Power amplifier/operational amplifier in ESP32

awaisahmed
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Power amplifier/operational amplifier in ESP32

Postby awaisahmed » Mon Aug 13, 2018 9:18 am

in the data sheet its written

''The output of the power amplifier is also adjustable''

how can i do this ? where can i find the option for it ?
i also want to measure the power consumption of Power amplifier/operational amplifier in ESP32

Franco
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Re: Power amplifier/operational amplifier in ESP32

Postby Franco » Mon Aug 13, 2018 1:57 pm

Hello Ahmed, designing with esp-idf you can call "make menuconfig" and set the PA output power, check line 1064 of https://github.com/espressif/esp-idf/bl ... 32/Kconfig

tommeyers
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Re: Power amplifier/operational amplifier in ESP32

Postby tommeyers » Mon Aug 13, 2018 4:14 pm

How are the kconfig values manipulated when using the Arduino IDE. Some appear in the IDE (clock) other no. Is it through esp32.h attributes/methods?
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Vader_Mester
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Re: Power amplifier/operational amplifier in ESP32

Postby Vader_Mester » Tue Aug 14, 2018 7:21 am

Franco wrote:Hello Ahmed, designing with esp-idf you can call "make menuconfig" and set the PA output power, check line 1064 of https://github.com/espressif/esp-idf/bl ... 32/Kconfig
Actually this mentioned section it's not for the OPamp, rather the wifi.

I just noticed that the OPamp description is removed from the latest Technical Reference Manual, dunno why.
Here you can see a short description and a way to set the gain.

If you know OPamps in general, this is an integrator configuration of the opamp.
https://en.wikipedia.org/wiki/Op_amp_integrator

Anyway I attached here the snippets from the old TRM.

On the WROOM and WROVER modules there are two 270pF caps already placed, which are to set the gain (seen in the attached sheet how). So you can only adjust it if you replace those components.
Attachments
ESP32_LNA_Opamp.png
ESP32_LNA_Opamp.png (176.73 KiB) Viewed 2292 times
There are 2 types of programmer people: The Expert programmer and The Smart programmer

The Expert programmer easily writes any code from scratch.
The Smart programmer uses his google/github powers first ;)

tommeyers
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Re: Power amplifier/operational amplifier in ESP32

Postby tommeyers » Tue Aug 14, 2018 7:51 pm

The opamp to ADC is starting to make sense to me. But I still have a gap between what I have and how to make it work. Do you know if there is there any sample code available?

It am a little uneasy with it having disappeared from the latest documentation. What do you think the significance is? not working/shelved for now/going away in v3

I ordered a TI LNA for my water/air pressure sensor but it is appealing to use the built-in amp.
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Archibald
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Re: Power amplifier/operational amplifier in ESP32

Postby Archibald » Wed Aug 15, 2018 2:41 am

tommeyers wrote:I ordered a TI LNA for my water/air pressure sensor but it is appealing to use the built-in amp.
If your pressure sensor has a Wheatstone bridge configuration and is insensitive, consider using the HX711 "24-Bit Analog-to-Digital Converter (ADC) for Weigh Scales". It's available as a chip, or as a breakout board from Sparkfun and elsewhere (note: Sparkfun wrongly describe it as an amplifier). Using an HX711 avoids the very poor 'noise' performance of the ADCs within the ESP32.

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Vader_Mester
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Re: Power amplifier/operational amplifier in ESP32

Postby Vader_Mester » Wed Aug 15, 2018 8:42 am

Honestly, I would not use the OPamp in the ESP, rather an external one, or a PIC with a built-in OPamp, which will do the conversion and use either SPI or I2C with the ESP to do the data sharing.
There are 2 types of programmer people: The Expert programmer and The Smart programmer

The Expert programmer easily writes any code from scratch.
The Smart programmer uses his google/github powers first ;)

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