- 您现在的位置：买卖IC网 > PDF目录224860 > PT8125A SMPS Controller PDF资料下载
参数资料
| 型号： | PT8125A |
| 英文描述： | SMPS Controller |
| 中文描述： | 开关电源控制器 |
| 文件页数： | 9/10页 |
| 文件大小： | 182K |
| 代理商： | PT8125A |
For technical support and more information, see inside back cover or visit www.ti.com
Application Notes
Using the On/Off Standby Function of the
PT8120 Series of Programmable ISRs
The PT8120 series of programmable ISRs incorporates
an On/Off Standby function. This feature may be used
to turn the regulated output of the module off while input
voltage is applied. This places the module in “standby”
mode. The standby control may be used for power-up
sequencing, or wherever there is a requirement to control
the module’s output status from another circuit.
The Standby function is provided by the STBY* control,
pin 6. If pin 6 is left open-circuit the regulator operates
normally, providing a regulated output when a valid sup-
ply voltage is applied to Vin (pins 10-16) with respect to
GND (pins 17-22). Connecting pin 6 to ground 1 places
the regulator in standby mode 2, and reduces the input
current to typically 35mA. Applying a ground signal to
pin 6 prior to power-up, will inhibit the output during
the period that input power is applied. When the ground
signal to pin 6 is removed, the regulator initiates a soft-
start to re-establish the set output voltage. 3 To ensure
that the regulator output is properly enabled, the STBY*
control pin must be open circuit.
Table 1 Standby Control Requirements 2
Parameter
Min
Typ
Max
VIH
—
Open Cct. 1
VIL
–0.2V
—
0.8V
ISTBY
–0.5mA
Notes:
1. The standby on a PT8120 series regulators must be
controlled with an open-collector (or open-drain)
transistor (See fig. 1). Do Not use a pull-up resistor.
Table 1 gives the STBY* pin parameters. The control
pin has an open-circuit voltage of 5Vdc. To shut the
regulator output off, the control pin must be “pulled” to
less than 0.8Vdc with a low-impedance sink to ground.
Figure 1
Figure 2
PT8120 Series & PT8139
2. In the standby mode the output of the regulator is tri-
state, and the output voltage falls at the rate that the
load circuit discharges the output filter capacitors.
3. When the ground signal to the Standby pin is
removed, the regulator output initiates a soft-start
cycle by first asserting a low impedance to ground. If
an external voltage is applied to the output bus, it will
sink current and possibly over-stress the part.
Turn-On Time
Turning Q1 in Figure 1 off, removes the low-voltage
signal at pin 6. After approximately 5-ms the regulator
output rises and reaches full regulation within 40ms.
Fig. 2 shows the typical waveforms of a PT8121 following
the prompt turn-off of Q1. The turn-off of Q1 corresponds
to the rise in Vstby. The output voltage was set to 3.3V,
and the waveforms were measured with a 12V input source,
and 18A resistive load.
L
O
A
D
C
OUT
+
C
IN
+
V
IN
V
O =3.3V
GND
V
O SENSE
1 =Off
L
in
1H
GND
PT8121
4321
31
23–30
617–22
12–16
5
11
VID4 – VID0
Sense
V
IN
V
OUT
STBY
GND
VID
Common
Q1
BSS138
Vo (1V/Div)
Iin (5A/Div)
Vstby (5V/Div)
HORIZ SCALE: 5ms/Div
相关PDF资料 |
PDF描述 |
|---|---|
| PT8125C | SMPS Controller |
| PT8125N | 100V Single N-Channel HEXFET Power MOSFET in a TO-220 FullPak (Iso) package |
| PT8139 | -100V Single P-Channel HEXFET Power MOSFET in a TO-220 FullPak (Iso) package |
| PT8139A | -55V Single P-Channel HEXFET Power MOSFET in a TO-220 FullPak (Iso) package |
| PT8402 | MP3/AAC Audio Decoder |
相关代理商/技术参数 |
参数描述 |
|---|---|
| PT8125C | 功能描述:DC/DC转换器 4.5-7.6V 28A 12V In Multiphase Prog ISR RoHS:否 制造商:Murata 产品: 输出功率: 输入电压范围:3.6 V to 5.5 V 输入电压（标称）: 输出端数量:1 输出电压（通道 1）:3.3 V 输出电流（通道 1）:600 mA 输出电压（通道 2）: 输出电流（通道 2）: 安装风格:SMD/SMT 封装 / 箱体尺寸: |
| PT8125N | 功能描述:开关变换器、稳压器与控制器 4.5-7.6V 28A 12V In Multiphase Prog ISR RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
| PT812BB | 功能描述:CBL ASSY PIGTAIL 12' BNCM BNCM RoHS:是 类别:电缆组件 >> 同轴，RF 系列:* 标准包装:1 系列:* |
| PT812NB | 功能描述:CBL ASSY PIGTAIL 12' NM BNCM RoHS:是 类别:电缆组件 >> 同轴，RF 系列:* 标准包装:1 系列:* |
| PT812NN | 功能描述:CBL ASSY PIGTAIL 12' NM NM RoHS:是 类别:电缆组件 >> 同轴，RF 系列:* 标准包装:1 系列:* |
发布紧急采购，3分钟左右您将得到回复。