US 12,442,698 B2
Strain sensor
Nicolas Roisin, Louvain-la-Neuve (BE); Denis Flandre, Louvain-la-Neuve (BE); Nicolas Andre, Louvain-la-Neuve (BE); and Thibault Delhaye, Louvain-la-Neuve (BE)
Assigned to UNIVERSITE CATHOLIQUE DE LOUVAIN, Louvain-la-Neuve (BE)
Appl. No. 18/016,902
Filed by UNIVERSITE CATHOLIQUE DE LOUVAIN, Louvain-la-Neuve (BE)
PCT Filed Jul. 30, 2021, PCT No. PCT/EP2021/071499
§ 371(c)(1), (2) Date Jan. 19, 2023,
PCT Pub. No. WO2022/023571, PCT Pub. Date Feb. 3, 2022.
Claims priority of application No. 20188775 (EP), filed on Jul. 30, 2020.
Prior Publication US 2023/0296455 A1, Sep. 21, 2023
Int. Cl. G01L 1/22 (2006.01); G01P 15/12 (2006.01)
CPC G01L 1/225 (2013.01) [G01L 1/2281 (2013.01); G01P 15/123 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A strain sensor comprising a self-biasing reference circuit arranged to reach an operating state that, at least at first order, is at least supply-voltage independent, the strain sensor providing an output signal that is defined by the operating state of the self-biasing reference circuit, wherein at least one component in the self-biasing reference circuit has an electrical characteristic that depends on a strain to which the at least one component is subjected so that the operating state of the self-biasing reference circuit depends on the strain and, as a result, the output signal of the strain sensor varies as a function of the strain to which the at least one component is subjected, wherein the self-biasing reference circuit comprises:
a sensing circuit including a component having an electrical characteristic that depends on a strain to which the component is subjected so that the sensing circuit has a transfer function from an input to an output that varies as a function of the strain to which the component is subjected; and
a complementary circuit having an input coupled to the output of the sensing circuit and an output coupled to the input of the sensing circuit, the complementary circuit having a different transfer function from its input to its output,
wherein the operating state of the self-biasing reference circuit is defined by the transfer function of the sensing circuit and the different transfer function of the complementary circuit, and
wherein the sensing circuit comprises two strain-sensitive transistors of the field-effect type that affect the transfer function of the sensing circuit, the two transistors being oriented differently with respect to each other on a substrate.