Time measuring circuit and temperature sensor circuit

Patent metadata

Field	Value
Publication number	US-10037011-B2
Application number	US-201615057271-A
Country	US
Kind code	B2
Filing date	Mar 1, 2016
Priority date	Mar 13, 2015
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

Abstract

A time measuring circuit is provided with an oscillating circuit configured to generate a low-speed clock signal and a high-speed clock signal; and a measuring circuit configured to measure target time based on clock number of the low-speed clock signal and the high-speed clock signal outputted from the oscillating circuit, wherein the low-speed clock signal has a relatively low frequency and the high-speed clock signal has a relatively high frequency. The oscillating circuit is configured to switch from outputting the low-speed clock signal to outputting the high-speed clock signal when elapsed time from when a measurement of the target time started reaches a set value, and the set value is calculated by subtracting a predetermined value from a preliminary value which is provided by a preliminary measurement measuring the target time using only the low-speed clock signal.

First claim

What is claimed is:

1. A time measuring circuit comprising:
an oscillating circuit configured to generate a low-speed clock signal and a high-speed clock signal; and
a measuring circuit configured to measure target time based on clock number of the low-speed clock signal and the high-speed clock signal outputted from the oscillating circuit,
wherein the low-speed clock signal has a relatively low frequency and the high-speed clock signal has a relatively high frequency,
the oscillating circuit is configured to switch from outputting the low-speed clock signal to outputting the high-speed clock signal when elapsed time from when a measurement of the target time started reaches a set value, and
the set value is calculated by subtracting a predetermined value from a preliminary value which is provided by a preliminary measurement measuring the target time using only the low-speed clock signal.

2. The time measuring circuit according to claim 1 , wherein
the oscillating circuit comprises a ring oscillator with a plurality of a bootstrap type CMOS inverters connected in a ring shape.

3. A temperature sensor circuit comprising:
an oscillating circuit configured to generate a low-speed clock signal and a high-speed clock signal;
a delay circuit configured to generate a delay signal; and
a measuring circuit configured to measure delay time of the delay signal based on clock number of the low-speed clock signal and the high-speed clock signal outputted from the oscillating circuit;
wherein the low-speed clock signal has a relatively low frequency and the high-speed clock signal has a relatively high frequency,
the delay time of the delay signal has a temperature dependency,
the oscillating circuit is configured to switch from outputting the low-speed clock signal to outputting the high-speed clock signal when elapsed time from when a measurement of the delay time started reaches a set value, and
the set value is calculated by subtracting a predetermined value from a preliminary value which is provided by a preliminary measurement measuring the delay time using only the low-speed clock signal.

4. The temperature sensor circuit according to claim 3 , wherein
the oscillating circuit comprises a ring oscillator with a plurality of a bootstrap type CMOS inverters connected in a ring shape.

Assignees

• Toyota Chuo Kenkyusho Kk

Inventors

• Shimada Hideto
• Mizuno Kentaro

Classifications

• G04F10/04 Primary

  by counting pulses or half-cycles of an AC {(G04F10/005 takes precedence)} · CPC title

• G01K7/346

  for measuring temperature based on the time delay of a signal through a series of logical ports · CPC title

• G04F10/005

  Time-to-digital converters [TDC] (analog-to-digital converters with intermediate conversion to time or phase H03M1/50, H03M1/60) · CPC title