Is the eFuse really a one stop solution?

As an indeterminate hobbyist I often find the lack of experience leads to some form of failure in a downstream system, whether it be short circuit, overvoltage, current limiting - the list goes on...
So I've often wondered is the eFuse really a solution, at least in the face of inexperience, to protect against the myriad of unforeseen and uncalculated mishaps.

I'm looking at the TPS2660x. https://www.ti.com/lit/gpn/TPS2660 in HTSSOP16 package, easy to solder, has reverse input protection, current limiting, inrush current ramp and OVP/UVLO (Overvoltage Protection/Undervoltage Protection).

I would be grateful for advice and general feedback and find out the pros cons of this device or suggestions on other devices.


Ill start with the reverse protection feature, which claims to withhold -60v on the input. This is an important feature for me and immediately eliminates a reverse polarity fet with associated zener and resistors. Although at a cost of 150mOhm RDSon, I find it quite reasonable as an integrated solution, other chips in the line offer very low Iq as low as 31mOhm but forfeit ratings on other features.


UVLO. (Undervoltage Lockout) Although Im sure it has its uses, I can only find that this feature is good for saving a battery draining, that is disabling the down stream supply when a low voltage condition occurs. According to the DS this has a delay of 10uS.

OVP. (Overvoltage Protection) with a delay of 6uS. Is this considered acceptable by means of protecting sensitive ICs such as MCUs, Modems, IMUs etc?

IN-RUSH current control. - Not my favourite subject, but for the layman, can it be harmful to downstream electronics to slowly ramp up. I say this because when developing a system, there may be one or many circuits (on the same power bus) that may or may not require inrush current control. Could a Minimum ramp time be defined where it be deemed safe for any or most applications? The DS states an internal Ramp of 23.9V/1.6mS but can be slowed with an external cap. Can an example be provided for an IN-RUSH situation

Then there's the current limiting feature, which incorporates a current monitoring pin. It does this by regulating the current through an amplifier, which causes a voltage drop? My Q (question) here is this just a glorified voltage regulator and turns on proportional to the over current?

 

It is always a compromise between costs and benefits whether you are a hobbyist or professional designer/engineer/manufacturer. Your objective ought to be to keep the solution as simple as possible.

You need to assess the cost of the added feature, the incidental cost of repair, the significance and implications of catastrophic loss.

What happens if your fancy eFuse solution fails via false positive or false negative?

What are the risks and incidental costs of not implementing protection features?

What kinds of failure are trying to protect against?

1. improper installation
2. high power overload
3. protection of expensive instruments

If you want to protect against improper power supply polarity you can use single or bridge rectifiers.

Fuses do not necessarily prevent damage to instruments. The purpose of a fuse is to remove power permanently to prevent further damage and fire. Over current fuses and over voltage crow-bar circuits are used to interrupt power permanently until the unit is repaired. The simplest protection is the basic one-time use fuse. Thermal cut-off fuses are used where excessive temperatures are to be avoided.

 

It is always a compromise between costs and benefits whether you are a hobbyist or professional designer/engineer/manufacturer. Your objective ought to be to keep the solution as simple as possible.

This is my objective, at least in the short term. I appreciate that there will be some downsides but on the whole is the eFuse a sensible solution as far as the hobbyist is concerned. It claims that problems such as REVERSE POLARITY, OVP,UVP, IN-RUSH LIMITING and CURRENT LIMITING are all addressed in a 5x7mm package together with current monitoring and PG status pins, seems like a claim too good to be true.
SO to the hobbyist this seems to be a package well worth considering, unless the downsides can be established first which is why I ask here.

 

What happens if your fancy eFuse solution fails via false positive or false negative?

I Did not appreciate that a false positive was possible! how likely is that? I mean is this something that you've experienced?

 

What kinds of failure are trying to protect against?

All and every, but as the eFuse claims to do the brunt of them, could it be a whole lot of time and space saved in just one package?

 

For the hobbyist (and the professional) firstly you need to consider what is your power source.

Assuming that for most hobby projects the power source is not going exceed 1A @ 5VDC, the simplest solution is a fuse rated for the project, for example 315mA fuse.