參數(shù)資料
型號(hào)： MAX1904EAI
廠商： MAXIM INTEGRATED PRODUCTS INC
元件分類： 穩(wěn)壓器
英文描述： 500kHz Multi-Output, Low-Noise Power-Supply Controllers for Notebook Computers
中文描述： 0.2 A DUAL SWITCHING CONTROLLER, 550 kHz SWITCHING FREQ-MAX, PDSO28
封裝： 5.30 MM, MO-150, SSOP-28
文件頁(yè)數(shù)： 16/33頁(yè)
文件大?。?/td> 649K
代理商： MAX1904EAI
M
500kHz Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
16
______________________________________________________________________________________
The output filter capacitors (Figure1, C1 and C2) set a
dominant pole in the feedback loop that must roll off the
loop gain to unity before encountering the zero intro-
duced by the output capacitor
’
s parasitic resistance
(ESR) (see the
Design Procedure
section). A 50kHz
pole-zero cancellation filter provides additional rolloff
above the unity-gain crossover. This internal 50kHz
low-pass compensation filter cancels the zero due to fil-
ter capacitor ESR. The 50kHz filter is included in the
loop in both fixed-output and adjustable-output modes.
Synchronous Rectifier Driver (DL)
Synchronous rectification reduces conduction losses in
the rectifier by shunting the normal Schottky catch
diode with a low-resistance MOSFET switch. Also, the
synchronous rectifier ensures proper startup of the
boost gate-driver circuit.
If the circuit is operating in continuous-conduction
mode, the DL drive waveform is simply the complement
of the DH high-side drive waveform (with controlled
dead time to prevent cross-conduction or
“
shoot
through
”
). In discontinuous (light-load) mode, the syn-
chronous switch is turned off as the inductor current falls
through zero. The synchronous rectifier works under all
operating conditions, including Idle Mode.
The SECFB signal further controls the synchronous switch
timing in order to improve multiple-output cross-regulation
(see the
Secondary Feedback Regulation Loop
section).
Internal VL and REF Supplies
An internal regulator produces the 5V supply (V
L
) that
powers the PWM controller, logic, reference, and other
blocks within the IC. This 5V low-dropout linear regula-
tor supplies up to 25mA for external loads, with a
reserve of 25mA for supplying gate-drive power.
Bypass V
L
to GND with 4.7μF.
Important:
Ensure that V
L
does not exceed 6V.
Measure V
L
with the main output fully loaded. If it is
pumped above 5.5V, either excessive boost-diode
capacitance or excessive ripple at V+ is the probable
cause. Use only small-signal diodes for the boost cir-
cuit (10mA to 100mA Schottky or 1N4148 are pre-
ferred), and bypass V+ to PGND with 4.7μF directly at
the package pins.
Table 3. SKIP PWM Table
SKIP
Low
Low
High
High
LOAD CURRENT
Light
Heavy
Light
Heavy
MODE
Idle
PWM
PWM
PWM
DESCRIPTION
Pulse-skipping, supply current = 250μA at V
IN
=12V, discontinuous inductor
Constant-frequency PWM continuous-inductor current
Constant-frequency PWM continuous-inductor current
Constant-frequency PWM continuous-inductor current
FB_
REF
CSH_
CSL_
SLOPE COMPENSATION
V
L
I1
R1
R2
TO PWM
LOGIC
OUTPUT DRIVER
UNCOMPENSATED
HIGH-SPEED
LEVEL TRANSLATOR
AND BUFFER
I2
I3
V
BIAS
Figure 4. Main PWM Comparator Block Diagram
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX1904EAI+ 功能描述:DC/DC 開(kāi)關(guān)控制器 500kHz Multi-Output Power-Supply Ctlr 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
MAX1904EAI+T 功能描述:DC/DC 開(kāi)關(guān)控制器 500kHz Multi-Output Power-Supply Ctlr 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
MAX1904EAI-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
MAX1904EAI-TG074 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
MAX1904ETJ 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
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