Temperature sensor of pulse-width modulation

Abstract

The invention discloses a temperature sensor for pulse-width modulation. The technical problem to be solved is to improve measuring accuracy of the temperature sensor. The temperature sensor for the pulse-width modulation comprises a band gap reference circuit, a temperature detection circuit and a pulse-width modulation oscillator circuit. Compared with the prior art, the temperature sensor adopts the band gap reference circuit based on standard CMOS technology and a temperature sensor circuit output by a pulse-width modulation PWM mode to effectively overcome the influence of power supply voltage and technological deviation under a frequency output mode on measuring accuracy, and generates PWM signal output of which the duty factor is directly proportional to the temperature through a current multiplexing oscillator circuit; and the duty factor is only relevant to band gap reference voltage and measurement temperature, but is irrelevant to the power supply voltage and magnitude of charging current and capacitance, the temperature sensor eliminates the influence of the technological deviation and offset voltage of a comparator on the duty factor, so the accuracy of temperature measurement is higher.

Description

technical field [0001] The invention relates to a temperature sensor circuit, in particular to a pulse width modulation temperature sensor circuit under standard CMOS technology. Background technique [0002] Integrated temperature sensors are used more and more in temperature detection systems and integrated chips that require temperature protection. Various temperature sensors with small area and low power consumption in the prior art mainly have three signal output modes: analog mode, digital mode and frequency mode. The temperature sensor using analog output needs to add linearization circuit and calibration, which increases the cost; the digital output needs to integrate A / D on the chip to convert the analog quantity into digital signal output, which occupies a large chip area and consumes relatively high power consumption. Large; the use of frequency output can simplify the circuit, lower power consumption, and more reliable performance, but the integrated oscillator ...

AI Technical Summary

Problems solved by technology

The temperature sensor using analog output needs to add linearization circuit and calibration, which increases the cost; the digital output needs to integrate A / D on the chip to convert the analog quantity into digital signal output, which occupies a large chip area and consumes relatively high power consumption. Large; the use of frequency output can simplify the circuit, lower power consumption, and more reliable performance, but the integrated oscillator circuit is affected by factors such as power supply voltage, charging current, capacitance, and process deviation, and the measurement accuracy is relatively poor

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