Patent ID: 8870454
Filing Date: 2014-10-28
Classification: H03L

Abstract:
1. A device, comprising: a drive circuit configured to generate a drive signal, having a fundamental frequency; an electrothermal filter (ETF), electrically coupled to the drive circuit, the ETF having a temperature-dependent time constant, wherein the ETF is configured to provide a signal having the fundamental frequency and a phase relative to the drive signal corresponding to the time constant; a second ETF, electrically coupled to the drive circuit, the second ETF having a second temperature-dependent time constant which is different than the time constant, wherein the second ETF is configured to provide a second signal having the fundamental frequency and a second phase relative to the drive signal corresponding to the second time constant; and a phase detector, electrically coupled to drive circuit, the ETF and the second ETF, configured to measure a phase-shift value corresponding to the phase and a second phase-shift value corresponding to the second phase, and configured to output a signal based on the phase-shift value and the second phase-shift value.