Abstract: A switching power-supply module includes circuit boards, power conversion circuit sections provided on the respective circuit boards, conductor land patterns provided with spacing therebetween along edges of the circuit boards, conductor terminals for interconnecting the conductor land patterns. The circuit boards are stacked with spacing therebetween with the corresponding conductor land patterns being aligned, and the aligned conductor land patterns are interconnected by the corresponding conductor terminals. At least one of the conductor terminals includes an interboard-connection portion for interconnecting the conductor land patterns of the circuit boards and a leg portion that extends from the interboard-connection portion in the stacking direction of the circuit boards and that defines an external-connection portion, and the other conductor terminals each function as an interboard-connection dedicated terminal for providing connection between the circuit boards.

Abstract: A first drive control signal regenerating circuit outputs an ON timing drive signal at turn-ON of a main switch element, and a second drive control signal regenerating circuit generates an OFF timing drive signal at turn-OFF of the main switch element. A rectifying switch controlling switch element connected between the gate and source of a rectifying switch element is driven by an output of the second drive control signal regenerating circuit. An output of the first drive control signal regenerating circuit connects to the gate of a commutating switch controlling switch element, which connects to one end of an auxiliary winding, the other end thereof being connected to the gate of a commutating switch element. Accordingly, the rectifying switch element is directly controlled from the primary side.

Abstract: A primary side is provided with an oscillation circuit arranged to turn on a power switch at a constant cycle. The secondary side is provided with an on period control circuit arranged to output an off signal for turning the power switch off by detecting output voltage and comparing with a reference triangle wave signal. An insulated signal transfer circuit is provided between the primary side and secondary side to transfer an on signal. The primary side is provided with a power switch off circuit arranged to turn off the power switch based on the on signal.

Abstract: A switching power supply unit includes an overcurrent protection circuit section and a latch-stop release signal output circuit section. The overcurrent protection circuit section performs an overcurrent protection operation for latching and stopping the switching operation of a main switch during an overcurrent state. The latch-stop release signal output circuit section outputs a signal, only in a predetermined latch-stop release period, for releasing the latch stop after a certain waiting time has elapsed from the time of the latch stop. This arrangement can virtually perform a hiccup-mode overcurrent protection operation at the time of overcurrent, and expands the scope of application of a switching power supply unit. Switching power supply circuits are interconnected by simultaneous starting connections. Switching controllers for the main switches are connected to match hiccup mode restart timings.

Abstract: A switching power-supply module includes circuit boards, power conversion circuit sections provided on the respective circuit boards, conductor land patterns provided with spacing therebetween along edges of the circuit boards, conductor terminals for interconnecting the conductor land patterns. The circuit boards are stacked with spacing therebetween with the corresponding conductor land patterns being aligned, and the aligned conductor land patterns are interconnected by the corresponding conductor terminals. At least one of the conductor terminals includes an interboard-connection portion for interconnecting the conductor land patterns of the circuit boards and a leg portion that extends from the interboard-connection portion in the stacking direction of the circuit boards and that defines an external-connection portion, and the other conductor terminals each function as an interboard-connection dedicated terminal for providing connection between the circuit boards.

Abstract: A DC-DC converter includes an ON-timing delay circuit in which, when an ON signal is output from a power switch driving circuit in a control IC to a power switch, the ON timing of the power switch is delayed by hindering the start of the ON operation of the power switch. An early turnoff circuit is provided in which, during delay of the ON timing of the power switch, a commutating synchronous rectifier has an ON and OFF switching operation that is inverse with respect to that of the power switch. A delay eliminating circuit is provided which promptly stops the delay operation of the ON-timing delay circuit when detecting the turnoff of the commutating synchronous rectifier which is caused by a drop in the gate of a commutating synchronous rectifier. When the delay operation of the ON-timing delay circuit continues after the turnoff the commutating synchronous rectifier, a loss caused by the continuation of the delay operation occurs. The problem can be prevented by the delay eliminating circuit.

Abstract: A DC-DC converter includes a reverse current detector for detecting a reverse current and a reverse current suppressor for increasing an input-output conversion ratio when a reverse current is detected. A choke coil increases the inductance in a current flowing region in which a very small reverse current flows and reduces the inductance in a current flowing region in which the current flowing is greater than or equal to that in a normal operation mode. In a reverse current flowing region in which the output current is negative, the DC-DC converter has unique regulation characteristics in which the amount of change in the output voltage relative to the amount of change in the output current is very large.

