Fujitsu Corporation

Canon Kabushiki Kaisha

Fujitsu Semiconductor Limited

Spansion LLC.

Fujitsu Microelectronics Limited

Kabushiki Kaisha Meidensha

Eiji Nishimori

Chikara Tsuchiya

Toshiaki Shingu

Yasuteru Ichida

Takao Watanabe

Takeshi Kimura

Takashi Kawabata

Naoki Ayata

Masaaki Imaizumi

Yukio Odaka

Yoshiaki Sano

Hidetoshi Masuda

Osamu Takahashi

Kimitoshi Niratsuka

Hiroshi Miyanari

Yoshihiko Matsuo

Kazunari Matsumoto

Mutsuo Hayashi

Takashi Matsui

Toshiyuki Sekizawa

Katsuyoshi Otsu

A DC-DC converter control circuit includes: a slope signal generation circuit that generates a reference voltage by superimposing a slope voltage onto a standard voltage; a comparator that performs comparison of the reference voltage with an output voltage and generates a signal according to a result of the comparison; an oscillator that generates a pulse signal with a substantially constant cycle; and a control signal generation circuit that generates a control signal that turns on a switch based on a comparator output signal and turns off the switch based on the pulse signal.

Control circuit for DC-DC converter, DC-DC converter, and method for controlling DC-DC converter

An input voltage signal VIN to be inputted to a gate terminal of a PMOS transistor Mis converted to a voltage value which was level shifted at the source terminal by an inter-terminal voltage between the gate and source of the PMOS transistor M. This conversion is carried out in accordance with a bias current Iflowing from the constant current source IS through the source terminal of the PMOS transistor M. The voltage thus converted is outputted from a source follower circuit through a capacitative element C. A low-pass filter is constituted of the impedance of the PMOS transistor Mand the capacitative element Cin a signal path extending from the input voltage signal VIN to the source follower circuit.

Constant voltage circuit, constant voltage supply system and constant voltage supply method

The invention presents a control circuit and a control method of DC-DC converter capable of suppressing subharmonic oscillation of coil current even if the on-duty is over 50%. An error amplified signal Vis an output voltage of an error amplifier ERA. An offset voltage unit Veoutputs a lower limit set voltage Vobtained by subtracting offset voltage efrom error amplified signal V. A voltage comparator COMPcompares lower limit set voltage Voutput from offset voltage Ve, and output voltage signal VIL. When the voltage value of output voltage signal VIL is decreased to lower limit set voltage V(region E), the output of voltage comparator COMPchanges from low level to high level. As a result, main transistor FETis set in conductive state. On the other hand, when the voltage value of output voltage signal VIL reaches an error amplified signal V(region E), main transistor FETis set in non-conductive state.

Control circuit and control method of current mode control type DC-DC converter

In a DC-to-DC converter control circuit and control method thereof, an arithmetic circuit for outputs an add-up signal generated by adding an output voltage signal obtained by adding an output voltage of a DC-to-DC converter and an AC current signal obtained according to an AC current component of a coil current, and a comparator compares the add-up signal with a reference signal. Switching control is executed according to a result of the comparison by the comparator. By the control circuit and method, variations in the coil current due to a change in load may be reliably captured by comparing the add-up signal with the reference signal, and compatibility between low ripple voltage characteristics and stable and fast response to sudden changes in load may be achieved.

DC-DC converter control circuit and DC-DC converter control method

An operational amplifier that cancels offset voltage while enabling its gain to be set to any value. The operational amplifier includes a first switch for short-circuiting the gates of two transistors in a first differential input unit. A capacitor is connected to the gates of two transistors in a second differential input unit, which is connected in parallel to the first differential input unit. The capacitor holds offset voltage derived from output voltage generated by an operational amplifier circuit. The capacitor generates a potential difference between the gates of the transistors in the second differential input unit to cancel the offset voltage.

Operational amplifier and method for canceling offset voltage of operational amplifier

A reduced-size bipolar supply voltage generator which produces a positive and negative voltages from a unipolar power source. A single inductor is employed for current switching operation, where electric energy supplied from a power source is stored in magnetic form, and the stored magnetic energy is released as electric energy. A first and second diodes are connected to first and second ends of the inductor, respectively. The inductor is grounded at the first end via a first switch, while its second end is connected to the power source via a second switch. A switching controller activates both switches to energize the inductor. It then deactivates the first switch alone, thus directing the inductor's energy to the positive voltage output through the first diode. The controller may turn off the second switch alone after energizing the inductor. The stored energy now appears at the negative voltage output through the second diode.

