1-200mA ,500 ohm load, boost current of instrumentation ampllifier

[balaji selva]

can u suggest a circuit to boost current o/p of instrumentation amplifier made using AD620...i need current o/p of about 1-200mA to drive a 500 ohm load

 

[godfreyl]

If you drive 200mA into a 500Ω load, the voltage across the load will be 100V, and the power dissipated in the load will be 20W.

Are you sure that's what you want? If so, you need to boost the output voltage from the opamp. An AD620 cannot give such high output voltage.

 

[balaji selva]

ya...that's what i require....can u suggest a better amplifier or any other means of achieving this................

 

[chuckey]

The best way would be to design a high voltage amplifier then a low impedance (source/emitter follower) output stage which needs to run at a high current. You have not specified what sort of signal you are using - DC?, low frequency AC?, high frequency?, precision DC. . .
Frank

 

[godfreyl]

Part of the answer is given in this thread. Max frequency is 2KHz. Existing power supply is +-12V.

Another approach (if DC is not required), is to run an amplifier from the +-12V supply and step up the output voltage with a transformer. e.g. a 240V toroidal power transformer connected backwards would go down to at least 25Hz and well beyond 2KHz.

 

[balaji selva]

immm...thanks my friend...could you please suggest a high level voltage amplifier