thermoelectric generator output voltage sensor

[Berend Kunze]

Hello, everyone.
You need to build a circuit.
The voltage generated by the TEG is between 0 and 1V.
When it is 0~0.5v, power must be guaranteed to device A, and between 0.5~1V, power must be supplied to device B.
The power generated by the TEG is up to 1W.
How should I configure the controller to perform this action?
I'm trying to solve it by using an op amp comparator.
However, it is not possible to select the correct element.
If satisfied through the conversation, a certain payment will be made
thanks.

 

[cupoftea]

It sounds like a comparator to measure the voltage, via a resistive divider, and switch on a pass FET switch to send the power to the device.
Do you have a higher voltage to power the comparator with?
Maybe a logic gate so both switches cant be on at the same time.(if thats what you want)
Or just discrete logic.

 

[Berend Kunze]

hi

--- Updated Feb 27, 2023 ---

It sounds like a comparator to measure the voltage, via a resistive divider, and switch on a pass FET switch to send the power to the device.
Do you have a higher voltage to power the comparator with?
Maybe a logic gate so both switches cant be on at the same time.(if thats what you want)
Or just discrete logic.

hi

--- Updated Feb 27, 2023 ---

are you here,

cupoftea​

?

 

[KlausST]

Hi,

What´s the idea behind this useless post above?

You need to build a circuit.

Who? Me?
Or is this the text of a school project?

How should I configure the controller to perform this action?

From my perspective a "requirement" without tolerance is likely to malfunction.
Tolearance here in the meaning of hysteresis. 0...0.5V ... 0.5 ... 1V.
There will be noise, thus when the voltage is 0.500V plus noise there will be malfunction.
Also if device B draws a little more current than device A there will be oscillation.

using an op amp comparator.

There is no such thing. It´s either an OPAMP or a comparator. They are two different electronic devices they sadly share the same schematic symbol. If you want to mistreat one for the other function you need to select a device that is able to do this.

However, it is not possible to select the correct element.

This is useless information as long as you don´t say why.

Klaus

 

[danadakk]

Sounds like an oversimplified school problem, eg. you are equipped with 10%
of the issues that need attention. So start by not complicating it. Example if
you are given no tolerance of switch point, assume no consideration here. Or
is there any minimum time a load, once switched on, has to stay on... Any safety
concerns ? But in closing of your design make a list of design considerations you have
thought of but not asked for in problem, that way prof (hopefully) will give you
more credits.

Basic decisions you have to make :

1) Power switched on low side or high side of load ?
2) Develop a Vref for the trip point, eg. the 0.5V trip point.
3) Power for the solution circuit, where does it come from.
4) As Klaus mentions, hysteresis, you will need to choose a width. And then
calculate the R's needed to implement.
5) Choose a comparator. You can get comparators as duals, some with Vref in them,
some a combination of a comparator and an opamp, many low power (if TEG is only
power in system every mW wasted on peripheral circuits a concern). To select a
comparator go to Digikey website and use filter tools to find what you want. or
just stipulate in solution comparator should have the following features......

Do you have to build a prototype solution ?

Lastly you can always consider a low end processor to do this, using A/D and its
internal Vref and code to implement the detection and hysteresis (in code). Like
an ATTINY85 Atmel type of chip.



Regards, Dana.