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Can we limit the current output of current booster circuit using a single resistor?

Hi, we are building hight current boosters using the reference design of AN18 Figure 2. LT1010 Based Output Stage.

Figure 2 of AN18

In this design we are replacing LT1056 with LT6018 using exactly the same topology (is it OK?) and the current are boost to 8A by replacing MJE with MJH6284.

Though, we would like to delive the product for different drivers. The maximum allowable RMS current ranging from 3A to 8A, can we limit the output current in this reference design with a single resistor? So that we can add a series of jumpers to our products.

Best regards.

  • H Benyuan, I'm currently looking into this. I'll have to look back for more information on this circuit to be sure on this. I'll get back to you as soon as possible Regards, Mon

  • Hi Benyuan, 

    I would not recommend swapping the LT1056 with the LT6018. The input stages for the LT1056 is different from the LT6018 and, if you were to swap them, you would not get the same performance as you would with the LT1056. If you really wanted to swap the LT1056 with another part, I would recommend finding a JFET/FET input amplifier that is comparable to the LT1056.

    I would also like to note that this circuit in AN18 is very specific to the component values and amplifiers/transistors chosen for this design. We can't guarantee this circuit will perform the same as described in AN18 if any of the components were changed.

    Regards,

    Sunny 

  • Thank you. We would like to build a precision voltage feedback current booster, that would be used alongside with DAC AD5791/AD5781 for driving precision DC coil. Besides AN18f, would you recommend any similar architecture?

    I filter the op-amps with specification similar to LT1056, are these JFET amplifiers (ADA4625, ADA4622, ADA4627, AD8510, etc.,) a better candidate? 

    Precision, JFET amplifiers similar to LT1056, https://www.analog.com/cn/parametricsearch/11070#/d=s18|5047|4089|5056|2687|4502|300|4501|4101|4500|4108|2839|2840|s3|s16|s5&sort=s18,desc&p4089=2n|4u&p4502=5M|25M&p4501=2.5u|1000u&p4101=850p|20n&p4500=20f|100p&p300=10|5.5k&p2687=1&p5056=JFET