Renesas Electronics Corporation

Nec Electronics Corporation

Tetsuhiro Koyama

Masaaki Hirano

Tetsuya Matsumoto

Chiaki Kumahara

It is possible to detect a failure in a temperature sensor while preventing enlarging of a circuit scale. A temperature measurement circuitincludes temperature sensorsand, and a comparator. The temperature sensorincludes a temperature detection unitincluding a resistive element, a resistance value of which varies in accordance with temperature changes, and an AD converter which converts a voltage of the temperature detection unitinto a temperature digital value D. The temperature sensorincludes a ring oscillatorwhich oscillates at a cycle that is temperature dependent, and generates a digital value Dbased on an oscillating signal output by the ring oscillator. The comparatorcompares the temperature digital values Dand D, and outputs a signal indicating whether the temperature sensoris normal or not based on a comparison result.

Temperature measurement circuit and method, and microcomputer unit

An analog-digital converter according to the present invention includes an input polarity switching unit, an integrator that integrates an input signal, an integrator output adjusting circuit that adjusts an output voltage of the integrator, a window comparator, and a controller that controls the input polarity switching unit, the integrator output adjusting circuit, and the window comparator, and generates a digital signal. When the output voltage of the integrator reaches a first reference voltage, the controller resets reference voltage of a high-voltage side comparator to a second reference voltage. Further, when the output voltage of the integrator reaches a third reference voltage, the controller resets reference voltage of a low-voltage side comparator to a fourth reference voltage. According to the analog-digital converter of the present invention, it is possible to prevent device breakdown and occurrence of through current due to fluctuation of the output voltage of the integrator.

Analog-digital converter

There is provided an analog-to-digital converter capable of performing analog-to-digital conversion with good accuracy. The analog-to-digital converter in accordance with the present invention includes a dither generation circuitwhich generates dither; an input polarity switching unitwhich switches a polarity of an input signal; an integrator; an integrator output regulator circuitwhich regulates an output voltage of the integrator; a window comparator; a control circuitwhich uses the comparison result of the window comparatorto control the input polarity switching unit, the integrator output regulator circuit, and the window comparatoras well as to generate a digital signal. The dither generation circuitgenerates dither in such a manner that a cycle in which the digital signal is read is an integral multiple of a dither cycle. Further, the dither generation circuitgenerates dither in such a manner that the number of times the count value is generated in the first half of one cycle of the dither is different from the number of times the count value is generated in the second half cycle thereof.

Analog-to-digital converter

According to one aspect of the present invention, there is provided a dither circuit including a dither generating circuit generating a plurality of complementary signal pairs, and a dither input circuit generating a plurality of dither signals from the plurality of complementary signal pairs to add the generated dither signals to an analog input signal, in which the plurality of complementary signal pairs have different frequencies with each other, the dither input circuit includes capacitors provided for each of the plurality of complementary signal pairs and a plurality of switch pairs including first and second switches having one terminals connected to each one terminal of the capacitors, and the other terminals of the capacitors are connected to an adding point to the analog input signal, the first switch supplies ones of the complementary signal pairs to one terminals of the capacitors when a clock signal is in effective state, and the second switch supplies the others of the complementary signal pairs to one terminals of the capacitors when an inverting clock signal of the clock signal is in effective state.

Dither circuit and analog digital converter having dither circuit

A semiconductor circuit apparatus includes a booster which is connected to a single power supply and outputs a power supply voltage of the power supply or a voltage different from the power supply voltage, and a boost controller which controls whether to output the power supply voltage of the power supply or the voltage different from the power supply voltage.

Growing community of inventors

Kanagawa, Japan

Tetsuhiro Koyama