Ultra low power thermally-actuated oscillator and driving circuit thereof

Patent metadata

Field	Value
Publication number	US-2016336941-A1
Application number	US-201514961252-A
Country	US
Kind code	A1
Filing date	Dec 7, 2015
Priority date	May 12, 2015
Publication date	Nov 17, 2016
Grant date	—

Abstract

An ultra low power thermally-actuated oscillator and driving circuit thereof are provided. The ultra low power thermally-actuated oscillator includes proof masses, thermally-actuated element and a plurality of driving elements. The proof masses is symmetrically disposed and suspended from a substrate by spring structure. The thermally-actuated element is a line structure to effectively reduce the motional impedance and direct current power. Wherein, the thermally-actuated element is connected to the proof masses or the spring structure. The plurality of driving elements are respectively disposed on both sides of the thermally-actuated element to provide a driving current. When the driving current flows through the thermally-actuated element, the thermally-actuated element will be deformed and thus the proof masses will be driven to produce a harmonic oscillation.

First claim

1 . An ultra low power thermally-actuated oscillator, comprising:
at least one set of proof masses, symmetrically disposed and suspended from a substrate by at least one spring structure; at least one thermally-actuated element, being a line structure to enhance electrical impedance of the thermally-actuated oscillator and reduce thermal capacitance of the thermally-actuated oscillator, the at least one thermally-actuated element connected to the at least one set of proof masses; and a plurality of driving elements, respectively disposed on both sides of the at least one thermally-actuated element to provide a driving current, when the driving current flows through the at least one thermally-actuated element, the at least one thermally-actuated element will be deformed and thus the at least one set of proof masses will be driven to produce a harmonic oscillation; wherein a structural thickness of at least one line of the line structure is smaller than the thickness of the proof masses.

2 . The ultra low power thermally-actuated oscillator of claim 1 , wherein
the line structure is a single-line line structure or an array-line line structure and with a width or thickness of at least one line of the line structure thereof is smaller than 2 μm.

3 . The ultra low power thermally-actuated oscillator of claim 1 , wherein the at least one spring structure comprises a stretching spring structure, a rotational spring structure or combinations thereof.

4 . The ultra low power thermally-actuated oscillator of claim 1 , wherein the plurality of driving elements further comprises two electrodes made of an electrically conductive material.

5 . An ultra low power thermally-actuated oscillator, comprising:
at least one set of proof masses, symmetrically disposed and suspended from a substrate by at least one spring structure; at least one thermally-actuated element, being a line structure to enhance electrical impedance of the thermally-actuated oscillator and reduce thermal capacitance of the thermally-actuated oscillator, the at least one thermally-actuated element being directly connected to the at least one spring structure; and a plurality of driving elements, respectively disposed on both sides of the at least one thermally-actuated element to provide a driving current, when the driving current flows through the at least one thermally-actuated element, the at least one thermally-actuated element will be deformed and thus the at least one set of proof masses will be driven to produce a harmonic oscillation.

6 . The ultra low power thermally-actuated oscillator of claim 5 , wherein the line structure is a single-line line structure or an array-line line structure with a structural thickness of at least one line thereof smaller than the thickness of the proof masses, and with a width or thickness of at least one line of the line structure thereof is smaller than 2 μm.

7 . The ultra low power thermally-actuated oscillator of claim 5 , wherein the at least one spring structure comprises a stretching spring structure, a rotational spring structure or combinations thereof.

8 . The ultra low power thermally-actuated oscillator of claim 5 , wherein the plurality of driving elements further comprises two electrodes made of an electrically conductive material.

9 . A driving circuit of thermally-actuated oscillator, comprising:
a thermally-actuated oscillator, comprising
at least two electrodes;
at least one set of proof masses, symmetrically disposed and suspended from a substrate by at least one spring structure;
at least one thermally-actuated element; and
a driving circuit, comprising a bias transistor, a bias voltage inputted at a control end of the bias transistor, a current input end and a current output end of the bias transistor and the at least two electrodes forming a current loop to drive a self-sustained oscillation of the thermally-actuated oscillator.

10 . The driving circuit of thermally-actuated oscillator of claim 9 , wherein the thermally-actuated element is a line structure.

11 . The driving circuit of thermally-actuated oscillator of claim 9 , wherein the driving circuit further comprises a positive feedback loop, the positive feedback loop is connected to the control end of the bias transistor to reduce the driving power.

12 . The driving circuit of thermally-actuated oscillator of claim 9 , wherein the driving circuit further comprises a negative resistance circuit, the negative resistance circuit is connected to the two ends of the thermally-actuated oscillator to reduce the driving power.

13 . The driving circuit of thermally-actuated oscillator of claim 9 , wherein the driving circuit comprises an amplifier in order to increase the control accuracy of the thermally-actuated oscillator.

Assignees

• Nat Univ Tsing Hua

Inventors

• Li Sheng-Shian
• Lee Kuan-Hsien
• Chen Cheng-Chi

Classifications

• H03L1/02 Primary

  against variations of temperature only · CPC title

• H03B5/30 Primary

  with frequency-determining element being electromechanical resonator · CPC title

• H03B5/04

  Modifications of generator to compensate for variations in physical values, e.g. power supply, load, temperature · CPC title

• H03H2009/02307

  Dog-bone-like structure, i.e. the elongated part of the "bone" is doubly clamped · CPC title

• B81B2203/0163

  Spring holders · CPC title