Hi Everyone!,
I'm trying to implement the circuit attached which was found in an older US patent.
http://www.google.com/patents?id=4uwnAAAAEBAJ&dq=5703490
I'm using a dual-hbridge in parallel so that I can access each bottom FET, so that is taken care of. I'm very worried about the bottom end of the circuit, which is the dual precision half-wave rectifiers along with the differential amplifier.
I am modifying the precision half-wave rectifier with an additional diode in the feedback path to prevent any stability problems, most will know what I am referring to. Apparently, this circuit will be able to sense both the direction and magnitude of current flow during fast-decay and slow-decay modes of operation.
My question is, will this circuit require a bipolar supply? I am thinking 'yes' because the current flow can induce a negative voltage across either sense resistor, which is bad news for a single supply opamp. Secondly, should I stick to the low-offset and drift opamps for this? What sort of diodes should I use for the best performance?
Apparently, I should use the most gain at the rectifier stage for better noise performance. This was mentioned to me by a professor and in the patent. My low-drift opamps have limited capabilities with 2.5MHz GBW. I want the highest frequency range possible that I can get. Should I split up the desired gain between the rectifier and differential amplifier stages?
Also, Will I get an overall positive output from this circuit? I would think so, if the current is overall positive in a single direction (which I need).
I am planning on using this opamp, since it has the lowest offset and stability. http://www.analog.com/en/prod/0,2877,AD8628,00.html
*** NOT ANYMORE , JUST REALIZED SINGLE SUPPLY OPERATION ***
I'm really stuck and would appreciate your input!
Kindest regards,
Stephen
I'm trying to implement the circuit attached which was found in an older US patent.
http://www.google.com/patents?id=4uwnAAAAEBAJ&dq=5703490
I'm using a dual-hbridge in parallel so that I can access each bottom FET, so that is taken care of. I'm very worried about the bottom end of the circuit, which is the dual precision half-wave rectifiers along with the differential amplifier.
I am modifying the precision half-wave rectifier with an additional diode in the feedback path to prevent any stability problems, most will know what I am referring to. Apparently, this circuit will be able to sense both the direction and magnitude of current flow during fast-decay and slow-decay modes of operation.
My question is, will this circuit require a bipolar supply? I am thinking 'yes' because the current flow can induce a negative voltage across either sense resistor, which is bad news for a single supply opamp. Secondly, should I stick to the low-offset and drift opamps for this? What sort of diodes should I use for the best performance?
Apparently, I should use the most gain at the rectifier stage for better noise performance. This was mentioned to me by a professor and in the patent. My low-drift opamps have limited capabilities with 2.5MHz GBW. I want the highest frequency range possible that I can get. Should I split up the desired gain between the rectifier and differential amplifier stages?
Also, Will I get an overall positive output from this circuit? I would think so, if the current is overall positive in a single direction (which I need).
I am planning on using this opamp, since it has the lowest offset and stability. http://www.analog.com/en/prod/0,2877,AD8628,00.html
*** NOT ANYMORE , JUST REALIZED SINGLE SUPPLY OPERATION ***
I'm really stuck and would appreciate your input!
Kindest regards,
Stephen