参数资料
型号: MAX1634AEAI+T
厂商: Maxim Integrated Products
文件页数: 13/29页
文件大小: 0K
描述: IC REG CTRLR BUCK PWM CM 28-SSOP
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 2,000
PWM 型: 电流模式,混合
输出数: 2
频率 - 最大: 330kHz
占空比: 99%
电源电压: 4.2 V ~ 30 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -40°C ~ 85°C
封装/外壳: 28-SSOP(0.209",5.30mm 宽)
包装: 带卷 (TR)
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
current value as a function of the output-voltage error
signal. In continuous-conduction mode, the average
inductor current is nearly the same as the peak current,
so the circuit acts as a switch-mode transconductance
amplifier. This pushes the second output LC filter pole,
normally found in a duty-factor-controlled (voltage-
mode) PWM, to a higher frequency. To preserve inner-
loop stability and eliminate regenerative inductor
current “staircasing,” a slope compensation ramp is
summed into the main PWM comparator to make the
apparent duty factor less than 50%.
The MAX1630A family uses a relatively low loop gain,
allowing the use of lower cost output capacitors. The rel-
ative gains of the voltage-sense and current-sense
inputs are weighted by the values of current sources
that bias three differential input stages in the main PWM
comparator (Figure 4). The relative gain of the voltage
comparator to the current comparator is internally fixed
at K = 2:1. The low loop gain results in the 2% typical
load-regulation error. The low value of loop gain helps
reduce output filter capacitor size and cost by shifting
the unity-gain crossover frequency to a lower level.
The output filter capacitors (Figure 1, 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
VL
(ESR) (see the Design Procedure section). A 60kHz
pole-zero cancellation filter provides additional rolloff
above the unity-gain crossover. This internal 60kHz low-
pass compensation filter cancels the zero due to filter
capacitor ESR. The 60kHz 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 synchro-
nous rectifier ensures proper startup of the boost gate-
driver circuit. If the synchronous power MOSFETs are
omitted for cost or other reasons, replace them with a
small-signal MOSFET, such as a 2N7002.
If the circuit is operating in continuous-conduction mode,
the DL drive waveform is 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 synchronous 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 syn-
chronous switch timing to improve multiple-output cross-
regulation (see the Secondary Feedback Regulation
Loop section).
R1
R2
UNCOMPENSATED
TO PWM
LOGIC
FB_
HIGH-SPEED
LEVEL TRANSLATOR
AND BUFFER
OUTPUT DRIVER
I1
I2
I3
V BIAS
REF
CSH_
CSL_
SLOPE COMPENSATION
Figure 4. Main PWM Comparator Block Diagram
______________________________________________________________________________________
13
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MAX1634CAI 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
MAX1634CAI+ 功能描述:DC/DC 开关控制器 Multi-Out Low-Noise Power-Supply Ctlr RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
MAX1634CAI+T 功能描述:DC/DC 开关控制器 Multi-Out Low-Noise Power-Supply Ctlr RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
MAX1634CAI-T 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
MAX1634EAI 功能描述:DC/DC 开关控制器 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK