| Patent application number | Description | Published |
|---|
| 20080224632 | CONSTANT CURRENT CIRCUIT AND LIGHT EMITTING DIODE DRIVE CIRCUIT - A constant current generator which includes a first transistor to supply current in accordance with a control signal, a second transistor that is a MOS transistor having an equal impurity type to the first transistor. To supply current to a load in accordance with the control signal, a gate and source of the second transistor are connected to a gate and source of the first transistor, respectively. Also, there is a voltage adjustor to adjust drain voltage of the first transistor in accordance with drain voltage of the second transistor, a constant current generation circuit including a first current source to supply first current to the first transistor through the voltage adjustor, and a level shifter to shift a voltage at a connection node of the voltage adjustor and the constant current generation circuit, output a shifted voltage to each gate of the first and second transistors. | 09-18-2008 |
| 20090066305 | SWITCHING REGULATOR - A switching regulator includes a first switch, an inductor, a second switch, a controller to control a switching operation by switching the first switch and switching the second switch complementally to the first switch, and a reverse current detector to detect a reverse current that flows from an output terminal toward the second switch. The reverse current detector generates a proportional voltage that is proportional to a voltage at a junction node between the second switch and the inductor, and detects a generation or an indication of the reverse current based on the proportional voltage. The controller turns the second switch off to create a shutdown state when the reverse current detector detects the generation or the indication of the reverse current. | 03-12-2009 |
| 20090066306 | CONSTANT VOLTAGE CIRCUIT - A constant voltage circuit converts a voltage input to an input terminal and outputs a predetermined constant voltage from an output terminal. The constant voltage circuit includes an output transistor that outputs an electrical current corresponding to a control signal input thereto to the output terminal, a differential amplifier circuit that outputs the control signal according to a difference between a comparative voltage proportional to the output voltage and a predetermined reference voltage, a current mirror circuit that serves as a load of a pair of input transistors included in the differential amplifier circuit, and a voltage comparator that compares a voltage at a control electrode of a transistor included in the current mirror circuit and a voltage of the control signal. The differential amplifier circuit controls a bias electrical current supplied to the pair of input transistors according to a comparison result of the voltage comparison. | 03-12-2009 |
| 20090115374 | Charging Circuit For Secondary Battery, Power Supply Switching Method In Charging Circuit For Secondary Battery, And Power Supply Unit - A disclosed charging circuit charges a secondary battery by using a first direct current power supply that generates and outputs a first voltage. A highest voltage among the first voltage of the first direct current power supply, a second voltage generated from power supplied from outside, and a secondary battery voltage of the secondary battery is supplied as a power supply to the charging circuit. | 05-07-2009 |
| 20090121693 | Constant Voltage Circuit - A voltage change detecting circuit part amplifies an output signal of a differential amplifying circuit so that a slew rate thereof may be larger than that of a control signal output from a first error amplifying circuit to an output transistor, responding to change of an output voltage output from an output terminal quicker than a control signal output from the first error amplifying circuit to a first transistor, and causing a discharging circuit part to carry out discharging operation. | 05-14-2009 |
| 20090128116 | SWITCHING REGULATOR - A switching regulator includes a switching element that switches between on and off according to a control signal, an inductor that is charged with the input voltage by switching of the switching element, a rectification element that discharges the inductor when the switching element is off and charging the inductor is stopped, a differential amplifier that amplifies a difference between a voltage proportional to the output voltage and a predetermined reference voltage, a voltage change detection circuit that detects changes in the output voltage, and a control circuit that causes the switching element to switch between on and off in a predetermined cycle depending on a voltage output from the differential amplifier. The control circuit turns on the switching element regardless of the predetermined cycle when the voltage change detection circuit detects that a decrease in the output voltage exceeds a predetermined first reference value. | 05-21-2009 |
| 20090309563 | REFERENCE VOLTAGE GENERATING CIRCUIT AND DC-DC CONVERTER INCLUDING THE SAME - A reference voltage generator includes a reference voltage generating circuit that outputs a second reference voltage; and a DA converter that DA-converts a digital signal from outside in accordance with the second reference voltage. The circuit includes a first constant voltage circuit that operates on a DC voltage and outputs a first constant voltage; a second voltage divider that divides the first constant voltage at a second dividing ratio and outputs a second partial voltage; an output transistor that operates on the DC voltage and allows current to flow therethrough according to a signal applied to its control electrode; a current-voltage converter that converts the current from the output transistor into a voltage and outputs the voltage (second reference voltage); and a second op-amplifier that operates on the first constant voltage and controls the output transistor so that the second reference voltage equals to the second partial voltage. | 12-17-2009 |
