PFM control method for boost converters

    公开(公告)号:US11264900B2

    公开(公告)日:2022-03-01

    申请号:US16793516

    申请日:2020-02-18

    Applicant: Apple Inc.

    Abstract: The present disclosure is directed to a pulse frequency modulation (PFM) control method for a boost converter and apparatus for carrying out the method. A boost converter includes an inductor and a transistor coupled thereto. A control circuit is arranged to control the transistor to cause current pulsed to be sourced through the inductor. When operating in a PFM mode, the control circuit may control the timing of pulses such that, at the beginning of a specified time period, current pulses may be sourced with no spacing between successive pulses. After a desired number of pulses have been sourced, no pulses are sourced for the remainder of the specified time period. Nevertheless, the number of pulses sourced over the time period corresponds to a desired average frequency of pulses.

    LED driver circuit
    2.
    发明授权

    公开(公告)号:US10694603B1

    公开(公告)日:2020-06-23

    申请号:US16684567

    申请日:2019-11-14

    Applicant: Apple Inc.

    Abstract: An LED driver circuit is disclosed. The LED driver circuit includes an amplifier having a first input coupled to receive a reference voltage and a second input coupled to receive a feedback voltage. The circuit further includes first and second transistors each having respective gate terminals coupled to an output of the first amplifier. In a first mode, a first switch alternately couples a source terminal of the first transistor to the second input of the amplifier (when the pulse is asserted) and a source terminal of the second transistor to the second input (when the pulse is de-asserted). A third transistor includes a gate terminal that is coupled to ground, by a second switch, when operating in the first mode. When operating in the second mode, the switch couples the third transistor to the output of the amplifier, while the pulse remains asserted.

    LED Driver Circuit
    4.
    发明申请

    公开(公告)号:US20210153320A1

    公开(公告)日:2021-05-20

    申请号:US16908425

    申请日:2020-06-22

    Applicant: Apple Inc.

    Abstract: An LED driver circuit is disclosed. The LED driver circuit includes an amplifier having a first input coupled to receive a reference voltage and a second input coupled to receive a feedback voltage. The circuit further includes first and second transistors each having respective gate terminals coupled to an output of the first amplifier. In a first mode, a first switch alternately couples a source terminal of the first transistor to the second input of the amplifier (when the pulse is asserted) and a source terminal of the second transistor to the second input (when the pulse is de-asserted). A third transistor includes a gate terminal that is coupled to ground, by a second switch, when operating in the first mode. When operating in the second mode, the switch couples the third transistor to the output of the amplifier, while the pulse remains asserted.

    LED driver circuit
    5.
    发明授权

    公开(公告)号:US11166355B2

    公开(公告)日:2021-11-02

    申请号:US16908425

    申请日:2020-06-22

    Applicant: Apple Inc.

    Abstract: An LED driver circuit is disclosed. The LED driver circuit includes an amplifier having a first input coupled to receive a reference voltage and a second input coupled to receive a feedback voltage. The circuit further includes first and second transistors each having respective gate terminals coupled to an output of the first amplifier. In a first mode, a first switch alternately couples a source terminal of the first transistor to the second input of the amplifier (when the pulse is asserted) and a source terminal of the second transistor to the second input (when the pulse is de-asserted). A third transistor includes a gate terminal that is coupled to ground, by a second switch, when operating in the first mode. When operating in the second mode, the switch couples the third transistor to the output of the amplifier, while the pulse remains asserted.

    PFM Control Method for Boost Converters

    公开(公告)号:US20210257911A1

    公开(公告)日:2021-08-19

    申请号:US16793516

    申请日:2020-02-18

    Applicant: Apple Inc.

    Abstract: The present disclosure is directed to a pulse frequency modulation (PFM) control method for a boost converter and apparatus for carrying out the method. A boost converter includes an inductor and a transistor coupled thereto. A control circuit is arranged to control the transistor to cause current pulsed to be sourced through the inductor. When operating in a PFM mode, the control circuit may control the timing of pulses such that, at the beginning of a specified time period, current pulses may be sourced with no spacing between successive pulses. After a desired number of pulses have been sourced, no pulses are sourced for the remainder of the specified time period. Nevertheless, the number of pulses sourced over the time period corresponds to a desired average frequency of pulses.

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