A temperature detector of the present invention includes a temperature sensor, a reference signal generation circuit, a level memory which rewritably stores therein a first signal level and a second signal level, a control circuit which controls the reference signal generation circuit so as to make a level of the reference signal change from the first signal level to the second signal level, a comparator circuit which compares the level of the reference signal and a level of the output signal, and a level rewriter which rewrites at least either one of the first signal level and the second signal level. When the level of the reference signal reaches the level of the output signal, the control circuit generates a detected temperature signal, and controls the level rewriter so as to change a range where a level of the reference signal changes.

An environmental information measurement device includes: a power source unit; an environmental information detector; a timer; and a controller. The power source unit generates, from an electromagnetic wave received, a power source voltage to be supplied to a load. The load includes the environmental information detector, the timer, and the controller. The environmental information detector includes a detector including a circuit element having an impedance or an electrostatic capacitance that varies according to a physical amount detected under an environment at a measurement target point, and outputs a signal that varies according to a response characteristic of the detector. The timer measures a duration from the time when measurement is initiated to the time when a voltage of the signal becomes a predetermined detection voltage. The controller controls an operation of the environmental information detector.

A thermistor amplifier device comprising a first amplifier and a second amplifier is provided. The first amplifier generates an analog temperature signal output based on a voltage across at least one thermistor. The second amplifier generates an offset voltage input to the first amplifier, wherein the offset voltage is based on maintaining the analog temperature signal within a predefined voltage range. The second amplifier selects the offset voltage corresponding to one of a plurality of range levels, wherein each of the plurality of range levels is associated with a temperature range of the at least one thermistor.

An ADC is disclosed which has, as a first stage, a successive approximation converter, or other compensated, direct comparison converter, followed by a sigma delta modulation converter as a second stage. The sigma delta converter may beneficially be a first order modulator. The resulting ADC combines accuracy with low power consumption per conversion, and thus is particularly suited for use in temperature sensors for applications such as RFID transponders. Such a temperature sensor and an RFID transponder are also disclosed. There is also disclosed a method of analog-to-digital conversion, comprising a first successive approximation register or other compensated, direct comparison conversion stage followed by a sigma delta modulation stage, which, further, may be combined with providing a proportional-to-absolute-temperature (PTAT) signal, for low-power, accurate temperature sensing.

The invention relates to temperature sensors, in particular to on-chip temperature sensors in CMOS integrated circuits using diode-connected bipolar junction transistors as temperature sensing elements, and discloses a temperature sensor module (400) comprising a temperature sensing circuit (107) comprising first and second bipolar junction transistors (402), a bias circuit (106) connected to the first and second transistors and configured to provide first and second bias currents to the first and second transistors respectively, a conversion circuit (108) connected to the transistors and configured to provide an output signal corresponding to a temperature of the first and second transistors derived from the base-emitter voltages across the first and second transistors, wherein the first and second transistors are each of NPN type and a feedback amplifier (403) is connected between the base and collector connections of each transistor.

A temperature detection circuit is provided which requires only a small number of additional components, thus minimizing an increase in costs and which offers an insulating property and high responsiveness. A temperature detection circuit 15 outputs a first PWM signal corresponding to a temperature of a first temperature sensor TD_X from a photointerrupter 32 as a signal insulated from the first temperature sensor TD_X. A temperature detection circuit 34 outputs a second PWM signal corresponding to a temperature of a second temperature sensor TD_U from a photointerrupter 56 as a signal insulated from the second temperature sensor TD_U. A controlling arithmetic apparatus 10 calculates a higher one of the temperatures detected by the first and second temperature sensors TD_U, TD_X based on the PWM signals output from the photointerrupter 32 and 56.

To provide a PDM output temperature sensor, which is reduced in area and consumption power, provided is a PDM output temperature sensor which includes no reference voltage circuit, thereby having a smaller area and consuming less power correspondingly.

A temperature detector of the present invention includes a temperature sensor, a reference signal generation circuit, a level memory which rewritably stores therein a first signal level and a second signal level, a control circuit which controls the reference signal generation circuit so as to make a level of the reference signal change from the first signal level to the second signal level, a comparator circuit which compares the level of the reference signal and a level of the output signal, and a level rewriter which rewrites at least either one of the first signal level and the second signal level. When the level of the reference signal reaches the level of the output signal, the control circuit generates a detected temperature signal, and controls the level rewriter so as to change a range where a level of the reference signal changes.