Automatic_reset

Published:2009/7/24 12:16:00 Author:Jessie | From:SeekIC

This circuit shows a DS1233 EconoReset chip that is used to monitor the power supply of a processor-based system and to provide automatic reset. The DS1233 contains a precision temperature-compensated reference and comparator circuit that is used to monitor the power-supply (VCC) status. When an out-of-tolerance condition is detected, RST becomes active, and shuts off the processor. When VCC returns to an in-tolerance condition, RST is kept in the active state for about 350 ms to allow the power supply and processor to stabilize. The DS1233 also debounces a pushbutton closure (when used), and generates a 350-ms reset pulse upon release. Notice that when an external pushbutton is used, a capacitor between 100 pF and 0.01μF must be connected between RST and ground. Where additional reset current is required, a minimum capacitance of 500 pF should be used, along with a parallel external pull-up 1-kΩ resistor (minimum). Dallas Semiconductors, Product Data Book, 1992/1993, p. 10-59.



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