Method and circuit for scalable cross point switching using 3-D die stacking

A method of configuring a cross point switch for cross connections of components on a component die, the method comprising:

• adding a first switching die over the component die, the first switching die including a plurality of ingress stage switches cross connected to multiplexers having outputs coupled to the inputs of a plurality of middle stage switches;
• coupling an input port to the inputs of the ingress switches of the first switching die;
• and
• controlling the multiplexers to select the inputs from the input port or the outputs of the ingress stage switch for the middle stage switch.

A configurable cross point switching unit comprising:

• a component die including an interconnection interface region including input ports and output ports;
• a plurality of switching dies stacked on the component die, each of the plurality of switching dies including a plurality of ingress switches, a plurality of multiplexers and a plurality of middle stage switches, wherein the outputs of the ingress switches are connected via the multiplexers to the inputs of the middle stage switches for each of the plurality of switching dies;
• a plurality of input through-silicon vias (TSVs) between the input ports of the interconnection interface region and the inputs of the ingress switches of the plurality of switching dies;
• a plurality of output TSVs between the output ports of the interconnection interfaces and the outputs of the ingress switches and the middle stage switches;
• and
• wherein at least one of the switching dies includes a first plurality of TSVs between the outputs of the ingress switches and the multiplexer of a switching die on top of the at least one of the switching dies and a second plurality of TSVs between the outputs of the ingress switches and the multiplexer of a switching die below the at least one of the switching dies.