Clock Switching in Always-On Component
First Claim
1. An integrated circuit comprising:
- one or more processors; and
a first circuit coupled to the one or more processors, wherein the first circuit, during use;
remains powered up during a time that the one or more processors are powered down;
receives a first plurality of audio samples captured by one or more audio input devices during the time that the one or more processors are powered down, wherein the first circuit operates according to a first clock during the time that the one or more processors are powered down;
detects a predetermined pattern in the first plurality of audio samples;
causes the one or more processors to power up responsive to detecting the predetermined pattern, wherein a second clock activates responsive to the power up; and
switches to the second clock responsive to the second clock becoming operable, wherein the switch is performed when both the first clock and the second clock are in a low phase to reduce a probability of losing an audio sample.
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Accused Products
Abstract
In an embodiment, a system on a chip (SOC) may include one or more central processing units (CPUs), a memory controller, and a circuit configured to remain powered on when the rest of the SOC is powered down. The circuit may be configured to receive audio samples and match those audio samples against a predetermined pattern. The circuit may operate according to a first clock during the time that the rest of the SOC is powered down. In response to detecting the predetermined pattern in the samples, the circuit may cause the memory controller and processors to power up. During the power up process, a second clock having one or more better characteristics than the first clock may become available. The circuit may switch to the second clock while preserving the samples, or losing at most one sample, or no more than a threshold number of samples.
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Citations
20 Claims
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1. An integrated circuit comprising:
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one or more processors; and a first circuit coupled to the one or more processors, wherein the first circuit, during use; remains powered up during a time that the one or more processors are powered down; receives a first plurality of audio samples captured by one or more audio input devices during the time that the one or more processors are powered down, wherein the first circuit operates according to a first clock during the time that the one or more processors are powered down; detects a predetermined pattern in the first plurality of audio samples; causes the one or more processors to power up responsive to detecting the predetermined pattern, wherein a second clock activates responsive to the power up; and switches to the second clock responsive to the second clock becoming operable, wherein the switch is performed when both the first clock and the second clock are in a low phase to reduce a probability of losing an audio sample. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An integrated circuit comprising:
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one or more processors; an oscillator circuit that generates a first clock during use; a phase locked loop circuit (PLL) that generates a second clock during use; and a first circuit coupled to the one or more processors, the oscillator circuit, and the PLL, wherein the first circuit, during use; remains powered up during a time that the one or more processors are powered down; receives a first plurality of audio samples captured by one or more audio input devices during the time that the one or more processors are powered down, wherein the first circuit operates according to the first clock during the time that the one or more processors are powered down; detects a predetermined pattern in the first plurality of audio samples; causes the one or more processors to power up responsive to detecting the predetermined pattern, wherein the PLL generates the second clock responsive to the power up; and switches to the second clock responsive to the PLL locking for the second clock. - View Dependent Claims (12, 13, 14, 15, 16)
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17. An integrated circuit comprising:
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one or more processors; and a first circuit coupled to the one or more processors, wherein the first circuit, during use; receives a first plurality of audio samples captured by one or more audio input devices during a time that the one or more processors are powered down, wherein the first circuit operates according to a first clock during the time that the one or more processors are powered down; detects a predetermined pattern in the first plurality of audio samples; causes the one or more processors to power up responsive to detecting the predetermined pattern, wherein a second clock activates responsive to the power up; switches to the second clock responsive to the second clock becoming operable; receives a second plurality of audio samples during operation with the second clock; writes the first plurality of audio samples and the second plurality of audio samples to memory as a single phrase even though the first plurality of samples and the second plurality of samples are captured according to different clocks. - View Dependent Claims (18, 19, 20)
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Specification