參數(shù)資料
型號(hào)： TPS40074RHL
廠商： TEXAS INSTRUMENTS INC
元件分類(lèi)： 穩(wěn)壓器
英文描述： 2 A SWITCHING CONTROLLER, 550 kHz SWITCHING FREQ-MAX, PQCC20
封裝： PLASTIC, QFN-20
文件頁(yè)數(shù)： 11/37頁(yè)
文件大?。?/td> 448K
代理商： TPS40074RHL
www.ti.com
TPS40074 POWER DISSIPATION
PD + Qg VDR fSW (Watts driver)
(12)
PT +
2
PD
VDR
) IQ
VIN (Watts)
(13)
PT + 2 Qg fSW ) IQ
VIN (Watts)
(14)
PT +
TJ * TA
qJA
(Watts)
(15)
fSW +
TJ*TA
qJA VIN
* IQ
2
Qg
(Hz)
(16)
BOOST DIODE
LOW VOLTAGE OPERATION
TPS40074
SLUS617–APRIL 2005
APPLICATION INFORMATION (continued)
The power dissipation in the TPS40074 is largely dependent on the MOSFET driver currents and the input
voltage. The driver current is proportional to the total gate charge, Qg, of the external MOSFETs. Driver power
(neglecting external gate resistance) can be calculated from:
where
VDR is the driver output voltage
The total power dissipation in the TPS40074, assuming the same MOSFET is selected for both the high-side and
synchronous rectifier is described in Equation 13.
or
where
IQ is the quiescent operating current (neglecting drivers)
The maximum power capability of the TPS40074 PowerPAD package is dependent on the layout as well as air
flow. The thermal impedance from junction to air ambient assuming 2-oz. copper trace and thermal pad with
solder and no air flow is θJA =60°C/W
The maximum allowable package power dissipation is related to ambient temperature by Equation 15.
Substituting Equation 15 into Equation 14 and solving for fSW yields the maximum operating frequency for the
TPS4007x. The result is described in Equation 16.
The TPS40074 has internal diodes to charge the boost capacitor connected from SW to BOOST. The drop
across this diode is rather large at 1.4-V nominal at room temperature resulting in the drive voltage to the
high-side MOSFET being reduced by this amount from the DBP voltage. If this drop is too large for a particular
application, an external diode may be connected from DBP (anode) to BOOST (cathode). This provides
significantly improved gate drive for the high-side MOSFET, especially at lower input voltages.
If the programmable UVLO is set to less than 6.5 V nominal, connect a 330-k resistor across the soft-start
capacitor. This eliminates a race condition inside the device that can lead to an output voltage overshoot on
power down of the part.
19
相關(guān)PDF資料
PDF描述
TPS40075RHLR 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PQCC20
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TPS40077PWPR 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TPS40074RHLR 功能描述:DC/DC 開(kāi)關(guān)控制器 Mid Input Sync Buck w/Vltg Feed-Fwd RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
TPS40074RHLRG4 功能描述:DC/DC 開(kāi)關(guān)控制器 Mid Input Sync Buck w/Vltg Feed-Fwd RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
TPS40074RHLT 功能描述:DC/DC 開(kāi)關(guān)控制器 Mid Input Sync Buck w/Vltg Feed-Fwd RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
TPS40074RHLTG4 功能描述:DC/DC 開(kāi)關(guān)控制器 Mid Input Sync Buck w/Vltg Feed-Fwd RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
TPS40075 制造商:TI 制造商全稱(chēng):Texas Instruments 功能描述:4.5V TO 18V INPUT 10 PIN SYNCHRONOUS BUCK CONTROLLER WITH POWER GOOD
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