參數(shù)資料
型號(hào)： TPS23753PW
廠商： TEXAS INSTRUMENTS INC
元件分類： 穩(wěn)壓器
英文描述： 0.505 A SWITCHING CONTROLLER, 273 kHz SWITCHING FREQ-MAX, PDSO14
封裝： GREEN, PLASTIC, TSSOP-14
文件頁(yè)數(shù)： 10/30頁(yè)
文件大?。?/td> 823K
代理商： TPS23753PW
RFBU
RFBL
TLV431
ROB
CIZ
RSS
CSS
DSS
FromRegulated
OutputVoltage
SLVS853C – JUNE 2008 – REVISED JANUARY 2010
www.ti.com
Care in design of the transformer and VC bias circuit is required to obtain hiccup overload protection.
Leading-edge voltage overshoot on the bias winding may cause VC to peak-charge, preventing the expected
tracking with output voltage. RVC (Figure 1) is often required slow the peak charging. Good transformer
bias-to-output-winding coupling results in reduced overshoot and better voltage tracking.
The startup current source transitions to a resistance as (VDD1 - VC) falls below 7 V, but will start the converter
from 12 V adapters within tST (VDD1 ≥ 10.2, V~85 ms). The bootstrap source provides reliable startup from widely
varying input voltages, and eliminates the continual power loss of external resistors. The startup current source
will not charge above the maximum recommended VVC if the converter is disabled and there is sufficient VDD1 to
charge higher.
The peak current limit does not have duty cycle dependency unless RS is used as shown in Figure 22 to increase
slope compensation. This makes it easier to design the current limit to a fixed value.
The TPS23753 blanker timing is precise enough that the traditional R-C filters on CS can be eliminated. This
avoids current-sense waveform distortion, which tends to get worse at light output loads. While the internally set
blanking period is relatively precise, almost all converters will require their own blanking period. The TPS23753
provides the BLNK pin to allow this programming. There may be some situations or designers that prefer an R-C
approach. The TPS23753 provides a pull-down on CS during the GATE off time to improve sensing when an
R-C filter must be used. The CS input signal should be protected from nearby noisy signals like GATE drive and
the MOSFET drain.
Converters require a softstart on the voltage error amplifier to prevent output overshoot on startup. Figure 21
shows a common implementation of a secondary-side softstart that works with the typical TL431 error amplifier
shown in Figure 1. This secondary-side error amplifier will not become active until there is sufficient voltage on
the secondary. The TPS23753 provides a primary-side softstart which persists long enough (~800
μs) for
secondary side voltage-loop softstart to take over. The primary-side current-loop softstart controls the switching
MOSFET peak current by applying a slowly rising ramp voltage to a second PWM control input. Figure 19 shows
an exaggerated handoff between the primary and secondary-side softstart that is most easily seen in the IPI
waveform. The output voltage rises in a smooth monotonic fashion with no overshoot. This handoff can be
optimized by decreasing the secondary-side softstart period.
Figure 21. Example of Softstart Circuit Added to Error Amplifier
The dc/dc controller has an OTSD that can be triggered by heat sources including the VB regulator, GATE driver,
bootstrap current source, and bias currents. The controller OTSD turns off VB, the GATE driver, resets the
softstart generator, and forces the VC control into an under-voltage state.
Special Switching MOSFET Considerations
Special care must be used in selecting the converter switching MOSFET. The TPS23753 converter section has
minimum VC operating voltage of ~5.5 V, which is reflected in the applied gate voltage. This will occur during an
output overload, or towards the end of a (failed) bootstrap startup. The MOSFET must be able to carry the
anticipated peak fault current at this gate voltage.
18
Copyright 2008–2010, Texas Instruments Incorporated
Product Folder Link(s): TPS23753
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TPS23753PW 制造商:Texas Instruments 功能描述:Controller IC
TPS23753PWG4 功能描述:熱插拔功率分布 PoE Interface & Iso Cnvrtr & Cntrlr RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube
TPS23753PWR 功能描述:熱插拔功率分布 Interface and Iso Cnvrtr and Cntrlr RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube
TPS23753PWRG4 功能描述:熱插拔功率分布 PoE Interface & Iso Cnvrtr & Cntrlr RoHS:否 制造商:Texas Instruments 產(chǎn)品:Controllers & Switches 電流限制: 電源電壓-最大:7 V 電源電壓-最小:- 0.3 V 工作溫度范圍: 功率耗散: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:MSOP-8 封裝:Tube
TPS23754EVM-383 功能描述:電源管理IC開發(fā)工具 TPS23754 Eval Mod 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
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