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參數資料
| 型號： | MAX17004AETJ+ |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 3.3 A DUAL SWITCHING CONTROLLER, 575 kHz SWITCHING FREQ-MAX, QCC32 |
| 封裝： | 5 X 5 MM, 0.80 MM HEIGHT, LEAD FREE, MO-220WHHD-2, QFN-32 |
| 文件頁數： | 20/36頁 |
| 文件大小： | 611K |
| 代理商： | MAX17004AETJ+ |
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MAX17003A/MAX17004A
High-Efficiency, Quad-Output, Main Power-
Supply Controllers for Notebook Computers
______________________________________________________________________________________
27
Setting the Current Limit
The minimum current-limit threshold must be great
enough to support the maximum load current when the
current limit is at the minimum tolerance value. The
peak inductor current occurs at ILOAD(MAX) plus half
the ripple current; therefore:
where ILIMIT_ equals the minimum current-limit thresh-
old voltage divided by the current-sense resistance
(RSENSE_). For the default setting, the minimum current-
limit threshold is 45mV.
Connect ILIM to LDO5 for a default 50mV current-limit
threshold. In adjustable mode, the current-limit thresh-
old is precisely 1/10 the voltage seen at ILIM. For an
adjustable threshold, connect a resistive divider from
REF to analog ground (GND) with ILIM connected to
the center tap. The external 0.5V to 2V adjustment
range corresponds to a 50mV to 200mV current-limit
threshold. When adjusting the current limit, use 1% tol-
erance resistors and a divider current of approximately
10mA to prevent significant inaccuracy in the current-
limit tolerance.
The current-sense method (Figure 7) and magnitude
determines the achievable current-limit accuracy and
power loss. Typically, higher current-sense limits pro-
vide tighter accuracy, but also dissipate more power.
Most applications employ a current-limit threshold
(VLIMIT) of 50mV to 100mV, so the sense resistor can
be determined by:
For the best current-sense accuracy and overcurrent
protection, use a 1% tolerance current-sense resistor
between the inductor and output as shown in Figure
7A. This configuration constantly monitors the inductor
current, allowing accurate current-limit protection.
However, the parasitic inductance of the current-sense
resistor can cause current-limit inaccuracies, especially
when using low-value inductors and current-sense
resistors. This parasitic inductance (LESL) can be can-
celed by adding an RC circuit across the sense resistor
with an equivalent time constant:
Alternatively, high-power applications that do not
require highly accurate current-limit protection may
reduce the overall power dissipation by connecting a
series RC circuit across the inductor (Figure 7B) with
an equivalent time constant:
and:
where RCS is the required current-sense resistance,
and RDCR is the inductor’s series DC resistance. Use
the typical inductance and RDCR values provided by
the inductor manufacturer.
Output Capacitor Selection
The output filter capacitor must have low enough equiva-
lent series resistance (ESR) to meet output ripple and
load-transient requirements, yet have high enough ESR to
satisfy stability requirements. The output capacitance
must be high enough to absorb the inductor energy while
transitioning from full-load to no-load conditions without
tripping the overvoltage fault protection. When using
high-capacitance, low-ESR capacitors (see stability
requirements), the filter capacitor’s ESR dominates the
output voltage ripple. So the output capacitor’s size
depends on the maximum ESR required to meet the out-
put voltage ripple (VRIPPLE(P-P)) specifications:
VRIPPLE(P-P) = RESRILOAD(MAX)LIR
In idle-mode, the inductor current becomes discontinuous,
with peak currents set by the idle-mode current-sense
threshold (VIDLE = 0.2VLIMIT). In idle-mode, the no-load
output ripple can be determined as follows:
V
VR
R
RIPPLE P P
IDLE ESR
SENSE
(– ) =
R
L
CR
R
DCR
EQ
=+
1
2
R
RR
R
CS
DCR
=
+
2
12
CR
L
R
EQ
ESL
SENSE
1
=
R
V
I
V
xI
CS
LIMIT
ILIM
LIMIT
==
10
II
LIMIT
LOAD MAX
IINDUCTOR
>
+
()
Δ
2
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相關代理商/技術參數 |
參數描述 |
|---|---|
| MAX17004AETJ+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX17004ETJ+ | 功能描述:電壓模式 PWM 控制器 Quad Out Main Power Supply Controller RoHS:否 制造商:Texas Instruments 輸出端數量:1 拓撲結構:Buck 輸出電壓:34 V 輸出電流: 開關頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| MAX17004ETJ+T | 功能描述:電壓模式 PWM 控制器 Quad Out Main Power Supply Controller RoHS:否 制造商:Texas Instruments 輸出端數量:1 拓撲結構:Buck 輸出電壓:34 V 輸出電流: 開關頻率: 工作電源電壓:4.5 V to 5.5 V 電源電流:600 uA 最大工作溫度:+ 125 C 最小工作溫度:- 40 C 封裝 / 箱體:WSON-8 封裝:Reel |
| MAX17005AETP+ | 功能描述:電池管理 1.2MHz High-Perf Charger RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
| MAX17005AETP+T | 功能描述:電池管理 1.2MHz High-Perf Charger RoHS:否 制造商:Texas Instruments 電池類型:Li-Ion 輸出電壓:5 V 輸出電流:4.5 A 工作電源電壓:3.9 V to 17 V 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 封裝 / 箱體:VQFN-24 封裝:Reel |
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