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how to drive a large capacitive load?

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katrin

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a circuit output is going to drive the next stage circuit which is a large capacitive load of the previous stage(please see the simplified picture below)

In order to drive this large capacitive load, should I consider about increasing the current flowing in the previous circuit or should I increase the size of the transistors Q1 and Q2?

In general, in order to drive a large capacitive load, how can I optimize the circuit?
 

darkk

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Put a super buffer between the 1st stage(q1/q2) and the loading cap.
 

    katrin

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smoked

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If you are driving the capacitive load with an inverter which is seen from your schematic, rather than using a single inverter use chain of inverters namely "tapered buffer".
 

    katrin

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supreet_95

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U will have to increase the current and correspondingly the size of transistors also, which will increase the input loading of that stage, u may have to add another stage before that to run it.
2 or 3 stage buffers can run a large capacitive load.
Hope this helps.
 

    katrin

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katrin

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normally, which kind of buffer can be used here, in order to obtain an output signal which is the same as the buffer input?
 

smoked

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katrin said:
normally, which kind of buffer can be used here, in order to obtain an output signal which is the same as the buffer input?

You can use a simple OTA with a unity gain feedback. Determine the current based on output capacitance and bandwith requirements of the signal.
 

    katrin

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supreet_95

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We can use two stage, differential to single ended buffer with 2nd stage being inverter with active load (with compensation).

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We can then connect the differential buffer in unity gain buffer configuration.
 

    katrin

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