Abstract: A power-on reset circuit is provided which uses a dual voltage detection circuit to output a voltage detection signal. The dual voltage detection circuit is coupled to a first supply voltage terminal, a second supply voltage terminal, and a ground terminal. The voltage detection signal indicates whether the first supply voltage provided on the first supply voltage terminal is greater than an adequate voltage level. Furthermore, the voltage detection signal is driven by circuits powered by a second supply voltage provided on the second supply voltage terminal. One embodiment of the dual-voltage detection circuit comprises a first transistor coupled in series with a second transistor between the first supply voltage terminal and the ground terminal, as well as a third transistor coupled in series with a fourth transistor between the second supply voltage terminal and the ground terminal.

Abstract: Problems associated with excessive crowbar current due to input signal transitions at a buffered programmable interconnect point are solved by inserting a transistor switch between power and ground. The inserted switch is in series with the input buffer and is controlled by a memory cell which also controls the pass/no-pass state of the interconnect. An OFF inserted switch blocks current that flows during switching when the memory cell output causes a no-pass state of the interconnect.