A pulse width modulation integrated circuit chip available as an 8-pin DIP or a 14-pin SOP package is characterized by simplified circuit complexity, high package density, more voltage regulation functions and more pin functions. An elastomeric hinge member is provided for connecting the closure member or flapper valve to the substantially cylindrical support member so that when closed the flapper valve or closure member conforms to the confronting cam shaped end of the cylindrical support member with the sealing member disposed therebetween. The second region has two side edges and there are first and second transition regions between the first region and the side edges of the second region. A switch element is adapted to connect one of the first ports to at least one of the second ports so that data may be exchanged between the ports for each device group and corresponding device group.