Apparatus for controlling circuit response during power-up

摘要

A circuit embodying the invention includes a gating circuit responsive to a first control signal and to a second externally supplied control signal having an active state and an inactive state. The first control signal is produced by a power supply circuit which is responsive to the application of an externally supplied operating voltage for producing an "internal" operating voltage and which produces the first control signal having an active state when the internal operating voltage reaches a predetermined value. The gating circuit has an output for producing a third control signal which is enabling only if the second control signal goes from its inactive state to its active state when the first control signal is already in, and remains in, its active state. The gating circuit prevents a chip from operating in an unintended mode at power-up.