Difference between revisions of "Mcu 0137-SLA-charge-controller"

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For me this charge controller is part of a bigger project, but since it should work fine as a stand-alone solution I thought I'd put it here for the world to see and use.
 
For me this charge controller is part of a bigger project, but since it should work fine as a stand-alone solution I thought I'd put it here for the world to see and use.
  
I will be using either the ATMega328 or a ATtiny84 for this design.
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I will be using the 8-pin 8-bit ATtiny84 for this design.
  
  
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This charge controller aims to do the following:
 
This charge controller aims to do the following:
  
* control charge voltage using a boost converter. This will allow us to charge batteries with very low input voltages (e.g. 5V from a USB port).
 
  
* use input voltage sensing to detect whether the boost converter should be activated or not.
+
* use battery voltage sensing to detect whether the charging circuit should be activated or not.
  
* use output voltage sensing to detect battery charge state.
+
* use a fixed charge current in combination with an LM317 to regulate charge current
  
* use current sensing to detect battery charge current.
+
* set final charge voltage using a trimpot
  
* set charge current using a trimpot
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* enter sleep mode on the microcontroller to save power when the battery is charged.
 +
 
 +
* signal charge state with an LED
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 +
 
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===OPTIONALLY:===
 +
 
 +
* use a boost converter to allow charging from low input voltages (e.g. 5V from a USB port).
 +
 
 +
 
 +
 
 +
The first version of the charge controller schematic:
  
* enter sleep mode to save power when the input voltage is insufficient or when the battery is charged.
 
  
  

Revision as of 13:38, 16 June 2019

For me this charge controller is part of a bigger project, but since it should work fine as a stand-alone solution I thought I'd put it here for the world to see and use.

I will be using the 8-pin 8-bit ATtiny84 for this design.


This charge controller aims to do the following:


  • use battery voltage sensing to detect whether the charging circuit should be activated or not.
  • use a fixed charge current in combination with an LM317 to regulate charge current
  • set final charge voltage using a trimpot
  • enter sleep mode on the microcontroller to save power when the battery is charged.
  • signal charge state with an LED


OPTIONALLY:

  • use a boost converter to allow charging from low input voltages (e.g. 5V from a USB port).


The first version of the charge controller schematic:



With these objectives defined, the next steps will be to work out the following features:

  • complete a rough schematic of the design (diptrace)
  • voltage detection of input and output
  • current detection of input and output
  • auto-adjustment of boost converter output voltage from mcu
  • design charge regime (boost - bulk - float)
  • minimise current draw when not charging (hopefully less than a few uA's)



(to be continued..)