Kabushiki Kaisha Toshiba

Nec Electronics Corporation

Yoshitaka Murasaka

Atsushi Iwata

Toshifumi Imamura

Shigeyuki Sakura

Toyoaki Uo

Hiroshi Suzunaga

Masaru Numano

Hisami Saitou

Motoharu Kishi

Sadao Igarashi

Kouichi Kobinata

An analog-to-digital converter includes a first switch circuit, a first integrator, a second switch circuit, a second integrator, a quantizer and a digital-to-analog converter. The first switch circuit receives an external analog signal, outputs the analog signal in reverse phase, and outputs the analog signal in positive phase. The first integrator receives and integrates the analog signal with cross-coupling. The second switch circuit outputs an output of the first integrator and a common mode output potential of the first integrator. The second integrator samples and integrates an output of the second switch circuit. The quantizer single-bit-quantizes an output of the second integrator to provide the output as a digital signal output. The digital-to-analog converter receives an output of the quantizer and provides the output as an analog signal output. Each of the first and second integrators receives and integrates an output of the digital-to-analog converter with cross-coupling.

Analog-to-digital converter, analog-to-digital conversion method, and optically coupled insulating device

In an optical coupled isolation circuit, a PWM encoder encodes a one-bit binary data signal supplied from a sigma-delta analog-digital converter in synchronization with a clock signal of a cycle T to produce a pulse width modulation signal. The pulse width modulation signal includes a narrower pulse having a width of 1/T and a wider pulse having a width of 3/T according to binary codes '0' and '1'. The pulse width modulation signal is transmitted to a decoder as a recovered pulse width modulation signal through a light emitting device, a light detector and an optical recovery circuit. A decoder decodes the recovered pulse width modulation signal at timing of a half of the clock cycle from each rising edge of the recovered pulse width modulation signal. The rising edge is synchronized with the clock signal. Thus, the clock signal and the data signal can be transmitted in one channel.

Optical coupled type isolation circuit

According to one aspect of this invention, there is provided a transmitting and receiving device including a transmitting device having a pulse width modulation encoder which generates a pulse width signal having a pulse width corresponding to the binary digital signals outputted from the plurality of sigma-delta analog-to-digital conversion units, and a light-emitting element drive unit which generates and transmits an optical signal by causing a light-emitting element to emit light on the basis of the pulse width signal, and a receiving device having an optical reception unit which converts a current signal, obtained by receiving the optical signal by a light-receiving element, into the pulse width signal, and a pulse width demodulation decoder which reconstructs the binary digital signals of a plurality of channels on the basis of the pulse width signal.

Transmitting and receiving device and transmitting device and receiving device

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Hiroshima, Japan

Yoshitaka Murasaka