HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

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xhr0428
 
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HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

Post by xhr0428 »

I am planning to use the POWERBOOST 500 + CHARGER as power manager in my project. One problem is by default the boost is on. When I add a push button between EN and GND to control it, the logic is opposite and confusing. Is there a good way to set up a push button?

I also checked your schematic for POWERBOOST 500 + CHARGER. It seems when EN is grounded, VBAT is also connected to ground via a resistor. Isn't it losing battery power when the boost is turned off?

Thanks

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Re: HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

Post by adafruit_support_rick »

The enable line must be pulled high to make the powerboost work, so shorting enable to ground is the only way to turn it off. That is a a very high value resistor used on the pullup. There will be a very small and negligible discharge through it.

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Re: HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

Post by xhr0428 »

adafruit_support_rick wrote:The enable line must be pulled high to make the powerboost work, so shorting enable to ground is the only way to turn it off. That is a a very high value resistor used on the pullup. There will be a very small and negligible discharge through it.
Hi Rick, thank you for your reply. How about the push button? Thx

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Re: HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

Post by adafruit_support_rick »

You need a push button with a Normally Closed pin, so that the powerBoost is disabled when the button is "unpressed". When you press it, the contact becomes open, which enables the PowerBoost.

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Re: HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

Post by xhr0428 »

adafruit_support_rick wrote:You need a push button with a Normally Closed pin, so that the powerBoost is disabled when the button is "unpressed". When you press it, the contact becomes open, which enables the PowerBoost.
Rick, I only have normal push button at hand. What should I do? THX
Can I just remove that resistor and replace it with the on/off push button?

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Re: HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

Post by adafruit_support_rick »

xhr0428 wrote:Can I just remove that resistor and replace it with the on/off push button?
No - that would leave the pin floating. How many pins does you pushbutton have? It may have a NC position.

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Re: HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

Post by xhr0428 »

adafruit_support_rick wrote:
xhr0428 wrote:Can I just remove that resistor and replace it with the on/off push button?
No - that would leave the pin floating. How many pins does you pushbutton have? It may have a NC position.
IT's just normal on/off pushbutton. There are only two pins available. I'm considering removing the resistor and connecting the two pins of pushbutton to BAT and EN pin out of the board. Will it work? If not, how should I do it?

I searched after you mentioning normally closed button. The only thing I can find is momentary pushbutton, which is not what I need. Can you guide me where I can find normally closed alternate pushbutton?
Thx

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Re: HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

Post by adafruit_support_rick »

This one will do what you want. But maybe it's too big for your application?
https://www.adafruit.com/products/915
This one might also work:
https://www.adafruit.com/products/1442
xhr0428 wrote:I'm considering removing the resistor and connecting the two pins of pushbutton to BAT and EN pin out of the board. Will it work? If not, how should I do it?
That won't work either, because then you wouldn't be grounding EN to turn it off.

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Re: HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

Post by xhr0428 »

adafruit_support_rick wrote:This one will do what you want. But maybe it's too big for your application?
https://www.adafruit.com/products/915
This one might also work:
https://www.adafruit.com/products/1442
xhr0428 wrote:I'm considering removing the resistor and connecting the two pins of pushbutton to BAT and EN pin out of the board. Will it work? If not, how should I do it?
That won't work either, because then you wouldn't be grounding EN to turn it off.
https://www.adafruit.com/products/1442
this one is still normally open, isn't it?

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Re: HOW TO SET UP PUSH BUTTON FOR POWERBOOST 500 + CHARGER

Post by adafruit_support_rick »

I think that one clicks like a ball-point pen. Click On, Click Off. The state is indicated by the LED, not by the position of the switch.

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