I picked up a few of the XL6009E1 boost converters
https://www.addicore.com/XL6009E1-Boost-Converter-p/ad456.htm
I was powering one from 4V and set it to an output of 6V to drive a solenoid which worked as I was expecting. When I went back to the boost converter after leaving it connected to the power supply for a couple of minutes, the output voltage had shifted to 19V and I discovered that the output wouldn't go below 9V now no matter how many turns on the potentiomenter I made.
This has happened with 2 of the units now. I have been searching around for this phenomenon and haven't been finding much. Is this something that boost converters do or are these faulty units?

 

Hello,

How is the solinoid connected to the boost converter?
Can you make a drawing of the connections?
Are you switching the solinoid?

Bertus

 

Hello,

How is the solinoid connected to the boost converter?
Can you make a drawing of the connections?
Are you switching the solinoid?

Bertus

Originally I had been driving the solenoid directly from the boost converter. However I had disconnected the solenoid from the boost converter, but had left the boost converter connected to a power supply set to 4V for a few minutes when the output drifted to 19V

 

Hello,

Is there a minimum load given for the boost converter?
There are some regulators that will need a minimum load of about 10 mA to have a good regulation.

Bertus

 

Figure 3 of the datasheet shows a signal labeled "Slop Compensation." Perhaps that is the problem. Regulation does seem to be very sloppy.

There simply is not enough information in the datasheet to determine what is happening, but my suspicion is that it performs poorly with very light loading. It switches at 400 kHz so minimum ON time may be an issue. It also uses current mode control ("inner loop" which directly controls PWM controls the peak current in the inductor). The peak switch current for the part is 4 A, so the sense voltage with just a few milliamps of inductor current is probably down in the noise floor.

I also recommend trying to add a load to the output to see if it helps and about 10 mA is as good a value to start with as any. Certainly a change for the better is expected, but 10 mA may be insufficient.

 

I picked up a few of the XL6009E1 boost converters
https://www.addicore.com/XL6009E1-Boost-Converter-p/ad456.htm
I was powering one from 4V and set it to an output of 6V to drive a solenoid which worked as I was expecting. When I went back to the boost converter after leaving it connected to the power supply for a couple of minutes, the output voltage had shifted to 19V and I discovered that the output wouldn't go below 9V now no matter how many turns on the potentiomenter I made.
This has happened with 2 of the units now. I have been searching around for this phenomenon and haven't been finding much. Is this something that boost converters do or are these faulty units?

Your spec sheet said input as low as 5 volts.