参数资料
型号: L6258
厂商: STMICROELECTRONICS
元件分类: 运动控制电子
英文描述: STEPPER MOTOR CONTROLLER, 1.5 A, PDSO36
封装: ROHS COMPLIANT, SOP-36
文件页数: 8/32页
文件大小: 364K
代理商: L6258
PWM current control loop
L6258
16/32
Doc ID 4588 Rev 10
3
PWM current control loop
3.1
Open loop transfer function analysis
Block diagram: refer to Figure 5.
Input parameters:
VS = 24V
LL = 12mH
RL = 12Ω
RS = 0.33Ω
RC = to be calculated
CC = to be calculated
Gs transconductance gain = 1/Rb
Gin transconductance gain = 1/Ra
Ampl. of the Tria_0_180 ref. = 1.6V (peak to peak)
Ra = 40KΩ
Rb = 20KΩ
Vr = Internal reference equal to VDD/2 (Typ. 2.5V)
these data refer to a typical application, and will be used as an example during the analysis
of the stability of the current control loop.
The block diagram shows the schematics of the L6258 internal current control loop working
in PWM mode; the current into the load is a function of the input control voltage VDAC , and
the relation between the two variables is given by the following formula:
ILOAD RS GS = VDAC Gin
where:
VDAC
is the control voltage defining the load current value
Gin
is the gain of the input transconductance amplifier ( 1/Ra )
Gs
is the gain of the sense transconductance amplifier ( 1/Rb )
Rs
is the resistor connected in series to the output to sense the load current
In this configuration the input voltage is compared with the feedback voltage coming from
the sense resistor, then the difference between this two signals is amplified by the error
amplifier in order to have an error signal controlling the duty cycle of the output stage
keeping the load current under control.
It is clear that to have a good performance of the current control loop, the error amplifier
must have an high DC gain and a large bandwidth.
I
LOAD
R
S
1
R
b
-------
V
DAC
1
R
a
-------
=
I
LOAD
V
DAC
R
b
R
a
R
s
----------------------
0.5
V
DAC
R
S
--------------- A
()
==
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L6258_07 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:PWM controlled high current DMOS universal motor driver
L6258A 制造商:未知厂家 制造商全称:未知厂家 功能描述:Stepper Motor Controller/Driver
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L6258E_07 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:PWM controlled high current DMOS universal motor driver
L6258EA 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:PWM controlled high current DMOS universal motor driver