Abstract: In a DC-DC converter, a voltage at a connecting point where a switching transistor is connected to an inductor is compared with a threshold voltage set within a variation range of the voltage at the connecting point during switching operation of the switching transistor. When a polarity in which the voltage at the connecting point and the threshold voltage are compared does not vary in a detection time longer than the predetermined period of a driving circuit, the switching transistor is determined to be operating in an active state with a risk of heat generation.

Abstract: In a DC-DC converter, a voltage at a connection point on the side of connection with a primary winding of a switching transistor is compared to a threshold voltage set within a variation range of the voltage at the connection point while the switching transistor is performing a switching operation, and, when the polarity by which the voltage was compared to the threshold voltage does not change during a detection period longer than the predetermined period of the drive signal for bringing the switching transistor under switching control, the switching transistor is determined as being operating in an active state with a danger of heat generation.

Abstract: An object of the present disclosure is to provide a DC-to-DC converter with a simple circuit configuration that continues the supply of direct current power to a load without providing a redundant power supply circuit even if a switching transistor operates abnormally in the active state. A protection circuit unit that converts an input voltage of a direct current input power supply to a different direct current voltage obtained by stepping down the input voltage, as in a direct current voltage conversion circuit unit including a first switching transistor, is connected between the direct current voltage conversion circuit unit and the direct current input power supply and, if the first switching transistor operates in an active state, direct current power of the direct current voltage converted by the protection circuit unit is supplied to a load causing the first switching transistor to maintain operating in the active state.

Abstract: An object of the present disclosure is to provide a DC-to-DC converter with a simple circuit configuration that continues the supply of direct current power to a load without providing a redundant power supply circuit even if a switching transistor operates abnormally in the active state. A protection circuit unit that converts an input voltage of a direct current input power supply to a different direct current voltage obtained by stepping down the input voltage, as in a direct current voltage conversion circuit unit including a first switching transistor, is connected between the direct current voltage conversion circuit unit and the direct current input power supply and, if the first switching transistor operates in an active state, direct current power of the direct current voltage converted by the protection circuit unit is supplied to a load causing the first switching transistor to maintain operating in the active state.

Abstract: Provided is a contact contacting structure that reliably prevents the development of arc discharge in a simple configuration regardless of the magnitude of electric energy accumulated between a pair of contacts that are connected and disconnected. An intermediate contact body disposed continuously with a first contact along a movement path of a second contact is formed from material with higher electric resistivity than the first contact in a shape such that the cross sectional area of a transverse section perpendicular to the movement path is gradually decreased in a separating direction along the movement path.

Abstract: Provided is a contact contacting structure that reliably prevents the development of arc discharge in a simple configuration regardless of the magnitude of electric energy accumulated between a pair of contacts that are connected and disconnected. An intermediate contact body disposed continuously with a first contact along a movement path of a second contact is formed from material with higher electric resistivity than the first contact in a shape such that the cross sectional area of a transverse section perpendicular to the movement path is gradually decreased in a separating direction along the movement path.

Abstract: In a DC-DC converter, a voltage at a connection point on the side of connection with a primary winding of a switching transistor is compared to a threshold voltage set within a variation range of the voltage at the connection point while the switching transistor is performing a switching operation, and, when the polarity by which the voltage was compared to the threshold voltage does not change during a detection period longer than the predetermined period of the drive signal for bringing the switching transistor under switching control, the switching transistor is determined as being operating in an active state with a danger of heat generation.

Abstract: In a DC-DC converter, a voltage at a connecting point where a switching transistor is connected to an inductor is compared with a threshold voltage set within a variation range of the voltage at the connecting point during switching operation of the switching transistor. When a polarity in which the voltage at the connecting point and the threshold voltage are compared does not vary in a detection time longer than the predetermined period of a driving circuit, the switching transistor is determined to be operating in an active state with a risk of heat generation.

Abstract: There is provided a self-excited switching power supply circuit. A cycle control capacitor is charged with a flyback voltage generated in a feedback winding of a transformer during OFF operation period in which an exciting current does not flow in a primary winding of the transformer. An OFF control capacitor the charging speed of which changes ON operation period is charged with the charging voltage of the cycle control capacitor during the ON operation period in which an exciting current flows in the primary winding. The charging voltage of the cycle control capacitor is changed with a periodic cycle Tc sufficiently longer than an oscillation cycle To to make the oscillation cycle To of continuous oscillating operation variable based on the periodic cycle Tc. As a result, the frequency of a harmonic is distributed.

Abstract: Provided is a power supply system which is capable of controlling a power receive device to have an input voltage or an input current at a predetermined input setting value even when a power supply device and the power receive device are connected to each other with an arbitrary power cable. The power receive device detects the input voltage or the input current inputted through the power cable and transmits a detected input voltage or input current as power-receive side information to the power supply device through the power cable. The power supply device controls the output value of an output voltage or an output current to be outputted to the power cable based on the power-receive side information received through the power cable so that the input voltage or the input current to be inputted to the power receive device is converged on a predetermined input setting value.

Abstract: There is provided a self-excited switching power supply circuit which shifts to continuous oscillating operation immediately after the self-excited switching power supply circuit is connected to an AC power supply and started and which does not cause start-up failure while using a start-up resistor of a high resistance value to maintain standby power consumption at a low level. A bypass charging circuit connected in series to a start-up resistor is connected between a high-voltage side terminal of a DC input power supply and the gate of an oscillation field effect transistor. A charging current flowing in the start-up resistor, and additionally, a charging current to charge a start-up capacitor through the bypass charging circuit flow in a transitional period during which the voltage of the DC input power supply increases.

