公开(公告)号：US11428987B2

公开(公告)日：2022-08-30

申请号：US17203340

申请日：2021-03-16

Applicant: Apple Inc.

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

IPC: G02F1/1335 ,  G02F1/13357 ,  H05B47/16 ,  H05B47/105 ,  H01L25/16 ,  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：US20220224219A1

公开(公告)日：2022-07-14

申请号：US17450910

申请日：2021-10-14

Applicant: Apple Inc.

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

IPC: H02M1/14 ,  H02M1/00

Abstract: A battery powered electronic device can include a battery to power one or more loads, a first DC-DC converter having an input coupled to the battery and an output, and a second DC-DC converter cascaded with the first DC-DC converter and coupled to a second load subject to pulsed operation. The first and second converters may be configured so as to isolate the one or more loads from transients associated with the pulsed operation of the second load. The second converter may have an input coupled to the output of the first converter and an output coupled to the second load. Alternatively, the second converter may be a bidirectional converter having first terminals coupled to the output of the first converter and second terminals coupled to an energy storage device.

公开(公告)号：US20210364861A1

公开(公告)日：2021-11-25

申请号：US17203311

申请日：2021-03-16

Applicant: Apple Inc.

Inventor： David W. Lum ,  Jingdong Chen ,  Mingxia Gu ,  Jun Qi

IPC: G02F1/1335 ,  G02F1/13357

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：US10728969B2

公开(公告)日：2020-07-28

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 ,  H05B45/10 ,  G09G3/34 ,  H05B45/37 ,  H05B45/46 ,  H05B45/395 ,  G02F1/1335 ,  G02F1/13357 ,  G02F1/1343

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：US10714028B2

公开(公告)日：2020-07-14

申请号：US16418882

申请日：2019-05-21

Applicant: Apple Inc.

Inventor： Jingdong Chen ,  Asif Hussain ,  Mohammad J. Navabi-Shirazi ,  Behzad Mohtashemi ,  Yanhui Xie ,  Jy Ryoo ,  Ming Gu

IPC: H02J1/10 ,  H02M1/00 ,  G09G3/34 ,  G09G3/32 ,  F21S4/20

Abstract: A display may have an array of pixels illuminated using a backlight unit. The backlight unit may include multiple strings of light-emitting diodes (LEDs) and a boost converter for providing an output voltage to the multiple LED strings. The boost converter may have a single-phase single-switch, single-phase multi-switch, and/or multi-phase multi-switch configuration, where the switches are turned off when the peak current is reached. When transitioning from a single phase to a dual phase operation, the second (slave) phase current may be slowly ramped up. When transition from the dual phase to the single phase operation, the output voltage may be elevated while slowing ramping down the slave phase current. The boost converter may include a current detection circuit for adjusting the peak current of each phase to balance the average current levels. The boost converter may also include an in-rush current controller configured to sense a short fault.

公开(公告)号：US10237936B2

公开(公告)日：2019-03-19

申请号：US15784943

申请日：2017-10-16

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: H05B37/02 ,  H05B33/08 ,  G02F1/1335 ,  G02F1/13357 ,  G02F1/1343

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：US10201049B1

公开(公告)日：2019-02-05

申请号：US15789885

申请日：2017-10-20

Applicant: Apple Inc.

Inventor： Yanhui Xie ,  Asif Hussain ,  Jingdong Chen ,  Manisha P. Pandya

IPC: G09G3/36 ,  H05B33/08 ,  G02F1/1335

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.

公开(公告)号：US10129941B1

公开(公告)日：2018-11-13

申请号：US15691672

申请日：2017-08-30

Applicant: Apple Inc.

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

IPC: H05B37/02 ,  H05B33/08

CPC classification number: H05B33/0824 ,  H05B33/0845

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.

公开(公告)号：US09826596B2

公开(公告)日：2017-11-21

申请号：US13679781

申请日：2012-11-16

Applicant: APPLE INC.

Inventor： Asif Hussain ,  Jingdong Chen ,  Manisha P. Pandya ,  Adrian E. Sun

IPC: H05B37/00 ,  H05B37/02 ,  H05B33/08 ,  G09G3/34

CPC classification number: H05B37/02 ,  G09G3/3426 ,  H05B33/0869

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.

公开(公告)号：US09345083B2

公开(公告)日：2016-05-17

申请号：US14503037

申请日：2014-09-30

Applicant: Apple Inc.

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

IPC: H05B37/02 ,  H05B33/08 ,  G09G3/34

CPC classification number: H05B33/0815 ,  G09G3/3406 ,  G09G3/342 ,  G09G2310/08 ,  G09G2320/0233 ,  G09G2320/064 ,  Y02B20/346

Abstract: The embodiments discussed herein relate to systems, methods, and apparatus for executing a pulse frequency modulation (PFM) mode of a boost converter in order to ensure that a switching frequency of the boost converter is a above an audible frequency threshold. In this way, a user operating a display device that is controlled by the boost converter will not be disturbed by audible noises generated at the display device. The PFM mode enforces an audible frequency threshold by using control circuitry designed to increase or decrease the frequency of a pulse signal depending on how the frequency of the pulse signal changes over time. The control circuitry can apply an additional load to the boost converter in order to increase the frequency of the pulse signal when the frequency is approaching the audible frequency threshold.

Abstract translation: 本文讨论的实施例涉及用于执行升压转换器的脉冲频率调制（PFM）模式的系统，方法和装置，以便确保升压转换器的开关频率高于可听频率阈值。 以这种方式，操作由升压转换器控制的显示装置的用户不会被在显示装置处产生的可听见的噪声所扰乱。 PFM模式通过使用设计用于根据脉冲信号的频率如何随时间而变化的脉冲信号的频率而设计的控制电路来实施可听频率阈值。 控制电路可以向升压转换器施加额外的负载，以便在频率接近可听频率阈值时增加脉冲信号的频率。