matte87
Member level 1
Hi everybody,
I’m focusing on a power supply circuit consisting of a LC filter and an opto Mos as switch controlled by a logic signal. Someone proposed me this circuit to power a capacitive load and assuring me it was a good solution to control the inrush current at startup (Since at the startup the load seen by the power supply is a “short circuit”, all capa discharged )
What is not clear to me is the role of the LC filter. I mean, I know that the inductance acts as a electric inertial mass making the current grow slower, while capacitors act as filter and energy storage. But I was thinking this was valid only if the inductance is discharged at the beginning of time. But in this case at the instant t=0, when the logic signal is high (the photomos conduces) both capa C1 and inductance L1 are already charged and I would expect that the inrush current would be greater since the contribution of these charged elements.
So I’m trying to test the real circuit measuring the load current with a current active probe in two cases, with and without inductance.
What I get is that the presence of the inductance really reduces the inrush current since in the first case the current is two times lower than the second case.
So, what is wrong with my reasoning?
I post a schematic view of the circuit.
Thanks
I’m focusing on a power supply circuit consisting of a LC filter and an opto Mos as switch controlled by a logic signal. Someone proposed me this circuit to power a capacitive load and assuring me it was a good solution to control the inrush current at startup (Since at the startup the load seen by the power supply is a “short circuit”, all capa discharged )
What is not clear to me is the role of the LC filter. I mean, I know that the inductance acts as a electric inertial mass making the current grow slower, while capacitors act as filter and energy storage. But I was thinking this was valid only if the inductance is discharged at the beginning of time. But in this case at the instant t=0, when the logic signal is high (the photomos conduces) both capa C1 and inductance L1 are already charged and I would expect that the inrush current would be greater since the contribution of these charged elements.
So I’m trying to test the real circuit measuring the load current with a current active probe in two cases, with and without inductance.
What I get is that the presence of the inductance really reduces the inrush current since in the first case the current is two times lower than the second case.
So, what is wrong with my reasoning?
I post a schematic view of the circuit.
Thanks