Murata Manufacturing Co., Ltd.

Yasuo Ohashi

Seiichi Takahashi

Tadahiko Matsumoto

Koji Nishi

Jun Nagai

Naoto Sano

Keiji Inoue

Syuichi Honda

Toru Yoshikawa

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.

Switching power-supply module

A plurality of module substrates have circuit boards, respectively. The circuit boards are stacked with a space therebetween, and are connected to first end portions of connecting members. The second end portions of the connecting members are connected to connecting pads disposed on a motherboard. The module substrates are thus stacked and mounted on the motherboard so as to increase the mounting density. By causing the connecting members for the upper circuit board to project further than the connecting members for the lower circuit board, the connecting members for the upper and lower circuit boards are prevented from touching each other.

Mounting structure for module substrates

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.

Coil device

In a switching power-supply unit in which a series circuit comprising a primary winding of a switching transformer and a switching device is provided across the terminals of an input power supply, a noise-eliminating bypass capacitor is connected across the ends of the series circuit. The bypass capacitor forms a short circuit path for high frequency noise having a frequency higher than the switching frequency of the switching device, thereby reducing high-frequency radiant noise.

Switching power-supply unit

A current-mode control device for controlling an output voltage of a DC power supply including: a switching element for supplying an output voltage of the DC power supply through an on/off switching action; an output voltage detector circuit for detecting the output voltage of the DC power supply and outputting an output voltage based on the output voltage of the DC power supply; a current sense circuit for converting into a voltage a switching current flowing through the switching element during the switch-on period of the switching element to sense and output the resulting voltage; an integrating circuit for converting the switching current of the switching circuit that increases at a gradient of a straight line linear function with time during of the switch-on period of the switching element into a voltage that increases at a rate defined by a quadratic or higher-order curved line with time by integrating the switching current of the switching circuit at least once and for superimposing the resulting voltage on the output voltage of the current sense circuit; and a switching control circuit for controlling the on/off switching action of the switching element in response to the output voltage of the output voltage detector circuit and the output voltage of the current sense circuit on which the output voltage of the integrating circuit is superimposed such that the output voltage of the DC power supply is stabilized.

Current-mode control device and switching power supply employing same

According to one embodiment of a switching power supply, a superimposition circuit including a resistor is connected in parallel to the primary coil of a transformer. A superimposition current is supplied to a current sensing circuit during a switching-on period of a switching element. The current sensing circuit detects the current flowing through the primary coil during the switch-on period. According to the detected current, a switch control circuit controls switching on and off of the switching element so as to stabilize the output voltage. When the current becomes low in a case in which the circuit has a light load or receives a high input voltage, noise generally causes substantial adverse effects. However, since the detected current in the current sensing circuit is biased to become larger by superimposing the superimposition current of the superimposition circuit on the current flowing through the primary coil, the output voltage is stabilized without receiving adverse effects of noise even if the current passing through the primary coil becomes low.

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Tokyo-to, Japan

Yasuo Ohashi