Data Sheet

TB67S279FTG
2017-09-15
17
• When the next current step/ratio is lower than the previous step
• When the Fast period continues beyond 1 fchop cycle (Current does not reach ADMDth within
1 fchop cycle.)
Timing charts may be simplified for explanatory purpose.
Fast
NF
NF
NF
The current is charged for a short period of time to
be compared in the RS comparator circuit. S
ince
the motor current level is higher than the next
NFth, the
operation will be switched
to Fast mode
instantly.
f
chop
f
chop
f
chop
f
chop
Slow
Fast
Charge
Slow
Fast
Charge
Fast
Slow Slow
Charge
Charge
Internal
OSC
waveform
NFth
ADMDth
NFth
ADMDth
Fast
NF
NF
f
chop
f
chop
f
chop
f
chop
Slow
Fast
Charge
Fast
Charge
Slow Slow
Charge
When
the motor current does not reach the
ADMDth
after 1 fchop cycle, the Fast
recirculating
sequence continues on until the
current level reaches the ADMDth.
Internal
OSC
waveform
NFth
ADMDth
NFth
ADMDth
The
current is charged for a short period of time to be
compared in the NF comparator circuit. S
ince the
motor current level is higher than the next NFth, the
operation
will be switched to Fast mode instantly.