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

A method of configuring a cross point switch on a first switching die for cross connections between a first plurality of electronic components and a second plurality of electronic components on a component die, the first switching die including a plurality of ingress stage switches each having outputs cross connected to inputs of a plurality of multiplexers, the plurality of multiplexers each having outputs coupled to inputs of a plurality of middle stage switches, the first switching die over the component die, the method comprising:

• selecting a plurality of input ports for the cross point switch, the plurality of input ports coupled to the first plurality of electronic components;
• selecting a plurality of output ports for the cross point switch, the plurality of output ports coupled to the second plurality of electronic components;
• coupling the plurality of input ports to inputs of the ingress switches of the first switching die;
• coupling the outputs of the middle stage switches to the plurality of output ports;
• and
• controlling the multiplexers via configuration information to select the input ports or the outputs of the ingress stage switches for sending signals to the inputs of the middle stage switches.

A configurable cross point switching unit having a variable number of active input ports and output ports cross connected to each other, the switching unit comprising:

• a component die having a switching interface region including a plurality of 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, each of the ingress switches, multiplexers and middle stage switches having inputs and outputs, wherein the outputs of the ingress switches are coupled via the multiplexers to the inputs of the middle stage switches;
• a first plurality of input through-silicon vias (TSVs) between the input ports of the switching interface region and the inputs of the ingress switches of the plurality of switching dies;
• a second plurality of output TSVs between the output ports of the switching interface region and the outputs of the ingress switches and the middle stage switches;
• and
• a third plurality of TSVs between the outputs of the ingress switches of a first switching die and the inputs of the multiplexers of a second switching die of the plurality of switching dies on top of the first switching die;
• a fourth plurality of TSVs between the outputs of the ingress switches of the first switching die of the plurality of switching dies and the multiplexers of a third switching die of the plurality of switching dies below the first switching die;
• and
• a controller coupled to the multiplexers to select a predetermined number of input ports of the switching interface region as active input ports and a predetermined number of output ports of the switching interface region as active output ports to be cross connected.