| CPC G01R 19/16533 (2013.01) [G06F 1/10 (2013.01); G06F 21/755 (2017.08); H03K 5/00 (2013.01); H03K 2005/00019 (2013.01)] | 20 Claims |
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1. An apparatus comprising:
a clock generator configured to generate a clock signal with one or more frequency fluctuations;
a clock line coupled to the clock generator and configured to propagate the clock signal with the one or more frequency fluctuations;
a first voltage-dependent circuit coupled to the clock line, the first voltage-dependent circuit configured to produce a first signal that is indicative of a voltage level responsive to the clock signal and based on a first voltage sensitivity, the first voltage-dependent circuit comprising:
a delay circuit coupled to the clock line and configured to delay the clock signal to produce a delayed clock signal, the delay circuit configured to provide a programmable delay amount to delay the clock signal and produce the delayed clock signal, the delay circuit comprising:
multiple delay units coupled together in series; and
at least one multiplexer including at least one control input; and
a sample circuit coupled between the delay circuit and a voltage analysis circuit, the sample circuit configured to sample the delayed clock signal to produce the first signal;
a second voltage-dependent circuit coupled to the clock line, the second voltage-dependent circuit configured to produce a second signal that is indicative of the voltage level responsive to the clock signal and based on a second voltage sensitivity; and
the voltage analysis circuit coupled to the first voltage-dependent circuit and the second voltage-dependent circuit, the voltage analysis circuit configured to:
detect a voltage-based attack by neutralizing the one or more frequency fluctuations of the clock signal based on a combination of the first signal and the second signal; and
generate a voltage alert signal based on detection of the voltage-based attack.
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