Oki Electric Industry Co., Ltd.

Mitsubishi Denki Kabushiki Kaisha

Seiichi Yamazaki

Sumihiro Takashima

Hiroaki Inoue

Mitsuya Ohie

Yasuhiro Shin

Yoshihiro Shona

Shintaro Mori

Toshihiro Abe

Yasuo Moriguchi

Fumihiko Terayama

Masahiro Kitamura

Keiichi Itoh

Hiroshisa Shishikura

In a microcomputer equipped with a built-in temperature sensor, diodes as a temperature sensor are incorporated in a pair of circuit blocks, respectively, and placed in opposite polarity connection to each other. When detecting a temperature of the microcomputer, a constant current If is supplied to the diodes through terminals commonly connected to both the diodes. A voltage Vf generated at each diode is read through terminals located at more adjacent nodes to the diode when compared in position with the terminals.

Microcomputer equipped with built-in temperature sensor

A frequency counter,includes a binary counter section,having a binary counter,for counting up frequency data, and a EEPROM counter section,having an EEPROM,containing frequency data. In a frequency count processing, frequency data of the EEPROM,are loaded into the binary counter,. The binary counter,executes count up by a specified frequency on the loaded frequency data. The counted up frequency data are written into the EEPROM,to update the frequency data of the EEPROM,. In one frequency count process, rewriting of the EEPROM,is completed once, which means that the number of time the EEPROM,is rewritten is reduced.

Counting circuit with rewritable non-volatile memory, and counting method

A flash analog-to-digital converter has CMOS comparators that compare an analog input signal with internal reference voltages and produce internal output signals. Each comparison is performed according to the threshold voltage of an inverter. A threshold control circuit in each comparator adjusts this threshold voltage according to the internal output signal, thereby providing hysteresis. A logic circuit receives the internal output signals from all the comparators and generates a digital output signal. The hysteresis of the comparators keeps the digital output signal from oscillating between adjacent values when the analog input signal is near one of the internal reference voltages.

CMOS flash analog-to-digital converter with hysteresis

A baud rate generator has a first oscillator that generates a first clock signal, and a second oscillator that generates a second clock signal with higher frequency but lower frequency accuracy. The first oscillator employs an external resonator but the second does not. The baud rate generator uses the first clock signal to measure the frequency of the second clock signal, then determines a division ratio by which to divide the frequency of the second clock signal, then divides the second clock signal by this division ratio to generate a crock signal for use in serial communication.

Low-power baud rate generator including two oscillators

There is provided a constant-current source having first current mirror circuit, connected between a first fixed voltage terminal and first and second nodes, having a first current gain; the first mirror circuit passing a first current through the first node based upon the first fixed voltage and passing a second current through the second node in accordance with the first current gain; a second current mirror circuit, connected both to the first and the second nodes, having a second current gain; the second current mirror circuit passing the second current through the second node and passing a third current in accordance with the second current gain based upon the first current passing through the first node; a current gain variation circuit, connected between the second current mirror circuit and a second fixed voltage terminal, for varying the second current gain in accordance with variation of the third current; a first activating circuit, connected between the first fixed voltage terminal and the first node, for passing a first off-leak current through the first node in accordance with the first current; a second activating circuit, connected between the second fixed voltage terminal and the second node, for passing a second off-leak current through the second node in accordance with the second current; and an output circuit, connected between an output terminal and the first fixed voltage terminal, for outputting a constant current.

Constant-current source circuit having a MOS transistor passing off-heat

An analog switch includes n-channel and p-channel MOSFETs formed in a surface of a semiconductor substrate. Each of the n-channel and p-channel MOSFETs has first, second and third diffused regions which are formed in the semiconductor surface with the width thereof substantially equal to each other. The first and third diffused regions are spaced from the second diffused region to form first and second channel regions, respectively. Each of the n-channel and p-channel MOSFETs has first and second gate electrodes which are interconnected in common to each other and placed on respective gate insulating layers overlaying the first and second channel regions, respectively. The first gate electrode has an end portion extending over part of the second diffused region by a predetermined length, while the second gate electrode has an end portion extending over another part, opposite to the earlier-mentioned part, of the second diffused region by a predetermined length. A sample and hold circuit including the analog switch is also provided.

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Tokyo, Japan

Seiichi Yamazaki