Hey everyone!
So, I have been taking a break from my endeavour of working on a buck converter controlled by a microcontroller and switched gears to another aspect f my project.
First, I have a DDS (AD983BRUZ) and the output of this is going to a non-inverting amplifier to bring the voltage up to the 5 V scale (min: 250 mV - max: 5 V). Then, this is going to a comparator, the AD790JNZ. I am incorporating hysteresis and I would like to get something less then 50 mV hysteresis. Which, I have gotten pretty close on the breadboard. Bandwidth wise, I need to be able to go up to at least 1 MHz.
Now, I am running into a snag because when I adjust the reference voltage and it gets to a certain point, the duty cycle jumps very quickly. This is when it gets close to 0%. Actually, probably closer to 10% when it does this. Very interesting. I as wondering if anyone else had that problem with this chip and if there was a way around it?
Alternativly, I am open to changing chips! If you feel that there is a better method for doing the same thing (or a better chip), please post here! I am attaching a copy of the circuit that I am building.
So, I have been taking a break from my endeavour of working on a buck converter controlled by a microcontroller and switched gears to another aspect f my project.
First, I have a DDS (AD983BRUZ) and the output of this is going to a non-inverting amplifier to bring the voltage up to the 5 V scale (min: 250 mV - max: 5 V). Then, this is going to a comparator, the AD790JNZ. I am incorporating hysteresis and I would like to get something less then 50 mV hysteresis. Which, I have gotten pretty close on the breadboard. Bandwidth wise, I need to be able to go up to at least 1 MHz.
Now, I am running into a snag because when I adjust the reference voltage and it gets to a certain point, the duty cycle jumps very quickly. This is when it gets close to 0%. Actually, probably closer to 10% when it does this. Very interesting. I as wondering if anyone else had that problem with this chip and if there was a way around it?
Alternativly, I am open to changing chips! If you feel that there is a better method for doing the same thing (or a better chip), please post here! I am attaching a copy of the circuit that I am building.
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