M63028/029FP
Spindle channel
The relationship between the differential voltage between SPIN and REF and the torque is shown in following
Figure.The voltage gain[Gvo] is 1.0 [V/V] .
The current gain[ Gio] is 2.0[ A/V] (at sensing resistor :0.5Ω,and R1=∞, R2=0 Ω)in forward torque directions,and the
dead zone is from 0mV to 80mV (at R1=∞, R2=0 Ω)
The coil current gain under the reverse torque is the same with in forward torque directions.And the limitation function
gets on when the differential voltage of VM1(12V) to RSP is 0.5V at forward and 0.28V at reverse.
In case of SELECT6 the differentialvoltage of VM1(12V)~RSP is 0.28V at forward.Therefore,this mode is available in
order to reduce a temperature under acceleration.
Therefore current- gain- control and current- limit of this IC is determined with sensing resister value,and more detail
control can be determined with setting a gain- resister outer this IC as below.
current limit
lim1F
Forward Torque
lim2F
Dead zone
Gio
Gio
Reverse Torque
CTL-REF (V)
Dead zone
lim1R
current limit
The example of current- gain and current- limit of SPINDLE.
Rs[Ω]
Ilim1F[A] Ilim2F[A]
0.50
1.00
0.56
0.75
0.66
0.37
1.00
0.50
0.28
Gio* = R1/[(R1+R2)•Rs] [A/V]
Ilim1R[A]
0.56
0.37
0.28
Gio*[A/V]
R1 = ∞ R2 = 0Ω
2.00
1.33
1.00
R1 = R2
1.00
0.66
0.50
R2 = 2•R1
0.66
0.44
0.33
Rev.1.0, Sep.16.2003, page 12 of 21