參數(shù)資料
型號(hào)： TPS54383PWPR
廠商： TEXAS INSTRUMENTS INC
元件分類(lèi)： 穩(wěn)壓器
英文描述： 7 A DUAL SWITCHING CONTROLLER, 375 kHz SWITCHING FREQ-MAX, PDSO14
封裝： GREEN, PLASTIC, HTSSOP-14
文件頁(yè)數(shù)： 17/58頁(yè)
文件大?。?/td> 1773K
代理商： TPS54383PWPR
www.ti.com
Bootstrap for the N-Channel MOSFET
Light Load Operation
I
DCM =
1
2
d TS
V
IN
OUT
-
L
(14)
SLUS774B – AUGUST 2007 – REVISED OCTOBER 2007
A bootstrap circuit provides a voltage source higher than the input voltage and of sufficient energy to fully
enhance the switching MOSFET each switching cycle. The PWM duty cycle is limited to a maximum of 90%,
allowing an external bootstrap capacitor to charge through an internal synchronous switch (between BP and
BOOTx) during every cycle. When the PWM switch is commanded to turn ON, the energy used to drive the
MOSFET gate is derived from the voltage on this capacitor.
To allow the bootstrap capacitor to charge each switching cycle, an internal pulldown MOSFET (from SW to
GND) is turned ON for approximately 140 ns at the beginning of each switching cycle. In this way, if, during light
load operation, there is insufficient energy for the SW node to drive to ground naturally, this MOSFET forces the
SW node toward ground and allow the bootstrap capacitor to charge.
Because this is a charge transfer circuit, care must be taken in selecting the value of the bootstrap capacitor. It
must be sized such that the energy stored in the capacitor on a per cycle basis is greater than the gate charge
requirement of the MOSFET being used.
DESIGN HINT
For the bootstrap capacitor, use a ceramic capacitor with a value between 22 nF and
82 nF.
NOTE:
For 5-V input applications, connect PVDDx to BP directly. This connection bypasses
the internal control circuit regulator and provides maximum voltage to the gate drive
circuitry. In this configuration, shutdown mode IDDSDN will be the same as quiescent
IDDQ.
There is no special circuitry for pulse skipping at light loads. The normal characteristic of a nonsynchronous
converter is to operate in the discontinuous conduction mode (DCM) at an average load current less than
one-half of the inductor peak-to-peak ripple current. Note that the amplitude of the ripple current is a function of
input voltage, output voltage, inductor value, and operating frequency, as shown in Equation 14.
Further, during discontinuous mode operation the commanded pulse width may become narrower than the
capability of the converter to resolve. To maintain the output voltage within regulation, skipping switching pulses
at light load conditions is a natural by-product of that mode. This condition may occur if the output capacitor is
charged to a value greater than the output regulation voltage, and there is insufficient load to discharge the
capacitor. A by-product of pulse skipping is an increase in the peak-to-peak output ripple voltage.
24
Copyright 2007, Texas Instruments Incorporated
Product Folder Link(s): TPS54383 TPS54386
相關(guān)PDF資料
PDF描述
TC7660SEOA SWITCHED CAPACITOR REGULATOR, 45 kHz SWITCHING FREQ-MAX, PDSO8
TPS3110E12DBVT 1-CHANNEL POWER SUPPLY MANAGEMENT CKT, PDSO6
TOP248F 7.2 A SWITCHING REGULATOR, 140 kHz SWITCHING FREQ-MAX, PZIP6
TD075-048-15M 1-OUTPUT 75 W DC-DC REG PWR SUPPLY MODULE
TD100-150-12M 1-OUTPUT 100 W DC-DC REG PWR SUPPLY MODULE
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TPS54383PWPRG4 功能描述:直流/直流開(kāi)關(guān)調(diào)節(jié)器 3A Non-Synch Buck Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
TPS54386 制造商:TI 制造商全稱(chēng):Texas Instruments 功能描述:SWIFT Converter Product Portfolio
TPS54386EVM 功能描述:電源管理IC開(kāi)發(fā)工具 TPS54386 Eval Mod RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類(lèi)型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V
TPS54386PWP 功能描述:直流/直流開(kāi)關(guān)調(diào)節(jié)器 DC/DC Controller RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數(shù)量: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5
TPS54386PWP 制造商:Texas Instruments 功能描述:DC/DC Controller
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(xiě)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

*
*
*