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參數(shù)資料
| 型號： | SMT4504F-172 |
| 英文描述： | Four-Channel Loss-Less TrakkerTM Power Supply Manager |
| 中文描述： | 四通道無損耗TrakkerTM電源管理器 |
| 文件頁數(shù)： | 9/20頁 |
| 文件大?。?/td> | 248K |
| 代理商： | SMT4504F-172 |
SMT4504
Preliminary Information
Summit Microelectronics, Inc
2071 1.1 01/07/05
9
SEQUENCING
The SMT4504 is a programmable controller for
lossless (requires no pass MOSFETs) power supply
sequencing/tracking. Up to four channels can be
sequenced in any order with several delay options.
Before the SMT4504 begins the power-on sequencing,
the UV sensors monitor the VDD and the
VCTRL_SUP inputs. The power-on sequencing will
not begin until both these inputs are above their UV
threshold.
In order for a power supply to be sequenced it must
first be enabled by a PUP output. This channel must
also be programmed to participate in the sequence
and be assigned a sequence position (one of 12). A
sequence position is given to each channel as an
order number in the sequence event. The sequence
position assignments must begin at position 1 and
must not skip positions. Also, multiple channels can be
programmed into the same sequence position to
enable voltage tracking of the supplies. Multiple
corresponding channels sharing a common sequence
position will have their voltages tracked during the
power-on and power-off events only if each channel
uses the VCTRL
X
pin on the converter. Otherwise the
PUP output simply enables this power supply with no
regard for closed loop voltage tracking.
Each channel selected for sequencing is given a
power-on and power-off delay. The first power-on
delay is a delay from assertion of the PWR_ON input
to the assertion of all PUP outputs (sequence position
1). The power-off delay is the delay from the VM
X
input
of one channel turning off to the beginning of another
VM
x
output turning off. Tracking or sequencing down
begins immediately when the PWR_ON pin is de-
asserted.
Power-on sequencing can be initiated by asserting the
PWR_ON/OFF input or by writing to the power-on bit
of the command register. For automatic start-up the
PWR_ON/OFF pin can be tied active. The power-on
sequencing begins with the power-on delay time of the
channel(s) in sequence position 1. Once this delay has
timed out all PUP outputs assigned to this position will
go active. At this point the supply connected to the
VM input will begin to turn on via the action between
the VCTRLX output and the supply’s TRIM or other
interface pin such as soft-start. When this supply
reaches its programmed threshold (under-voltage) and
the sequence delay timer is expired, the sequence
position counter will change to position 1 and the
power-on delay timer for the channel(s) in sequence
position 2 will begin. This will repeat until all channels
that were programmed for sequencing have turned on
and are not in fault conditions. Power-on sequencing
is considered complete when supplies assigned the
last used sequence position go above their UV setting.
Power-off sequencing can be initiated by de-asserting
the PWR_ON/OFF pin, by writing to the power-off bit
of the command register, or triggered off of a selected
fault condition. The SMT4504 is configured to
sequence the supplies off in the reverse order of the
power-on sequence. During the power-off sequence
power-on commands as well as activity on the
PWR_ON/OFF pin is ignored.
The power-off sequencing begins immediately with the
channel(s) in the last sequence position of the power-
on sequence (reverse order). Once the supplies in this
sequence position have reached 100mV or less and
the delay timer has timed out the PUP will turn off. At
this point the supply connected to the next sequence
position will begin to turn off. When this supply falls
below the 100mV limit, the sequence position counter
will change to the next position and the power-off
delay timer for the channel(s) in current sequence
position will begin.
This will repeat until all channels that were
programmed for sequencing have turned off. At this
point the SMT4504 will monitor the VDD and
VCTRL_SUP inputs as precursor conditions to power-
on sequencing.
During sequencing an abort timer is available. The
abort timer starts each time a PUP output goes active.
If the abort timer times out before the VM
X
input goes
out of fault, all channels are shut down and the abort
bit is set in the status register. This is to avoid the case
where one or more channels are not capable of
reaching their minimum level. The abort timer is
available for sequence up and sequence down. If the
abort
timer
shuts
the
PWR_ON/OFF pin must be toggled to re-start. The
timeout period of the abort timer is programmable.
sequencing
down the
APPLICATIONS INFORMATION
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| SMT45A-102 | 功能描述:固定電感器 RoHS:否 制造商:AVX 電感:10 uH 容差:20 % 最大直流電流:1 A 最大直流電阻:0.075 Ohms 工作溫度范圍:- 40 C to + 85 C 自諧振頻率:38 MHz Q 最小值:40 尺寸:4.45 mm W x 6.6 mm L x 2.92 mm H 屏蔽:Shielded 端接類型:SMD/SMT 封裝 / 箱體:6.6 mm x 4.45 mm |
| SMT45A-102LF | 功能描述:固定電感器 RoHS:否 制造商:AVX 電感:10 uH 容差:20 % 最大直流電流:1 A 最大直流電阻:0.075 Ohms 工作溫度范圍:- 40 C to + 85 C 自諧振頻率:38 MHz Q 最小值:40 尺寸:4.45 mm W x 6.6 mm L x 2.92 mm H 屏蔽:Shielded 端接類型:SMD/SMT 封裝 / 箱體:6.6 mm x 4.45 mm |
| SMT45A-103 | 功能描述:固定電感器 RoHS:否 制造商:AVX 電感:10 uH 容差:20 % 最大直流電流:1 A 最大直流電阻:0.075 Ohms 工作溫度范圍:- 40 C to + 85 C 自諧振頻率:38 MHz Q 最小值:40 尺寸:4.45 mm W x 6.6 mm L x 2.92 mm H 屏蔽:Shielded 端接類型:SMD/SMT 封裝 / 箱體:6.6 mm x 4.45 mm |
| SMT45A-103LF | 功能描述:固定電感器 RoHS:否 制造商:AVX 電感:10 uH 容差:20 % 最大直流電流:1 A 最大直流電阻:0.075 Ohms 工作溫度范圍:- 40 C to + 85 C 自諧振頻率:38 MHz Q 最小值:40 尺寸:4.45 mm W x 6.6 mm L x 2.92 mm H 屏蔽:Shielded 端接類型:SMD/SMT 封裝 / 箱體:6.6 mm x 4.45 mm |
| SMT45A-121 | 功能描述:固定電感器 RoHS:否 制造商:AVX 電感:10 uH 容差:20 % 最大直流電流:1 A 最大直流電阻:0.075 Ohms 工作溫度范圍:- 40 C to + 85 C 自諧振頻率:38 MHz Q 最小值:40 尺寸:4.45 mm W x 6.6 mm L x 2.92 mm H 屏蔽:Shielded 端接類型:SMD/SMT 封裝 / 箱體:6.6 mm x 4.45 mm |
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