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    SYSTEMS AND METHODS FOR LIGHT-LOAD EFFICIENCY IN DISPLAYS
    11.
    发明申请
    SYSTEMS AND METHODS FOR LIGHT-LOAD EFFICIENCY IN DISPLAYS 有权
    显示器中轻负载效率的系统和方法

    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。

    Methods and apparatus for controlling display backlight
    13.
    发明授权
    Methods and apparatus for controlling display backlight 有权

    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.

    LED driver gate clamp systems and methods
    15.
    发明授权
    LED driver gate clamp systems and methods 有权

    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.

    Transformerless AC line isolator
    16.
    发明授权
    Transformerless AC line isolator 有权

    公开(公告)号：US10075095B2

    公开(公告)日：2018-09-11

    申请号：US15148245

    申请日：2016-05-06

    Applicant: Apple Inc.

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

    IPC: H02M7/44 ,  H02M7/537 ,  H02M1/08 ,  H02M3/158 ,  H02M1/00

    CPC classification number: H02M7/537 ,  H02M1/08 ,  H02M3/158 ,  H02M2001/0009 ,  H02M2001/0058 ,  Y02B70/1425 ,  Y02B70/1483 ,  Y02B70/1491

    Abstract: Various systems, apparatuses, and methods are disclosed herein, which provide a new power conversion topology for isolated systems that does not include a transformer. Embodiments of the inventive systems comprise: a switching system utilizing high voltage, low leakage switches, e.g., Silicon Carbide (SiC) MOS-FETs; a power source; an inductor and a capacitor operating as a link stage resonant LC circuit; and a load. The switching system may be configured to be controlled in a synchronized ‘four phase’ control loop process, wherein the input switches are prevented from being closed at the same time as the output switches, thereby providing electrical isolation between the input power source and the load—without the use of a transformer. The techniques disclosed herein are applicable to any number of isolated systems that supply power to electronic systems such as: digital cameras, mobile phones, watches, personal data assistants (PDAs), portable music players, displays, and computers.

    Multi-signal digital controller for isolated system feedback loop
    17.
    发明授权
    Multi-signal digital controller for isolated system feedback loop 有权

    公开(公告)号：US10063155B2

    公开(公告)日：2018-08-28

    申请号：US15148870

    申请日：2016-05-06

    Applicant: Apple Inc.

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

    IPC: H02M3/335 ,  H02M1/32 ,  H02M1/00

    CPC classification number: H02M3/33523 ,  H02M1/32 ,  H02M2001/0009

    Abstract: Various systems and methods are disclosed herein, which provide isolated systems with an auxiliary, multi-signal digital feedback loop for reporting a plurality of different potential fault conditions in an output system (e.g., output short circuit, output over-voltage, output under-voltage, output over temperature, etc.) to a Primary Controller in an input system. The signals may be sent according to any desired standardized (or proprietary) data transmission protocols. Use of a digital feedback loop allows the signals to be passed to the Primary Controller more quickly than is allowed by traditional analog feedback paths—and while using only a single optocoupler device for the transmission of all fault conditions. The techniques disclosed herein are applicable to any number of isolated systems that supply power to electronic systems such as: digital cameras, mobile phones, watches, personal data assistants (PDAs), portable music players, monitors, as well as desktop, laptop, and tablet computers.

    Boost converter with a pulse frequency modulation mode for operating above an audible frequency
    18.
    发明授权
    Boost converter with a pulse frequency modulation mode for operating above an audible frequency 有权
    具有脉冲频率调制模式的升压转换器，用于在可听频率之上操作

    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。

    Current Load Transient Mitigation in Display Backlight Driver
    20.
    发明申请
    Current Load Transient Mitigation in Display Backlight Driver 有权

    公开(公告)号：US20230085621A1

    公开(公告)日：2023-03-23

    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

    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.

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