Rohm Co., Ltd.

Maxell Holdings, Ltd.

Yoshinori Sato

Satoru Nate

Hiroshi Hayashi

Hideaki Katayama

Toshihiro Abe

Manabu Oyama

Nobuaki Matsumoto

Yifei Tang

Yohei Akamatsu

Yuta Shiroishi

Hiroaki Sawaoka

The present disclosure provides a control device for a power factor correction circuit. The power factor correction circuit is disposed in a power supply device configured to generate a direct current output voltage from an alternating current voltage applied to a pair of power supply terminals. The power factor correction circuit is disposed between a full-wave rectifier circuit configured to generate a full-wave rectified voltage by full-wave rectifying the AC voltage and an output wiring configured to apply the output voltage. The power factor correction circuit includes an inductor inserted between the full-wave rectifier circuit and the output wiring, and a switching element configured to switch between an on state and an off state to control a current flowing through the inductor.

Control device of power factor correction circuit, power factor correction circuit and power supply device

A power control device includes a mode setter configured to effect a change from a normal mode to a low-power mode upon detecting a light load in a burst operation, and a minimum on-period setter configured to, in response to a change to the low-power mode, change the minimum on-period of the switching transistor from a first minimum on-period to a second minimum on-period longer than the first minimum on-period.

Power control device, DC-DC converter, and AC-DC converter

There is provided a power supply controller including: a monitor voltage generation part configured to generate a monitor voltage according to a primary voltage of a transformer that forms an insulated switching power supply; a sample/hold part configured to sample/hold the monitor voltage and output a feedback voltage; and a controller configured to turn on/off a primary current of the transformer by a fixed on-time method according to the feedback voltage, wherein the sample/hold part samples/holds the primary voltage at a plurality of different timings and outputs one of a plurality of hold values as the feedback voltage.

Power supply controller and insulated switching power supply

This power supply IC is a semiconductor integrated circuit device serving as a main part for controlling a switching power supply and is formed by integrating a feedback resistor and an output feedback control unit on a single semiconductor substrate, said feedback resistor generating a feedback voltage by dividing the output voltage of the switching power supply (or the induced voltage appearing across an auxiliary winding provided on the primary side of a transformer included in an insulation-type switching power supply), said output feedback control unit performing output feedback control of the switching power supply in accordance with the feedback voltage. The feedback resistor is a polysilicon resistor having a withstand voltage of 100 V or more. A high-voltage region having higher withstand voltage in the substrate thickness direction than the other region is formed in the semiconductor substrate, and the feedback resistor is formed on the high-voltage region.

Power IC including a feedback resistor, and a switching power supply and electronic appliance including the power IC

A control device of a power factor correction circuit disposed in a power supply device that generates a direct-current output voltage from an alternating-current voltage applied to a power supply terminal pair, the power factor correction circuit including an inductor that is disposed between a full-wave rectification circuit that generates a full-wave rectified voltage by carrying out full-wave rectification of the alternating-current voltage and an output interconnect line to which a smoothing capacitor is connected and to which the output voltage is applied, and is inserted between the full-wave rectification circuit and the output interconnect line, and a switching element for controlling an inductor current that flows in the inductor. The control device controls a state of the switching element based on a pulsating voltage obtained by rectifying a voltage between the power supply terminal pair and the full-wave rectification circuit and a feedback voltage according to the output voltage.

Control device of power factor correction circuit, power factor correction circuit, power supply device, and semiconductor device

A non-isolated buck converter generates an output voltage by stepping down an input voltage obtained by subjecting an alternating-current voltage to full-wave rectification and smoothing, by using a step-down circuit including a switching element, an inductor, and a freewheeling diode. The switching element is disposed between a first terminal and a second terminal. A semiconductor device in charge of switching control operates with a potential at the second terminal as a reference. A control circuit provided in the semiconductor device includes a protecting circuit capable of referring to an evaluation voltage corresponding to a voltage between the first terminal and the second terminal at a sampling timing at which a predetermined period of time has passed from turning off of the switching element, and performing a protecting operation that fixes the switching element to an off state on the basis of the evaluation voltage.

