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AC current source of 6A

shivakumar L V
Prodigy 90 points
Other Parts Discussed in Thread: OPA549

Hi 

i have used two OPA549 in master slave configuration as represented in datasheet  with +/-24V supply. can this circuit will deliver current source of  6A with both positive and negative cycle

  • 0
    TI__Guru* 93105 points

    Hello Shivakumar,

    Connecting two OPA549 amplifiers in the master-slave configuration essentially doubles the output current and power output capability over a single device connection. Each amplifier provides approximately half the output current whether sinking, or sourcing, the output current.

    The amplifier configuration in data sheet figure 14 uses a single, positive supply (V- is connected to ground). If the output load is connected to ground, then the output would only be able to source current through the load. If dual supplies, such as the +/-24 V supply you mention is used, the same configuration will be able to sink and source current through a load connected to ground.

    The master-slave pair of OPA549 devices can sink/source 6 Amps providing the safe operating area (SOA) curves, shown in data sheet figure 6 are observed. Note that the 3 Amp Output Current level would be used for each amplifier. It is then a matter of having an output voltage level that is within the safe SOA for the power supply being used and output current being delivered. Data sheet pages 10 and 11 provide much useful information.

    Regards, Thomas

    PA - Linear Applications Engineering

  • 0 in reply to Thomas Kuehl
    Prodigy 90 points

    Thank you Thomas Kuehl

    Just be advice could you please recommend any circuit in which I can get current of 10A output with only positive supply. I planned to design digitally controlled current source using multiplying DAC and the Power amplifier(OPA549). Is this combination works? 

  • 0 in reply to shivakumar L V
    TI__Guru* 93105 points

    Hello Shivakumar,

    Figure 11 in the OPA549 data sheet shows a digitally-controlled (DAC) programmable power supply. The OPA549 is connected using a single, +30 V supply. The figure indicates an output voltage range of 7 V to 25 V, and 0 to 10 A output current. But do note if the load is connected to ground the OPA549 will only source current to the load. The OPA549 has common mode input range that extends down to zero, but the output swing isn't to 0 V in a single-supply configuration. How close it pulls up from 0 V depends on the level of current the output is sourcing.

    If you decide to go this route I would suggest using two OPA549 devices in the master-slave arrangement. 10 Amps is the peak current output of a single device and can be difficult to manage thermally. The SOA curves must be observed to prevent overheating.

    Regards, Thomas

    PA - Linear Applications Engineering

     

     

  • 0 in reply to Thomas Kuehl
    Prodigy 90 points

    ok thank you  for the advice