Increasing output current from LDO

[EthanAlef]

I created a LDO circuit for MCU and other components with maximum current output 1000mA. However, when I add a Wifi Module with the voltage supply (3.3V) from the LDO circuit, the voltage at 3.3V drops to 1.9V. I find out that the insufficient current from the LDO should the problem. My idea to maintain the voltage at 3.3V is to add another LDO in parallel to the original one. Please comment on such idea. :roll:

For the LDO circuit, please view the attached. Thanks!

 

[Ice-Tea]

Paralleling LDOs is not a very good idea. Minor differences in tuning/output voltage between the two will lead to great load imbalance. That said, you're already burning over 1,7W here. Maybe time to switch to a buck solution?

 

[amayilsamy]

The 5 V regulator can't support at 1000mA current. Because the Max. output current of the CM7R1117-50 1000 mA.

If you draw the current 1000 mA the regulator damaged.

So you choose LM317 it support 1500 mA must provide the heat sink. It's a adjustable one.

And how much current draw in 3.3V Regulator?

If you draw less then 600mA in 3.3V regulator. Change the output capacitor 100uF and remove 0.1 uf capacitor in output. this is the same for 5 V regulator.

And also change the input capacitor 10 uF or 33 uF.

 

[dick_freebird]

You could split your loads and power (say) the MCU from
one 3.3V LDO and the WiFi from another - then you could
also do things like shed load when inactive, etc. simply.
Provided they are both reasonably accurate you ought
to not have any logic level issues. You might also see
some benefit from not putting MCU noise onto your WiFi
supply.

Upstream limitations, are another matter.