E-L8150 STMICROELECTRONICS [STMicroelectronics], E-L8150 Datasheet - Page 20

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

Operating description
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Figure 10. Rectangular Drive Pattern (Reverse)
Smooth Drive mode is activated when three consecutive periods shorter than TMAX are
detected and device will keep driving in Smooth mode until an external command is applied
(through FR pin) or motor electrical period becomes longer than the maximum period the
device is able to follow.
Startup phase (rectangular driving) is activated in one of the following conditions:
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●
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During all working conditions a current limitation circuit is active. It is composed of a
current comparator sensing current flowing in the sense resistor (usually a sense resistor is
connected between the sources of all power low side driver transistors and ground) and of
some control logic.
Current limitation is achieved in three possible ways according to the different motor
situations.
The current limiter control method is a consequence of the rotation speed and the detected
direction of the motor.
Let's divide the possible situations in two different cases:
1.
2.
In case 1) even if the detected rotation direction is different from the desired direction, the
current limiter control method is to force two phases to GND and one phase is left in high
impedance state.
In case 2) the possible situations can be the following:
2a) The desired direction is equal to the detected direction and sinusoidal mode is applied,
the current limiter control method is forcing all the phases to GND
when the Period Counter saturates;
when the desired rotation direction (coming from FR command) is different from the
detected rotation direction;
SD = High → Low
The motor is rotating and its frequency is lower than the one used to switch between
rectangular and sinusoidal driving pattern
The motor is rotating and its frequency is bigger than the one used to switch between
rectangular and sinusoidal driving pattern
HallW
HallW
HallW
HallU
HallU
HallU
HallV
HallV
HallV
OutW
OutW
OutU
OutU
OutV
OutV
L8150