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公开(公告)号：US10678092B2
公开(公告)日：2020-06-09
申请号：US15711932
申请日：2017-09-21
Applicant: Apple Inc.
Inventor： Ji Yeoul Ryoo , Asif Hussain , Jingdong Chen , Mohammad J. Navabi-Shirazi , Yanhui Xie
IPC: G06F5/00 , G02F1/13357 , G09G3/34 , G09G3/36 , H05B45/00 , H05B45/37 , H05B45/46 , H05B47/10 , G02F1/1335 , G06F3/041
Abstract: Aspects of the subject technology relate to display circuitry such as backlight control circuitry for operating parallel strings of light-emitting diodes (LEDs). A voltage supply circuit of the backlight control circuitry provides a common supply voltage to the strings of LEDs. Headroom control circuitry samples a residual voltage at the end of each string, determines a minimum of the residual voltages, and provides feedback, based on the determined minimum voltage, to the voltage supply circuit. A headroom control feedback loop may be provided including sampling lines coupled to the second end of each string of LEDs for sampling a residual voltage of each string. Headroom control circuitry may modify the supply voltage based on the minimum residual voltage. Sample-and-hold circuitry may be provided that holds the sampled residual voltages until the voltage supply circuit is ready for an update.
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公开(公告)号：US10555389B2
公开(公告)日：2020-02-04
申请号：US16232913
申请日：2018-12-26
Applicant: Apple Inc.
Inventor： Yanhui Xie , Asif Hussain , Jingdong Chen , Manisha P. Pandya
IPC: H05B37/00 , H05B33/08 , G02F1/1335
Abstract: Aspects of the subject technology relate to display of an electronic device. The display includes a backlight unit having a voltage source, a string of light-emitting diodes and a bypass switch for each light-emitting diode in the string. The string of light-emitting diodes can receive, at a first end, a supply voltage from the voltage source. The bypass switch for each light-emitting diode is controllable to pulse-width-modulate that light-emitting diode. The headroom voltage feedback circuit is coupled to a second end of the string.
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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
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.
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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
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.
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公开(公告)号：US11876439B2
公开(公告)日：2024-01-16
申请号：US17450910
申请日：2021-10-14
Applicant: Apple Inc.
Inventor： Yanhui Xie , Asif Hussain , Jingdong Chen , Zhiyuan Hu
CPC classification number: H02M1/14 , H02M1/0077 , H02M3/04
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.
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Patent Agency Ranking
公开(公告)号：US20210273562A1
公开(公告)日：2021-09-02
申请号：US16805577
申请日：2020-02-28
Applicant: Apple Inc.
Inventor： Erhan Ozalevli , Yanhui Xie , Dharmesh C. Bhagatwala
Abstract: Embodiments relate to a switching regulator having a dual mode control. The switching regulator includes an error amplifier configured to receive an output voltage of a power source, and to generate an error voltage based on a difference between the output voltage of the power source and a reference voltage. The switching regulator additionally includes a PFM controller configured to receive the error voltage from the error amplifier, and to generate a clock signal having a switching frequency based on a difference between the error voltage and a modulation voltage. Moreover, the switching regulator includes a PWM controller configured to receive the clock signal and an error signal determined based on a load current sensed at an output of the power source, and to generate a control signal to control the power source.
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公开(公告)号：US10269307B2
公开(公告)日：2019-04-23
申请号：US15683648
申请日：2017-08-22
Applicant: Apple Inc.
Inventor： Yanhui Xie , Asif Hussain , Jingdong Chen , Mohammad J. Navabi-Shirazi
Abstract: Aspects of the subject technology relate to control circuitry for operating light-emitting diodes (LEDs). The control circuitry may include a pulse-width-modulation (PWM) driver for the LEDs and headroom voltage control circuitry. The PWM driver may adjust a rising edge or a trailing edge of the PWM cycles for various LEDs to ensure a headroom voltage detection window for the headroom voltage control circuitry to sample the headroom voltage of those LEDs without being affected by the rising edge of the PWM cycle for LED or the falling edge of the PWM cycle for another LED.
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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
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.
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公开(公告)号：US11342842B2
公开(公告)日：2022-05-24
申请号：US16805577
申请日：2020-02-28
Applicant: Apple Inc.
Inventor： Erhan Ozalevli , Yanhui Xie , Dharmesh C. Bhagatwala
Abstract: Embodiments relate to a switching regulator having a dual mode control. The switching regulator includes an error amplifier configured to receive an output voltage of a power source, and to generate an error voltage based on a difference between the output voltage of the power source and a reference voltage. The switching regulator additionally includes a PFM controller configured to receive the error voltage from the error amplifier, and to generate a clock signal having a switching frequency based on a difference between the error voltage and a modulation voltage. Moreover, the switching regulator includes a PWM controller configured to receive the clock signal and an error signal determined based on a load current sensed at an output of the power source, and to generate a control signal to control the power source.
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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.
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