Patent ID: 6720673
Filing Date: 2004-04-13
Classification: H02J

Abstract:
An electronic device comprising:a voltage island switchable between a normal power supply and a standby power supply, said voltage island including circuits for receiving input signals; a voltage detector outputting a power sense signal in response to a fall to a first voltage value from a reference value or a rise to a second voltage value from said reference value of the voltage of said normal power supply; a standby clock generating a standby clock signal; a standby clock synchronizing circuit receiving said power sense signal and said standby clock signal, synchronizing said power sense signal to said standby clock domain and outputting a standby clock synchronized power sense signal; a counter receiving said standby clock synchronized power sense signal and said power sense signal, adding a delay to said standby clock synchronized power sense signal and outputting a delayed standby clock synchronized power sense signal; a normal clock synchronizing circuit receiving said delayed standby clock synchronized power sense signal, synchronizing said delayed standby clock synchronized power sense signal to said normal clock domain and outputting a delayed normal clock synchronized power sense signal; and a fencing logic circuit receiving said delayed normal clock synchronized power sense signal and forcing said input signals high or low synchronously with said delayed normal clock synchronized power sense signal.