No! Not that button!

I own a smartphone, an e-reader and a tablet. And, as is the case with most consumer electronics, they tend to malfunction every so often (Murphy’s Law never fails, does it?). The screen freezes up or apps decide not to launch. Sometimes the device just works sluggishly or provides me with an ever-frustrating blank screen. Whenever this happens, I bang on random keys, let out a sigh of frustration, and resort to ye olde trouble-shooter:  the restart.

I am positive that this is something that most of us experience in some capacity. Given that we are surrounded by so many gadgets either at home or work or somewhere in between, it’s a safe bet that all of us will encounter some sort of error.  It might not even be with a smartphone or tablet: pedometers, fitness wristbands, insulin monitors and even toys are all prone to some sort of failure.  Also, more and more products are now maximizing touchscreen space (as few buttons as possible is desirable) and/or incorporate an embedded battery, so unlike older generation models where you could push a specific button or just take the battery out and restart the device, now-a-days that’s not always the case.

So how are these gadget manufacturers going to solve this problem going forward?  A trend we are seeing is the incorporation of push-button reset controllers. Conveniently, they do exactly what their name implies: by pressing a button, the controller triggers a system reset. That’s great when you need it, but that’s not the entire story.  What if I push the button accidentally?  Sometimes my fingers have a mind of their own, and I can see myself resetting the system every time I mistakenly press that button, or my personal favorite, resetting it from my pocket.

What value, then, do push-button reset controllers bring to the table?

TI’s push-button controllers provide a reset only after the button is held down for a set period of time. Or, to make unintentional resets even less likely, a reset is only triggered after two buttons are held down for a set duration. This helps to prevent unintended system resets (whoops!).  As well, it provides a reliable solution independent of the microprocessor or power management IC since it is designed in to be isolated from them, providing an extra line of security in case of software malfunction.  When the button is pushed and the reset signal is generated, the controller can function in one of two ways:

  1. Used to disconnect the battery from the rest of the system:  provides a hard reset to the entire system.
  2. Fed into the accompanying microprocessor:  provides a user-intended reset.  By virtue of selecting a long input delay, any existing buttons in your system could be used to trigger a reset, with no need for a dedicated reset button.

What can make these devices even more attractive is their low power consumption and small form factor. TI’s new push-button reset controllers consume just nano-amps of current, effectively lengthening highly-sought after battery life.  A super-small package makes them a good choice for portable gadgets where space is a concern. 

It will be a great day when all of our electronics function perfectly and never need a reboot.  But until then, a system reset is a small price to pay for the utility they provide us. Until that day, manufacturers are minimizing the frustration associated with rebooting devices and designing in push-button reset controllers to do just that.

Check out TI’s new family of both dual input (TPS3420, TPS3421) and single input (TPS3422) that allow a delay of 7.5 seconds, 12.5 seconds or longer.  Share your experience with these products here on Power House.

  • Please implement something better than 'press-and-hold', such as 'double-click' or 'triple-tap'.  A full reset should be something that is not so likely to happen accidentally while the device is in a pocket or bag.  Even a multi-button 'press-and-hold' can happen easily by accident.

    A 'press-and-hold' is exactly what an accidental press looks like.  Pocketable gadgets really should ignore 'press-and-hold' on any external button.  The 'press-and-hold' idea was ok for a desktop pc power button, but it was a mistake to bring that precedent to portable devices.  The 'double-click' much less likely to happen accidentally.  Even better, have the reset controller watch the power button for 'double-click-wait-double-click'.  This is the sort of thing that comes naturally when a gadget is frozen, and something quite unlikely to happen by accident in a pocket or bag.  

  • Thank you for the comment.  A double- or triple-click can be another way of signaling a hard reset. It’s important to note that the double-click mechanism is already used in many phones and gadgets for other functions such as activating voice commands, taking a screenshot, etc. TI’s TPS3420 and TPS3421 are dual channel devices, meaning a user would have to hold two buttons for a fixed duration (~7s) to generate a reset. You are correct that even with this added level of security, a reset could still be triggered unintentionally in someone’s pocket, for example. Rather than promoting these devices as stand-alone measures to ensure that a reset is only triggered when intended, TI sees the TPS342X family as complimentary solutions within an entire user design that seeks to provide the most reliable reset capabilities. Again, we highly appreciate your input and look forward to your future suggestions.