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Adaptively controlling drive strength of multiplexed power from supply power rails in a power multiplexing system to a powered circuit

  • US 10,684,671 B2
  • Filed: 05/12/2017
  • Issued: 06/16/2020
  • Est. Priority Date: 05/27/2016
  • Status: Active Grant
First Claim
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1. A power multiplexing system, comprising:

  • a power multiplexing circuit, comprising;

    a first supply selection circuit coupled between a first supply power rail having a first voltage and an output power rail coupled to at least one powered circuit;

    a second supply selection circuit coupled between a second supply power rail having a second voltage and the output power rail;

    the first supply selection circuit configured to selectively drive the first voltage at the first supply power rail to the output power rail at a first drive strength based on a first drive strength indicator to variably adjust the output impedance of the first supply selection circuit; and

    the second supply selection circuit configured to selectively drive the second voltage at the second supply power rail to the output power rail at a second drive strength based on a second drive strength indicator to variably adjust the output impedance of the second supply selection circuit;

    wherein the first supply selection circuit further comprises a diode drop control circuit configured to establish a first diode drop connection between the first supply power rail and the output power rail, in response to a supply power rail switch signal indicating a supply power rail switch enable state to switch from supplying power to the output power rail via the first supply selection circuit to supplying power via the second supply selection circuit while the first diode drop connection is established; and

    at least one control circuit configured to;

    receive a first supply power rail selection indicator indicating a first supply power rail selection enable state in response to the second voltage being a voltage level less than a threshold voltage;

    receive a second supply power rail selection indicator indicating a second supply power rail selection enable state in response to the second voltage being a voltage level equal to or higher than the threshold voltage;

    monitor an output voltage of the output power rail; and

    in response to the first supply power rail selection indicator indicating the first supply power rail selection enable state;

    compare a voltage level of the output voltage at the output power rail to a first reference voltage level associated with the first supply selection circuit; and

    selectively generate the first drive strength indicator based on the comparison of the voltage level of the output voltage at the output power rail to the first reference voltage level; and

    in response to the second supply power rail selection indicator indicating the second supply power rail selection enable state;

    compare the voltage level of the output voltage at the output power rail to a second reference voltage level associated with the second supply selection circuit; and

    selectively generate the second drive strength indicator based on the comparison of the voltage level of the output voltage at the output power rail to the second reference voltage level.

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