Voltage Clamping/Regulation.
Voltage Clamping/Regulation.
(OP)
I am currently designed a simple instrumentation amplifier "INA125" from Burr-Brown. I am powering with a 7662 charge pump to provide a bi-polar voltage. My design specification is that the amplifier operate from 12-24 VDC. The INA125 operates to a max of +/-18 VDC and the charge pump to +/- 15 VDC. Basically I want to limit the voltage to power the INA and charge pump to 12VDC. I want to be able to operate the INA to produce a 0-10 VDC output. But in order to get a 10 VDC output the INA requires a minimum of at least 11.5 VDC. I tried using an 12 V Zener Diode and Resistor but found the volt drops below the required when I apply the load. If I drop the protection resistor too much, it over heats the Diode, and I don't want to use a high wattage diode. I also tried using a 12V regulator, but that required at least a 13 volt input to generate a 12 volt signal. What would be the best way to take care of this problem. I need to be able to limit the voltage to these chips to prevent damage.





RE: Voltage Clamping/Regulation.
12-24 V and use LDO (low drop-out ) regulators e.g.
from <www.maxim-ic>. They have both + and - LDO-s.
<nbucska@pcperipherals.com>
RE: Voltage Clamping/Regulation.
RE: Voltage Clamping/Regulation.
mentioned in your original posting.
The INA125 or the 7662 can't supply 100mA !
What are you using the INA output for ?( ADC, etc.)
What is your signal frequency range ? How much accuracy
do you really need ? Other requirements ?
What do you need 100mA for ? could you reduce the +/- 10V ?
How many circuits do you need ? Is price/space/power critical?
Is the V+ input stable? Could you afford to build
a discrete regulator with pass-FET ?
what is the spectrum/waveform of the signal like ?
You may exploit the good power supply rejection
of the INA to use a swinging supply !
<nbucska@pcperipherals.com>
RE: Voltage Clamping/Regulation.
RE: Voltage Clamping/Regulation.
Use a switching regulator for positive 12-14 V for the INA and the 7662. The 7662 must supply only the INA, voltage is not critical.
<nbucska@pcperipherals.com>
RE: Voltage Clamping/Regulation.