Renesas Electronics Corporation

Tetsuo Matsui

Takashi Oshima

Masaki Fujiwara

Mitsuya Fukazawa

Takahiro Miki

Tatsuji Matsuura

Hiroto Suzuki

Tomohiko Yano

Tomohiko Ebata

Kunihiko Usui

Naoki Yada

Keisaku Sento

Tetsuro Matsuno

Katsuki Tateyama

Akihiro Kitagawa

A MASH type sigma delta AD converter includes a modulator, an analog filter filtering an extraction signal obtained by extracting a probe signal and an quantization error generated in a quantizer within a sigma delta modulator, a low speed AD converter performing an AD conversion of an output signal of the analog filter, a first adaptive filter searching for a transfer function of the sigma delta modulator, a second adaptive filter searching for a transfer function from an output of the modulator to the low speed AD converter via the analog filter, and a noise cancellation circuit cancelling the probe signal and the quantization error included in an output signal of the quantizer using the search results by the first and second adaptive filters.

AD converter device and millimeter wave radar system

A conventional analog-to-digital conversion circuit has a problem that conversion errors cannot be suppressed. According to one embodiment, the analog-to-digital conversion circuit includes a first digital-to-analog conversion circuitof a capacitance distribution type, a second digital-to-analog conversion circuitof a capacitance distribution type, and a comparison circuitfor comparing output voltages of the two digital-to-analog conversion circuits, and before performing a successive comparison operation for successively changing a reference voltage applied to the first digital-to-analog conversion circuit, generates an intermediate digital value having a digital value corresponding to a voltage value of an analog input signal, determines a reference voltage to be applied to the second digital-to-analog conversion circuitin accordance with the intermediate digital value, and thereafter performs a successive comparison operation using the first digital-to-analog conversion circuitin a state in which the state of the second digital-to-analog conversion circuitis held.

Analog-to-digital conversion circuit and signal conversion method thereof

A modulator includes an analog integrator including an analog circuit and a quantizer quantizing its output signal. An external input signal is input thereto. A modulator is coupled to the latter stage of the modulator, and includes a quantizer. A probe signal generation circuit injects a probe signal to the modulator. An adaptive filter searches for a transfer function of the modulator by observing an output signal of the quantizer in accordance with a probe signal. Another adaptive filter searches for a transfer function of the modulator by observing an output signal of the quantizer in accordance with the probe signal. A noise cancel circuit cancels a quantization error generated by the quantizer using search results of the adaptive filters.

Analog/digital converter and milimeter wave radar system

A processing speed can be improved while the accuracy of AD conversion is enhanced. An AD converter includes: a higher-order DAC that samples an analog input signal and performs DA conversion corresponding to higher-order bits of a digital output signal; an extension DAC that performs DA conversion to positive and negative polarities on an extension bit for expanding bits of the higher-order DAC; a lower-order DAC that performs DA conversion corresponding to lower-order bits of the digital output signal; a comparator that compares a comparison reference voltage with output voltages of the higher-order DAC, the extension DAC, and the lower-order DAC; and a successive approximation logic that controls successive approximation performed by the higher-order DAC, the extension DAC, and the lower-order DAC based on a comparison result of the comparator and generates the digital output signal.

AD converter, AD convert apparatus, and AD convert method

To improve resolution of a built-in A/D converter by reducing the area occupied by a chip of the built-in A/D converter in a semiconductor integrated circuit that is mounted in an on-vehicle millimeter wave radar device and which incorporates an A/D converter and an MPU. In the semiconductor integrated circuit, a plurality of reception signals of the radar device is A/D-converted by a single digital correction type A/D converter. The digital correction type A/D converter of the single A/D converter is a foreground digital correction type A/D converter that sequentially A/D-converts the reception signals output from a multiplexer of a receiving interface. The single A/D converter includes a pipeline type A/D converter having a plurality of cascade-coupled converters. The semiconductor integrated circuit comprises a correction signal generating unit, a digital correction D/A converter, and a digital correction unit for digital correction.

Semiconductor integrated circuit and method of operating the same

Growing community of inventors

Tokyo, Japan

Tetsuo Matsui