Mitsubishi Denki Kabushiki Kaisha

Takeshi Shigenobu

Masao Ito

Toshio Kumamoto

Takahiro Miki

Hiroshi Komurasaki

A coupler/isolator alternatively couples and isolates unit amplifiers of a multiple stage chopper amplifier to shift gradually and slightly reset timing and amplification timing of the chopper amplifiers. In this way, a first-stage chopper amplifier to an n-th timing of the chopper amplifiers. In this way, a first-stage chopper amplifier to an n-th stage chopper amplifier are sequentially reset. The first-stage chopper amplifier to the n-th stage chopper amplifier are sequentially operated to amplify, in a pipeline format, a differential voltage between a signal voltage input to a signal voltage input terminal and a reference voltage input to a reference voltage input terminal, and supply the amplified differential voltage to a next-stage circuit.

Multistage amplifier circuit

An object is to obtain an A/D converter with improved A/D conversion accuracy. The resistor elements (R) and (R) are connected through wiring (L,) (2&times;L,, L,, 2&times;L,) mostly with two resistor elements left therebetween. For example, the resistor elements (R,) and (R,) are connected through the partial wiring (L,) and (L,) extended to the left in the diagram, and the resistor elements (R,) and (R,) are connected through the partial wiring (L,) and (L,) extended to the right in the diagram. Thus all of the wiring (L,) connecting electrically adjacent resistor elements (R) and (R) are formed of a combination of partial wiring &lcub;2&times;L,L,2&times;L

Folding and interpolation analog-to-digital converter

In a sample hold circuit (,) capable of relaxing a dependency of a voltage of an analogue input signal on an ON resistance of a switch (,). In the sample hold circuit (,), plural reference voltages VrefN are supplied, and unit switches (,) forming the switch (,) are selectively activated (an ON state) based on a comparison results (whether or not the voltage of the analogue input signal is greater than each reference voltage) from plural comparison circuits (,) whose operations are performed based on the voltage of the analogue input signal (,).

Sample hold circuit having a switch

An A/D converter simplifies its circuit configuration without deteriorating accuracy in A/D conversion. A circuit is formed of a folding and interpolation type. A gain-variable pre-amplifier group 11 amplifies each of reference voltages Vref1 to VrefN and an analog input voltage Vin, to output the result to a folding amplifier group 12, while a gain-variable pre-amplifier group 21 amplifies each of reference voltages Vrr1 to VrrJ and the analog input voltage Vin, to output the result to a comparator group 24. Each of pre-amplifiers constituting the gain-variable pre-amplifier groups 11 and 21 has an amplification factor that varies in upper and lower comparison periods according to a clock control signal .PHI.cnt.

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Tokyo, Japan

Takeshi Shigenobu