L6258EX STMicroelectronics, L6258EX Datasheet - Page 19
L6258EX
Manufacturer Part Number
L6258EX
Description
IC MOTOR DRIVER UNIV 36-PWRSOIC
Manufacturer
STMicroelectronics
Type
Driverr
Datasheet
1.E-L6258EXTR.pdf
(32 pages)
Specifications of L6258EX
Applications
DC Motor Driver, Stepper Motor Driver
Number Of Outputs
2/1
Current - Output
1.5A
Voltage - Load
12 V ~ 40 V
Voltage - Supply
4.75 V ~ 5.25 V
Mounting Type
Surface Mount
Package / Case
PowerSO-36 Exposed Bottom Pad
Operating Supply Voltage
12 V to 40 V
Supply Current
15 mA
Mounting Style
SMD/SMT
Operating Temperature
150 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Operating Temperature
-
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
Other names
497-3702-5
E-L6258EX
E-L6258EX
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
L6258EX
Manufacturer:
WOLFSON
Quantity:
1 440
Part Number:
L6258EX
Manufacturer:
ST
Quantity:
20 000
Part Number:
L6258EXTR
Manufacturer:
ST
Quantity:
20 000
L6258EX
3.4
Before analysing the error amplifier block and the sense transconductance block, we have to
do this consideration:
Aloop
Ax|
and
Bx|
this means that Ax|dB is the sum of the power amplifier and load blocks;
Ax|
The BODE analysis of the transfer function of Ax is:
Figure 7.
The Bode plot of the Ax|dB function shows a DC gain of -1.9dB and a pole at 163Hz.
It is clear now that (because of the negative gain of the Ax function), Bx function must have
an high DC gain in order to increment the total open loop gain increasing the bandwidth too.
Error amplifier and sense amplifier
As explained before the gain of these two blocks is:
Bx
Being the voltage across the sense resistor the input of the Bx block and the error amplifier
voltage the output of the same, the voltage gain is given by:
dB
dB
dB
dB
= ACerr
dB
= ACpw|
= ACerr|
= (29,5) + (-31.4) = -1.9dB
= Ax
Ax bode plot
dB
dB
dB
dB
+ Bx
+ ACsense
+ ACsense|
+ ACload|
dB
ib
dB
dB
dB
=
Vsense
⋅
Gs
=
Vsense
⋅
------- -
Rb
1
PWM current control loop
19/32