- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄67754 > L5989DTR (STMICROELECTRONICS) 5.06 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO16 PDF資料下載
參數(shù)資料
| 型號： | L5989DTR |
| 廠商： | STMICROELECTRONICS |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 5.06 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封裝： | ROHS COMPLIANT, HTSSOP-16 |
| 文件頁數(shù)： | 13/51頁 |
| 文件大小： | 1947K |
| 代理商： | L5989DTR |
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頁當前第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頁第36頁第37頁第38頁第39頁第40頁第41頁第42頁第43頁第44頁第45頁第46頁第47頁第48頁第49頁第50頁第51頁
Functional description
L5989D
20/51
Doc ID 15778 Rev 3
5.5.2
Current limiting
The current limiting feature acts in different ways depending on the operative conditions.
●
In case an overcurrent detection happens after the soft-start phase, the internal logic
will trigger the “HICCUP” mode. Both switches are turned off and the soft-start
capacitor is discharged with a constant current of 22 μA (typ.). When the SS/INH
voltage drops below the INH threshold a new SS cycle will start.
●
During the soft-start phase the overcurrent information is used to provide a constant
current protection. In this way additional current is available to charge the output
capacitor during power up.
The most common way is to sense the current flowing through the power MOSFETs.
However, due to the noise created by the switching activity of the power MOSFETs, the
current sense is disabled during the initial phase of the conduction time. This avoids an
erroneous detection of a fault condition. This interval is generally known as “masking time”
or “blanking time”. For this reason, the current cannot be sensed through the high-side
MOSFET in the case of extremely low duty cycles, nor through the low-side MOSFET in the
case of very high duty cycles.
The L5989D assures the effective protection sensing the current flowing in both embedded
switches. The protection achieved by sensing the current in the high-side MOSFET is called
“peak overcurrent protection”, while the protection achieved by sensing the current in the
low-side MOSFET is called “valley overcurrent protection”. When the current limit is reached
during normal operation, the so called HICCUP mode is triggered, and the soft-start cap is
discharged and recharged. However, during the start-up phase, additional current is
required to charge the output capacitor. This could continuously trigger the HICCUP
intervention preventing the system from reaching a steady working condition. For this
reason the HICCUP feature is disabled during the start-up phase and a constant current
mode is active to charge the output capacitor. In this case, when the peak current limit is
triggered after a conduction time equal to the “masking time”, the high-side MOSFET is
turned off and the low side MOSFET is kept on until the flowing current goes below the
“valley” current limit. If necessary, some switching pulses are skipped, as illustrated in
Figure 10. Thus, the combination of the “peak” and “valley” current limits assure the
effectiveness of the overcurrent protection even in extreme duty cycle conditions. The
current threshold of the low side is designed higher than the high side one to guarantee the
proper protection.
The constant current mode during the soft-start phase limits the maximum current up to:
The overcurrent limit protection is adjustable (higher or lower than the nominal value)
through an external resistor. To guarantee effective protection, both thresholds (valley and
peak) are in tracking.
The typical active thresholds in case of ILIM-ADJ pin left floating are IPEAK_TH = 4.0 A,
IVALLEY_TH = 4.58 A. The dimensioning of the pull up resistor versus VREF to decrease the
peak (and valley) thresholds follows the formula:
I
MAX
I
VALLEY_TH
V
IN
V
OUT
–
L
------------------------------ T
MASK
+
=
R
3 kΩ
()
270.6
Ipk A
() 4.026
–
--------------------------------------,
=
Ivy A
()
287
R
3 kΩ
()
--------------------
4.58
+
=
相關PDF資料 |
PDF描述 |
|---|---|
| L5989D | 5.06 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
| L5991D013TR | 1.5 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
| L6258EX | STEPPER MOTOR CONTROLLER, 1.5 A, PDSO36 |
| L6470PD | STEPPER MOTOR CONTROLLER, 7 A, PDSO36 |
| L6566BTR | 0.8 A POWER FACTOR CONTROLLER, 900 kHz SWITCHING FREQ-MAX, PDSO16 |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| L5991 | 功能描述:電流型 PWM 控制器 Prog Current Mode RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| L5991_01 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:PRIMARY CONTROLLER WITH STANDBY |
| L5991A | 功能描述:電流型 PWM 控制器 Prog Current Mode RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
| L5991AD | 功能描述:開關變換器、穩(wěn)壓器與控制器 Prog Current Mode RoHS:否 制造商:Texas Instruments 輸出電壓:1.2 V to 10 V 輸出電流:300 mA 輸出功率: 輸入電壓:3 V to 17 V 開關頻率:1 MHz 工作溫度范圍: 安裝風格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel |
| L5991AD13TR | 功能描述:電流型 PWM 控制器 Prog Current Mode RoHS:否 制造商:Texas Instruments 開關頻率:27 KHz 上升時間: 下降時間: 工作電源電壓:6 V to 15 V 工作電源電流:1.5 mA 輸出端數(shù)量:1 最大工作溫度:+ 105 C 安裝風格:SMD/SMT 封裝 / 箱體:TSSOP-14 |
發(fā)布緊急采購，3分鐘左右您將得到回復。