參數(shù)資料
型號(hào): MAX1636
廠商: Maxim Integrated Products, Inc.
英文描述: Low-Voltage, Precision Step-Down Controller for Portable CPU Power
中文描述: 低電壓、高精度降壓型控制器,用于便攜式CPU電源
文件頁(yè)數(shù): 15/24頁(yè)
文件大?。?/td> 219K
代理商: MAX1636
Output Overvoltage Protec tion (OV P)
The overvoltage crowbar protection circuit is intended
to blow a fuse in series with the battery if the main
SMPS output rises significantly higher than its preset
level. In normal operation, the output is compared to
the internal precision reference voltage. If the output
goes 7% above nominal, the synchronous rectifier
MOSFET turns on 100% (the high-side MOSFET is
simultaneously forced off) in order to draw massive
amounts of battery current to blow the fuse. This safety
feature does not protect the system against a failure of
the controller IC itself but is intended primarily to guard
against a short across the high-side MOSFET. A crow-
bar event is latched and can only be reset by a rising
edge on
SHDN
(or by removal of the V+ supply volt-
age). The overvoltage-detection decision is made rela-
tive to the regulation point.
The overvoltage comparators are kept inactive in
standby mode. Instead, the DL driver is simply left in
the high state. However, DL does not turn on until the
output has decayed to less than 1V. This prevents con-
flicts in systems where the output is held up by an
external source in suspend or backup mode. The OVP
pin has an internal pulldown resistor that is only turned
on during the reset phase. The OVP pin’s state is then
sampled and stored internally. A floating OVP pin
implies no overvoltage protection.
Boost High-S ide Gate-Drive S upply (BS T )
Gate-drive voltage for the high-side N-channel switch is
generated by a flying-capacitor boost circuit (Figure 2).
The capacitor between BST and LX is alternately
charged from the VL supply and placed parallel to the
high-side MOSFET's gate-source terminals.
On start-up, the synchronous rectifier (low-side MOS-
FET) forces LX to 0V and charges the boost capacitor
to 5V. On the second half-cycle, the SMPS turns on the
high-side MOSFET by closing an internal switch
between BST and DH. This provides the necessary
enhancement voltage to turn on the high-side switch,
an action that boosts the 5V gate-drive signal above
the battery voltage.
M
Low-Voltage, Prec ision S tep-Down
Controller for Portable CPU Power
______________________________________________________________________________________
15
MODE
SHDN
OVP
HOW ENTERED
STATUS
NOTES
Output
UVLO
High
Run
High
High
All circuit blocks
active
Normal operation
Don’t care
V
OUT
< 70% of
nominal after
20–30ms timeout
expires
Standby
Low
High
VL = on
REF = off
DL = high
RESET
= high-Z
(high state)
DL = high to enforce overvoltage
protection
VL = on
REF = off
DL = low
RESET
= low
Cycling
SHDN
or a power-on reset exits
output UVLO.
Shutdown
Low
Low
All circuit blocks
inactive
Lowest possible quiescent consumption
Thermal
Shutdown
High
Overvoltage
(crowbar)
High
High
V
OUT
> 7% too high
VL = on
REF = off
DL = high
RESET
= low
Cycling
SHDN
or a power-on reset exits
crowbar.
High
T
J
> +150°C
VL = on
REF = off
DL = high
RESET
= low
Cycling
SHDN
or a power-on reset exits
thermal shutdown.
Thermal
Shutdown
High
Low
T
J
> +150°C
All circuit blocks
inactive
Cycling
SHDN
or a power-on reset exits
thermal shutdown.
Table 5. Operating Modes
相關(guān)PDF資料
PDF描述
MAX1636EAP Low-Voltage, Precision Step-Down Controller for Portable CPU Power
MAX1637 Miniature, Low-Voltage, Precision Step-Down Controller
MAX1637EEE Miniature, Low-Voltage, Precision Step-Down Controller
MAX1638 High-Speed Step-Down Controller with Synchronous Rectification for CPU Power
MAX1638EAG High-Speed Step-Down Controller with Synchronous Rectification for CPU Power
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX1636CPUEVKIT 制造商:Maxim Integrated Products 功能描述:LOW VOLTAGE, PRECISION STEP DOWN CONTROLLER F - Bulk
MAX1636EAP 功能描述:DC/DC 開(kāi)關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
MAX1636EAP+ 功能描述:DC/DC 開(kāi)關(guān)控制器 Precision Step-Down for Portable CPU Pwr RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
MAX1636EAP+T 功能描述:DC/DC 開(kāi)關(guān)控制器 Precision Step-Down for Portable CPU Pwr RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK
MAX1636EAP-T 功能描述:DC/DC 開(kāi)關(guān)控制器 RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開(kāi)關(guān)頻率: 輸出電壓:1.215 V to 80 V 輸出電流:3.5 A 輸出端數(shù)量:1 最大工作溫度:+ 125 C 安裝風(fēng)格: 封裝 / 箱體:CPAK