Apparatus and method to maintain stable clocking

    公开(公告)号:US11256287B2

    公开(公告)日:2022-02-22

    申请号:US16440890

    申请日:2019-06-13

    Abstract: Both before and after a surprise clock stop, the apparatus and method of various embodiments supplies a stable and continuous clock to a memory module with a unique arrangement of circuit components, including a clock detector circuit, a clock-smoothing circuit, and one or more PLLs. Upon detection of a stopped host clock, a first PLL seamlessly switches to an alternate reference clock from an on-board crystal oscillator. A clock smoothing circuit allows the first PLL to maintain a steady phase and frequency without inducing glitches or period excursions greater than the natural jitter of the locked PLL; one or more optional downstream PLLs may drive additional clock domains.

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