L6258E View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L6258E' PDF : 20 Pages View PDF
L6258E
ACloaddB
=
20
⋅
log
V-----S----–-----B----e----m------f
VS
⋅
-R----L--R--+---S--R-----S-
we can see that the Bemf influences only the gain of the load block and does not introduce any other additional
pole or zero, so from the stability point of view the effect of the Bemf of the motor is not critical because the
phase margin remains the same.
Practically the only effect of the Bemf is to limit the gain of the total Aloop with a consequent variation of the
bandwidth of the system.
APPLICATION INFORMATION
A typical application circuit is shown in Fig.4.
Note: For avoid current spikes on falling edge of DISABLE a "DC reaction" would be added to the ERROR Am-
plifier. (R1-R2 on Fig. 4).
Interference
Due to the fact that the circuit operates with switch mode current regulation, to reduce the effect of the wiring
inductance a good capacitor (100nF) can be placed on the board near the package, between the power supply
line (pin 13,31) and the power ground (pin 1,36,18,19) to absorb the small amount of inductive energy.
It should be noted that this capacitor is usually required in addition to an electrolytic capacitor, that has poor
performance at the high frequencies, always located near the package, between power supply voltage (pin
13,31) and power ground (pin 1,36,18,19), just to have a current recirculation path during the fast current decay
or during the phase change.
The range value of this capacitor is between few µF and 100µF, and it must be chosen depending on application
parameters like the motor inductance and load current amplitude.
A decoupling capacitor of 100nF is suggested also between the logic supply and ground.
A non inductive resistor is the best way to implement the sensing. Whether this is not possible, some metal film
resistor of the same value can be paralleled.
The two inputs for the sensing of the winding motor current (SENSE_A & SENSE_B) should be connected di-
rectly on the sensing resistor Rs terminals, and the path lead between the Rs and the two sensing inputs should
be as short as possible.
Figure 4. Typical Application Circuit.
10nF
100nF
VS
1nF
VCP1
10
VCP2
11
VBOOT
12
VS
TRI_CAP
13,31
7
PH1
I0_1
I1_1
I2_1
I3_1
PH2
I0_2
I1_2
I2_2
I3_2
DISABLE
2
4
3
32
33
17
15
16
23
22
6
29
EA_IN1
L6258E
SOP36
PACKAGE
30
25
EA_OUT1
EA_IN2
0.33
21
OUT2B
20
SENSE2
OUT2A
14
SENSE1
35
0.33
34
OUT1B
5
OUT1A
9
GND
1,36
18,19
8
27
PWR_GND
VDD
SIG_GND
28
26
24
EA_OUT2
VREF1
VREF2
STEPPER
M
MOTOR
12mH 10Ω
VDD(5V)
VREF
1M 820pF
R1 1M
1M 820pF
R2 1M
D97IN626E
15/20
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