Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Akio Yokoyama

Masayuki Ozasa

Hitoshi Kobayashi

Fumihito Inukai

Akira Kawabe

Shiro Sakiyama

Takashi Morie

Hiroshi Komori

Kouji Okamoto

Norihide Kinugasa

Makoto Ikuma

Mamoru Arayashiki

Hideki Nishino

Hisashi Takahashi

Fumiaki Senoue

Michiyo Yamamoto

Yoichi Morita

Kiyotaka Tanimoto

Takao Soramoto

Manabu Ookubo

A actuator driver includes a digital filter configured to perform phase compensation of a digital torque command signal using a fed-back digital signal; a digital PWM generator configured to generate a plurality of pulse-width modulated PWM control signals in response to an output of the digital filter; at least one H bridge configured to select and output a first or second terminal voltage in response to the plurality of PWM control signals; first and second continuous time &#x394;&#x3a3; A/D converters configured to convert the first and second terminal voltages from analog to digital, respectively; and a feed-back filter configured to decimate outputs of the first and second continuous time &#x394;&#x3a3; A/D converters to feed back the digital signal to the digital filter.

Actuator driver

An auxiliary current source is provided that includes MOS transistors feeding startup auxiliary current to the input portion of an output common mode voltage generation circuit amplifying the output of a differential amplifier and generating an output common voltage, and a correction current source is provided that includes MOS transistors feeding correction current corresponding to the auxiliary current to a common mode feedback comparator. Thereby, a control loop that controls the output common voltage to a predetermined voltage even when the input of the differential amplifier is outside the dynamic range at the beginning is correctly started up, thereby stabilizing the output common voltage at a desired voltage.

Fully differential amplification device

A digital analog converter includes a current conversion section and a voltage conversion section. The current conversion section has a first output terminal and a second output terminal. The first output terminal outputs a first current and a second output terminal outputs a second current, the first current varying in value according to inputted digital data, the sum of the first current and the second current becoming a constant current. The voltage conversion section converts the first current to a corresponding first voltage and produces an offset voltage on the basis of the constant current and outputs the sum of the first voltage and the offset voltage as an output voltage.

Current addition type digital analog converter

Four input nodes I-Ifor inputting 4-phase signals, four resistors R-R, four capacitors C-C, and four output nodes O-Ofor outputting 4-phase signals are provided. The resistors and the capacitors are connected alternately in a loop, and the input nodes and output nodes are connected alternately to the respective nodes between the resistors and the capacitors sequentially. Each of the four resistors is composed of a group of three or more partial resistors, and three groups of the partial resistors R-R, R-Rand R-Rare collected respectively and arranged in the same attitude, while the partial resistors R-Rof the remaining group are distributed into the other groups and arranged in the same line the same attitude as the partial resistors of each of the other groups. The regions of the thus collected groups are arranged in one direction. By simplifying the layout of the components and the shape of the wirings, influences on the characteristics by the parasitic elements are reduced, and complication in the layout and wirings can be suppressed even when using plural stages.

Passive polyphase filter

In a differential amplifier and an operational amplifier each for amplifying a signal, a differential signal composed of first and second signals is inputted to a couple of input terminals (). When the voltage of the first signal is, e.g., less than the voltage value of a reference voltage source (), a comparator () senses it and a switch circuit () switches to a first current source () and a current from a third current source () flows into the first current source () so that a current is inhibited from flowing in the first differential couple (). As a result, the inputted differential signal is amplified and outputted only through a second differential couple (). In a situation in which the voltage of the first signal exceeds the voltage of the reference voltage source (), on the other hand, the switch circuit () switches to a current source () so that the inputted differential signal is amplified and outputted only through the first differential couple (). As a result, a gain is equal over the entire range of input operating voltage and a high-speed operation is performed.

Differential amplifier and operational amplifier

Differential amplifier and calculation amplifier

A first second- or higher-order delta sigma modulator and a second second- or higher-order delta sigma modulator having a notch characteristic are cascaded together, and a delayed signal of the output of the first delta sigma modulator and a differential signal of the output of the second delta sigma modulator are added together. The amount of feedback from the output portion to the input portion of the first delta sigma modulator and the amount of feedback from the output portion to the input portion of the second delta sigma modulator are made the same.

Delta sigma modulating apparatus

A delta-sigma modulation quantization loop, comprising an integration circuit for integrating the difference between an analog input signal and a feedback reference voltage, a local quantizer for quantizing the output of the integration circuit into a digital signal, and a DA converter for generating the feedback reference voltage from the digital output of the local quantizer, is used as a single stage, and a plurality of the stages are cascade-connected. In the second-stage and subsequent modulation quantization loops, the difference signal between the input of the local quantizer of the previous stage and the output of the DA converter of the previous stage is used as an analog input signal. The feedback reference voltages of the respective delta-sigma modulation quantization loops are set individually so as to be higher than the specified maximum voltage of the analog input signal to limit the gains of the respective delta-sigma modulation quantization loops. Gain setting devices are provided in a noise reduction circuit to roughly compensate the gains limited in the respective delta-sigma modulation quantization loops.

Cascade delta-sigma modulator

The object of the present invention is to obtain a high precision notch filter or all-pass filter. Therefore, two transconductance circuits for adjustment, which perform a voltage-current conversion of a difference between a voltage of a filter input terminal and a voltage of a filter output terminal, are added to two integrators comprising two transconductance circuits for the integrators, and two capacitors. An output current of one transconductance circuit for adjustment is added to an output current of the transconductance circuit for the integrators, and an output current of the other transconductance circuit for adjustment is subtracted from an output current of the transconductance circuit for the integrators. Therefore, by adjusting conductance values of the two transconductance circuits for adjustment, even when non-ideal characteristics would exist in the transconductance circuits for the integrators, those can be canceled.

Filter

To tune the center frequency of a gm-C filter, which is a bandpass filter with a narrow bandwidth, to a target frequency, only while the filter is being tuned, the original circuit configuration of the filter is replaced with an alternative configuration that realizes a high signal-to-noise ratio. A characteristic tuner generates and inputs an impulse signal, pulse signal or step signal to the filter being tuned and thereby detects and adjusts the center frequency of the filter. And the tuning result is stored on a nonvolatile memory for future reuse. When the filter is operated, the characteristic tuner stops operating to cut down the power dissipation.

Automatic filter tuning control system

A variable impedance circuit includes a first differential amplifier circuit having an input terminal pair, an output terminal pair and a capacitive element connected between the emitters of a transistor pair. The variable impedance circuit further inclludes a second differential amplifier circuit having an input terminal pair and an output terminal pair. The output terminal pair of the first differential amplifier circuit is connected to the input terminal pair of the second differential amplifier circuit. Furthermore, the output terminal pair of the second differential amplifier circuit is connected to the input terminal pair of the first differential amplifier circuit.

Growing community of inventors

Ibaraki, Japan

Akio Yokoyama