RL,
Thank you for taking a look but I still have an issue. The bridge nodes that you renamed now disconnected the ZVS circuit of the chip because the nodes have been renamed to SWAB and SWCD the SWT and SWB nodes are no longer connected and are left floating.
Also when the when the input power supply drops to 18V the regulation of the 165V rail is not kept.
I would also appreciate it if you could tell me how you came to derive all of the compensation values.
Thanks for your help.
Leo
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--- In LTspice@..., legg@... wrote:
--- In LTspice@..., "viperlenny" <viperlenny@> wrote:
Hello,
I am trying to make a power supply using a 3722-1.
The input is 18 to 30Vdc and output is 165V@
The issue that I am having is that at low input voltages like 24V or 18V the power supply is not able to reach full output level. At 30V the output level is reached but regulation is poor.
There's nothing wrong with the model, as such, but there seems to be a couple of issues with the circuit that you're simulating.
If you overcompensate it, you'll get a better idea about what is going on in the power train, as the control circuit will not be responsible for cycle by cycle variations.
There should be an overcompensated example posted in the temp files shortly.
In the working model, there is a shoot-through current occurring quite regularly. I don't know whether this is the result of intentional values placed in the drive delay circuits.
In real life, such spikes would invoke irregular limiting behavior in the 3722 that you'll want to avoid.
As to power throughput with reducing input voltage, you should take a look at the current waveforms and decide for yourself where the limitation lays.
RL
