參數(shù)資料
型號(hào)： L6223A
文件頁數(shù)： 19/33頁
文件大?。?/td> 1335K
代理商： L6223A
2) Back EMF (BEMF) equal to 80% of its peak
during the phase change and equal to 50% of its
peak during the choppingperiod.
3) Constant slope of the current during t
ON
, t
OFF
and for power calculation during the phase
change (See t
1
in Fig.27).
4) Current imbalancesupposed to be zero.
5) Current ripple during the chopping neglegible.
As was previously stated, the current chopping is
obtained by means of one PWM Loop that con-
trols the charge time t
ON
of the inductance of the
windings, A and B for example in fig.22.
This time starts each clock pulse and stops when
Q5 is switched OFF because of thecondition:
V
ref
= 2 R
S
I
p
.
A factor 2 is required because the single sensing
resistor R
S
is crossed by the peak current I
p
flow-
ing through each of the two energized windings
(A of MA; B of MB).
This configuration can produce an imbalance be-
tween the two peak currents because at the
phasechange the BEMF of one winding (MA) can
be out of phase with respect to the BEMF of the
other one (MB); in addition, an imbalance may
also occur at the phase change when the Power
Supply Voltage selected is too low and/or when
one motoris driven with too large Lm/Rm ratio.
Neverthelessin most of the applicationsthe dissi-
pated power is not increased and there is no sig-
nificantchange in torque.
During t
ON
the current Ip, flowing through the
phaseA (seg. Fig. 24), is definedby V
ON
V
ON
V
S
- R
tot
Ip - BEMF
where R
tot
= R
S
+ R
m
+ R
DSON tot
in which R
m
is the winding resistance of the
phase A and R
DSON tot
is the sum of the R
DSON
of
Q1 and Q5: R
m
and BEMF are not shown on the
Figure24.
At the end of t
ON
, the current starts its slow decay
and jumps to I
p
/2 (see Fig. 25) since the total in-
ductance becomes four times L
m
(perfect cou-
pling) that is the inductanceof the phase A alone.
The recirculationtime t
OFF
is defined by:
V
OFF
2BEMF+ I
P
(R
m
+ R
DSONQ1
)
sinceR
DSONQ1
= R
DSONOQ2
.
The current through Q1 is shown in Fig. 26: the
current ripple is on lp and I
P
/2 during t
ON
and t
OFF
respectively. It can be obtainedthe Duty Cycle:
DC = V
OFF
/ (2V
ON
+ V
OFF
)
since2V
ON
t
ON
= V
OFF
t
OFF
The slow decay allows a small current ripple as
earlier It is considered equal to zero. The current
through the phases A and B can be seen in Fig.
27 where the InA and InB signals (see Fig. 22)
are shown as well.
These two signals are 90
°
out of phase with each
other and they are 180
°
out of phase with the cor-
responding inputs of the IC. In A and In B are not
shown in the Figure.
During the time Tp the motor goes through four
steps and the rotation speed V
rot
(step/sec) can
be given by:
V
rot
= 4/T
p
.
Byconsidering what was statedabove, the follow-
ing can be applied:
1) Dissipated power by the 4 sink power DMOS
(Q1to Q4).
PdL
4 R
DSONQ1
I
p
2
T
P
T
1
3
+
T
p
2
+
T
1
1
+
DC
2
2) Dissipated power by Q5 (PdH).
PdH
4R
DSONQ5
I
p
2
DC
+
T
1
T
p
4
3
4DC
where the phasechange durationis:
T
1
=
L
m
R
tot
log
e
1
2
R
tot
I
p
V
s
1.6 BEMF
+
R
tot
I
P
The chopping produces little power dissipation.
It’svalue can be approximatedby:
3) Pdch
8
10
-3
V
s
I
p
The sum of 1) + 2) + 3) gives the dissipated
power of the output stage. To obtain the total
amount of dissipated power it’s necessary to in-
clude the power dissipation produced by the qui-
escent currents I
S
(from the power stage) and I
SS
(fromthe Logical circuits):
P
do
= V
S
I
S
+ V
SS
I
SS
,
considering I
S
constatversusV
S
. Finally:
P
tot
= PdL + PdH + Pdch + Pdo
Example
SupplyVoltage
LogicVoltage
Peakcurrent (per phase)I
p
= 0.7A
Motorresistance
Motorinductance
Rotation speed
Peakof theBEMF
Max ambienttemperature T
amb
= 50
°
C
Max junctiontemperature T
j
= 125
°
C
From the Electrical Characteristics of the L6223A
(Typical value):
InternalReferenceVoltage V
ref
= 0.5V
SinkDMOS R
DSON
R
DSON
L = 1.2
SourceDMOS R
DSON
R
DSON
H = 0.7
Power SupplyCurrent
LogicSupply Current
V
S
= 36V
V
SS
= 5V
R
m
= 9
L
m
=6mH
V
rot
= 500step/sec(const)
BEMF = 1 Vp
atT
amb
=50
°
C
at
Tj = 25
°
C
Worst
Case
I
S
= 4 mA
I
SS
= 20 mA
From Fig. 3 (seepag. 6) the followingis obtained:
α
1.65 at Tj = 125
°
C.
The DMOS ON-Resistancesbecome(worst case):
L6223A
19/33
相關(guān)PDF資料
PDF描述
L6258A Stepper Motor Controller/Driver
L6258EP PWM CONTROLLED - HIGH CURRENT DMOS UNIVERSAL MOTOR DRIVER
L6258 PWM CONTROLLED - HIGH CURRENT DMOS UNIVERSAL MOTOR DRIVER
L6261 Servo/Spindle Motor Controller/Driver
L6372 OCTAL INDUSTRIAL INPUT INTERFACE(253.91 k)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
L6225 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:DMOS DUAL FULL BRIDGE DRIVER
L6225_03 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:DMOS DUAL FULL BRIDGE DRIVER
L6225D 功能描述:馬達(dá)/運(yùn)動(dòng)/點(diǎn)火控制器和驅(qū)動(dòng)器 Dual Full Bridge RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Stepper Motor Controllers / Drivers 類型:2 Phase Stepper Motor Driver 工作電源電壓:8 V to 45 V 電源電流:0.5 mA 工作溫度:- 25 C to + 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:HTSSOP-28 封裝:Tube
L6225DTR 功能描述:馬達(dá)/運(yùn)動(dòng)/點(diǎn)火控制器和驅(qū)動(dòng)器 Dual Full Bridge RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Stepper Motor Controllers / Drivers 類型:2 Phase Stepper Motor Driver 工作電源電壓:8 V to 45 V 電源電流:0.5 mA 工作溫度:- 25 C to + 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:HTSSOP-28 封裝:Tube
L6225N 功能描述:馬達(dá)/運(yùn)動(dòng)/點(diǎn)火控制器和驅(qū)動(dòng)器 Dual Full Bridge RoHS:否 制造商:STMicroelectronics 產(chǎn)品:Stepper Motor Controllers / Drivers 類型:2 Phase Stepper Motor Driver 工作電源電壓:8 V to 45 V 電源電流:0.5 mA 工作溫度:- 25 C to + 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:HTSSOP-28 封裝:Tube
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*