Author Topic: Suggestions wanted for "Soft Latching Power Switch" ICs  (Read 4997 times)

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Offline ManuautoTopic starter

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Suggestions wanted for "Soft Latching Power Switch" ICs
« on: July 08, 2018, 07:51:13 pm »
Hi,

I'd appreciate any suggestions for cheap, available and preferably easy to use ICs which are designed to be used in a latching On/Off Power Button circuit.
I am aware that Dave made a video on this topic, describing how this function can be achieved with jelly-bean parts.
This circuit has it's flaws and isn't exactly very (noob-) user friendly.

While looking for something a bit more practical and "advanced", I came across the Henry HR810: https://www.aliexpress.com/item/6A-DC-3V-3-3V-3-7V-5V-Electronic-Switch-Latch-Bistable-Self-locking-Trigger-Board/32795061369.html
The module works great.

Sadly I cannot find a way to purchase the IC cheaply without the mosfet etc.

Other requirements:
- low voltage operation (battery power, singe cell Li-Ion)
- low quiescent current / low power consumption
- low price  ;) (Aliexpress would be good because of the usually free shipping)!

Less important
- maybe even a built-in mosfet
- reasonably large footprint, maybe even "DIP-friendly"

I am not asking for the "perfect solution" and am very happy about simple hints and general ideas as to which components could be used.  :D

When searching the internet for suitable parts, I came across several Ti parts which weren't available on Aliexpress. Digikey has them (TPS3422) but I'd have to pay shipping...  :-\

Thanks in advance!
« Last Edit: July 08, 2018, 08:02:43 pm by Manuauto »
 

Offline Zero999

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Re: Suggestions wanted for "Soft Latching Power Switch" ICs
« Reply #1 on: July 09, 2018, 08:06:49 am »
Look at flip-flop ICs, such as the 74HC74, which contain two. They're also available in single, to save space, but they're SMT only.
 

Offline ManuautoTopic starter

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Re: Suggestions wanted for "Soft Latching Power Switch" ICs
« Reply #2 on: July 09, 2018, 09:25:26 am »
Thanks for the suggestion. I came across several circuits with flip-flop ICs when looking for ways to implement this function.
I thought, that they are not exactly "zero-power when off" but actually they seem to be a viable option!
 

Offline tautech

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Re: Suggestions wanted for "Soft Latching Power Switch" ICs
« Reply #3 on: July 09, 2018, 11:00:32 am »
4013 is another option just check the datasheets for low voltage operation and select a low gate voltage MOSFET that'll work at the voltage you use.
CD varieties might just work or you could be better off with an HEF version.
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Offline Zero999

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Re: Suggestions wanted for "Soft Latching Power Switch" ICs
« Reply #4 on: July 09, 2018, 11:10:14 am »
Thanks for the suggestion. I came across several circuits with flip-flop ICs when looking for ways to implement this function.
I thought, that they are not exactly "zero-power when off" but actually they seem to be a viable option!
There really is no such thing as zero power when off. Any circuit will consume a tiny amount of power.

The NLX1 will consume 1µA worst case (it'll probably be  much less than that, around 100nA), at an operating temperature of less than 25°C and less than 10µA, at an ambient temperature of 125°C. It's very difficult to beat that.
https://assets.nexperia.com/documents/data-sheet/74LVC1G74.pdf
 
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