Patent ID: 7046054
Filing Date: 2006-05-16
Classification: H03K

Abstract:
1. A power up signal generator, comprising: a signal converter for converting an external source voltage signal to an internal supply voltage signal applied at a node in response to the external source voltage signal reaching a first threshold, the signal converter not requiring a reset signal; a reference current source for maintaining a reference current I a first inverter for outputting the external source voltage signal until the internal supply voltage signal at the node reaches a second threshold, the first inverter outputting a low level signal when the internal supply voltage reaches the second threshold; and a second inverter for outputting the external source voltage signal as a power up signal after the first inverter outputs the low level signal, the reference voltage generator further including a first and second resistor connected to at least one NMOS transistor in the reference voltage generator, wherein the reference voltage generator and the reference current source are configured such that the internal supply voltage signal reaches the second threshold when the external source voltage reaches a trip voltage V wherein V r β