參數(shù)資料
型號(hào)： TPS62261DRV
廠商： Texas Instruments, Inc.
英文描述： 2.25 MHz 600 mA Step Down Converter in 2x2SON/TSOT-23 Package
中文描述： 2.25兆赫600毫安降壓轉(zhuǎn)換器2x2SON/TSOT-23包
文件頁(yè)數(shù)： 15/32頁(yè)
文件大?。?/td> 951K
代理商： TPS62261DRV
www.ti.com
DETAILED DESCRIPTION
OPERATION
The TPS62260 step down converter operates with typically 2.25 MHz fixed frequency pulse width modulation
(PWM) at moderate to heavy load currents. At light load currents the converter can automatically enter Power
Save Mode and operates then in PFM mode.
POWER SAVE MODE
The Power Save Mode is enabled with MODE Pin set to low level. If the load current decreases, the converter
will enter Power Save Mode operation automatically. During Power Save Mode the converter skips switching
and operates with reduced frequency in PFM mode with a minimum quiescent current to maintain high
efficiency. The converter will position the output voltage typically +1% above the nominal output voltage. This
voltage positioning feature minimizes voltage drops caused by a sudden load step.
Dynamic Voltage Positioning
TPS62260, TPS62261, TPS62262
SLVS763–JUNE 2007
During PWM operation the converter use a unique fast response voltage mode control scheme with input
voltage feed-forward to achieve good line and load regulation allowing the use of small ceramic input and output
capacitors. At the beginning of each clock cycle initiated by the clock signal, the High Side MOSFET switch is
turned on. The current flows now from the input capacitor via the High Side MOSFET switch through the
inductor to the output capacitor and load. During this phase, the current ramps up until the PWM comparator
trips and the control logic will turn off the switch. The current limit comparator will also turn off the switch in case
the current limit of the High Side MOSFET switch is exceeded. After a dead time preventing shoot through
current, the Low Side MOSFET rectifier is turned on and the inductor current will ramp down. The current flows
now from the inductor to the output capacitor and to the load. It returns back to the inductor through the Low
Side MOSFET rectifier.
The next cycle will be initiated by the clock signal again turning off the Low Side MOSFET rectifier and turning
on the on the High Side MOSFET switch.
The transition from PWM mode to PFM mode occurs once the inductor current in the Low Side MOSFET switch
becomes zero, which indicates discontinuous conduction mode.
During the Power Save Mode the output voltage is monitored with a PFM comparator. As the output voltage falls
below the PFM comparator threshold of V
OUT
nominal +1%, the device starts a PFM current pulse. The High
Side MOSFET switch will turn on, and the inductor current ramps up. After the On-time expires, the switch is
turned off and the Low Side MOSFET switch is turned on until the inductor current becomes zero.
The converter effectively delivers a current to the output capacitor and the load. If the load is below the delivered
current, the output voltage will rise. If the output voltage is equal or higher than the PFM comparator threshold,
the device stops switching and enters a sleep mode with typical 15
μ
A current consumption.
If the output voltage is still below the PFM comparator threshold, a sequence of further PFM current pulses are
generated until the PFM comparator threshold is reached. The converter starts switching again once the output
voltage drops below the PFM comparator threshold.
With a fast single threshold comparator, the output voltage ripple during PFM mode operation can be kept small.
The PFM Pulse is time controlled, which allows to modify the charge transferred to the output capacitor by the
value of the inductor. The resulting PFM output voltage ripple and PFM frequency depend in first order on the
size of the output capacitor and the inductor value. Increasing output capacitor values and inductor values will
minimize the output ripple. The PFM frequency decreases with smaller inductor values and increases with larger
values.
The PFM mode is left and PWM mode entered in case the output current can not longer be supported in PFM
mode. The Power Save Mode can be disabled through the MODE pin set to high. The converter will then
operate in fixed frequency PWM mode.
This feature reduces the voltage under/overshoots at load steps from light to heavy load and vice versa. It is
active in Power Save Mode and regulates the output voltage 1% higher than the nominal value. This provides
more headroom for both the voltage drop at a load step, and the voltage increase at a load throw-off.
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參數(shù)描述
TPS62261DRVR 功能描述:直流/直流開(kāi)關(guān)調(diào)節(jié)器 2.25MHz 600mA Step- Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開(kāi)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
TPS62261DRVRG4 功能描述:直流/直流開(kāi)關(guān)調(diào)節(jié)器 2.25MHz 600mA Step- Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開(kāi)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
TPS62261DRVT 功能描述:直流/直流開(kāi)關(guān)調(diào)節(jié)器 2.25MHz 600mA Step- Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開(kāi)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
TPS62261DRVTG4 功能描述:直流/直流開(kāi)關(guān)調(diào)節(jié)器 2.25MHz 600mA Step- Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開(kāi)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
TPS62261TDRVRQ1 功能描述:直流/直流開(kāi)關(guān)調(diào)節(jié)器 2.25MHz 600mA Step- Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開(kāi)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
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