Digitizing temperature measurement system
First Claim
1. A temperature measurement system comprising:
- a switched excitation circuit coupled to excite a temperature sensing element for generating an input voltage step; and
an analog-to-digital converter (ADC) circuit coupled to sample said input voltage step and generate a temperature output signal, said ADC circuit comprising;
a modulator coupled to integrate charge associated with said input voltage step and balance said charge with a charge domain reference signal generated entirely in the charge domain, said modulator generating a digital output signal, said digital output signal forming a digital data stream over a plurality of sampling cycles where said digital data steam has an ones density proportional to the magnitude of said input voltage step; and
post processing circuit coupled to receive said digital data stream and generating a digital number indicative of the occurrence of ones in said digital data stream within said plurality of sampling cycles as said temperature output signal.
1 Assignment
0 Petitions
Accused Products
Abstract
A digitizing temperature measurement system for providing a digital temperature measurement includes an excitation source for providing switched excitation currents to two or three temperature sensing elements and an ADC circuit including a charge-balancing modulator and a digital post processing circuit. The system utilizes synchronous AC excitation of the temperature sensing elements and an AC coupled analog-to-digital converter input. The temperature measurement system also implements correlated double sampling for noise cancellation to provide low noise and highly accurate analog-to-digital conversions. The modulator receives a charge domain reference signal generated by a reference charge packet generator incorporating a charge based bandgap subsystem. Therefore, the temperature measurement system can be operated at very low supply voltages, such as 1.0 Vdc. A low noise and highly accurate temperature measurement system is thus realized where temperature measurements of very high resolutions (up to 16 bit) can be attained.
-
Citations
26 Claims
-
1. A temperature measurement system comprising:
-
a switched excitation circuit coupled to excite a temperature sensing element for generating an input voltage step; and
an analog-to-digital converter (ADC) circuit coupled to sample said input voltage step and generate a temperature output signal, said ADC circuit comprising;
a modulator coupled to integrate charge associated with said input voltage step and balance said charge with a charge domain reference signal generated entirely in the charge domain, said modulator generating a digital output signal, said digital output signal forming a digital data stream over a plurality of sampling cycles where said digital data steam has an ones density proportional to the magnitude of said input voltage step; and
post processing circuit coupled to receive said digital data stream and generating a digital number indicative of the occurrence of ones in said digital data stream within said plurality of sampling cycles as said temperature output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
-
Specification