- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄98064 > PTH04040WAST (TEXAS INSTRUMENTS INC) 1-OUTPUT DC-DC REG PWR SUPPLY MODULE PDF資料下載
參數(shù)資料
| 型號： | PTH04040WAST |
| 廠商： | TEXAS INSTRUMENTS INC |
| 元件分類： | 電源模塊 |
| 英文描述： | 1-OUTPUT DC-DC REG PWR SUPPLY MODULE |
| 封裝： | ROHS COMPLIANT, DIP-20 |
| 文件頁數(shù)： | 3/22頁 |
| 文件大小： | 747K |
| 代理商： | PTH04040WAST |
Application Notes
For technical support and further information visit http://power.ti.com
PTH/PTV Series of Wide-Output Adjust
Power Modules (3.3/5-V Input)
Auto-Track Function
The Auto-Track function is unique to the PTH/PTV
family, and is available with the all POLA-compatible
products. Auto-Track was designed to simplify the amount
of circuitry required to make the output voltage from each
module power up and power down in sequence. The
sequencing of two or more supply voltages during power
up is a common requirement for complex mixed-signal
applications, that use dual-voltage VLSI ICs such as DSPs,
micro-processors, and ASICs.
How Auto-Track Works
Auto-Track works by forcing the module’s output voltage
to follow a voltage presented at the Track control pin. This
control range is limited to between 0 V and the module’s
set-point voltage. Once the Track input is raised above
the set-point voltage, the module’s output remains at its
set-point 1. As an example, if the track pin of a 2.5-V regu-
lator is at 1 V, the regulated output will be 1 V. But if the
voltage at the track pin rises to 3 V, the regulated output
will not go higher than 2.5 V.
When the track input is used to connect a number of
modules together, it forces the output voltage from each
module to follow a common signal during power-up and
power-down. The control signal can be an externally
generated master ramp waveform, or the output voltage
from another power supply circuit 3. For convenience
each module’s track input incorporates an internal RC
charge circuit. This operates off the module’s input volt-
age to provide a suitable rising voltage ramp waveform.
Typical Application
Connecting the Track inputs of two or more modules
forces their track input to follow the same collective RC
ramp waveform, and allows their power-up sequence to
be coordinated from a common track control signal.
This can be an open-collector (or open drain) device,
such as a power-up reset voltage supervisor IC.
To coordinate a power-up sequence the Track control
must first pulled to ground potential. This should be
done at or before input power is applied to the modules.
The ground signal should be maintained for at least 10 ms
after input power has been applied. This brief period gives
the modules time to complete their internal soft-start
initialization, enabling them to produce an output voltage.
A low-cost supply voltage supervisor IC, that includes a
built-in time delay, is an ideal component for automatically
controlling the track inputs at power up.
Figure 3-5 shows how the TPS3808G50 supply voltage
supervisor IC (U3) can be used to coordinate the se-
quenced power-up of two 5-V input Auto-Track modules.
The output of the TPS3808 supervisor becomes active
above an input voltage of 0.8 V, enabling it to assert a
ground signal to the common track control well before
the input voltage has reached the module’s under-voltage
lockout threshold. The ground signal is maintained until
approximately 27 ms after the input voltage has risen above
U3’s voltage threshold, which is 4.65 V. The 27-ms time
period is controlled by the capacitor C3. The value of
4700 pF provides sufficient time delay for the modules
to complete their internal soft-start initialization. The
output voltage of each module remains at zero until the
track control voltage is allowed to rise. When U3 removes
the ground signal, the track control voltage automatically
rises to the input voltage. This causes the output voltage
of each module to rise simultaneously with the other
modules, until each reaches its respective set-point voltage.
Figure 3-6 shows the output voltage waveforms for the
circuit of Figure 3-5 after input power is applied to the
circuit. The waveforms V
O1 and VO2 represent the
output voltages from the two power modules, U1 (3.3 V)
and U2 (1.8 V) respectively. V
O1 and VO2 are shown
rising together to produce the desired simultaneous
power-up characteristic.
This same circuit also provides a power-down sequence.
When the input voltage falls below U3’s voltage thresh-
old, the ground signal is re-applied to the common track
control. This pulls the track inputs to zero volts, forcing
the output of each module to follow. Power-down is nor-
mally complete before the input voltage has fallen below
the modules’ under-voltage lockout. This is an important
constraint. Once the modules recognize that an input
voltage is no longer present, their outputs can no longer
be controlled to follow the voltage applied at their track
input.
During a power-down sequence, the fall in the output volt-
age from the modules is limited by Auto-Track’s slew rate
capability.
Notes on Use of Auto-Track
1. The Track pin voltage must be allowed to rise above
the module’s set-point voltage before the module can
regulate at its adjusted set-point voltage.
2. The Auto-Track function will track almost any voltage
ramp during power up, and is compatible with ramp
speeds of up to 1 V/ms.
3. The absolute maximum voltage that may be applied to the
Track pin is V
I.
4. The module will not follow a voltage at its track input until
it has completed its soft-start initialization. This takes at
least 10 ms from the time that the module has sensed that
a valid voltage is present. During this period, the track
input should be held at ground potential.
相關PDF資料 |
PDF描述 |
|---|---|
| PTH04070WAH | 3 A SWITCHING REGULATOR, PDMA5 |
| PTH04070WAST | 3 A SWITCHING REGULATOR, PDMA5 |
| PTH04070WAD | 3 A SWITCHING REGULATOR, PDMA5 |
| PTH04T231WAS | 1-OUTPUT DC-DC REG PWR SUPPLY MODULE |
| PTH04T230WAZ | 1-OUTPUT DC-DC REG PWR SUPPLY MODULE |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| PTH04040WAZ | 功能描述:DC/DC轉換器 60A 3.3/5V-In Wide Output Adj Pwr Mdl RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風格:SMD/SMT 封裝 / 箱體尺寸: |
| PTH04040WAZT | 功能描述:DC/DC轉換器 2.95-5.5Vin 0.8-3.6V 2.045" x1.045"x0.357 RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風格:SMD/SMT 封裝 / 箱體尺寸: |
| PTH04070W | 制造商:TI 制造商全稱:Texas Instruments 功能描述:3-A, 3.3/5-V INPUT ADJUSTABLE SWITCHING REGULATOR |
| PTH04070W_07 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:3-A, 3.3/5-V INPUT ADJUSTABLE SWITCHING REGULATOR |
| PTH04070WAD | 功能描述:DC/DC轉換器 3-A 3.3/5-V Input Adj Swtch Regulator RoHS:否 制造商:Murata 產(chǎn)品: 輸出功率: 輸入電壓范圍:3.6 V to 5.5 V 輸入電壓（標稱）: 輸出端數(shù)量:1 輸出電壓（通道 1）:3.3 V 輸出電流（通道 1）:600 mA 輸出電壓（通道 2）: 輸出電流（通道 2）: 安裝風格:SMD/SMT 封裝 / 箱體尺寸: |
發(fā)布緊急采購，3分鐘左右您將得到回復。