Hello All,
I seem to be having an issue with a high voltage op amp circuit I have made. I used a LM675T (http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=120926)
to take a 0V to ~5V sinewave and make it into a 0V to ~60V sinewave of various frequencies. I did this by making a simple non-inverting amplifier with a compensating resistor where the R1 = 1K and R2 = 11k (making a gain of 12). I also added a compensating resistor on the positive port of the Op Amp of R1 || R2 which is ~930ohms. The rails are connected to 60V and 0V.
The issue I am having is that I have a pretty severely capacitive load. I would imagine to the Op Amp it would look like two capacitors connected to the output with one going to 0V and one going to 60V. Without any load the current draw of the circuit is around 4 milliamps yet with the load attached the current draw becomes 500 to 600 milliamps (at 60V!). How can I decrease this current draw? It heats the amplifier far to much for my tastes.
Another issue is that the output of the amplifier is somewhat noisy even without a load. I was hoping that I could somehow smooth it out.
Additionally, If anyone can recommend a better amplifier to use in this sort of application I would love to hear it.
Any thoughts?
I seem to be having an issue with a high voltage op amp circuit I have made. I used a LM675T (http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=120926)
to take a 0V to ~5V sinewave and make it into a 0V to ~60V sinewave of various frequencies. I did this by making a simple non-inverting amplifier with a compensating resistor where the R1 = 1K and R2 = 11k (making a gain of 12). I also added a compensating resistor on the positive port of the Op Amp of R1 || R2 which is ~930ohms. The rails are connected to 60V and 0V.
The issue I am having is that I have a pretty severely capacitive load. I would imagine to the Op Amp it would look like two capacitors connected to the output with one going to 0V and one going to 60V. Without any load the current draw of the circuit is around 4 milliamps yet with the load attached the current draw becomes 500 to 600 milliamps (at 60V!). How can I decrease this current draw? It heats the amplifier far to much for my tastes.
Another issue is that the output of the amplifier is somewhat noisy even without a load. I was hoping that I could somehow smooth it out.
Additionally, If anyone can recommend a better amplifier to use in this sort of application I would love to hear it.
Any thoughts?