I’m trying to use the output not with LEDs, but with another type of load. The voltage drop across my load is about 1.8 V, but it doesn’t turn on the channels. However, if I connect, for example, two LEDs in parallel, it works. Is there any way to configure or program the chip so I can power a device that has a 1.8 V voltage drop?
Hello Cristian,
In short, no, you cannot configure the MPQ7228 channels to drive a 1.8V low voltage non-LED load because this IC is a current-sink LED driver.
In this scenario, the MPQ7228 acts as a current sink expecting the load with an LED that is some forward voltage and a pre-regulator such that Vout is greater or equal to the Vload + some headroom. If this voltage for Vout isn’t met, then the channel won’t behave normally, or the protection features may activate.
The parallel LEDs working changed the operating voltage/current point giving the board enough voltage to operate with.
I suppose you could add a small series resistor or diode to force a higher voltage drop such that the sum if Vload + headroom voltage exceeds the minimum headroom voltage that this IC expects.
Test this at the channel current that you plan on using and verify the pre-regulator output voltage and channel don’t activate any faults.
Hope this provides some insight.
Best,
Krishan
This topic was automatically closed after 9 days. New replies are no longer allowed.