U3V70F6 voltage dips


I’m using the U3V70F6 step-up regulator connected with a lithium ion battery on its input and two small servomotors on its output. When doing my initial testing, I was getting a constant 6V output. However, after using it for about two days, I noticed that the voltage coming out of the regulator was randomly toggling between 3.5V and 6V. The day after, I noticed that it would occasionally even drop all the way to 0V. Note however that I never get any intermediate voltages - only 0V, 3.5V, or 6V.

The input voltage at the regulator contacts is constant, and ranges between 3.7 and 4.2V, even when the output goes to 0V. I disconnected the servomotors from the regulator and tried again with the same results. Any ideas of what may be going on? The motor current draw is within the specs of the regulator, at a max of 2.4A total on stall conditions, but did I inadvertently destroy it some other way?


That is a strange issue. Could you post pictures of the setup that show all connections and a link to specifications for your servos? Could you look at the regulator’s output and battery voltage with an oscilloscope when the voltage is dipping? Does the regulator get hot?