Abstract: A switching power-supply module includes a coil pattern of a transformer or an inductor disposed on a substrate. A portion of the coil pattern projects into an edge portion of the substrate. A plurality of terminals are arranged in the substrate edge portion so that they do not touch the coil pattern. The substrate edge portion is soaked in molten solder in the production procedure in order to fix the terminals onto the substrate with solder after components are solder-connected on the substrate. For this reason, the components were previously prohibited from being mounted in the substrate edge portion, and this region has been previously considered to be a dead space. However, in the present invention, since a portion of the coil pattern projects into the substrate edge portion, dead space is minimized, and the size of the substrate, that is, of the switching power supply module is greatly reduced.

Abstract: A DC-DC converter includes an ON-timing delay circuit in which, when an ON signal is output from a power switch driving circuit in a control IC to a power switch, the ON timing of the power switch is delayed by hindering the start of the ON operation of the power switch. An early turnoff circuit is provided in which, during delay of the ON timing of the power switch, a commutating synchronous rectifier has an ON and OFF switching operation that is inverse with respect to that of the power switch. A delay eliminating circuit is provided which promptly stops the delay operation of the ON-timing delay circuit when detecting the turnoff of the commutating synchronous rectifier which is caused by a drop in the gate of a commutating synchronous rectifier. When the delay operation of the ON-timing delay circuit continues after the turnoff the commutating synchronous rectifier, a loss caused by the continuation of the delay operation occurs. The problem can be prevented by the delay eliminating circuit.

Abstract: In order to improve efficiency of core rubbing operation and also to facilitate reduction in thickness of a coil device, a core-combining member includes substantially U-shaped topside and backside cover members, and a pair of core members are clamped and combined together from top and backsides by fitting the topside and backside cover members to each other. Legs of the topside cover member are provided with leg-openings formed therein while legs of the backside cover member are provided with convex parts for retaining to edges of the leg-openings so as to prevent detachment. A play clearance in the front and rear direction is provided between the convex part and an edge of the leg opening. Core rubbing is performed by relatively moving the cover members in the front and rear direction so as to integrally move the core members while maintaining the core members to be clamped. Stopper means is provided for restricting the relative displacement in the front and rear direction.

Abstract: An insulating-type switching electric power source device has an input voltage Vin of a primary side that is converted at an input/output ratio determined by switching operations of a switching device, and then is output. Voltage subjected to rectifying and smoothing by a primary-side rectification smoothing circuit is used as detecting signals of the output voltage, to control the time ratio of the switching device. A load regulation correcting circuit outputs load regulation correcting signals correlated with the amount of output current. A temperature compensating circuit corrects the load regulation correcting signals according to the ambient temperature. The load regulation correcting signals correct the output voltage detecting signals according to the fluctuations of the output voltage according to fluctuations in the output current and fluctuations in the ambient temperature.

Abstract: A switching power supply unit includes an overcurrent protection circuit section and a latch-stop release signal output circuit section. The overcurrent protection circuit section performs an overcurrent protection operation for latching and stopping the switching operation of a main switch during an overcurrent state. The latch-stop release signal output circuit section outputs a signal, only in a predetermined latch-stop release period, for releasing the latch stop after a certain waiting time has elapsed from the time of the latch stop. This arrangement can virtually perform a hiccup-mode overcurrent protection operation at the time of overcurrent, and expands the scope of application of a switching power supply unit. Switching power supply circuits are interconnected by simultaneous starting connections. Switching controllers for the main switches are connected to match hiccup mode restart timings.

Abstract: A DC-DC converter has a primary-side circuit connected to a DC power supply and a converter for converting voltage supplied by the DC power supply into an AC signal; a secondary-side circuit for rectifying and smoothing the AC signal transmitted from the primary-side circuit to supply power to a load; and an auxiliary rectifying and smoothing circuit for rectifying and smoothing the AC signal transmitted from the primary-side circuit to supply sub-power supply voltage to the converter of the primary-side circuit. The primary-side circuit further has a monitoring circuit for monitoring the sub-power supply voltage supplied from the auxiliary rectifying and smoothing circuit to the converter and a stop circuit for latching a conversion operation of the converter into an OFF state.

