Abstract: Methods, systems, and computer program products for abstracting device driver development by layering certain functionality. A driver layer encapsulates device commands and data within a format that is independent of the type of connection between the device and a host computer. Once encapsulated, the device commands and data pass through an intermediate layer responsible for transferring the encapsulated device commands and data to a connection-specific layer. The connection-specific layer then places the encapsulated device commands and data on the particular connection that couples the device and host computer. A single driver layer, potentially provided by an operating system, can thus operate a plurality of devices. Accordingly, hardware developers can be freed from the burden of writing the numerous host-based device drivers that are otherwise required to support an increasing number of connections between devices and host computers, specifically exemplified by improved bus and networking technologies.

Abstract: A low loss clamp circuit is provided for a dc to dc converter. The converter has a transformer with a secondary winding and a secondary circuit and a center tap primary winding. A dc voltage input is supplied to the primary winding center tap and to a circuit ground. A rectifier such as a bridge rectifier connects to two ends of the secondary winding and to the circuit ground to supply a dc output voltage. A pair of semiconductor switches such as FET switches are provided. Each end of the primary winding is connected through a respective switch to the common ground. The various circuits have energy storage means including the input capacitor 31 and input choke 32 in circuit with the primary winding. It will also be noted that the output capacitor 29 is a part of the energy storage means. This energy storage means is connected to return energy to the secondary circuit, not the primary circuit.