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參數(shù)資料
| 型號： | SP6122ACU-15 |
| 英文描述： | Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters |
| 中文描述： | 低電壓，微8，PFET的，降壓控制器適合第1A至5A，占地面積小，DC - DC電源轉(zhuǎn)換器 |
| 文件頁數(shù)： | 6/19頁 |
| 文件大?。?/td> | 174K |
| 代理商： | SP6122ACU-15 |
6
Date: 10/02/04
SP6122 Low Voltage, Micro 8, PFET, Buck Controller Copyright 2004 Sipex Corporation
OPERATION
General Overview
The SP6122 is a minimum on-time,
PFM/PWM controller for low cost DC/DC
step down converters. The main control loop
consists of a REFERENCE COMPARATOR,
an ON-TIME CLOCK, a LOOP LATCH and
a BLANKING ONESHOT. The REFERENCE
comparator has 10mV of internal hysteresis
and a 1.25V internal reference. Both
hysteresis and reference voltage are
multiplied upward by the internal feedback
resistor divider, K1 (K1 = 1 for the adjustable
version). This value is set by the factory and
determines the output voltage of the
converter. This divider is also used in the on-
time algorithm for the controller. If the output
voltage drops below K1*1.25V, then the
DRIVER LOGIC tells the PFET switch to be
“on” for a certain minimum time. The on-time
is set by the Soft Start CLOCK frequency and
is factory programmed to run at 300kHz.
When the part is enabled, through V
CC
or the
ENABLE pin, the DRIVER LOGIC is
configured to first look at the fixed frequency
Soft Start loop. The output voltage is then
controlled by a 0.5V/ms internal ramp. When
the output voltage reaches K1*1.25V, the
Soft Start loop is switched off and the main
loop takes over.
Fault management is controlled either
through power-on-reset (POR) or R
DS(ON)
sense over current protection. Should an
over current condition occur, the SP6122
will completely “l(fā)ock-up” and turn the PFET
switch off. The only way to recover will be to
either cycle the ENABLE pin or V
CC
. A Fault
flag output (FFLAG) has been included to
either signal the upstream circuitry or to
engage a hiccup mode that will restart the
SP6122. Tying FFLAG to ENABLE allows
the controller to restart without assistance.
Lastly, the SP6122 includes a powerful 4
PFET driver stage designed to drive a PFET
associated with high speed converter de-
signs in the 1 A – 5 A range.
Enable
Low quiescent mode or “Sleep Mode” is
initiated by pulling the ENABLE pin below
650mV. The ENABLE pin has an internal
4
μ
A pull-up current and does not require
any external interface for normal operation.
If the ENABLE pin is driven from a voltage
source, the voltage must be above 1.45V in
order to guarantee proper “awake” opera-
tion. Assuming that V
CC
is above about
2.9V, the SP6122 transitions from “Sleep
Mode” to “Awake Mode” in about 20
μ
s –
30
μ
s and from “Awake Mode” to “Sleep
Mode” in a few microseconds. SP6122 qui-
escent current in sleep mode is 5
μ
A typical.
During Sleep Mode, the PFET switch is
turned off, the internal SS voltage is held
low and the FFLAG pin is high impedance.
Low Current Operation
If over current fault protection is not needed,
the SP6122 offers two options to lower its
quiescent current. By grounding both I
SET
and I
SENSE
pins, the circuitry responsible for
over current detection is turned off. This
option results in a saving of about 50
μ
A in
quiescent current. Option two requires that
I
SET
is grounded and ISENSE is greater
than 1.3V. This option put the SP6122 in a
low performance mode that cuts the operat-
ing frequency roughly in half and slows
down critical comparators in the main loop.
Option two can result in additional saving of
100
μ
A bringing the total quiescent current
to only 150
μ
A (typ).
Power On Reset (POR)
The POR command is given every time the
bandgap reference is started. The internal
1.25 V reference is compared against a 1V
NFET threshold. When the reference is below
the threshold, FAULT and RUN latches are
reset, the internal SS voltage is discharged
and the PFET switch is “off”. The SP6122 is
allowed to begin a soft start cycle when the
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| SP6122CU | Evaluation Board Manual |
| SP6122EB | Evaluation Board Manual |
| SP6122UEB | Evaluation Board Manual |
| SP6122ACU-1.5 | Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters |
| SP6122 | Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| SP6122ACU-15/TR | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters |
| SP6122ACU-L | 功能描述:DC/DC 開關(guān)控制器 Low Voltage, Micro 8 PFET Controller RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(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 |
| SP6122ACU-L/TR | 功能描述:DC/DC 開關(guān)控制器 Low Voltage, Micro 8 PFET Controller RoHS:否 制造商:Texas Instruments 輸入電壓:6 V to 100 V 開關(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 |
| SP6122ACU-L-1-5 | 制造商:Exar Corporation 功能描述:BUCK CONTROLLER LOW VOLT PFET 6122 |
| SP6122CU | 制造商:SIPEX 制造商全稱:Sipex Corporation 功能描述:Evaluation Board Manual |
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