Using the internal supply voltage ramp rate to prevent premature enabling of a device during power-up

摘要

A semiconductor device disables itself during power-up until the internal power supply voltage and other circuits reach states in which the device can operate properly. The internal power supply voltage is coupled to the input terminal of an inverter through a delay network. During power-up, the device remains disabled until the voltage at the input terminal of the inverter reaches the inverter trip point. The delay network and the inverter are designed so that the voltage at the inverter's input terminal does not reach the inverter trip point until the internal power supply voltage and other circuits have reached states in which the device can operate properly. When the (device is turned off, the inverter input terminal is discharged quickly by a diode or resistor. Therefore, if the power is turned back on immediately, a suitable delay will be provided.