Abstract: A power converter having a primary circuit (e.g. full bridge) and a secondary circuit (e.g. current doubler) has switches in the secondary circuit that are controlled by a drive circuit. The drive circuit is connected to a swing node in the primary circuit, and is powered by the swing node. The drive circuit has an isolation device such as a transformer to provide electrical isolation between the primary circuit and secondary circuit. The drive circuit provides a current source for driving the secondary switch gates, thereby reducing power consumption. The present drive circuit provides clean gate drive signals without noise and oscillations. The drive circuits of the invention are simple, and require only a few components.

Abstract: A sleeved case design which provides variable increases in creepage distance for toroidal inductors mounted in a case for automatic insertion into circuit boards by means of sleeves protruding upward into the case from mounting holes in the case floor. A sleeve surrounds the hole so that the shortest distance from the case floor at the point of closest contact with the inductor along a case surface to the hole is up the outside of the sleeve and down the inside of the sleeve. The wire leads of the secondary for the inductor are routed through the sleeves.

Abstract: A digital filter having a small amount of hardware is realized by constructing a cosine roll-off filter. In the filter the first and fifth multipliers and the second to fourth multipliers are respectively shared. Three selectors are provided corresponding to the multipliers, and coefficient groups ka1 to ka3, and kb1 and kb3 are inputted by the selectors to the corresponding multipliers by time sharing. The results of multiplications by the multipliers when the coefficient groups kb1 to kb3 are inputted, are added between corresponding multipliers by adders. A final output is derived from an output selector.