E-L8150 STMICROELECTRONICS [STMicroelectronics], E-L8150 Datasheet - Page 25

• Manufacturer Part Number: E-L8150
• Description: Brushless motor predriver
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

L8150
Assumed this operation mode, it is easy to understand that as soon as the startup sequence
is over, Hall effects commutations are filtered using a fraction of the electrical period given
by the following equation, since T∆ZC is equal to TEL when two consecutive zero-crossing
signals generated by a rising edge on signal HallU are detected:
●
Figure 15. Startup sequence forced by FS comparator, supposing the motor rotating
When the signal coming from the FS comparator has a falling edge, by default a zero-
crossing signal is generated and the logic waits for a Hall effect commutation and applies to
it a filtering time of T
generated.
Also the second Hall effect commutation is filtered using T
zero-crossing signal is generated.
Starting from the second Hall effect commutation, after the acquisition of the filtered Hall
commutation, the logic outputs start applying the right pattern, and the motor is able to
accelerate again.
The next filtering time used for the Hall commutation is a fraction of the elapsed time
between the first two Hall effect commutations, according to the previous T
This filtering time is used until the first rising edge on signal HallU is detected and a zero-
crossing signal is generated. After that the filtering time used is a fraction of the elapsed
time between the last two detected zero-crossing signals, in other words between the
second Hall effect commutation and the rising edge on signal HallU. Finally, when the
second rising edge on signal HallU is detected, the filtering time used is a fraction of the
electrical period, as described in previous T
●
Let's consider a startup sequence forced by FS comparator, supposing the motor
rotating quickly in the direction imposed by the FR signal:
Let's consider a startup sequence forced by FS comparator, supposing the motor
rotating quickly in the direction opposite to that imposed by the FR signal:
FS
ZC
HALL BUS
FILTER TIME
PHASES
quickly in the direction imposed by the FR signal:
PRECHARGE
T
FILTER ROATING
400 us
–
=400µsec. The first significant zero-crossing signal is
T∆zc’
400 us
Precharge and hall effects filtering time description
PHASES EXCITED
MOTOR ACCELERATING
T∆zc’/576
=
FILTER-ROTATING
--------- - T∆
576
1
T∆zc’’
⋅
T∆zc’/576
ZC
=
PRECHARGE
equation.
--------- - T
576
T∆zc’/576
1
⋅
U
EL
T∆zc’’/576
, after that the second
Tel
FILTER
T∆zc’’/576
equation.
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