Dear All,
I am a university PhD student interested in designing a voltage buffer with adjustable current output compliance value. The buffer should arrogate enough current to the load until the desired value, when the current value should remain fixed (while the voltage across the device will change of course). The load, in fact, can change drastically the resistance value (from1 Megohm to 1 kohm) and the current spike potentially destroys it. There are also some references design as the SBVA011 from BURR-BROWN using REG1117 to limit current and then generic an op amp. I tried with LM334 current source (instead of REG1117) and a LTC6258IS6 low power, but it is not working.
To better explain what I would like, I study resistive switching memories (ReRAMs) at university. These devices instantaneously change the resistance value after a threshold voltage, passing from 1 MegOhm to some KOhm. During the swithing the current should be clamped, in order to protect the device from permanent short-circuit. For example: I apply 1 ms pulse with 2 V amplitude and the device reaches 1 KOhm. The current should be 2 mA, but I want to stop at 100 uA. In our laboratory, we use a Keysight B1500 parameter analyzer (which have a compliance current system), but I would like to substitute it with a custom circuit, which can be handled more easily with commercial microcontrollers (thus I can do more experiments). the instrument uses an active system, which read the current and adjust the voltage (which decreases) to keep the current at the value selected (compliance current). In the meantime of this "active system" the device can potentially be broken. I don't have requirements on the bandwidth, I usually use pulses with a minimum duration of 1ms. Obviously, the "clamping circuit" should be as fast as possible. Hereattached a sketch on how the IV curve should look like.
Thank in advanced for the time you will spent for this post.
