L6258EXTR STMicroelectronics, L6258EXTR Datasheet - Page 20

IC MOTOR DRVR UNIV PWM PWRSO-36

L6258EXTR

Manufacturer Part Number
L6258EXTR
Description
IC MOTOR DRVR UNIV PWM PWRSO-36
Manufacturer
STMicroelectronics
Type
Driverr
Datasheet

Specifications of L6258EXTR

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
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

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
L6258EXTR
Manufacturer:
ST
0
Part Number:
L6258EXTR
Manufacturer:
ST
Quantity:
20 000
Part Number:
L6258EXTR-1LF
Manufacturer:
ST
0
PWM current control loop
20/32
because ib = icwe have:
In the case of no external RC network is used to compensate the error amplifier, the typical
open loop transfer function of the error plus the sense amplifier is something with a gain
around 80dB and a unity gain bandwidth at 400kHz. In this case the situation of the total
transfer function Aloop, given by the sum of the Ax
Figure 8.
The BODE diagram shows together the error amplifier open loop transfer function, the Ax
function and the resultant total Aloop given by the following equation:
The total Aloop has an high DC gain of 78.1dB with a bandwidth of 15KHz, but the problem
in this case is the stability of the system; in fact the total Aloop cross the zero dB axis with a
slope of -40dB/decade.
Now it is necessary to compensate the error amplifier in order to obtain a total Aloop with an
high DC gain and a large bandwidth. Aloop must have enough phase margin to guarantee
the stability of the system.
A method to reach the stability of the system, using the RC network showed in the block
diagram, is to cancel the load pole with the zero given by the compensation of the error
amplifier.
The transfer function of the Bx block with the compensation on the error amplifier is:
Aloop bode plot (uncompensated)
Verr_out = -(ic · Zc) so ic = -(Verr_out ·
Vsense ·
Bx
Aloop
=
------- -
Rb
1
Verr_out
----------------------- -
dB
Vsense
= AxdB + Bx
= -(Verr_out ·
=
dB
and Bx
------- -
Rb
Zc
dB
------ -
Zc
1
dB
is:
)
------ -
Zc
1
)
L6258EX

Related parts for L6258EXTR