Abstract: 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.

Abstract: A switching power supply device having: a power supply terminal VCC connected to one end of an output capacitor Co2; a high-voltage terminal VH connected to the input side of an input voltage Vdc; and a starting circuit 101 provided between the power supply terminal VCC and the high-voltage terminal VF, the starting circuit 101 passing a first current for charging the output capacitor Co2 via the power supply terminal VCC. The switching power supply device is provided with: a control circuit 10 for turning a switching element M1 on and off; and a current-supplementing circuit 30 to which the input voltage Vdc is inputted, the current-supplementing circuit 30 being connected to the high-voltage terminal VH, the current-supplementing circuit 30 passing a second current to the output capacitor side on the basis of the first current. A load L2 can be connected to the other end of the output capacitor.

Abstract: A semiconductor device includes an integration of a first external terminal to which a DC input voltage is input, a second external terminal to which a rectifying and smoothing circuit is externally connected, an output transistor connected between the first external terminal and the second external terminal, a control circuit arranged to turn on and off the output transistor so that a desired DC output voltage can be obtained from the rectifying and smoothing circuit, a current detection circuit arranged to generate a sense voltage corresponding to an on-current of the output transistor, and an overcurrent protection circuit arranged to monitor the sense voltage so as to perform an overcurrent protection operation.

Abstract: A switching regulator has: a switching device; a rectifying device having the anode thereof connected to an output terminal from which an output voltage is output; an inductor arranged between the switching device and the output terminal; a controller having an error amplifier configured to produce an error signal commensurate with a difference between a voltage commensurate with the cathode voltage of the rectifying device and a reference voltage, the controller using the cathode voltage of the rectifying device as a supply voltage and turning ON and OFF the switching device according to the cathode voltage of the rectifying device; a monitor configured to monitor a current that flows through the inductor; and a current varier configured to increase, based on the result of monitoring by the monitor, a current that flows through the rectifying device with increase in the current flowing through the inductor.

Abstract: A power source apparatus comprises: a transformer that insulates a primary system and a secondary system and uses primary/secondary windings to transform an input voltage into an output voltage; a switching control device that is disposed in the primary system to drive the primary winding, and an output monitor device that is disposed in the secondary system to monitor the output voltage. The transformer includes a first auxiliary winding disposed in the primary system and a second auxiliary winding disposed in the secondary system. The output monitor device drives the second auxiliary winding to generate an induced voltage in the first auxiliary winding when the output voltage becomes smaller than a predetermined threshold voltage. The switching control device temporarily stops driving of the first winding upon detecting a light load state and resumes the driving of the first winding upon detecting the induced voltage in the first auxiliary winding.

Abstract: A switching power supply device having: a power supply terminal VCC connected to one end of an output capacitor Co2; a high-voltage terminal VH connected to the input side of an input voltage Vdc; and a starting circuit 101 provided between the power supply terminal VCC and the high-voltage terminal VF, the starting circuit 101 passing a first current for charging the output capacitor Co2 via the power supply terminal VCC. The switching power supply device is provided with: a control circuit 10 for turning a switching element M1 on and off; and a current-supplementing circuit 30 to which the input voltage Vdc is inputted, the current-supplementing circuit 30 being connected to the high-voltage terminal VH, the current-supplementing circuit 30 passing a second current to the output capacitor Co2 side on the basis of the first current. A load L2 can be connected to the other end of the output capacitor.

Abstract: A primary side controller for controlling a switching transistor on a primary side of an insulated DC/DC converter, includes: a low voltage state detecting circuit configured to detect a low voltage state in which an output voltage of the DC/DC converter is lower than a predetermined value; and a pulse width modulator configured to generate a pulse signal whose ON time is adjusted depending on a feedback signal from a secondary side, wherein a period of the pulse signal in the low voltage state is longer than a period of the pulse signal in a non-low voltage state in which the output voltage is higher than the predetermined value.

Abstract: A switching regulator has: a switching device; a rectifying device having the anode thereof connected to an output terminal from which an output voltage is output; an inductor arranged between the switching device and the output terminal; a controller having an error amplifier configured to produce an error signal commensurate with a difference between a voltage commensurate with the cathode voltage of the rectifying device and a reference voltage, the controller using the cathode voltage of the rectifying device as a supply voltage and turning ON and OFF the switching device according to the cathode voltage of the rectifying device; a monitor configured to monitor a current that flows through the inductor; and a current varier configured to increase, based on the result of monitoring by the monitor, a current that flows through the rectifying device with increase in the current flowing through the inductor.

Abstract: A semiconductor device includes an integration of a first external terminal to which a DC input voltage is input, a second external terminal to which a rectifying and smoothing circuit is externally connected, an output transistor connected between the first external terminal and the second external terminal, a control circuit arranged to turn on and off the output transistor so that a desired DC output voltage can be obtained from the rectifying and smoothing circuit, a current detection circuit arranged to generate a sense voltage corresponding to an on-current of the output transistor, and an overcurrent protection circuit arranged to monitor the sense voltage so as to perform an overcurrent protection operation.

Abstract: A power source apparatus comprises: a transformer that insulates a primary system and a secondary system and uses primary/secondary windings to transform an input voltage into an output voltage; a switching control device that is disposed in the primary system to drive the primary winding, and an output monitor device that is disposed in the secondary system to monitor the output voltage. The transformer includes a first auxiliary winding disposed in the primary system and a second auxiliary winding disposed in the secondary system. The output monitor device drives the second auxiliary winding to generate an induced voltage in the first auxiliary winding when the output voltage becomes smaller than a predetermined threshold voltage. The switching control device temporarily stops driving of the first winding upon detecting a light load state and resumes the driving of the first winding upon detecting the induced voltage in the first auxiliary winding.

