參數(shù)資料
型號(hào): TPS40075RHLTG4
廠商: TEXAS INSTRUMENTS INC
元件分類: 穩(wěn)壓器
英文描述: 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PQCC20
封裝: PLASTIC, QFN-20
文件頁(yè)數(shù): 20/44頁(yè)
文件大?。?/td> 806K
代理商: TPS40075RHLTG4
www.ti.com
P
QSW + PQSW(CON) ) PQSW(SW) ) PQSW(GATE)
(25)
P
QSW(CON) + RDS(on)
I
D
2
+ RDS(on)
V
O
V
IN
I
LOAD
2
) D
I2
12
(26)
P
QSW(SW) + VIN
f
SW
I
LOAD )
DI
2
Q
gs1 ) Qgd
Ig
)
Q
OSS(SW) ) QOSS(SR)
2
(27)
P
QSW(GATE) + Qg(TOT)
Vg
F
SW
(28)
SLUS676A – MAY 2006 – REVISED SEPTEMBER 2007
Equation 25 through Equation 28 can be used to calculate the power loss, PQSW, in the switching MOSFET
where
P
QSW(CON) = conduction losses
P
QSW(SW) = switching losses
P
QSW(GATE) = gate drive losses
Q
gd = drain source charge or miller charge
Q
gs1 = gate source post threshold charge
I
g = gate drive current
Q
OSS(SW) = switching MOSFET output charge
Q
OSS(SR) = synchronous MOSFET output charge
Qg
(TOT) = total gate charge from zero volts to the gate voltage
Vg = gate voltage
If the total estimated loss is split evenly between conduction and switching losses, Equation 25 and Equation 26
yields preliminary values for RDS(on) and (Qgs1 + Qgd). Note output losses due to QOSS and gate losses have been
ignored here. Once a MOSFET is selected these parameters can be added.
The switching MOSFET for this design should have an RDS(on) of less than 9 m. The sum of Qgd and Qgs should
be approximately 4 nC.
It is not always possible to get a MOSFET which meets both these criteria so a comprise may have to be made.
Also by selecting different MOSFETs close to this criteria and calculating power loss the final selection can be
made. It was found that the PH6325L MOSFET from Philips semiconductor gave reasonable results. This device
has an RDS(on) of 6.3 m and a (Qgs1+Qgd) of 5.9 nC. The estimated conduction losses are 0.178 W and the
switching losses are 0.270 W. This gives a total estimated power loss of 0.448 W versus 0.5 W for our initial
boundary condition. Note this does not include gate losses of approximately 10 mW and output losses of less
than 1 mW.
3.1.5 Rectifier MOSFET, QSR
Similar criteria can be used for the rectifier MOSFET. There is one significant difference. Due to the body diode
conducting, the rectifier MOSFET switches with near zero voltage across its drain and source so effectively with
near zero switching losses. However, there are some losses in the body diode. These are minimized by reducing
the delay time between the transition from the switching MOSFET turn off to rectifier MOSFET turn on and vice
versa. The TPS40075 incorporates TI's proprietary predictive gate drive which helps reduce this delay to
between 10 ns and 20 ns.
Copyright 2006–2007, Texas Instruments Incorporated
27
Product Folder Link(s) :TPS40075
相關(guān)PDF資料
PDF描述
TPS40077PWPR 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16
TPS40077PWPRG4 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16
TPS40077PWPG4 2 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16
TPS40090QPWRQ1 SWITCHING CONTROLLER, 1200 kHz SWITCHING FREQ-MAX, PDSO24
TPS40101RGET 1.3 A SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PQCC24
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
TPS40077 制造商:TI 制造商全稱:Texas Instruments 功能描述:HIGH-EFFICIENCY, MIDRANGE-INPUT, SYNCHRONOUS BUCK CONTROLLER WITH VOLTAGE FEED-FORWARD
TPS40077_07 制造商:TI 制造商全稱:Texas Instruments 功能描述:HIGH-EFFICIENCY, MIDRANGE-INPUT, SYNCHRONOUS BUCK CONTROLLER WITH VOLTAGE FEED-FORWARD
TPS40077EVM-001 功能描述:電源管理IC開發(fā)工具 TPS40077 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
TPS40077PWP 功能描述:DC/DC 開關(guān)控制器 Synchronous Buck Controller RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(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
TPS40077PWPG4 功能描述:DC/DC 開關(guān)控制器 Hi Eff Mid-Range Inp Synch Buck Cntrlr RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(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