EVAL6730 STMicroelectronics, EVAL6730 Datasheet - Page 26

• Manufacturer Part Number: EVAL6730
• Description: EVAL BOARD FOR L6730XX
• Manufacturer: STMicroelectronics
• Type: Motor / Motion Controllers & Driversr

Specifications of EVAL6730

• Main Purpose: DC/DC, Step Down
• Outputs And Type: 1, Non-Isolated
• Power - Output: 66W
• Voltage - Output: 3.3V
• Current - Output: 20A
• Voltage - Input: 4.5 ~ 14V
• Regulator Topology: Buck
• Frequency - Switching: 400kHz
• Board Type: Fully Populated
• Utilized Ic / Part: L6730
• Input Voltage: 8 V to 52 V
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: L6208
• Other names: 497-5501

AN1451 APPLICATION NOTE
2.15 Choosing the Stepping Sequence
The device can provide three different sequences to run a stepper motor: full step two phase on (Normal drive),
full step one phase on (Wave drive) and Half step.
If Half Step driving is used, the motor advances by half a step after each clock pulse, obtaining a higher position
resolution and reducing instability due to low-torque regions in certain motors' speed-torque diagrams, when
used in full step mode (see Figure 27).
Figure 27. Torque instability in full step mode.
Using this driving method the torque is affected by ripple, because in odd-numbered states, when both coils are
driven, the total current in the motor windings is double than in even-numbered states.
A way to avoid the high torque ripple in half step mode is to supply to the motor a higher current (by a factor of
reference voltage at the V
Figure 28. Balanced Half Step for low torque ripple.
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2
) during the even numbered states, in which only one winding is energized, simply by applying a
Startup or
Reset
Balanced Half Step
Torque
3
2
1
refA
, V
4
8
refB
pins during these states (see Figure 28) [2].
5
6
7
V
ref A
=V
Clock
I
I
A
B
ref B
1
2
V
3
ref
V
ref
4
* 2
5
Speed
6
7
8
2
higher