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| 型号： | MAX1980ETP+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 16/33页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM 20-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 系列： | Quick-PWM™ |
| PWM 型： | 控制器 |
| 输出数： | 1 |
| 频率 - 最大： | 550kHz |
| 占空比： | 50% |
| 电源电压： | 4.5 V ~ 5.5 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： | 0°C ~ 85°C |
| 封装/外壳： | 20-WQFN 裸露焊盘 |
| 包装： | 管件 |
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Quick-PWM Slave Controller with
Driver Disable for Multiphase DC-DC Converter
Table 4. Operating Mode Truth Table
DD
V CC
GND
ILIM
High
(> 0.25V)
High
(> 0.25V)
DL
Switching
Low
MODE
Normal
Operation
Driver
Disable
COMMENTS
Low-noise, fixed-frequency, PWM operation. The inductor current
reverses with light loads.
Light load, single-phase operation. The MAX1980 disables the drivers
by forcing DL and DH low, effectively disabling the slave controller.
Low-power, standby mode (I CC + I DD = 20μA typ). DL and DH
X
GND
(< 0.25V)
Low
Standby
forced low, and the PWM controller disabled. However, the bias and
fault-protection circuitry remain active so the MAX1980 can
continuously monitor the ILIM input.
X = Don ’ t Care
When the slave controller ’ s current-limit voltage (V ILIM ) is
set through a resistive-divider between the master con-
troller ’ s reference and GND (see the Current-Limit
Circuitry section), the MAX1980 automatically enters low-
power standby mode when the master controller shuts
down. As the master ’ s reference powers down, the resis-
tive-divider pulls ILIM below 250mV, automatically acti-
vating the MAX1980 ’ s low-power standby mode.
Current-Limit Circuitry
When the master ’ s inductor current exceeds its valley
current limit, the master extends its off time by forcing
DL high until the inductor current falls below the current-
limit threshold. Without a transition on the master ’ s low-
side gate driver, the slave cannot initiate a new on-time
pulse so the slave ’ s inductor current ramps down as
well, maintaining the current balance. Therefore, the
slave ’ s valley current limit only needs to protect the
slave controller if the current balance circuitry or the
master current limit fails. The slave ’ s ILIM input voltage
should be selected to properly adjust the master ’ s cur-
rent-limit threshold.
Dual-Mode ILIM Input
The current-limit input (ILIM) features dual-mode opera-
tion, serving as both the standby mode control input
and the current-limit threshold adjustment. The slave
controller enters a low-power standby mode when the
ILIM voltage (V ILIM ) is pulled below 250mV. For ILIM
voltages from 400mV to 1.5V, the current-limit threshold
voltage is precisely 0.1 ? V ILIM . The current-limit volt-
age may be accurately set with a resistive voltage-
divider between the master controller ’ s reference and
GND, allowing the MAX1980 to automatically enter the
low-power standby mode.
Slave Current Limit
The slave current-limit circuit employs a unique “ valley ”
current-sensing algorithm. If the current-sense signal is
above the current-limit threshold, the MAX1980 will not ini-
tiate a new cycle (Figure 3). The actual peak inductor cur-
rent is greater than the current-limit threshold by an
amount equal to the inductor ripple current. Therefore, the
exact current-limit characteristic and maximum load
capability are a function of the current-limit threshold,
inductor value, and input voltage. The reward for this
uncertainty is robust, overcurrent sensing. When com-
bined with master controllers that contain output under-
voltage protection circuits, this current-limit method is
effective in almost every circumstance.
There also is a negative current limit that prevents
excessive reverse inductor currents when V OUT is sink-
ing current. The negative current-limit threshold is set to
approximately 150% of the positive current-limit thresh-
old, and tracks the positive current limit when ILIM is
adjusted.
The MAX1980 uses CS+ and CS- to differentially measure
the current across an external sense resistor (R CS ) con-
nected between the inductor and output capacitors. This
configuration provides precise current balancing, current
limiting, and voltage positioning with a 1% current-sense
resistor. Reducing the sense voltage decreases power
dissipation but increases the relative measurement error.
Carefully observe the PC board layout guidelines to
ensure that noise and DC errors don ’ t corrupt the cur-
rent-sense signals measured at CS+ and CS-. The IC
should be mounted relatively close to the current-sense
resistor with short, direct traces making a Kelvin sense
connection.
Master Current-Limit Adjustment (LIMIT)
The Quick-PWM controllers that may be used as the
master controller typically use the low-side MOSFET ’ s
on-resistance as its current-sense element. This depen-
dence on a loosely specified resistance with a large tem-
perature coefficient causes inaccurate current limiting.
As a result, high current-limit thresholds are needed to
16
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1980ETP+ | 功能描述:DC/DC 开关控制器 PWM Slave Controller w/Driver Disable 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 |
| MAX1980ETP+T | 功能描述:DC/DC 开关控制器 PWM Slave Controller w/Driver Disable 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 |
| MAX1980ETP+TG075 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX1980ETP-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 |
| MAX1980ETP-TG075 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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