Other Parts Discussed in Thread: TINA-TI
Tool/software: TINA-TI or Spice Models
Hi
I'm trying to simulate a sequence of charging a supercapacitor from a very low voltage until it gets close to 5V. The output is controlled both by a stepped voltage applied to the SS input (will be from an MCU with built in DAC), and from a voltage added to the bottom of the feedback potential divider by the supercap charge current flowing through a low value resistor.
Using default transient analysis settings it is possible to simulate, for example, 100ms. The inductor current, output voltage etc looks reasonable. It could take over 10 seconds to charge the supercapacitor, and it may not be feasible to simulate such a long sequence. If I try, then previewing the waveforms gives a result that looks like aliasing. It might have been possible to run the simulation for as long as available, maybe a couple of days, then find out by using preview if that is enough to indicate that it works as intended, even if the output voltage is not near to 5V. The apparent aliasing makes that not a valid approach.
Is there an good solution to this? Do I need to stop trying to simulate this as a switchmode supply, and instead build the control loop around a power opamp and use that to simulate the charge current?
Andrew Armstrong
