- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383236 > L6238 (意法半導(dǎo)體) Sensorless Spindle Motor Driver(無傳感器主軸電機(jī)驅(qū)動(dòng)器) PDF資料下載
參數(shù)資料
| 型號(hào)： | L6238 |
| 廠商： | 意法半導(dǎo)體 |
| 英文描述： | Sensorless Spindle Motor Driver(無傳感器主軸電機(jī)驅(qū)動(dòng)器) |
| 中文描述： | 傳感器主軸電機(jī)驅(qū)動(dòng)器（無傳感器主軸電機(jī)驅(qū)動(dòng)器） |
| 文件頁數(shù)： | 24/35頁 |
| 文件大?。?/td> | 383K |
| 代理商： | L6238 |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁當(dāng)前第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁
Referring back to figure 18, the rate at which the
upper and lower drivers turn OFF is programma-
ble viaan external resistor, R
slew
connectedto the
SLEW RATE
pin. This resistor defines a current
which is utilized internally to limit the voltage slew
rate at the outputs during transition, thus minimiz-
ing the loadchange that the power supply sees.
Figure 23 is a plot of the slew rate that will be ob-
tained as a function of the resistor connected to
the
SLEW RATE
pin. The voltage at the this pin
is typically 2.4V.
To insure proper operation the range of resistor
values indicated should not be exceeded and in
some applications values near the end points
should be avoided as discussed below.
Low Values of Rslew
- If a relativelylow value of
Rslew is selected, the resultant fast slew rate will
result in increased commutation cross-over cur-
rent, higher EMI, and large amount of commuta-
tion current.
This last case can cause voltage spikes at the
output that can go as much as lV below ground
level. This situation must be avoided in this inte-
grated circuit (as in most) since it causes unpre-
dictableoperation.
High Values of Rslew
- Higher values of Rslew
result of course in slow slew rates at the outputs
which is, under most conditions, the desired case
since the problems associated with fast rates are
reduced. The additional advantage is lower
acousticalnoise.
Problems can occur though if the slew rate for a
given applicationis tooslow. Figure 5-10 is an os-
cillograph takenon a devicethat had a fairlylarge
value for Rslew and failed to spin up and phase
Figure24:
Effect of Slow SlewRate.
lock amotor.
The problem manifests itself as the motor begins
to spin up. At lower RPMs, the Bemf of the motor
is relatively small resulting in higher amounts of
commutation current. In figure 24, the upper
waveform is the voltage appearing at
OUTPUT
relative to the
CENTER TAP
input. The lower
waveform is the actual output of the Bemf ampli-
fier available on specialengineeringprototypes.
The oscillograph was taken just as the problem
occured. The period between zero crossings was
~800
μ
s resultingin a mask time period of 200
μ
s.
As can be seen, the excessively long slew rate
Figure 23:
Output VoltageSlewRate vs Rslew.
L6238
24/35
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| L6239 | 12V Disk Drive Spindle Driver(12V磁盤驅(qū)動(dòng)主軸驅(qū)動(dòng)器) |
| L6242 | VOICE COIL MOTOR DRIVER |
| L6243 | VOICE COIL MOTOR DRIVER |
| L6243D | VOICE COIL MOTOR DRIVER |
| L6243DS | VOICE COIL MOTOR DRIVER |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| L6238S | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:12V SENSORLESS SPINDLE MOTOR CONTROLLER |
| L6238SQA | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:12V SENSORLESS SPINDLE MOTOR CONTROLLER |
| L6238SQT | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:12V SENSORLESS SPINDLE MOTOR CONTROLLER |
| L6239 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述: |
| L623C | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:THYRISTOR MODULE|BRIDGE|HALF-CNTLD|CA|280V V(RRM)|46A I(T) |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。