rsdio writes: This looks like a great idea any time you’re worried that your custom firmware might crash at the wrong moment. You don’t necessarily need the MAX8607 LED driver, just the MAX6421 or maybe even a 555 equivalent.
This protection feature enables reliable high-power LED operation over a long life cycle and prevent the burnout of the LED in case of a software problem. The timeout function consists of a simple supervisor circuit with capacitor adjustable delay. More generally, this hardware protection function could be implemented very simply, every time a peripheral needs to be protected against software activation problems.
A similar version of this article appeared in the April 30, 2007 issue of EE Times magazine.
How is this different to a watchdog timer? Most microcontrollers have one, and work asynchronously to the main processor.