公开(公告)号：US08976092B2

公开(公告)日：2015-03-10

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: G09G3/34 ,  G09G3/36 ,  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：US20220376616A1

公开(公告)日：2022-11-24

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 ,  H02M1/08

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：US20200105185A1

公开(公告)日：2020-04-02

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: G09G3/32 ,  F21S4/20 ,  H02J1/10

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：US10034343B2

公开(公告)日：2018-07-24

申请号：US15478549

申请日：2017-04-04

Applicant: Apple Inc.

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

IPC: H05B37/00 ,  H05B33/08

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.

公开(公告)号：US20170208661A1

公开(公告)日：2017-07-20

申请号：US15478549

申请日：2017-04-04

Applicant: Apple Inc.

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

IPC: H05B33/08

CPC classification number: H05B33/0851 ,  G09G3/3426 ,  H05B33/0818

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.

公开(公告)号：US09185768B2

公开(公告)日：2015-11-10

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: G06F1/26 ,  H05B33/08 ,  H02M3/156 ,  H02M1/00

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：US08970200B2

公开(公告)日：2015-03-03

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: H02M3/158 ,  H02M3/04 ,  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。

公开(公告)号：US20140159614A1

公开(公告)日：2014-06-12

申请号：US13754640

申请日：2013-01-30

Applicant: APPLE INC.

Inventor： Asif Hussain ,  Jingdong Chen ,  Mohammad Jafar Navabi-Shirazi ,  Manisha Pandya

IPC: H05B37/02

CPC classification number: H05B33/086 ,  G09G3/3406 ,  G09G2320/041 ,  G09G2320/062 ,  G09G2320/064 ,  H05B33/0863

Abstract: An electronic device may be provided with display circuitry that includes a display timing controller, a backlight driver, a light source, and other associated backlight structures. The backlight control circuitry may generate a control signal having an adjustable duty cycle to the backlight driver. The backlight driver may include a boost converter, a current driver, and backlight control circuitry. The current driver may only be activated when the control signal is high. The backlight control circuitry may output an enable signal to the boost converter. The backlight control circuitry may activate the boost converter a predetermined amount of time before each rising clock edge in the control signal by asserting the enable signal for a longer period of time than when the control signal is high. The control signal and the enable signal may be deasserted at around the same times.

Abstract translation: 电子设备可以设置有显示电路，显示电路包括显示定时控制器，背光驱动器，光源和其它相关联的背光结构。 背光控制电路可以产生对背光驱动器具有可调占空比的控制信号。 背光驱动器可以包括升压转换器，电流驱动器和背光控制电路。 当控制信号为高电平时，只能激活当前驱动器。 背光控制电路可以向升压转换器输出使能信号。 背光控制电路可以在控制信号中的每个上升时钟沿之前的预定时间量内激活升压转换器，该时间长于当控制信号为高时，将使能信号置为更长的时间段。 控制信号和使能信号可以在大约相同的时间被解除。

公开(公告)号：US20140097765A1

公开(公告)日：2014-04-10

申请号：US13679781

申请日：2012-11-16

Applicant: APPLE INC.

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

IPC: H05B37/02

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.

Abstract translation: 提供了用于控制显示器背光的亮度的装置和方法。 显示器背光控制器可以通过改变驱动LED电流的PWM信号的占空比来控制显示器背光的亮度。 然而，由于LED效能和响应时间，最终的输出亮度（NITS）可能在0％到100％之间不是线性的。 所公开的方法可以用于使用预定的校正因子校正亮度。 此外，可以限制或校正输出调光占空比的最小和最大占空比。 在一个示例中，背光控制器接收输入占空比并且确定输入占空比和最大占空比的乘积以产生减小的占空比。 此外，背光驱动器可以使用校正因子来确定校正的占空比。 然后可以确定最终的输出占空比和LED电流。

公开(公告)号：US11823612B2

公开(公告)日：2023-11-21

申请号：US17853247

申请日：2022-06-29

Applicant: Apple Inc.

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

IPC: G09G3/20

CPC classification number: G09G3/2092 ,  G09G2310/0264 ,  G09G2310/08

Abstract: A display device include a first light emitting diode (LED), a second LED, and at least one processor of a driver. The processor drives the first LED and the second LED. The processor determines a first pulse width associated with the first LED and a second pulse width associated with the second LED based on a level of brightness to be emitted by the first LED and the second LED. The processor also receives a gap clock and determines a first pulse start time and a first pulse end time for the first LED based on the first pulse width. Moreover, the processor determines a second pulse start time and a second pulse end time for the second LED based on the first pulse end time, the second pulse width, and/or the gap clock, in which the first pulse end time and the second pulse end time are different.