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參數(shù)資料
| 型號： | TPS62291TDRVRQ1 |
| 廠商： | TEXAS INSTRUMENTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 1 A SWITCHING REGULATOR, 2500 kHz SWITCHING FREQ-MAX, PDSO6 |
| 封裝： | 2 X 2 MM, 0.8 MM HEIGHT, GREEN, PLASTIC, SON-6 |
| 文件頁數(shù)： | 3/25頁 |
| 文件大?。?/td> | 817K |
| 代理商： | TPS62291TDRVRQ1 |
www.ti.com
SLVSAI5 – SEPTEMBER 2010
DETAILED DESCRIPTION
OPERATION
The TPS6229x-Q1 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.
During PWM operation, the converter use a unique fast response voltage mode controller 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 turns off the switch. The current limit comparator also turns off the switch if 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 ramps down. The current flows now from the inductor to
the output capacitor and to the load. It returns to the inductor through the Low Side MOSFET rectifier.
The next cycle is initiated by the clock signal again turning off the Low Side MOSFET rectifier and turning on the
on the High Side MOSFET switch.
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.
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 VOUT nominal +1%, the device starts a PFM current pulse. For
this 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 15mA 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.
Dynamic Voltage Positioning
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.
Copyright 2010, Texas Instruments Incorporated
11
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| TPS62293DRVR | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.25MHz 1A Step-Down Cnvrtr RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(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: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62293DRVRG4 | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.25MHz 1A Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(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: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62293DRVT | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.25MHz 1A Step-Down Cnvrtr RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(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: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62293DRVTG4 | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 2.25MHz 1A Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(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: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62293TDRVRQ1 | 功能描述:直流/直流開關(guān)調(diào)節(jié)器 AC 2.25MHz 1A Step- Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關(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: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
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