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參數(shù)資料
| 型號： | TPS28225DT |
| 廠商： | Texas Instruments, Inc. |
| 英文描述： | High-Frequency 4-A Sink Synchronous MOSFET Driver |
| 中文描述： | 高頻率的4 - A水槽同步MOSFET驅(qū)動器 |
| 文件頁數(shù)： | 14/30頁 |
| 文件大?。?/td> | 951K |
| 代理商： | TPS28225DT |
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DETAILED DESCRIPTION
UNDER VOLTAGE LOCKOUT (UVLO)
The TPS28225 incorporates an under voltage lockout circuit that keeps the driver disabled and external power
FETs in an OFF state when the input supply voltage V
DD
is insufficient to drive external power FETs reliably.
During power up, both gate drive outputs remain low until voltage V
reaches UVLO threshold, typically 3.5V.
Once the UVLO threshold is reached, the condition of gate drive outputs is defined by the input PWM and
EN/PG signals. During power down the UVLO threshold is set lower, typically 3.0V. The 0.5-V hysteresis is
selected to prevent the driver from turning ON and OFF while the input voltage crosses UVLO thresholds,
especially with low slew rate. The TPS28225 has the ability to send a signal back to the system controller that
the input supply voltage V
DD
is insufficient by internally pulling down the EN/PG pin. The TPS28225 releases
EN/PG pin immediately after the V
DD
has risen above the UVLO threshold.
OUTPUT ACTIVE LOW
The output active low circuit effectively keeps the gate outputs low even if the driver is not powered up. This
prevents open gate conditions on the external power FETs and accidental turn ON when the main power stage
supply voltage is applied before the driver is powered up. For the simplicity, the output active low circuit is
shown in a block diagram as the resistor connected between LGATE and GND pins with another one connected
between UGATE and PHASE pins.
ENABLE/POWER GOOD
The Enable/Power Good circuit allows the TPS28225 to follow the PWM input signal when the voltage at EN/PG
pin is above 2.1 V maximum. This circuit has a unique two-way communication capability. This is illustrated by
Figure 19
.
Thermal SD
UVLO
7
EN/PG
6
System
Controller
20 k
V
CC
V
DD
= 4.5 V to 8 V
Driver TPS28225
1 k
1 M
R
DS(on)
= 1 k
2 V Rise
1 V Fall
TPS28225
SLUS710–MAY 2006
Figure 19. Enable/Power Good Circuit
The EN/PG pin has approximately 1-k
internal series resistor. Pulling EN/PG high by an external
≥
20-k
resistor allows two-way communication between controller and driver. If the input voltage V
DD
is below UVLO
threshold or thermal shut down occurs, the internal MOSFET pulls EN/PG pin to GND through 1-k
resistor.
The voltage across the EN/PG pin is now defined by the resistor divider comprised by the external pull up
resistor, 1-k
internal resistor and the internal FET having 1k
R
DS(on)
. Even if the system controller allows the
driver to start by setting its own enable output transistor OFF, the driver keeps the voltage at EN/PG low. Low
EN/PG signal indicates that the driver is not ready yet because the supply voltage V
DD
is low or that the driver is
in thermal shutdown mode. The system controller can arrange the delay of PWM input signals coming to the
driver until the driver releases EN/PG pin. If the input voltage V
DD
is back to normal, or the driver is cooled down
below its lower thermal shutdown threshold, then the internal MOSFET releases the EN/PG pin and normal
operation resumes under the external Enable signal applied to EN/PG input. Another feature includes an internal
1M
resistor that pulls EN/PG pin low and disables the driver in case the system controller accidentally loses
connection with the driver. This could happen if, for example, the system controller is located on a separate PCB
daughter board.
14
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| TPS28225TDRBRQ1 | 功能描述:功率驅(qū)動器IC AC 8P Hi Fre 4A Sink Sync MOSFET Driver RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| TPS28225TDRQ1 | 功能描述:IC MOSFET DVR SINK SYNC 4A 8SOIC 制造商:texas instruments 系列:* 零件狀態(tài):在售 標準包裝:1 |
| TPS28226D | 功能描述:功率驅(qū)動器IC Hi Fre 4A Sink Synch MOSFET Driver RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| TPS28226DG4 | 功能描述:功率驅(qū)動器IC 8P Hi Freq 4A Sink Synch MOSFET Drvr RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
| TPS28226DR | 功能描述:功率驅(qū)動器IC Hi Fre 4A Sink Synch MOSFET Driver RoHS:否 制造商:Micrel 產(chǎn)品:MOSFET Gate Drivers 類型:Low Cost High or Low Side MOSFET Driver 上升時間: 下降時間: 電源電壓-最大:30 V 電源電壓-最小:2.75 V 電源電流: 最大功率耗散: 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOIC-8 封裝:Tube |
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