Semiconductor device for non-isolated buck converter, non-isolated buck converter, and power supply device

A current limiter 200 (corresponding to an example of a current detection circuit) has a comparator 210 and a variable delay unit 220. The comparator 210 switches a comparison signal OCP from a low level to a high level when the current to be monitored, which flows through an output switch, reaches a predetermined threshold value (in the present figure, when a sense voltage Vcs reaches an overcurrent detection voltage Vocp). The variable delay unit 220 measures a first time Tfrom when the output switch turns on by SET=H until when the comparison signal OCP switches to the high level and delays the comparison signal OCP by a second time T(=K&#xb7;T) proportional to the square of the first time Tto generate an overcurrent detection signal Sc. The variable delay unit 220 includes a first timer 223 for measuring the first time Tand a second timer 224 for generating the overcurrent detection signal Sc by delaying the comparison signal OCP by the second time T

Current sense circuit

There is provided a power supply control device as a control main entity of a switching power supply. The power supply control device includes a minimum ON width setting part configured to set a minimum ON width of an output switch according to a load.

Power supply control device for setting minimum on width of output switch

A power control device that acts as a principal controlling agent in an isolating switching power supply has a controller configured to monitor a first output detection signal commensurate with a direct-current output voltage to a load and a second output detection signal commensurate with the difference between the direct-current output voltage and its target value switch among a plurality of operating modes with varying power consumption according to the results of monitoring of the two output detection signals. The power control device may instead have a peak current switch configured to raise the peak current value of a primary current passing in an output switch on detecting a light load.

Power control device switchable between multiple operating modes having different power consumption

A discharge circuit has a voltage divider arranged to divide an alternating-current input voltage to produce a divided voltage, a high-pass filter arranged to pass a high-frequency component of the divided voltage to produce a monitoring voltage, a comparator arranged to compare the monitoring voltage with a threshold voltage to produce a comparison signal, a timer arranged to generate a timer signal indicating whether or not the comparison signal has been kept at the same logic level for a mask period, a controller arranged to generate a discharge control signal according to the timer signal, and a discharger arranged to discharge, according to the discharge control signal, an X capacitor connected to a node to which the alternating-current input voltage is applied.

Discharge circuit and power supply device therewith

A switching power supply device includes a switching control circuit that generates a switching control signal such that a desired output voltage is generated from an input voltage, a drive circuit that turns on/off an output transistor in accordance with the switching control signal, and an on-pulse stop circuit that generates a pulse stop signal such that the number of ON pulses of the switching control signal is reduced in a state where a load is heavier than a first threshold but is lighter than a second threshold.

Switching power supply device

A control circuit of a DC/DC converter having a transformer, a switching transistor, and a detector includes: a feedback terminal receiving a feedback voltage corresponding to an output voltage of the DC/DC converter; a current detection terminal receiving a detection voltage generated in the detection resistor; a conversion circuit configured to amplify, attenuate and/or level-shift at least one of the feedback voltage and the detection voltage, wherein a gain and/or a shift of the conversion circuit are variable; and a gain controller configured to control the gain and/or the shift of the conversion circuit.

DC/DC converter, control circuit thereof, power supply, power adapter and electronic apparatus using the same

A control circuit of a DC/DC converter includes: a pulse modulator configured to generate a pulse signal; and a driver configured to switch a switching transistor based on the pulse signal. The pulse modulator includes an on signal generator to generate an on signal. The on signal generator includes: a bottom detection comparator configured to compare a voltage of one end of an auxiliary winding with a predetermined threshold voltage and generate a bottom detection signal; a first time-out circuit configured to generate a first time-out signal asserted when the bottom detection signal is not asserted; a second time-out circuit configured to generate a second time-out signal asserted when the bottom detection signal is not asserted; and a logic part configured to generate the on signal based on the bottom detection signal, the first time-out signal and the second time-out signal.

DC/DC converter, control circuit and control method thereof, power supply, power adapter and electronic apparatus using the same

An external resistor is connected to a detection terminal. A pulse modulator is configured to generate a pulse signal Shaving a duty ratio adjusted such that the output voltage Vof a DC/DC converter approaches a target value. A pulse modulator is configured to switch the pulse signal Sto a level that corresponds to the off level of the switching transistor according to a detection voltage Vthat develops at the detection terminal. A short-circuit detection circuit is configured to generate a short-circuit detection signal which is asserted when the detection voltage Vis higher than a predetermined threshold voltage Vafter a judgment time elapses after the pulse signal Sis switched to an on level that corresponds to the on state of the switching transistor. When the short-circuit detection signal is asserted, the pulse modulator is configured to switch the pulse signal Sto the off level.

Growing community of inventors

Kyoto, Japan

Yoshinori Sato