Abstract: A power source apparatus comprises: a transformer that insulates a primary system and a secondary system and uses primary/secondary windings to transform an input voltage into an output voltage; a switching control device that is disposed in the primary system to drive the primary winding, and an output monitor device that is disposed in the secondary system to monitor the output voltage. The transformer includes a first auxiliary winding disposed in the primary system and a second auxiliary winding disposed in the secondary system. The output monitor device drives the second auxiliary winding to generate an induced voltage in the first auxiliary winding when the output voltage becomes smaller than a predetermined threshold voltage. The switching control device temporarily stops driving of the first winding upon detecting a light load state and resumes the driving of the first winding upon detecting the induced voltage in the first auxiliary winding.

Abstract: A second control circuit is configured to switch a pulse signal to a level which turns off a second switching transistor when a coil current that flows through a primary winding reaches a predetermined threshold current. The second control circuit is configured to start a switching operation when a power supply for an electronic device is turned on, to set the threshold current to a first value when an intermediate voltage is higher than a predetermined level, and to set the threshold current to a second value that is lower than the first value when the intermediate voltage is lower than a predetermined level. A first control circuit is configured to start a switching operation upon receiving an instruction from a microcontroller to start operating.

Abstract: Provided is a switching power supply circuit including an output transistor arranged to be turned on and off to generate a desired output voltage from a pulsating voltage obtained by rectifying an AC input voltage, an oscillator arranged to generate an ON signal at a switching frequency varying periodically in synchronization with the AC input voltage or the pulsating voltage, a controller arranged to generate an OFF signal so that the output voltage is adjusted to a target value while a power factor becomes close to one, a logic circuit arranged to generate a switch control signal in accordance with the ON signal and the OFF signal, and a driver arranged to turn on and off the output transistor in accordance with the switch control signal.

Abstract: The PD device includes: a DC/DC converter disposed between an input and an output; a primary-side controller configured to control an input current of the DC/DC converter; and a secondary-side controller connected with AC coupling to the output, and configured to feed back electric power information of the output to the primary-side controller. The primary-side controller varies an output voltage value and an available output current capacity of the DC/DC converter by controlling the input current on the basis of the electric power information fed back from the secondary-side controller.

Abstract: A power supply adapter receives an AC voltage, converts the AC voltage into a DC voltage, and supplies the DC voltage to an electronic device. A DC/DC converter converts the voltage smoothed by a smoothing capacitor into the DC voltage. A device-side connector is connected to the DC/DC converter via a cable, and is configured to be detachably connected to the electronic device. The device-side connector includes a detection unit detecting whether or not the electronic device is connected, and generates a connection detection signal indicating whether or not the electronic device is connected. A control circuit of the DC/DC converter is connected to the detection unit of the device-side connector via the cable, and is set to an operating state when the connection detection signal indicates that the electronic device is connected, and is set to a non-operating state when the connection detection signal indicates that the electronic device is not connected.

Abstract: Provided is a switching power supply circuit including an output transistor arranged to be turned on and off to generate a desired output voltage from a pulsating voltage obtained by rectifying an AC input voltage, an oscillator arranged to generate an ON signal at a switching frequency varying periodically in synchronization with the AC input voltage or the pulsating voltage, a controller arranged to generate an OFF signal so that the output voltage is adjusted to a target value while a power factor becomes close to one, a logic circuit arranged to generate a switch control signal in accordance with the ON signal and the OFF signal, and a driver arranged to turn on and off the output transistor in accordance with the switch control signal.

Abstract: The present invention provides an Alternating Current/Direct Current (AC/DC) converter employing measures not only against residual voltage but also to reduce power consumption. The AC/DC converter receives an Alternating Current (AC) voltage through a concentric plug and converts the AC voltage into a Direct Current (DC) voltage. A discharge path is disposed on a path from a discharge terminal to a ground terminal. A detection circuit compares a wave detection voltage with a predetermined threshold voltage, and enables the discharge path to be turned on when the wave detection voltage is continuously lower than the threshold voltage for a predetermined detection time.

Abstract: The PD device comprises a primary-side controller configured to control an input current of a DC/DC converter disposed between an input and an output, and a secondary-side controller connected with AC coupling to the output, and configured to feed back electric power information of the output to the primary-side controller. The primary-side controller varies an output voltage value and an available output current capacity of the DC/DC converter by controlling the input current on the basis of the electric power information fed back from the secondary-side controller. The primary-side controller can change an overpower detecting set value in accordance with the target equipments connected to the output, thereby executing the power change of the DC/DC converter.

Abstract: A pulse modulator generates a pulse modulation signal SPM having a duty ratio which is adjusted according to a feedback voltage Vfb that corresponds to the output voltage VOUT of a DC/DC converter. A second oscillator generates a second cyclic signal which is asserted with each of a predetermined second period. A light load detection circuit generates a light load detection signal which is asserted when the feedback voltage Vfb becomes lower than a first threshold voltage. A driving circuit drives a switching transistor according to the pulse modulation signal SPM. Furthermore, the driving circuit suspends the driving of the switching transistor during a period until the second cyclic signal is next asserted after the light load detection signal is asserted.

Abstract: 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.