Seiko Instruments Inc

Other

Yoshihide Kanakubo

Yasuhiro Moya

Kazutoshi Ishii

Tatsuya Kitta

Sumitaka Gotou

Minoru Ariyama

Toshiyuki Koike

Tadao Akamine

Atsuo Fukui

Tomohiro Oka

Takeshi Naka

Sumitaka Goto

Tatuya Kitta

A synchronous rectifying type switching regulator control circuit has a first reference voltage circuit that receives a soft start signal from a soft start circuit and outputs a first reference voltage. An error amplifying circuit amplifies a difference of the first reference voltage and a divided voltage from a voltage dividing circuit and outputs an error voltage Verr. A first comparing circuit compares a triangular wave from an oscillator with the error voltage Verr and outputs an output pulse Vcomp. A second comparing circuit compares a second reference voltage from a second reference voltage circuit with the error voltage Verr and outputs a voltage ERRcomp. A logic circuit receives the soft start signal, the output pulse Vcomp, and the voltage ERRcomp and outputs a voltage Vcomp2. The logic circuit outputs the output pulse Vcomp when the error voltage Verr is higher than the second reference voltage during a soft start period. A synchronous rectifying circuit outputs a drive signal for driving a switching element when the logic circuit outputs the output pulse Vcomp to the synchronous rectifying circuit in accordance with the soft start signal and the voltage ERRcomp.

Synchronous rectifying type switching regulator control circuit and semiconductor integrated circuit including the same

An overcurrent protection circuit for a voltage regulator has a first transistor having a gate for connection to a gate of an output transistor of the voltage regulator, a resistor connected to a drain of the first transistor, an output voltage detecting transistor having a gate connected to an output terminal of a dividing resistance circuit of the voltage regulator, and a current mirror circuit having an input terminal connected to the drain of the output voltage detecting transistor. A second transistor has a gate connected to the drain of the first transistor and a drain connected to an output terminal of the current mirror circuit. A third transistor has a gate connected to the output terminal of the current mirror circuit and a drain for connection to the gate of the output transistor of the voltage regulator.

Voltage regulator having overcurrent protection circuit

The present invention provides a voltage regulator which has high-speed responsibility with a low consumption current, and which can stably operate with a low output capacity. The voltage regulator includes: a reference voltage circuit, a voltage division circuit, a differential amplifier, an output transistor, a MOS transistor which has a gate to which an output of the differential amplifier is connected, a constant current circuit connected between a drain of the MOS transistor and the ground, and parallel-connected resistor and capacitor for phase compensation are connected between the drain of the MOS transistor and a gate of the output transistor.

Voltage regulator with phase compensation

The present invention provides a PWM switching regulator circuit capable of reducing power consumption while it is operated under a light load. When load condition is changed from a heavy load to a light load, an internal oscillation frequency is changed from a first oscillation frequency to a second oscillation frequency lower than the first oscillation frequency, while when the load condition is changed from the light load to the heavy load, the internal oscillation frequency is returned from the second oscillation frequency back to the first oscillation frequency in accordance with an ON/OFF ratio of a signal used to control a switch of a PWM switching regulator circuit.

PWM switching regulator and electronic apparatus

To provide a resistor circuit with which a resistance ratio among voltage division resistors in a semiconductor integrated circuit can be realized with high accuracy. The resistor circuit of the present invention includes: a reference resistor portion; and a resistor portion including resistor elements and fuse connected in parallel with the resistor elements, respectively, for trimming the resistor elements. The resistor elements are arranged in order from the resistor element having a largest resistance value so as to be adjacent to the reference resistor portion in the periphery of the reference resistor portion. As a result, it is possible to obtain accurately the ratio between a resistance value of a reference resistor and a desired resistance value determined with the ratio from the resistance value of the reference resistor.

Resistor circuit

A boosting and step-down switching regulator includes one error amplifying circuit, and an output of the error amplifying circuit is compared with a triangular wave for boosting and a triangular wave for step-down different in voltage level from each other but synchronous with each other in comparison circuits, respectively, to switch the boosting operation and the step-down operation over to each other. Thus, the boosting operation and the step-down operation can be readily switched over to each other irrespective of an input voltage and an output voltage.

Boosting and step-down switching regulator controlling circuit and boosting and step-down switching regulator for use in the same

A constant-current FET functions as a constant current element by application of a constant voltage to the gate thereof. A first switch FET is disposed between the constant-current FET and a power supply without another switching element being disposed between the constant current FET and an output terminal. A second switch FET that performs an on/off operation in association with an on/off operation performed by the first switch FET is connected between the output terminal and ground.

Constant-current output driver with reduced over-shoot

A voltage regulator circuit comprises a reference voltage circuit for generating a reference voltage, an error amplifying circuit for receiving the reference voltage from the reference voltage circuit and comparing the reference voltage with a given voltage resulting from dividing the output voltage of an output terminal by a pair of resistors connected in series, and an output transistor portion having two or more switchable transistors different in driving capability. A switching circuit drives a selected one of the switchable transistors in accordance with a result of the comparison by the error amplifying circuit to thereby limit overshoot of the output voltage.

Voltage regulator circuit having output terminal with limited overshoot and method of driving the voltage regulator circuit

A thermal head driving integrated circuit capable of preventing the lowering of data transfer speed, and in which the number of bonding pads can be reduced as well as current consumption has a driver circuit in which at least two shift registers are series-arranged in front and rear stages to sequentially transfer print data in a serial signal manner to be read out in a batch mode to drive a plurality of heating resistive elements. A switch circuit is interposed between an output terminal of the front-staged shift register and an input terminal of the rear-staged shift register to selectively connect and disconnect the two shift registers.

Thermal head driving integrated circuit

A thermal head driving integrated circuit may be used to perform an &ldquo;n&rdquo; color or &ldquo;n&rdquo; gradation printing operation with a simplified circuit having a reduced size by employing a single delay element connected to a plurality of resistive heating elements. The integrated circuit has a plurality of drive units each for driving a respective one of the heating elements and each having a drive transistor for driving a respective heating element, one or more delay elements, the number of delay elements being less than &ldquo;n&rdquo;, for supplying delayed print data to the drive transistor, a print data storing unit for storing the print data of each of the &ldquo;n&rdquo; types, and a print data supplying unit for supplying print data stored in the print data storing unit to the &ldquo;n&rdquo; delay elements.

Reducing the chip area while improving the manufacturing efficiency as well as reducing costs in a semiconductor integrated circuit device such as a thermal head driver IC. A plurality of terminal electrodes were provided within an external data input/output circuit with an input terminal and output terminal being electrically connected to each other. In addition, an input/output protection circuit was provided to a respective one of such plurality of terminal electrodes with the input terminal and output terminal electrically connected together.

Semiconductor integrated circuit device

Since a field effect MOS transistor can be formed with a reduced number of manufacturing processes, a semiconductor integrated circuit device can be materialized at a low cost. A semiconductor device has a structure in which a gate electrode is provided in the vicinity of the surface of a semiconductor substrate through a gate insulating film, a second conductive type heavily doped impurity region is provided in a region adjacent to a part of the gate electrode through a part of the gate insulating film and a part of a thick oxide film, another second conductive type heavily doped impurity region is provided in a region adjacent to an opposite part of the gate electrode opposing the part of the gate electrode through the part of the gate insulating film and a part of another thick oxide film, and a first conductive type heavily doped impurity region for device isolation is provided so as to surround the gate electrode and the second conductive type heavily doped impurity regions.

Growing community of inventors

Chiba, Japan

Yoshihide Kanakubo