold. Accurate detection of the over-current condition is achieved by calibrating the RDS-ON (i.e., internal resistance between drain and source, when transistor is on) of the power-line transistor. In one embodiment, the calibration of RDS-ON is performed by ramping down the threshold from an initial value and using the tripped threshold to determine the actual value for RDS-ON. In another embodiment, the calibration of RDS-ON is performed by using two thresholds, a first threshold to calibrate RDS-ON and a second threshold to detect the over-current condition.

Abstract translation: 电力线晶体管两端的测量电压降被用作传感元件，以测量电流并检测LED背光系统的过电流状态。 当测量的电压降超过阈值时，检测到过电流或短路状况。 通过校准电源线晶体管的RDS-ON（即，在晶体管导通时漏极和源极之间的内部电阻）来实现过电流状态的精确检测。 在一个实施例中，RDS-ON的校准是通过从初始值降低阈值并使用跳闸阈值来确定RDS-ON的实际值来执行的。 在另一个实施例中，通过使用两个阈值来执行RDS-ON的校准，第二阈值是用于校准RDS-ON的第一阈值和用于检测过电流状态的第二阈值。

公开(公告)号：US20140132641A1

公开(公告)日：2014-05-15

申请号：US13673695

申请日：2012-11-09

Applicant: APPLE INC.

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

IPC: G09G5/10

CPC classification number: G09G5/10 ,  G09G3/3406 ,  G09G2300/0426 ,  G09G2320/0233

Abstract: Systems and methods for light-load efficiency in displays may include a backlight driver circuit that may adjust a gate drive voltage provided to a gate of a metal-oxide-semiconductor field-effect transistor (MOSFET) in the boost converter based on the load conditions of light-emitting diodes used to illuminate the display panel. The backlight driver circuit may also switch between two different voltage sources to further broaden a range of gate drive voltages available to drive the gate of the MOSFET in the boost converter. As a result, the backlight driver circuit may decrease gate drive losses associated with the MOSFET, thereby increasing the efficiency of the boost converter.

Abstract translation: 显示器中轻负载效率的系统和方法可以包括背光驱动器电路，其可以基于负载条件来调节提供给升压转换器中的金属氧化物半导体场效应晶体管（MOSFET）的栅极的栅极驱动电压 的用于照亮显示面板的发光二极管。 背光驱动器电路还可以在两个不同的电压源之间切换，以进一步扩大可用于驱动升压转换器中的MOSFET的栅极的栅极驱动电压的范围。 结果，背光驱动器电路可以减小与MOSFET相关联的栅极驱动损耗，从而提高升压转换器的效率。