J
john
- Jan 1, 1970
- 0
Hi,
Please go the following link and then figure 16 page # 13.
http://focus.ti.com/lit/ds/symlink/ina2133.pdf
I can not find a way to post the schematic on the web so i am
explaining that I what did I do with the circuit. The INA133 is getting
the input from a voltage ouput DAC ( span is +/- 2.5 volts) . DAC is
connected to pin# 3 of the INA133 and pin#2 in grounded. A capacitor of
47uf and is connected between the non-inverting pin of the OPA131 and a
relay1 ( which connects the output of the capacitor to two different
loads ). The capacitor provides AC coupling. The relay1 connects the
current source to one laod at one time. The power supply of the circuit
is +/- 16 volts. Inorder to discharge the capacitor, I connected a
relay2 in series with a resistor at the input of the capacitor or at
the node where the OPA131 and the capacitor connects together. So, when
the capacitor gets charged I just turn on the relay2 and connect the
node to zero volts. Resistor is grounded.
The problem is that when I switch from load A to load B then I get DC
offset acorss the load B . i thought that What if I just turn off and
on the +/- 16 volt supply of the INA2133
by using two relays simulataneously. The DAC will always be power up (
but generating
only zero at the output ). So, the current source always have input
voltage at its voltage inout pins. Can this voltage be harmful to the
chips if the power supply of the current source or INA 133 is OFF.? If
not then I think this will solve the problem. Turn OFF
the power supply, swith the relay to load B and then turn ON the power
supply again?
Please advice!
Regards
John
Please go the following link and then figure 16 page # 13.
http://focus.ti.com/lit/ds/symlink/ina2133.pdf
I can not find a way to post the schematic on the web so i am
explaining that I what did I do with the circuit. The INA133 is getting
the input from a voltage ouput DAC ( span is +/- 2.5 volts) . DAC is
connected to pin# 3 of the INA133 and pin#2 in grounded. A capacitor of
47uf and is connected between the non-inverting pin of the OPA131 and a
relay1 ( which connects the output of the capacitor to two different
loads ). The capacitor provides AC coupling. The relay1 connects the
current source to one laod at one time. The power supply of the circuit
is +/- 16 volts. Inorder to discharge the capacitor, I connected a
relay2 in series with a resistor at the input of the capacitor or at
the node where the OPA131 and the capacitor connects together. So, when
the capacitor gets charged I just turn on the relay2 and connect the
node to zero volts. Resistor is grounded.
The problem is that when I switch from load A to load B then I get DC
offset acorss the load B . i thought that What if I just turn off and
on the +/- 16 volt supply of the INA2133
by using two relays simulataneously. The DAC will always be power up (
but generating
only zero at the output ). So, the current source always have input
voltage at its voltage inout pins. Can this voltage be harmful to the
chips if the power supply of the current source or INA 133 is OFF.? If
not then I think this will solve the problem. Turn OFF
the power supply, swith the relay to load B and then turn ON the power
supply again?
Please advice!
Regards
John