- 您現在的位置：買賣IC網 > PDF目錄382679 > TPS62044DRC (Texas Instruments, Inc.) 1.2 A/1.25 MHZ, HIGH EFFICIENCY STEP DOWN CONVERTER PDF資料下載
參數資料
| 型號： | TPS62044DRC |
| 廠商： | Texas Instruments, Inc. |
| 英文描述： | 1.2 A/1.25 MHZ, HIGH EFFICIENCY STEP DOWN CONVERTER |
| 中文描述： | 1.2 A/1.25兆赫，高效降壓轉換器 |
| 文件頁數： | 10/21頁 |
| 文件大小： | 372K |
| 代理商： | TPS62044DRC |
SLVS463A JUNE 2003 REVISED OCTOBER 2003
www.ti.com
10
DETAILED DESCRIPTION
OPERATION
The TPS6204x is a synchronous step-down converter operating with typically 1.25 MHz fixed frequency. At moderate
to heavy load currents, the device operates in pulse width modulation (PWM), and at light load currents, the device
enters power save mode operation using pulse frequency modulation (PFM). When operating in PWM mode, the
typical switching frequency is 1.25 MHz with a minimum switching frequency of 1 MHz. This makes the device
suitable for xDSL applications minimizing RF (radio frequency) interference.
During PWM operation the converter uses a unique fast response voltage mode controller scheme with input voltage
feedforward 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 (S) the P-channel MOSFET switch turns on and the
inductor current ramps up until the comparator trips and the control logic turns off the switch. The current limit
comparator also turns off the switch in case the current limit of the P-channel switch is exceeded. After the dead time
preventing current shoot through, the N-channel MOSFET rectifier is turned on and the inductor current ramps down.
The next cycle is initiated by the clock signal, again turning off the N-channel rectifier and turning on the P-channel
switch.
The Gm amplifier as well as the input voltage determines the rise time of the saw tooth generator, and therefore, any
change in input voltage or output voltage directly controls the duty cycle of the converter, giving a very good line and
load transient regulation.
POWER SAVE MODE OPERATION
As the load current decreases, the converter enters power save mode operation. During power save mode the
converter operates with reduced switching frequency in PFM mode and with a minimum quiescent current
maintaining high efficiency.
The converter monitors the average inductor current and the device enters power save mode when the average
inductor current is below the threshold. The transition point between PWM and power save mode is given by the
transition current with the following equation:
Itransition
VI
18.66
During power save mode the output voltage is monitored with the comparator by the threshold’s comp low and comp
high. As the output voltage falls below the comp low threshold set to typically 0.8% above the nominal output voltage,
the P-channel switch turns on. The P-channel switch remains on until the transition current (1) is reached. Then the
N-channel switch turns on completing the first cycle. The converter continues to switch with its normal duty cycle
determined by the input and output voltage but with half the nominal switching frequency of 625-kHz typ. Thus the
output voltage rises and as soon as the output voltage reaches the comp high threshold of 1.6%, the converter stops
switching. Depending on the load current, the converter switches for a longer or shorter period of time in order to
deliver the energy to the output. If the load current increases and the output voltage can not be maintained with the
transition current , equation (1), the converter enters PWM again. See Figure 11 and Figure 12 under the typical
graphs section and Figure 14 for power save mode operation. Among other techniques this advanced power save
mode method allows high efficiency over the entire load current range and a small output ripple of typically 1% of
the nominal output voltage.
Setting the power save mode thresholds to typically 0.8% and 1.6% above the nominal output voltage at light load
current results in a dynamic voltage positioning achieving lower absolute voltage drops during heavy load transient
changes. This allows the converter to operate with small output capacitors like 22
μ
F and still having a low absolute
voltage drop during heavy load transient. Refer to Figure 14 as well for detailed operation of the power save mode.
(1)
相關PDF資料 |
PDF描述 |
|---|---|
| TPS62224DDC | 400-mA, 1.25-MHz, HIGH-EFFICIENCY, STEP-DOWN CONVERTER IN THIN-SOT23 |
| TPS62220DDC | 400-mA, 1.25-MHz, HIGH-EFFICIENCY, STEP-DOWN CONVERTER IN THIN-SOT23 |
| TPS62221DDC | 400-mA, 1.25-MHz, HIGH-EFFICIENCY, STEP-DOWN CONVERTER IN THIN-SOT23 |
| TPS62222DDC | 400-mA, 1.25-MHz, HIGH-EFFICIENCY, STEP-DOWN CONVERTER IN THIN-SOT23 |
| TPS62229DDC | 400-mA, 1.25-MHz, HIGH-EFFICIENCY, STEP-DOWN CONVERTER IN THIN-SOT23 |
相關代理商/技術參數 |
參數描述 |
|---|---|
| TPS62044DRCR | 功能描述:直流/直流開關調節器 1.8V Out 1.2A Hi-Ef Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62044DRCRG4 | 功能描述:直流/直流開關調節器 1.8V Out 1.2A Hi-Ef Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62046DGQ | 功能描述:直流/直流開關調節器 3.3V Out/1.2A Hi-Eff Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62046DGQG4 | 功能描述:直流/直流開關調節器 3.3V Out/1.2A Hi-Eff Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
| TPS62046DGQR | 功能描述:直流/直流開關調節器 3.3V Out/1.2A Hi-Eff Step-Down Converter RoHS:否 制造商:International Rectifier 最大輸入電壓:21 V 開關頻率:1.5 MHz 輸出電壓:0.5 V to 0.86 V 輸出電流:4 A 輸出端數量: 最大工作溫度: 安裝風格:SMD/SMT 封裝 / 箱體:PQFN 4 x 5 |
發布緊急采購，3分鐘左右您將得到回復。