- 您現(xiàn)在的位置：買(mǎi)賣(mài)IC網(wǎng) > PDF目錄368342 > PT5812C (Texas Instruments, Inc.) 20-A 3.3-V Input Adjustable Integrated Switching Regulator PDF資料下載
參數(shù)資料
| 型號(hào)： | PT5812C |
| 廠(chǎng)商： | Texas Instruments, Inc. |
| 英文描述： | 20-A 3.3-V Input Adjustable Integrated Switching Regulator |
| 中文描述： | 20 - 3.3 - V輸入可調(diào)集成開(kāi)關(guān)穩(wěn)壓器 |
| 文件頁(yè)數(shù)： | 5/11頁(yè) |
| 文件大小： | 202K |
| 代理商： | PT5812C |
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
Startup of the PT5800 & PT5810 Series ISRs
with Back-Feeding Source (Pre-Bias Capability)
In complex digital systems an external voltage can
sometimes be present at the output of the regulator
during power up. For example, this voltage may be
backfed through a dual-supply logic component such as
an FPGA or ASIC. Another path might be via a clamp
diode (to a lower supply voltage) as part of a power-up
sequencing implementation.
Although the PT5800 (5-V input) and PT5810 (3.3-V
input) series of regulators will sink current under steady-
state operating conditions, they will not do so during
startup
1
as long as certain conditions are maintained
2
.
This feature allows these regulators to start up while an
external voltage is simultaneously applied to the output.
Figure 2-1 is an application schematic that demonstrates
this capability. The waveforms in Figure 2-2 show the
behavior of the circuit as input power is applied. Note
that the plot of the regulator output current (I
o
) is approxi-
mately zero up to the timestamp ‘A’, even though a voltage
is initially backfed to the output via the 3.3-V input supply
and diodes D
1
& D
2
. The regulator sources current
3
when
it begins raising the output above the back-fed voltage to
its nominal regulation value.
Notes
1. Startup includes both the application of a valid input
source voltage, or the removal of a ground signal from
the
Inhibit*
control (pin 2) with a valid input source
applied. The output of the regulator is effectively off
(tri-state), during the period that the
Inhibit*
control is
held low.
Vin (1V/Div)
Vo (1V/Div)
Io (5A/Div)
HORIZ SCALE 5ms/Div
A
Figure 2-2; Power-up Waveforms with Back-Feeding Source
Figure 2-1; Schematic Demonstrating Startup into Pre-Bias Capability
PT5812
14
–
17
9
–
13
5
–
7V
IN
V
OUT
GND
C
out
+
C
IN
+
(3.3 VDC)
COM
COM
V
IN
V
O
(2.5 V)
8
18
Sense(+)
Sense(
–
)
D
2
I
o
D
1
2. To ensure that the regulator does not sink current, the
input voltage must always be greater or equal to the
output voltage throughout the power-up and power-down
sequence.
3. If an external source backfeeding the regulator’s output
is greater than the nominal regulation voltage, the output
will begin sinking current at the end of its soft-start
power-up sequence. If this current exceeds the rated
output, the module could be overstressed.
PT5800 & PT5810 Series
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。