Random bit stream generation by amplification of thermal noise in a CMOS process
AssigneeAgilent Technologies, Inc.
InventorRobert H. Miller JR.
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Abstract
A method and circuit is presented for generating a random bit stream based on thermal noise of a CMOS device. A circuit implementing the invention preferably includes at least a pair of identically implemented thermal noise generators whose outputs feed a differential amplifier. The differential amplifier measures and amplifies the difference between the noise signals. A sampling circuit compares the difference with a threshold value that is selected to track with process/voltage/temperature variations of the noise generator circuits to output a binary bit having a bit value determined according to the polarity of the noise difference signal relative to the threshold value. The sampling circuit may be clocked to generate a random bit stream.
Claims20
A random bit generator, comprising:
- a first noise generator circuit which generates a first noise signal;
- a second noise generator circuit which generates a second noise signal;
- a first difference circuit which receives said first noise signal and said second noise signal, determines a first difference between said first noise signal and said second noise signal, and generates a first noise difference signal;
- and
- a sampling circuit which samples said first noise difference signal and generates an output bit having a bit value based on said first noise difference signal.
A method for generating a random bit stream, comprising:
- generating a first noise signal representing thermal noise on a first CMOS device;
- generating a second noise signal representing thermal noise on a second CMOS device;
- measuring a difference between said first noise signal and said second noise signal;
- amplifying said difference to generate an amplified difference signal;
- sampling said amplified difference signal;
- and
- generating an output bit having a bit value based on said amplified difference signal.
A random bit generator, comprising:
- a noise generator circuit comprising:
- a complementary CMOS inverter having an inverter input and an inverter output on which a noise generator output signal is generated;
- and
- a feedback FET exhibiting thermal noise which generates an AC component on said noise generator output signal, and which is conductively coupled between said inverter output and said inverter input to maintain a DC component of said noise generator output signal;
- and
- a sampling circuit which compares said noise generator output signal to a threshold voltage and generates an output bit having a bit value based on a voltage level of said noise signal relative to said threshold voltage.
Dependencies are inferred from the claim text.