2.
FSM Idle
: after
TO_IDLE
time elapses, wait for the AC mains to reach the uvAC value (
OK_SOURCE
).
After checking the load current, a new timeout is set (
TO_INIT
) to prevent PLL instability. FSM moves to
FSM_Init
. All relays are maintained in the off state.
Figure 41.
FSM_Idle block diagram
3.
FSM_Init
: handles the inrush current control. If the grid voltage is correct, the status source is equal to
OK_SOURCE
. The bulk capacitors are at low voltage and the inrush current must be limited. For this reason,
during this state, the inrush relays are considered in series with a high resistance. On the basis of their
values, the inrush is completed. The state machine state is still maintained to stabilize the output voltage
according to the grid amplitude. After a configurable time, the FSM moves to start state (
FSM_Start
).
Figure 42.
FSM_Init block diagram
UM2979
Startup procedure
UM2979
-
Rev 1
page 24/70
