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    MITIGATION OF BATTERY OUTPUT VOLTAGE RIPPLE UNDER PULSE LOAD
    54.
    发明申请
    MITIGATION OF BATTERY OUTPUT VOLTAGE RIPPLE UNDER PULSE LOAD 有权

    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.

    Methods and apparatus for controlling display backlight
    56.
    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.

    Local display backlighting systems and methods
    59.
    发明授权
    Local display backlighting systems and methods 有权

    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.

    LED driver gate clamp systems and methods
    60.
    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.

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