US 6,637,934 B1 · Constant offset buffer for reducing sampling time in a semiconductor temperature sensor

Abstract

A data acquisition system for sampling a temperature signal from a temperature sensor includes: a programmable current source, a buffer with a constant offset, and an analog-to-digital converter (ADC). The programmable current source selectively provides bias currents to the temperature sensor, which produces response voltages in response to the applied bias current. The buffer receives the response voltages and produces buffered response voltages that include a constant offset. The ADC is arranged to produce digital codes in response to the buffered response voltages. The digital codes are used to determine a temperature associated with the temperature sensor. The buffer isolates the temperature sensor from the ADC such that loading effects are minimized and set-up times for the conversion are minimized.

Claims19

Dependent claims

A method of sampling a response voltage from a temperature sensor that includes a PN junction, the method comprising:

applying a first bias current to the temperature sensor such that the PN junction produces a first PN junction voltage, and the temperature sensor produces a first response voltage;
buffering the first response voltage to produce a first buffered response voltage with a buffer that has an associated constant offset voltage;
applying a second bias current to the temperature sensor such that the PN junction produces a second PN junction voltage, and the temperature sensor produces a second response voltage, wherein the second bias current is different than the first bias current;
buffering the second response voltage to produce a second buffered response voltage with the buffer;
and
converting the first and second buffered response voltages to corresponding values using a converter that has an associated input impedance that is isolated from the temperature sensor by the buffer such that a setup time associated with applying the first and second bias currents is minimized.

3 more elements

An apparatus for sampling response voltages from a temperature sensor that includes a PN junction, comprising:

a means for applying a first bias current that is arranged to apply a first bias current to the temperature sensor at a first time, such that the PN junction produces a first PN junction voltage, and the temperature sensor produces a first response voltage at the first time;
a means for applying a second bias current that is arranged to apply a second bias current to the temperature sensor at a second time that is different from the first time, such that the PN junction produces a second PN junction voltage that is different from the first PN junction voltage, and the temperature sensor produces a second response voltage at the second time;
a means for buffering that is arranged to buffer response voltages from the temperature sensor and provide buffered response voltages that have a constant offset, such that the buffered response voltage is one of a first buffered response voltage and a second buffered response voltage when the response voltage is a corresponding one of the first and second response voltages;
and
a means for converting that is arranged to convert the first and second buffered response voltages to values, wherein the means for converting has an associated input impedance that is isolated from the temperature sensor by the means for buffering such that loading effects associated with the temperature sensor are minimized.

2 more elements

Dependencies are inferred from the claim text.

Constant offset buffer for reducing sampling time in a semiconductor temperature sensor

Life of this patent

Constant offset buffer for reducing sampling time in a semiconductor temperature sensor

Life of this patent

Abstract

Claims19