L6470PD STMicroelectronics, L6470PD Datasheet - Page 34

• Manufacturer Part Number: L6470PD
• Description: Motor / Motion / Ignition Controllers & Drivers dSPIN 7.0A 8 - 45 V DMOS Motor Driver
• Manufacturer: STMicroelectronics
• Type: 2 Phase Stepper Motor Driverr

Specifications of L6470PD

• Rohs: yes
• Product: Stepper Motor Controllers / Drivers
• Operating Temperature: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• Package / Case: POWERSO-36
• Number Of Outputs: 4
• Output Current: 3 A
• Output Voltage: 3.2 V
• Power Dissipation: 5 W

Phase current control
7
7.1
34/70
Phase current control
The L6470 controls the phase current applying a sinusoidal voltage to motor windings.
Phase current amplitude is not directly controlled but depends on phase voltage amplitude,
load torque, motor electrical characteristics and rotation speed. Sinewave amplitude is
proportional to the motor supply voltage multiplied by a coefficient (K
0 to 100% and the sinewave amplitude can be obtained through the following formula:
Equation 1
Different K
phases and when the motor is stopped (HOLD phase) through the KVAL_ACC, KVAL_DEC,
KVAL_RUN and KVAL_HOLD registers (see
according to the following formula:
Equation 2
where K
KVAL_DEC, KVAL_RUN or KVAL_HOLD), BEMF_COMP is the BEMF compensation curve
value, VSCOMP and K_THERM are the motor supply voltage and winding resistance
compensation factors and microstep is the current microstep value (fraction of target peak
current).
The L6470 offers various methods to guarantee a stable current value, allowing the
compensation of:
●
●
●
●
PWM sinewave generators
The two voltage sinewaves applied to the stepper motor phases are generated by two PWM
modulators.
The PWM frequency (f
obtained through the following formula:
Equation 3
'N' is the integer division factor and 'm' is the multiplication factor. 'N' and 'm' values can be
programmed by the F_PWM_INT and F_PWM_DEC parameters in the CONFIG register
(see
Available PWM frequencies are listed in
low speed optimization
back electromotive force value
motor supply voltage variation
windings resistance variation
Table 28
VAL_X
VAL
K
VAL
and
is the starting K
values can be programmed for acceleration, deceleration and constant speed
=
[
Table
(
K
VAL_X
PWM
29,
) is proportional to the oscillator frequency (f
+
(Section 7.3
Section
BEMF_COMP
VAL
Doc ID16737 Rev 5
value programmed for present motion phase (KVAL_ACC,
(Section
(Section 7.5
(Section 7.4
f
V
9.1.21).
PWM
OUT
Section 9.1.21
7.3)
=
=
)
7.67.6).
×
-------------------- -
512
V
Section
f
VSCOMP
S
OSC
⋅
⋅
7.5)
7.4)
K
N
VAL
⋅
9.1.10). KVAL value is calculated
m
from
×
K_THERM
Table 30
]
VAL
×
to
microstep
OSC
). K
Table
VAL
) and can be
33.
ranges from
L6470