- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄97995 > L4992 (STMICROELECTRONICS) SWITCHING CONTROLLER, 300 kHz SWITCHING FREQ-MAX, PQFP32 PDF資料下載
參數(shù)資料
| 型號(hào)： | L4992 |
| 廠商： | STMICROELECTRONICS |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SWITCHING CONTROLLER, 300 kHz SWITCHING FREQ-MAX, PQFP32 |
| 封裝： | TQFP-32 |
| 文件頁數(shù)： | 24/26頁 |
| 文件大小： | 296K |
| 代理商： | L4992 |
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
t
5V
OSC
0V
H5GATE
H3GATE
D97IN574
400ns min.
Figure 1: Synchronization signal and operation.
DETAILED FUNCTIONAL DESCRIPTION (continued)
CLOCK
S
R
Q
_
REG5
HSTRAP
L
Rsense
E.S.
+
-
+
-
+
VREF
SLOPE
COMP.
VIN
Rf
Cf
Co
ESR
Ro
Figure 2: L4992 Control Loop.
The error summing, by comparing the above mentioned signals, determines the moment in which the
output latch is to be reset. The high-side MOSFET is then turned off and the synchronous rectifier is
turned on after the appropriate delay (typ. 75 ns), thus making the inductor current recirculate. This state
is maintained until the next oscillator pulse.
With reference to the schematic of fig. 2, the open-loop transfer function of such a kind of control system,
under the assumption of an ideal slope compensation, is:
F
(s) = A
RO
Rsense
1
+ s ESR CO
(1 + s RO CO) (1 + s RF CF)
where A is the gain of the error summing comparator, which is 2 by design.
The system is inherently very fast since it tends to correct output voltage deviations nearly on a cycle-by-
cycle basis. Actually, in case of line or load changes, few switching cycles can be sufficient for the tran-
sient to expire.
The operation above illustrated is modified during particular or anomalous conditions. Leaving out other
circumstances (described in "Protections" section) for the moment, consider when the load current is low
enough or during the first switching cycles at start-up: the inductor current may become discontinuous,
that is it is zero during the last part of each cycle. In such a case, a "zero current comparator" detects the
event and turns off the synchronous rectifier, avoiding inductor current reversal and reproducing the
natural turn-off of a diode when reverse biased. Both MOSFET’s stay in off state until the next oscillator
pulse.
L4992
7/26
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| L5953 | 1.2 A SWITCHING REGULATOR, 425 kHz SWITCHING FREQ-MAX, PDSO36 |
| L5962 | SWITCHING REGULATOR, PDSO36 |
| L5973DD | 3.5 A SWITCHING REGULATOR, 280 kHz SWITCHING FREQ-MAX, PDSO8 |
| L5988D | 5.6 A SWITCHING REGULATOR, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
| L5994A | 1 A DUAL SWITCHING CONTROLLER, 345 kHz SWITCHING FREQ-MAX, PQFP32 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| L4993 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Low drop voltage regulator |
| L4993D | 功能描述:低壓差穩(wěn)壓器 - LDO Low drop voltage regulator RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| L4993DTR | 功能描述:低壓差穩(wěn)壓器 - LDO Low drop voltage regulator RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| L4993MD | 功能描述:低壓差穩(wěn)壓器 - LDO Low drop voltage regulator RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| L4993MDTR | 功能描述:低壓差穩(wěn)壓器 - LDO 5V 150mA LW DROP VLT REGULATOR RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動(dòng)電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。