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| 型号： | MAX1634AEAI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 10/29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： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 28-SSOP（0.209"，5.30mm 宽） |
| 包装： | 带卷 (TR) |
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Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
_______________Detailed Description
The MAX1630A is a dual, BiCMOS, switch-mode power-
supply controller designed primarily for buck-topology
regulators in battery-powered applications where high effi-
ciency and low quiescent supply current are critical. Light-
load efficiency is enhanced by automatic Idle Mode
operation, a variable-frequency pulse-skipping mode that
reduces transition and gate-charge losses. Each step-
down, power-switching circuit consists of two n-channel
MOSFETs, a rectifier, and an LC output filter. The output
voltage is the average AC voltage at the switching node,
which is regulated by changing the duty cycle of the
MOSFET switches. The gate-drive signal to the n-channel
high-side MOSFET must exceed the battery voltage, and
is provided by a flying-capacitor boost circuit that uses a
100nF capacitor connected to BST_.
Devices in the MAX1630A family contain 10 major circuit
blocks (Figure 2).
The two PWM controllers each consist of a Dual Mode
feedback network and multiplexer, a multi-input PWM
comparator, high-side and low-side gate drivers, and
logic. The MAX1630A/MAX1631A/MAX1632A contain
fault-protection circuits that monitor the main PWM out-
puts for undervoltage and overvoltage. A power-on
sequence block controls the power-up timing of the
main PWMs and determines whether one or both of the
outputs are monitored for undervoltage faults. The
MAX1630A/MAX1632A/MAX1633A/MAX1635A include
a secondary feedback network and 12V linear regulator
to generate a 12V output from a coupled-inductor fly-
back winding. The MAX1631A/MAX1634A have an
SECFB instead, which allows a quasi-regulated,
adjustable-output, coupled-inductor flyback winding to
be attached to either the 3.3V or the 5V main inductor.
VL/CSL5 bootstrap switch connected to the +5V PWM,
and SECFB. The heart of each current-mode PWM con-
troller is a multi-input, open-loop comparator that sums
three signals: the output voltage error signal with
respect to the reference voltage, the current-sense sig-
nal, and the slope compensation ramp (Figure 3). The
PWM controller is a direct-summing type, lacking a tra-
ditional error amplifier and the phase shift associated
with it. This direct-summing configuration approaches
ideal cycle-by-cycle control over the output voltage.
When SKIP = low, Idle Mode circuitry automatically
optimizes efficiency throughout the load current range.
Idle Mode dramatically improves light-load efficiency
by reducing the effective frequency, which reduces
switching losses. It keeps the peak inductor current
above 25% of the full current limit in an active cycle,
allowing subsequent cycles to be skipped. Idle Mode
transitions seamlessly to fixed-frequency PWM opera-
tion as load current increases.
With SKIP = high, the controller always operates in
fixed-frequency PWM mode for lowest noise. Each
pulse from the oscillator sets the main PWM latch that
turns on the high-side switch for a period determined
by the duty factor (approximately V OUT /V IN ). As the
high-side switch turns off, the synchronous rectifier
latch sets; 60ns later, the low-side switch turns on. The
low-side switch stays on until the beginning of the next
clock cycle.
In PWM mode, the controller operates as a fixed-
frequency current-mode controller where the duty ratio
is set by the input/output voltage ratio. The current-
mode feedback system regulates the peak inductor
Table 3. SKIP PWM Table
Bias generator blocks include the 5V IC internal rail (VL)
linear regulator, 2.5V precision reference, and automatic
bootstrap switchover circuit. The PWMs share a com-
SKIP
LOAD
CURRENT
MODE
DESCRIPTION
mon 200kHz/300kHz synchronizable oscillator.
Pulse-skipping, supply cur-
These internal IC blocks are not powered directly from
the battery. Instead, the 5V VL linear regulator steps
down the battery voltage to supply both VL and the
gate drivers. The synchronous-switch gate drivers are
directly powered from VL, while the high-side switch
gate drivers are indirectly powered from VL through an
external diode-capacitor boost circuit. An automatic
bootstrap circuit turns off the +5V linear regulator and
powers the IC from the 5V PWM output voltage if the
output is above 4.5V.
Low
Low
High
High
Light
Heavy
Light
Heavy
Idle
PWM
PWM
PWM
rent = 250μA at V IN = 12V,
discontinuous inductor
current
Constant-frequency PWM,
continuous inductor current
Constant-frequency PWM,
continuous inductor current
Constant-frequency PWM,
continuous inductor current
PWM Controller Block
The two PWM controllers are nearly identical. The only
differences are fixed output settings (3.3V vs. 5V), the
10
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相关代理商/技术参数 |
参数描述 |
|---|---|
| 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 |
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