L6482
Phase current control
Doc ID 023768 Rev 1
37/73
Figure 19.
Adaptive decay - fast decay tuning
When two or more fast decays are performed with the present target current, the control
system adds a fast decay at the end of every off-time keeping the OFF state duration
constant (tOFF is split into tOFF, SLOW and tOFF, FAST). When the current threshold is
increased by a microstep change (rising step), the system returns to normal decay mode
(slow decay only) and the tFAST value is halved.
Stopping the motor or reaching the current sinewave zero crossing causes the current
control system to return to the reset state.
reference c
u
rrent
1
s
t
f
as
t dec
a
y:
Tf
as
t = TOFF_FA
S
T/
8
2
nd
f
as
t dec
a
y (*):
Tf
as
t = TOFF_FA
S
T/4
(*)Note:
s
t
a
rting from 2
nd
f
as
t dec
a
y the
s
y
s
tem com
b
ine
s
f
as
t
a
nd
s
low dec
a
y d
u
ring the OFF ph
as
e.
3
rd
f
as
t dec
a
y:
Tf
as
t = TOFF_FA
S
T/2
Ton > TON_MIN
Tf
as
t = TOFF_FA
S
T/2
AM15050v1