參數(shù)資料
型號： TPS54357MPWPREP
廠商： TEXAS INSTRUMENTS INC
元件分類： 穩(wěn)壓器
英文描述： 6.5 A SWITCHING REGULATOR, 700 kHz SWITCHING FREQ-MAX, PDSO16
封裝： PLASTIC, HTSSOP-16
文件頁數(shù)： 4/35頁
文件大?。?/td> 1132K
代理商： TPS54357MPWPREP
T
delay +
1000
s (kHz)
ms
(6)
Bias Voltage (VBIAS)
Bootstrap Voltage (BOOT)
Error Amplifier
Voltage Reference
PWM Control and Feed Forward
SLVS684A – JANUARY 2007 – REVISED JULY 2009 ....................................................................................................................................................... www.ti.com
Once the PWRGD pin presents a high impedance (i.e., power is good), a VSENSE pin out-of-bounds condition
forces PWRGD low (i.e., power is bad) after a time delay. This time delay is a function of the switching frequency
and is calculated using equation 6:
The VBIAS regulator provides a stable supply for the internal analog circuits and the low-side gate driver. Up to 1
mA of current can be drawn for use in an external application circuit. The VBIAS pin must have a bypass
capacitor value of 1
F. X7R- or X5R-grade dielectric ceramic capacitors are recommended because of their
stable characteristics over temperature.
The BOOT capacitor obtains its charge cycle by cycle from the VBIAS capacitor. A capacitor from the BOOT pin
to the PH pins is required for operation. The bootstrap connection for the high-side driver must have a bypass
capacitor of 0.1
F.
The VSENSE pin is the error amplifier inverting input. The error amplifier is a true voltage amplifier, with 1.5 mA
of drive capability with a minimum of 60 dB of open-loop voltage gain and a unity-gain bandwidth of 2 MHz.
The
voltage-reference
system
produces
a
precision
reference
signal
by
scaling
the
output
of
a
temperature-stable bandgap circuit. During production testing, the bandgap and scaling circuits are trimmed to
produce 0.891 V at the output of the error amplifier, with the amplifier connected as a voltage follower. The trim
procedure improves the regulation, since it cancels offset errors in the scaling and error-amplifier circuits.
Signals from the error-amplifier output, oscillator, and current-limit circuit are processed by the PWM control
logic. Referring to the internal block diagram, the control logic includes the PWM comparator, PWM latch, and
the adaptive dead-time control logic. During steady-state operation below the current-limit threshold, the PWM
comparator output and oscillator pulse train alternately reset and set the PWM latch.
Once the PWM latch is reset, the low-side driver and integrated pulldown MOSFET remain on for a minimum
duration set by the oscillator pulse width. During this period, the PWM ramp discharges rapidly to the valley
voltage. When the ramp begins to charge back up, the low-side driver turns off and the high-side FET turns on.
The peak PWM ramp voltage varies inversely with input voltage to maintain a constant modulator and
power-stage gain of 8 V.
As the PWM ramp voltage exceeds the error-amplifier output voltage, the PWM comparator resets the latch, thus
turning off the high-side FET and turning on the low-side FET. The low-side driver remains on until the next
oscillator pulse discharges the PWM ramp.
During transient conditions, the error-amplifier output can be below the PWM ramp valley voltage or above the
PWM peak voltage. If the error amplifier is high, the PWM latch is never reset and the high-side FET remains on
until the oscillator pulse signals the control logic to turn the high-side FET off and the internal low-side FET and
driver on. The device operates at its maximum duty cycle until the output voltage rises to the regulation set point,
setting VSENSE to approximately the same voltage as the internal voltage reference. If the error-amplifier output
is low, the PWM latch is reset continually and the high-side FET does not turn on. The internal low-side FET and
low-side driver remain on until the VSENSE voltage decreases to a range that allows the PWM comparator to
change states. The TPS5435x is capable of sinking current through the external low-side FET until the output
voltage reaches the regulation set point.
The minimum on time is designed to be 180 ns. During the internal slow-start interval, the internal reference
ramps from 0 V to 0.891 V. During the initial slow-start interval, the internal reference voltage is very small,
resulting in skipped pulses because the minimum on time causes the actual output voltage to be slightly greater
than the preset output voltage, until the internal reference ramps up.
12
Copyright 2007–2009, Texas Instruments Incorporated
相關(guān)PDF資料
PDF描述
TPS54354MPWPREP 6.5 A SWITCHING REGULATOR, 700 kHz SWITCHING FREQ-MAX, PDSO16
TPS54362QPWPRQ1 8 A SWITCHING REGULATOR, 2200 kHz SWITCHING FREQ-MAX, PDSO20
TPS54373PWP 6 A SWITCHING REGULATOR, 762 kHz SWITCHING FREQ-MAX, PDSO20
TPS54377RHFRG4 7.5 A SWITCHING REGULATOR, 1600 kHz SWITCHING FREQ-MAX, PQCC24
TPS54377RHFTG4 7.5 A SWITCHING REGULATOR, 1600 kHz SWITCHING FREQ-MAX, PQCC24
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TPS54357PWP 功能描述:直流/直流開關(guān)調(diào)節(jié)器 4.5 to 20V Inp 3-A Synch PWM Switch RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(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
TPS54357PWPG4 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 4.5 to 20V Inp 3-A Synch PWM Switch 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(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
TPS54357PWPR 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 4.5 to 20V Inp 3-A Synch PWM Switch 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(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
TPS54357PWPRG4 功能描述:開關(guān)變換器、穩(wěn)壓器與控制器 4.5 to 20V Inp 3-A Synch PWM Switch 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(guān)頻率:1 MHz 工作溫度范圍: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:WSON-8 封裝:Reel
TPS5435X 制造商:TI 制造商全稱:Texas Instruments 功能描述:SWIFT Converter Product Portfolio
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。

采購需求

(若只采購一條型號，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進(jìn)入我的后臺，查看報價

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進(jìn)入我的后臺，查看報價

*型號 *數(shù)量 廠商 批號 封裝
添加更多采購

我的聯(lián)系方式

*
*
*