| 摘要 |
A VDD power-up detection circuit is provided having a p-channel transistor having a source coupled to a VDD voltage supply terminal and a gate coupled to a ground supply terminal. A first resistor or a diode element is coupled between the drain of the p-channel transistor and the ground supply terminal. An n-channel transistor has a source coupled to the ground supply terminal and a gate coupled to the drain of the p-channel transistor. A second resistor is coupled between a drain of the n-channel transistor and the VDD voltage supply terminal. A trigger circuit is coupled to the drain of the n-channel transistor. As the VDD supply voltage increases during power-up, the p-channel and n-channel transistors are both turned on. At this time, the trigger circuit asserts a control signal that enables an associated circuit to operate in response to the VDD supply voltage.
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