Abstract: A DC-DC converter includes a reverse current detector for detecting a reverse current and a reverse current suppressor for increasing an input-output conversion ratio when a reverse current is detected. A choke coil increases the inductance in a current flowing region in which a very small reverse current flows and reduces the inductance in a current flowing region in which the current flowing is greater than or equal to that in a normal operation mode. In a reverse current flowing region in which the output current is negative, the DC-DC converter has unique regulation characteristics in which the amount of change in the output voltage relative to the amount of change in the output current is very large. Thus, an increase in the reverse current is prevented, the components are protected from damage by the reverse current flowing, and an increase in the loss is prevented.

Abstract: An insulating-type switching electric power source device has an input voltage Vin of a primary side that is converted at an input/output ratio determined by switching operations of a switching device, and then is output. Voltage subjected to rectifying and smoothing by a primary-side rectification smoothing circuit is used as detecting signals of the output voltage, to control the time ratio of the switching device. A load regulation correcting circuit outputs load regulation correcting signals correlated with the amount of output current. A temperature compensating circuit corrects the load regulation correcting signals according to the ambient temperature. The load regulation correcting signals correct the output voltage detecting signals according to the fluctuations of the output voltage according to fluctuations in the output current and fluctuations in the ambient temperature.

Abstract: In order to improve efficiency of core rubbing operation and also to facilitate reduction in thickness of a coil device, a core-combining member includes substantially U-shaped topside and backside cover members, and a pair of core members are clamped and combined together from top and backsides by fitting the topside and backside cover members to each other. Legs of the topside cover member are provided with leg-openings formed therein while legs of the backside cover member are provided with convex parts for retaining to edges of the leg-openings so as to prevent detachment. A play clearance in the front and rear direction is provided between the convex part and an edge of the leg opening. Core rubbing is performed by relatively moving the cover members in the front and rear direction so as to integrally move the core members while maintaining the core members to be clamped. Stopper means is provided for restricting the relative displacement in the front and rear direction.

Abstract: A switching power-supply module includes a coil pattern of a transformer or an inductor disposed on a substrate. A portion of the coil pattern projects into an edge portion of the substrate. A plurality of terminals are arranged in the substrate edge portion so that they do not touch the coil pattern. The substrate edge portion is soaked in molten solder in the production procedure in order to fix the terminals onto the substrate with solder after components are solder-connected on the substrate. For this reason, the components were previously prohibited from being mounted in the substrate edge portion, and this region has been previously considered to be a dead space. However, in the present invention, since a portion of the coil pattern projects into the substrate edge portion, dead space is minimized, and the size of the substrate, that is, of the switching power supply module is greatly reduced.

Abstract: A DC-DC converter having a switching element and a synchronous rectifier, the switching element undergoing a switching operation, the converter performing a voltage conversion of an input voltage to provide a converted output voltage at an output/input conversion ratio that is determined by the switching operation of said switching element, the converter delivering the converted output voltage to a load, said DC-DC converter further comprising: a reverse current detector for detecting a reverse current which flows from an output of the converter to an input of the converter, and a reverse current suppressor, the reverse current suppressor controlling the switching operation of said switching element so as to increase the output/input conversion ratio when a reverse current is detected by the reverse current detector, thereby suppressing the reverse current.

Abstract: A transformer of a switching power-supply circuit is placed and mounted nearly in the middle area of a circuit board. The transformer is of a low-profile type, and a broad and flat upper surface of the transformer functions as a suction surface for a suction nozzle. When a surface-mount type switching power-supply unit is mounted in a mother board, firstly, the upper surface of the above transformer is held by the suction nozzle, the surface-mount type switching power-supply unit is transferred to a target mounting area on the mother board by the suction nozzle, and the surface-mount type switching power-supply unit is surface mounted in the mother board. Because it is not required to provide a nozzle suction surface for the suction nozzle's exclusive use, transfer molding is not needed, and accordingly a low-profile and low-cost surface-mount type switching power-supply unit can be facilitated.

Abstract: A switching power supply has a transformer for power transmission. A core is provided having an intermediate leg and at least a pair of external legs arranged at equal intervals from the intermediate leg; a first printed coil is provided on a first substrate which has an intermediate hole and a pair of external holes respectively inserted in the intermediate leg and the pair of external legs of the core, the first printed coil being wound around the intermediate hole; a second printed coil is provided on a second substrate which has an intermediate hole and a pair of external holes respectively inserted in the intermediate leg and the pair of external legs of the core, the second printed coil including a pair of external printed coils which are connected in series and are respectively wound around the pair of the external holes and each having the same number of turns but wound in opposite directions.