Hello, I have a voltage difference of 400V. This consists of 200V positive and -200V negative. I use the middle point of this voltage as a GND reference for 2 microcontrollers. The first microcontroller is supplied with MP9488 easily because of the positive voltage input (+200V to +16V to +5V to +3.3V). The second microcontroller should be supplied with a positive voltage (+3.3V) derived from -200V with respect to GND. The difficulty starts here. How can I make (-200V to +16V) by using MP9488. Will the following work?
I doubt it, how is energy being added to the output inductor when the internal FET shorts between Drain and Source? I don’t see a current path. How about do a 200V to isolated 16V converter?
Input side is Ground to -200, output side is Gnd to +16V output.
Is your ground low impedence?
Thank you for your reply. Indeed the drawing is not correct and will not work. An isolated converter is a very good idea but I don’t have PCB space for additional components. Now I use the same +200V supply to supply the microcontrollers for both on the positive and on the negative side. Thus I get the power supply from the plus side for both microcontrollers.
There is no inductance on the ground level. I assume it is a low impedance.