Bipolar supply voltage generator and semiconductor device for same

An operational amplifier for canceling an offset and continuously generating an output signal. The operational amplifier includes a first operational amplification unit and a second operational amplification unit each having at least one electrical characteristic that is substantially the same as one another. One of the operational amplification units performs a canceling operation (holding operation and compensation operation) of the offset voltage while the other operational amplification unit performs a non-canceling operation and generates the output voltage by amplifying an input voltage. Both operational amplification units alternately perform the canceling operation and the non-canceling operation.

Operational amplifier

A multiphase DC-DC converter that equalizes the output current of a plurality of converter units while improving responsiveness with respect to sudden changes in the output voltage. The converter includes a control unit for controlling the converter units. The control unit includes a comparator for comparing the output voltage of each of the converter units with a reference voltage, a first control circuit for sequentially selecting each of the converter units in accordance with an output signal of the comparator to activate the output transistor of the selected converter unit, and a second control circuit for controlling the inactivation timing of the output transistors of the converter units so as to equalize the output current of the converter units.

Multiphase DC-DC converter

A switching regulator circuit includes an inductor, a first condenser which provides a potential stored therein as a first output of the switching regulator circuit, a second condenser which provides a potential stored therein as a second output of the switching regulator circuit, and a switch set including a plurality of switches, the switch set establishing a first path, a second path, and a third path, the first path supplying energy from a DC power supply to the inductor for accumulation of the energy therein, the second path supplying the energy accumulated in the inductor to the first condenser, and the third path supplying the energy accumulated in the inductor to the second condenser.

Switching regulator having two or more outputs

In a digital temperature compensated crystal oscillator, ADC circuit and DAC circuit are combined into a data conversion circuit which comprises a first section for DA conversion, a second section for converting an analog temperature voltage signal into a digital form in cooperation with the first section, and a third section for supplementing the DA conversion of the first section and thereby generating an analog control voltage for a VCO from a digital temperature compensation data. There is further provided a switch circuit for connecting the output of the first section to either of the second and third section.

Temperature compensated crystal oscillator

Disclosed is an evaluation method and apparatus used as when inspecting the mounted state of an IC. The evaluation method and apparatus are adapted to acquire the image of an object under inspection, subject the image to two types of image processing based upon two different evaluation methods, and inspect and evaluate the object as regards to the acceptability of soldered state, for example, based upon the results of the two evaluations.

Method of evaluating object based upon image processing and inspection

A mark position detecting method and apparatus, suitably usable in a semiconductor device manufacturing exposure apparatus, called a stepper, prints images of a pattern of a reticle upon different shot areas on a semiconductor wafer, and aligns the reticle and the wafer. In this method, fuzzy reasoning is made by using, for example, a membership function which empirically represents the relationship between a mark signal and an alignment result. By using a conclusion of the fuzzy reasoning, the position of the mark is detected. Thus, the alignment accuracy can be improved significantly.

Method and apparatus for detecting position of a mark

Disclosed is a focus adjustment information forming device of the kind arranged to measure distances at a plurality of distance measuring areas on a picture plane specified by optical means which has its focal point being adjusted and to form information on adjustment of the focal point, the plurality of distance measuring areas including a center distance area located approximately in the center of the picture plane. The device comprises first priority means for giving priority to a measured distance value which represents the nearest distance among measured distance values obtained from the distance measuring areas; a second priority means for giving priority to the measured distance value obtained from the center distance measuring area according to its relations to the measured distance values of other distance measuring areas when one of the measured distance values of the distance measuring areas other than the center distance measuring area represents the nearest distance; and focus adjustment information forming means for forming information on adjustment of the focal point of the optical means on the basis of outputs of the first and second priority means.

Focus adjustment information forming device

A gate circuit for analog signals composed of field effect transistors is provided. The analog signal is switched on and off by variation of the conductance of the FETs. Distortion of the signal is a crucial problem for such circuits, which is overcome by detecting the voltages at both the source and drain sides of the switching transistor which controls the signals to be on and off, and by feeding the voltages back to the gate of the switching transistor. The inner resistance of the switching transistor when it is in the on state is reduced, and becomes symmetric at both sides of V.sub.DS0. As a result the second order distortion is greatly reduced.

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Kasugai, Japan

Eiji Nishimori