I'm designing my first ever circuit for a hobby project. I've a sensor that outputs in mV (1 to 2) and a controller with ADC. The ADC is 16 bits, VDDA = 3.0 V, Temp = 25 °C, fADCK = 1.0 MHz. Since the sensor voltage that is fed is to the controller is low I'm in a predicament! Should I use a low pass filter or a band pass filter in this application? Do you have a circuit that I can relate to? I've attached an example plot and a circuit that I cooked up with LTC6085. I wanted a single supply instrumentation amplifier that will work with low power consumption. Any advice is appreciated. Thanks.
Filter-Amplifier circuit for Low Voltage circuitry
- Thread starter ramv
- Start date
Hi,
I did not realize that I'm overdriving the amp! I was actually wondering why the Vout is clipped. I was hoping to see peaks and troughs on either side of zero. I'd replace the 2mV supply with my piezoelectric sensor. Any advice to fix it? would the addition of a simple series resistor do (1k maybe)? But I wouldn't want the circuit to be less reliable. Let me know
hi,
Do you have a model number or datasheet for your sensor.?
For a DC amp with a single supply, the Vout will not swing below zero volts.
If you are inputting sinusoidal signals from your sensor, it may be possible to AC couple it so that Vout swings above and below a fixed DC voltage.
Tell me more about the signal from the sensor and what it is measuring.
E
Do you have a model number or datasheet for your sensor.?
For a DC amp with a single supply, the Vout will not swing below zero volts.
If you are inputting sinusoidal signals from your sensor, it may be possible to AC couple it so that Vout swings above and below a fixed DC voltage.
Tell me more about the signal from the sensor and what it is measuring.
E
Hi,
The sensor is piezoelectric, I had screen printed it myself. But, I had attached a voltage response from the sensor.
Attachments
Hi,
Good morning. Thank you very much, could you please tell me quickly about the approach? Will come in handy in the future
Good day. Thanks.hi,
You can see that the sensor input is AC coupled by using the 1uF.
The two 10k's on the Non inverting input of the OPA bias that input to half the Vsupply rail, so the Vout of the OPA is fixed at ~ Vsup/2.
The sensor input is amplified by the OPA and amplified Vout swings about the Vsup/2 value.
On the 2nd option the Vout is AC coupled via the 1uF, to the 10K load, so the Vout at the load swings about zero volts.
When doing it this way, you will have to consider what effect any loading in parallel will have on the swing.
Do you follow OK.?
E
You can see that the sensor input is AC coupled by using the 1uF.
The two 10k's on the Non inverting input of the OPA bias that input to half the Vsupply rail, so the Vout of the OPA is fixed at ~ Vsup/2.
The sensor input is amplified by the OPA and amplified Vout swings about the Vsup/2 value.
On the 2nd option the Vout is AC coupled via the 1uF, to the 10K load, so the Vout at the load swings about zero volts.
When doing it this way, you will have to consider what effect any loading in parallel will have on the swing.
Do you follow OK.?
E
