Patent ID: 7706115
Filing Date: 2010-04-27
Classification: H03K

Abstract:
1. An over-voltage indicator capable of providing an indication signal to reflect a first voltage at an I/O port, the over-voltage indicator comprising: a comparator connected between the I/O port and a sample node, determining whether the first voltage at the I/O port is higher than a first predetermined voltage; if so, the comparator connects the I/O port to the sample node; if not, the comparator terminates connecting the I/O port to the sample node; a switch connected between the sample node and a detection node; wherein when the switch is turned on, the switch connects the sample node to the detection node; when the switch is turned off, the switch terminates connecting between the sample node and the detection node; a timer capable of providing a timing signal; wherein when the timer is triggered, the timer starts timing for a predetermined interval, and the timer reflects completion of timing using the timing signal; a detector connected to the detection node; determining whether a second voltage at the detection node is higher than a second predetermined voltage; if so, the detector triggers the timer to start timing; a control circuit connected between the timer, the detector and the switch, wherein when the detector detects that the second voltage at the detection node is not higher than the second predetermined voltage or when the timing signal reflects completion of timing, the control circuit turns the switch on, otherwise the control circuit keep the switch off; a trigger circuit capable of providing a trigger signal according to detection result of the detector and a third voltage at the sample node; and a latch connected to the sample node, the latch capable of providing the indication signal according to the trigger signal; wherein the comparator, the sample node, the switch and the detection node are connected in series.