US 12,470,204 B2
Entropy source circuit and entropy value generation method
Chi-Yi Shao, Hsinchu County (TW); Kai-Hsin Chuang, Hsinchu County (TW); and Meng-Yi Wu, Hsinchu County (TW)
Assigned to PUFsecurity Corporation, Hsinchu County (TW)
Filed by PUFsecurity Corporation, Hsinchu County (TW)
Filed on Jul. 6, 2023, as Appl. No. 18/219,082.
Claims priority of application No. 111132291 (TW), filed on Aug. 26, 2022.
Prior Publication US 2024/0072776 A1, Feb. 29, 2024
Int. Cl. H03K 3/03 (2006.01); H03K 5/00 (2006.01); H03K 5/01 (2006.01); H03K 17/687 (2006.01); H03K 19/21 (2006.01)
CPC H03K 3/0315 (2013.01) [H03K 5/01 (2013.01); H03K 17/6871 (2013.01); H03K 19/21 (2013.01); H03K 2005/00013 (2013.01)] 14 Claims
OG exemplary drawing
 
1. An entropy source circuit, comprising:
a first adjustable ring oscillator, configured to operate under a first setting or a second setting according to a first control signal, wherein the first adjustable ring oscillator generates a first oscillating clock signal under the first setting and generates a second oscillating clock signal under the second setting, wherein the first oscillating clock signal and the second oscillating clock signal have different frequencies;
a first sampling circuit, configured to sample the first oscillating clock signal by a sampling frequency to generate a plurality of first sampling values, and configured to sample the second oscillating clock signal by the sampling frequency to generate a plurality of second sampling values;
a first detection circuit, configured to detect a first distribution of the first sampling values;
a control circuit, configured to determine if a setting of the first adjustable ring oscillator should be changed according to the first distribution, wherein the control circuit generates the first control signal to switch the first setting to the second setting when the first distribution does not meet a predetermined distribution;
a second adjustable ring oscillator, configured to operate under a third setting or a fourth setting according to a second control signal, wherein the second adjustable ring oscillator generates a third oscillating clock signal under the third setting and generates a fourth oscillating clock signal under the fourth setting, wherein the third oscillating clock signal and the fourth oscillating clock signal have different frequencies;
a second sampling circuit, configured to sample the third oscillating clock signal by the sampling frequency to generate a plurality of third sampling values, and configured to sample the fourth oscillating clock signal by the sampling frequency to generate a plurality of fourth sampling values;
a second detection circuit, configured to detect a second distribution of the third sampling values, wherein the control circuit determines if a setting of the second adjustable ring oscillator should be changed according to the second distribution of the third sampling values, wherein the control circuit generates the second control signal to switch the third setting to the fourth setting when the second distribution does not meet the predetermined distribution; and
an XOR circuit, configured to generate entropy values according to the first sampling values, the second sampling values, the third sampling values or the fourth sampling values;
wherein the entropy source circuit outputs the generated entropy values.