Issue link: https://resources.mouser.com/i/1527303
The manual reset setup period (t MR ) is the time required for the manual reset to hold and complete before it triggers a reset output. Some supervisors are made to have a long manual reset setup period to add protection to the system. These are common on consumer products that require users to hold the button for several seconds to reset the system. This method avoids accidental and unintended reset, thus adding protection and reliability. With the manual reset setup period, all the short- duration transients and glitches when pushing on the switch are ignored, as shown in Figure 7a, thus helping the system to be glitch-immune. The same concept applies to the debounce time (t DB ). Like the setup period, debounce time ignores the high-frequency, periodic voltage transients when pushing on or off a switch. These high- Figure 7: The manual reset setup period and debounce time diagram of a supervisor (MAX6444) with a long manual reset setup period: (a) the manual reset setup period (t MR ) needs to be completed first before a reset signal asserts; (b) to be considered as a valid input signal, debounce time (t DB ) is required to be completed. (Source: Analog Devices) 1 https://www.analog.com/media/en/training-seminars/tutorials/why-what-how-when-of-using-microprocessor-supervisors.pdf 2 https://www.analog.com/en/resources/technical-articles/supervisors-in-multivoltage-systems.html 3 https://www.analog.com/en/resources/analog-dialogue/articles/adding-hysteresis-for-smooth-undervoltage-and-overvoltage-lockout.html Adobe Stock / Hseyin – stock.adobe.com frequency transients are considered invalid and do not trigger a reset, as shown in Figure 7b. When the signal exceeds the debounce time, that is the time it will be considered a valid input signal from a switch or a push button. Conclusion Without voltage supervisors, systems are at risk of brownout conditions and malfunction during voltage transients and glitches. Voltage supervisors solve this by putting processors into reset mode during such scenarios. All the parameters discussed— including reset timeout period, threshold hysteresis, threshold overdrive, manual reset setup period, and debounce time—improve the reliability of voltage supervisors in monitoring power supply voltages by making them immune to glitches and transients. This gives stability and reliability to overall system performance. 21 Advanced Power Solutions for Efficiency and Robustness | ADI