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USE TGS8100 IN A:Using the CF2 for gas source localization and mapping
Posted: Mon May 20, 2019 12:43 pm
by Rosmel
I am very passionate about technology, and I am developing a project that basically has to do with the TGS8100 sensor. The fact esque the datasheet of this component shows a configuration where to the pin 2 a BJT transistor must go, I have tested it without many results, when I saw the development of its project and the integration of this component I saw that they used a MOSFET, I would like know why? and if they had the design of the PCB board, provide it to me. Thank you.
Re: USE TGS8100 IN A:Using the CF2 for gas source localization and mapping
Posted: Mon May 20, 2019 9:22 pm
by jburgues8
Dear Rosmel,
The transistor in the TGS8100 datasheet is connected to the sensor output, for powering the voltage divider intermittently (using the pulsed control signal that you can see in the diagram). The goal of this is to reduce the power consumption during read out of the sensor signal.
In our case, we don't use a transistor at the output because we consider that the read-out power consumption is negligible, so we continuously supply +5V to the voltage divider. The MOSFET you see in our design is placed at the input of the circuit, for delivering power to the sensor heater intermittently. Why? Because the supply voltage (Vcc) of the CrazyFlie uC is 3.7V and the TGS8100 requires 1.8V. Thus, by means of the MOSFET and PWM we can convert 3.7V to 1.8V (more specifically, we ensure that the average power received by the sensor is the equivalent of 1.8V).
I hope this helps.
Best regards,
Javier.