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Capacitor for smoothing voltage needed?
Posted: Thu Mar 15, 2018 8:49 pm
by Kazuya91
Hello,
I have a question regarding a circuit for the ESP32.
I want to use a Wemos Lolin32 (not the Lite Version) with a Li-Ion Battery and a HT7833 LDO-Regulator. I use Lithium-Ion Battery instead of LiFePo4 to get more capacity. The ESP32 shall be powered via the 3,3V Pin.
My question is: Do I need capacitors to smooth the voltage which is coming out of the HT7833 regulator?
If yes, how much µF should I use? Can you recommend a specific one? (maybe a Link?)
Thanks in advance!
Re: Capacitor for smoothing voltage needed?
Posted: Thu Mar 15, 2018 10:25 pm
by loboris
Just connect the battery to the Wemos Lolin32
battery connector !
Re: Capacitor for smoothing voltage needed?
Posted: Thu Mar 15, 2018 10:44 pm
by Kazuya91
I know that the Board has a LiPo Connector. The problem here is that using the 3,3V Pin i get a much lower current consumption than using the LiPo Connector. I want to have the lowest consumption possible.
Re: Capacitor for smoothing voltage needed?
Posted: Fri Mar 16, 2018 1:16 am
by ESP_Angus
Kazuya91 wrote:I know that the Board has a LiPo Connector. The problem here is that using the 3,3V Pin i get a much lower current consumption than using the LiPo Connector. I want to have the lowest consumption possible.
The WeMos board will have sufficient onboard capacitance for the ESP32 on its 3.3V rail already. However, you'll want some capacitance directly on both the input and output of the HT7833 LDO to keep the regulator stable (assuming there's a cable going from the LDO board to the WeMos board). You probably won't need a lot, the HT7833 datasheet and/or application circuit should give some suggestions.
Re: Capacitor for smoothing voltage needed?
Posted: Fri Mar 16, 2018 11:14 am
by Kazuya91
ESP_Angus wrote:Kazuya91 wrote:I know that the Board has a LiPo Connector. The problem here is that using the 3,3V Pin i get a much lower current consumption than using the LiPo Connector. I want to have the lowest consumption possible.
The WeMos board will have sufficient onboard capacitance for the ESP32 on its 3.3V rail already. However, you'll want some capacitance directly on both the input and output of the HT7833 LDO to keep the regulator stable (assuming there's a cable going from the LDO board to the WeMos board). You probably won't need a lot, the HT7833 datasheet and/or application circuit should give some suggestions.
Here is the datasheet of the HT7833:
http://www.holtek.com.tw/documents/1017 ... 99f2d0f6d7
On basic circuits, they recommend 1µF on V_in and 2,2µF on V_out. I guess i will take those. But do you know which type of capacitor is the best? There are ceramic and elektrolytic ones.