Method and apparatus for switching clock frequency in a system-in-package device

摘要

An apparatus includes a first clock source, a second clock source and circuitry configured to supply a clock signal to a circuit. The circuitry operates to change the clock signal from one frequency to another different frequency. This change is made in a manner whereby no clock signal is supplied during a period of time when the change from the one frequency to the another different clock frequency is being made.

主权项

1. An apparatus, comprising:
a first clock source; a second clock source; and circuitry configured to supply a clock signal to a circuit, said circuitry configured to change the clock signal from one frequency to another different frequency such that no clock signal is supplied when changing from said one frequency to said another different clock frequency; wherein said circuitry comprises:
a first delay chain clocked at one of said frequency or different frequency and having a plurality of taps;a logic circuit coupled to the taps of the first delay chain and configured to generate a first control signal indicating to stop use of said frequency and generate a second control signal enabling frequency change for said clock signal; anda second delay chain clocked at one of said frequency or different frequency and reset in response to said first control signal and having an output configured to generate a third control signal indicating to start use of said different frequency.