Abstract: There is provided a self-excited switching power supply circuit which shifts to continuous oscillating operation immediately after the self-excited switching power supply circuit is connected to an AC power supply and started and which does not cause start-up failure while using a start-up resistor of a high resistance value to maintain standby power consumption at a low level. A bypass charging circuit connected in series to a start-up resistor is connected between a high-voltage side terminal of a DC input power supply and the gate of an oscillation field effect transistor. A charging current flowing in the start-up resistor, and additionally, a charging current to charge a start-up capacitor through the bypass charging circuit flow in a transitional period during which the voltage of the DC input power supply increases.

Abstract: There is provided a self-excited switching power supply circuit. A cycle control capacitor is charged with a flyback voltage generated in a feedback winding of a transformer during OFF operation period in which an exciting current does not flow in a primary winding of the transformer. An OFF control capacitor the charging speed of which changes ON operation period is charged with the charging voltage of the cycle control capacitor during the ON operation period in which an exciting current flows in the primary winding. The charging voltage of the cycle control capacitor is changed with a periodic cycle Tc sufficiently longer than an oscillation cycle To to make the oscillation cycle To of continuous oscillating operation variable based on the periodic cycle Tc. As a result, the frequency of a harmonic is distributed.

Abstract: In a synchronous rectification switching power supply circuit, a primary winding of a transformer and a main switching device are serially connected to a direct current input power supply. A secondary winding and a synchronous rectification device on the secondary side are serially connected between output terminals. A power supply apparatus has a capacitor charged with a voltage across the winding on the secondary side of the transformer by turning the main switching device on and off. An electronic instrument, to which the power supply apparatus is connected, has a control IC which sends a control signal to the gate terminal of the synchronous rectification device. When the synchronous rectification device is turned on, the output capacitor is charged and the direct current input power supply recovers power from the output capacitor through the transformer, thereby supplying output electric power set by the control IC to the electronic instrument.

Abstract: The present invention provides a constant voltage output control method and a constant voltage output control device for a switching power supply circuit that allow accurate execution of a constant voltage control of an output voltage, even if there is variation in a utilized circuit element or an integrated circuit. A set voltage V2aset is obtained based on equation (1), V2ASET=NP÷NS×V2BSET??(1) where, V2bset represents an output voltage of a secondary output winding that is subject to the constant voltage control, Np represents a number of turns of a primary winding, and Ns represents a number of turns of the secondary output winding; and the set voltage V2aset is compared with a flyback voltage V2a of the primary winding.

Abstract: A self-excited switching power supply circuit is provided which reduces a discharge current generated when an oscillating field effect transistor (3) is turned on, whereby it is possible to reduce energy loss and generation of noise when switching is executed. A time constant of an ON-control circuit (12, 23) is set such that when a polarity of a voltage of a feedback winding (2b) has reversed, a gate voltage of the oscillating field effect transistor (3) exceeds a threshold voltage VTH. Accordingly, after a voltage of a primary winding (2a) has become equal to or less than a power supply voltage, the oscillating field effect transistor (3) is turned on, and electrical charge stored in stray capacitance between the windings of the primary winding (2a) and in parasitic capacitance of the oscillating field effect transistor (3) is discharged gradually.

Abstract: In a synchronous rectification switching power supply circuit, a primary winding of a transformer and a main switching device are serially connected to a direct current input power supply. A secondary winding and a synchronous rectification device on the secondary side are serially connected between output terminals. A power supply apparatus has a capacitor charged with a voltage across the winding on the secondary side of the transformer by turning the main switching device on and off. An electronic instrument, to which the power supply apparatus is connected, has a control IC which sends a control signal to the gate terminal of the synchronous rectification device. When the synchronous rectification device is turned on, the output capacitor is charged and the direct current input power supply recovers power from the output capacitor through the transformer, thereby supplying output electric power set by the control IC to the electronic instrument.

Abstract: A constant current output control method and device for a switching power supply circuit for constant current output control of an output current I2o of a rectifying smoothing. An OFF adjustment time T3 is: T3=T2×(Np÷Ns×Ipref÷2÷I2oset?1)?T1??(1) in which, I2oset represents a set output current of the rectifying smoothing circuit, Np represents a number of turns of a primary winding, Ns represents a number of turns of a secondary winding, T1 being a fixed time representing an ON time, Ipref representing a reference peak current flowing in the primary winding, and T2 representing an output time during which output is generated from the rectifying smoothing circuit. Output current I2o during an oscillation period T becomes set output current I2oset, and constant current output control can be executed by repeating this method.

Abstract: A self-excited switching power supply circuit is provided which reduces a discharge current generated when an oscillating field effect transistor (3) is turned on, whereby it is possible to reduce energy loss and generation of noise when switching is executed. A time constant of an ON-control circuit (12, 23) is set such that when a polarity of a voltage of a feedback winding (2b) has reversed, a gate voltage of the oscillating field effect transistor (3) exceeds a threshold voltage VTH. Accordingly, after a voltage of a primary winding (2a) has become equal to or less than a power supply voltage, the oscillating field effect transistor (3) is turned on, and electrical charge stored in stray capacitance between the windings of the primary winding (2a) and in parasitic capacitance of the oscillating field effect transistor (3) is discharged gradually.

Abstract: A constant current output control method and device for a switching power supply circuit for constant current output control of an output current I2o of a rectifying smoothing.