- 您现在的位置：买卖IC网 > PDF目录97995 > L6238SQT (STMICROELECTRONICS) BRUSHLESS DC MOTOR CONTROLLER, 5 A, PQFP64 PDF资料下载
参数资料
| 型号： | L6238SQT |
| 厂商： | STMICROELECTRONICS |
| 元件分类： | 运动控制电子 |
| 英文描述： | BRUSHLESS DC MOTOR CONTROLLER, 5 A, PQFP64 |
| 封装： | TQFP-64 |
| 文件页数： | 16/31页 |
| 文件大小： | 3465K |
| 代理商： | L6238SQT |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页当前第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页
Coff to discharge to dischargte through Rslew, initi-
ating the Constant-OFF time-out. When the volt-
age on Coff reaches 1.2V, comparator A1switches
state toggling the latch in the opposite state, turn-
ing the upper driver back ON. SW1 also closed
quickly charging up Coff for the next cycle.
5.1 PWM Design Considerations
In order to select the parameters associated with
PWM operation, the following factors must be
taken into consideration:
1. PWM Switching Frequency
2. Duty Cycle
3. Motor Currents
4. Minimum ON Time
5. Noise Blanking
6. Bemf Masking/Sampling
5.1.1. PWM Switching Frequency
The PWM switching frequency Fpwm is found
from:
Fpwm
=
1
Ton
+ Toff
(5.1.1)
where:
Ton = The time required for the motor current
to reach the commanded level.
Toff = The programmed OFF time.
The two main considerations for this parameter
are the minimum and maximum switching fre-
quency.
The maximum switching frequency occurs during
the Start-up and should be kept below 50KHz due
tointentional bandwidth limitations and output
switching losses.
5.1.2 Duty Cycle
Besides reducing the power dissipation of the
controller output stage, running in PWM offers 2
additional "free" benefits:
A. Reduced Powe Supply Current at Start Up
B. Lower Power Rating for the Motor Current
Sense Resistor.
Figure 5-2 is the current path during the ON time
of a phase period. The current from the supply
passes through the upper sourcing DMOS, Q3
transistor through the two driven winding, the
lower DMOS, Q2 and finally through the current
sensing resistor Rsns. Since both Q3 and Q4 are
ON, while Q3 is turned OFF. The voltage, causing
the current to continue to flow through Q2, and
Q4.
If the duty cycle is nearor at 50%, then for 1/2 the
PWM cycle, no current is flowing from the power
supply or the sense resistor while current is still
flowing in the motor. This lowers the requirement
for both the Power Supply and the Power Rating
for the sensing resistor.
5.1.3 Motor Currents
Note: It is not the objective of this section to describe the principles
of brushless DC motor, but to provide sufficient information about the
parameters associated with PWM operation in order to optimize an
application.
A simplified model of a motor is shown in figure 5-
4. For this discussion, lower order effects due to
mutual inductance between windings, resistance
due to losses in the magnetic circuit, etc. are not
shown.
The motor at stall is equal to a resistance, Rmtr,
in series with an inductance, Lmtr. When the mo-
tor is rotating, there is an induced emf that ap-
pears across the armaure terminals and is shown
in figure 5-4 as an internally generated voltage
Ibemf), Eg.
L1
L2
OUTPUTA
OUTPUTB
D2
D1
D4
D3
Q1
Q2
Q3
Q4
VPOWER
RSENSE
RSNS
D95IN319
Figure 5-2
L1
L2
OUTPUTA
OUTPUTB
D2
D1
D4
D3
Q1
Q2
Q3
Q4
VPOWER
RSENSE
RSNS
D95IN320
Figure 5-3
L6238S
23/31
相关PDF资料 |
PDF描述 |
|---|---|
| L6238S013TR | BRUSHLESS DC MOTOR CONTROLLER, 5 A, PQCC44 |
| L6246 | VOICE COIL MOTOR CONTROLLER, 3 A, PQFP44 |
| L6258EA | STEPPER MOTOR CONTROLLER, 2 A, PDSO36 |
| L6268 | VOICE COIL MOTOR CONTROLLER, 2.1 A, PQFP44 |
| L6269 | VOICE COIL MOTOR CONTROLLER, 2.1 A, PQFP44 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| L6239 | 制造商:未知厂家 制造商全称:未知厂家 功能描述: |
| L623C | 制造商:未知厂家 制造商全称:未知厂家 功能描述:THYRISTOR MODULE|BRIDGE|HALF-CNTLD|CA|280V V(RRM)|46A I(T) |
| L623F | 制造商:未知厂家 制造商全称:未知厂家 功能描述:THYRISTOR MODULE|BRIDGE|HALF-CNTLD|CA|280V V(RRM)|46A I(T) |
| L624 | 制造商:CRYDOM 制造商全称:Crydom Inc., 功能描述:Power Modules |
| L6242 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:VOICE COIL MOTOR DRIVER |
发布紧急采购，3分钟左右您将得到回复。