Patent ID: 7388414

Claim:
A glitch-free trigger circuit comprising: a trigger circuit to generate a first signal that identifies when a power supply voltage has risen from a first voltage that is insufficient for normal chip operation to a second voltage that is sufficient for normal chip operation; and a logic device connected to the trigger circuit, the logic device having a first input to receive the first signal, a second input to receive a second signal, and an output, the second signal having a first logic state before the first signal indicates that the power supply voltage is sufficient for normal chip operation, and a second logic state after the first signal indicates that the power supply voltage is sufficient for normal chip operation, the logic device to change the output from a first logic state to a second logic state when the first signal indicates that the power supply voltage is sufficient for normal chip operation, and hold the output at the second logic state as long as the second signal has the second logic state, the second signal having only the second logic state during a period that includes a time for the trigger circuit to detect a voltage glitch, and change the first signal from a first logic level to a second logic level and back to the first logic level in response to the voltage glitch.