Ring oscillator and semiconductor device
First Claim
1. A ring oscillator comprising a plurality of delay circuits to be ring-connected, whereinat least one of the plurality of delay circuits includes a delay element formed in a layout region including the same layout shape as the layout shape of an SRAM cell, and a path circuit connected in parallel to the delay element,the delay element outputs an output signal to a delay circuit in the next stage within the plurality of delay circuits in response to one of rise transition and fall transition of a signal input to an input terminal of the delay element from a delay circuit in the previous stage within the plurality of delay circuits, andthe path circuit outputs an output signal to the delay circuit in the next stage in response to the transition other than the one transition, whereina signal delayed by one of the delay element or the path circuit of the delay circuit in the previous stage is delayed by the other of the delay element or the path circuit of the delay circuit in the next stage.
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Accused Products
Abstract
There are provided a ring oscillator having a plurality of delay circuits to be ring-connected. At least one of the plurality of delay circuits has a delay element formed in a layout region including the same layout shape as the layout shape of an SRAM cell, and a path circuit connected in parallel to the delay element. The delay element outputs an output signal to a delay circuit in the next stage within the plurality of delay circuits in response to one of rise transition and fall transition of a signal input to the input terminal of the delay element from a delay circuit in the previous stage within the plurality of delay circuits. The path circuit outputs an output signal to the delay circuit in the next stage in response to the transition other than the one transition.
7 Citations
10 Claims
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1. A ring oscillator comprising a plurality of delay circuits to be ring-connected, wherein
at least one of the plurality of delay circuits includes a delay element formed in a layout region including the same layout shape as the layout shape of an SRAM cell, and a path circuit connected in parallel to the delay element, the delay element outputs an output signal to a delay circuit in the next stage within the plurality of delay circuits in response to one of rise transition and fall transition of a signal input to an input terminal of the delay element from a delay circuit in the previous stage within the plurality of delay circuits, and the path circuit outputs an output signal to the delay circuit in the next stage in response to the transition other than the one transition, wherein a signal delayed by one of the delay element or the path circuit of the delay circuit in the previous stage is delayed by the other of the delay element or the path circuit of the delay circuit in the next stage.
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10. A semiconductor device comprising:
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an SRAM cell array including a plurality of SRAM cells; and a ring oscillator comprising a plurality of delay circuits to be ring-connected, wherein; at least one of the plurality of delay circuits includes a delay element formed in a layout region including the same layout shape as the layout shape of an SRAM cell, and a path circuit connected in parallel to the delay element, the delay element outputs an output signal to a delay circuit in the next stage within the plurality of delay circuits in response to one of rise transition and fall transition of a signal input to an input terminal of the delay element from a delay circuit in the previous stage within the plurality of delay circuits, and the path circuit outputs an output signal to the delay circuit in the next stage in response to the transition other than the one transition, wherein a signal delayed by one of the delay element or the path circuit of the delay circuit in the previous stage is delayed by the other of the delay element or the path circuit of the delay circuit in the next stage.
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Specification