參數(shù)資料
型號(hào)： TPS54318RTET
廠商： TEXAS INSTRUMENTS INC
元件分類： 穩(wěn)壓器
英文描述： 5.5 A SWITCHING REGULATOR, 2000 kHz SWITCHING FREQ-MAX, PQCC16
封裝： 3 X 3 MM, PLASTIC, QFN-16
文件頁(yè)數(shù)： 6/36頁(yè)
文件大?。?/td> 1388K
代理商： TPS54318RTET
EN1=2V/div
Vout1=1V/div
Vout2=1V/div
Time=5msec/div
SS
TPS54318
EN
PWRGD
SS
TPS54318
EN
PWRGD
W
1.0793
311890
RT (k ) =
Fsw(kHz)
0.9393
133870
Fsw(kHz)
RT(k )
=
W
SLVS975 – SEPTEMBER 2009 ......................................................................................................................................................................................... www.ti.com
Figure 26. Schematic for Ratiometric Start-Up
Figure 27. Ratiometric Start-Up using Coupled SS
Sequence
Pins
CONSTANT SWITCHING FREQUENCY and TIMING RESISTOR (RT/CLK Pin)
The switching frequency of the TPS54318 is adjustable over a wide range from 200 kHz to 2000 kHz by placing
a maximum of 1000k
and minimum of 85 k, respectively, on the RT/CLK pin. An internal amplifier holds this
pin at a fixed voltage when using an external resistor to ground to set the switching frequency. The RT/CLK is
typically 0.5 V. To determine the timing resistance for a given switching frequency, use the curve in Figures 5
and 6, or Equation 5.
(5)
(6)
To reduce the solution size one would typically set the switching frequency as high as possible, but tradeoffs of
the efficiency, maximum input voltage and minimum controllable on time should be considered.
The minimum controllable on time is typically 60 ns at full current load and 110 ns at no load, and limits the
maximum operating input voltage or output voltage.
OVERCURRENT PROTECTION
The TPS54318 implements a cycle by cycle current limit. During each switching cycle the high side switch
current is compared to the voltage on the COMP pin. When the instantaneous switch current intersects the
COMP voltage, the high side switch is turned off. During overcurrent conditions that pull the output voltage low,
the error amplifier responds by driving the COMP pin high, increasing the switch current. The error amplifier
output is clamped internally. This clamp functions as a switch current limit.
FREQUENCY SHIFT
To operate at high switching frequencies and provide protection during overcurrent conditions, the TPS54318
implements a frequency shift. If frequency shift was not implemented, during an overcurrent condition the low
side MOSFET may not be turned off long enough to reduce the current in the inductor, causing a current
runaway. With frequency shift, during an overcurrent condition the switching frequency is reduced from 100%,
then 75%, then 50%, then 25% as the voltage decreases from 0.8 to 0 volts on VSENSE pin to allow the low
side MOSFET to be off long enough to decrease the current in the inductor. During start-up, the switching
frequency increases as the voltage on VSENSE increases from 0 to 0.8 volts. See Figure 7 for details.
14
Copyright 2009, Texas Instruments Incorporated
Product Folder Link(s) :TPS54318
相關(guān)PDF資料
PDF描述
TPS54318RTER 5.5 A SWITCHING REGULATOR, 2000 kHz SWITCHING FREQ-MAX, PQCC16
TPS54319RTER SWITCHING REGULATOR, PQCC16
TPS54319RTE SWITCHING REGULATOR, PQCC16
TPS54326PWP 5.5 A SWITCHING REGULATOR, 700 kHz SWITCHING FREQ-MAX, PDSO14
TPS54326RGTR 5.5 A SWITCHING REGULATOR, 700 kHz SWITCHING FREQ-MAX, PQCC16
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TPS54318RTET 制造商:Texas Instruments 功能描述:Voltage Regulator IC 制造商:Texas Instruments 功能描述:IC, SYNC STEP-DOWN SWITCHER, QFN-16
TPS54319 制造商:TI 制造商全稱:Texas Instruments 功能描述:2.95-V to 6-V Input, 3-A Output, 2-MHz, Synchronous Step-Down Switcher With Integrated FETs ( SWIFTa?￠)
TPS54319_1 制造商:TI 制造商全稱:Texas Instruments 功能描述:2.95-V to 6-V Input, 3-A Output, 2-MHz, Synchronous Step-Down Switcher With Integrated FETs ( SWIFTa?￠)
TPS54319EVM-626 功能描述:電源管理IC開(kāi)發(fā)工具 Evaluation Module for TPS54319 RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評(píng)估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V
TPS54319RTE 制造商:TI 制造商全稱:Texas Instruments 功能描述:2.95-V to 6-V Input, 3-A Output, 2-MHz, Synchronous Step-Down Switcher With Integrated FETs ( SWIFT?)
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