| 20100046250 | DC-DC CONVERTER - A DC-DC converter includes a switching transistor connected to an inductor and a power input terminal, with the inductor connected to an output terminal, a synchronous rectification transistor connected to a junction node therebetween, a first electric current detector to detect whether or not an electric current flowing through the synchronous rectification transistor is larger than a first electric current, a second electric current detector to detect whether or not the electric current flowing through the synchronous rectification transistor is larger than a second electric current that is larger than the first electric current, and a selection mechanism to select one of the first and second electric current detectors in accordance with a control signal. The synchronous rectification transistor is turned off by outputting an output signal the selected current detector. | 02-25-2010 |
| 20100060250 | CURRENT-MODE CONTROL TYPE DC-DC CONVERTER AND CONTROL METHOD THEREFOR - A current-mode control type DC-DC converter includes a switching transistor turned on with a clock signal output in predetermined cycles, an inductor supplied with electric current when the switching transistor is turned on, an error amplifier circuit to output an error voltage that is an amplified difference between a predetermined reference voltage and a divided output voltage of the DC-DC converter, a slope voltage generation circuit to generate a slope voltage by performing slope compensation on an inductor current, a PWN comparator to compare the slope voltage with the error voltage and generate a reset pulse to turn off the switching transistor when the slope voltage reaches the error voltage, and a slope voltage maintenance mechanism to keep the slope voltage at the ground voltage from when the reset pulse is generated to when a subsequent clock signal is generated. | 03-11-2010 |
| 20100066333 | CURRENT MODE CONTROL TYPE SWITCHING REGULATOR - A switching regulator for converting input voltage to output voltage includes a switch; an inductor energized by input voltage by the switch; a rectifier for discharging the inductor; and a slope voltage generator for generating slope voltage inclined responsive to current of the inductor, amplifies a difference between reference voltage and divided output voltage, and compares the amplified voltage and the slope voltage to generate signal for controlling the switch. The slope voltage generator includes a detector for converting current flowing through the inductor when the switch is on into voltage; and a voltage generator for generating ramp voltage. These voltages are added as the slope voltage. The voltage generator includes constant current; a resistor; and a ramp capacitor charged by the constant current through the resistor. Voltage drop of the resistor is added to terminal voltage of the ramp capacitor to output the ramp voltage. | 03-18-2010 |
| 20100231175 | POWER SUPPLY CIRCUIT, CHARGING UNIT HAVING THE POWER SUPPLY CIRCUIT, AND POWER SUPPLY METHOD - A power supply circuit supplying power to a charge control circuit charging a secondary battery is disclosed. The power supply circuit includes a direct-current power supply configured to generate and output a predetermined voltage; and a DC-DC converter configured, to detect the voltage of the secondary battery, convert the predetermined voltage input from the direct-current power supply into a voltage according to the detected voltage of the secondary battery, and output the converted voltage to the charge control circuit. | 09-16-2010 |
| 20110018347 | POWER SOURCE DEVICE AND OUTPUT VOLTAGE CHANGING METHOD OF THE POWER SOURCE DEVICE - A power source device includes a main power source circuit, a sub power source circuit whose output voltage is changed when the output voltage of the main power source circuit is changed, a voltage difference detecting circuit which detects whether a voltage difference between the output voltages of the main and sub power source circuits is within a predetermined voltage difference, and a voltage control circuit which controls the output voltages of the main and sub power source circuits based on a voltage changing signal and an output from the voltage difference detecting circuit. The voltage control circuit controls so that the voltage difference between the output voltages of the main and sub power source circuits is within the predetermined voltage difference by controlling output voltage changing speed when the voltage difference between the output voltages of the main and sub power source circuits is over the predetermined voltage difference. | 01-27-2011 |
| 20110018513 | VARIABLE VOLTAGE DC-DC CONVERTER - A DC-DC converter configured to vary an output voltage includes an oscillator circuit configured to output a first clock signal; a digital-to-analog converter controlled based on the first clock signal input thereto and configured to output a voltage according to a voltage setting signal; a delay circuit configured to output a second clock signal delayed by a predetermined delay time with respect to the first clock signal input thereto; an error amplifier circuit having the output voltage of the digital-to-analog converter input thereto as a reference voltage; a pulse width modulation comparator provided with an output of the error amplifier circuit and a voltage into which a current flowing through an inductor is converted; and a control part configured to control a switching transistor of the DC-DC converter based on the second clock signal output by the delay circuit and an output of the pulse width modulation comparator. | 01-27-2011 |
| 20110043955 | ELECTROSTATIC DISCHARGE PROTECTION CIRCUIT, CONTROL METHOD THEREFOR, AND SWITCHING REGULATOR USING SAME - A protection circuit to protect an element against static electricity includes a clamp element connected in parallel to the protected element and a static electricity detection circuit connected to the protected element, to detect static electricity applied to the protected element. The static electricity detection circuit clamps a voltage applied to the protected element by turning on the clamp element when the detected static electricity exceeds a predetermined value and, in response to an externally input enable signal, turns off the clamp element, thereby stopping clamping the voltage applied to the protected element. | 02-24-2011 |
