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参数资料
| 型号： | MAX1544ETL+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 35/42页 |
| 文件大小： | 0K |
| 描述： | IC QUICK-PWM DUAL-PHASE 40-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| 系列： | Quick-PWM™ |
| 应用： | 控制器，AMD Hammer |
| 输入电压： | 2 V ~ 28 V |
| 输出数： | 1 |
| 输出电压： | 0.68 V ~ 1.55 V |
| 工作温度： | -40°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 40-WFQFN 裸露焊盘 |
| 供应商设备封装： | 40-TQFN-EP（6x6） |
| 包装： | 管件 |
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Dual-Phase, Quick-PWM Controller for
AMD Hammer CPU Core Power Supplies
medium-sized MOSFETs. However, high-current appli-
cations driving large, high-side, MOSFETs require
boost capacitors larger than 0.1μF. For these applica-
tions, select the boost capacitors to avoid discharging
the capacitor more than 200mV while charging the
high-side MOSFET ’ s gates:
Setting Voltage Positioning
Voltage positioning dynamically lowers the output volt-
age in response to the load current, reducing the
processor ’ s power dissipation. When the output is
loaded, an operational amplifier (Figure 5) increases
the signal fed back to the Quick-PWM controller ’ s feed-
back input. The adjustable amplification allows the use
C BST =
N x Q GATE
200 mV
of standard, current-sense resistor values, and signifi-
cantly reduces the power dissipated since smaller cur-
rent-sense resistors can be used. The load transient
where N is the number of high-side MOSFETs used for
one regulator, and Q GATE is the gate charge specified in
the MOSFET ’ s data sheet. For example, assume two
IRF7811W N-channel MOSFETs are used on the high
side. According to the manufacturer ’ s data sheet, a
single IRF7811W has a maximum gate charge of 24nC
(V GS = 5V). Using the above equation, the required boost
capacitance would be:
response of this control loop is extremely fast, yet well
controlled, so the amount of voltage change can be
accurately confined within the limits stipulated in the
microprocessor power-supply guidelines.
The voltage-positioned circuit determines the load current
from the voltage across the current-sense resistors
(R SENSE = R CM = R CS ) connected between the inductors
and output capacitors, as shown in Figure 10. The voltage
C BST =
2 x 24nC
200 mV
= 0 . 24 μ F
drop can be determined by the following equation:
V VPS = A VPS I LOAD R SENSE
Selecting the closest standard value, this example
requires a 0.22μF ceramic capacitor.
A VPS =
η SUM R F
η TOTAL R B
Current-Balance Compensation (CCI)
The current-balance compensation capacitor (C CCI )
integrates the difference between the main and sec-
ondary current-sense voltages. The internal compensa-
tion resistor (R CCI = 20k ? ) improves transient response
by increasing the phase margin. This allows the
dynamics of the current balance loop to be optimized.
Excessively large capacitor values increase the inte-
gration time constant, resulting in larger current differ-
ences between the phases during transients.
Excessively small capacitor values allow the current
loop to respond cycle-by-cycle but can result in small
DC current variations between the phases. Likewise,
excessively large resistor values can also cause DC
current variations between the phases. Small resistor
values reduce the phase margin, resulting in marginal
stability in the current-balance loop. For most applica-
tions, a 470pF capacitor from CCI to the switching reg-
ulator ’ s output works well.
Connecting the compensation network to the output
(V OUT ) allows the controller to feed forward the output
voltage signal, especially during transients. To reduce
noise pickup in applications that have a widely distrib-
uted layout, it is sometimes helpful to connect the com-
pensation network to the quiet analog ground rather
than V OUT .
where η SUM is the number of phases summed together
for voltage-positioning feedback, and η TOTAL is the total
number of active phases. When the slave controller is
disabled, the current-sense summation maintains the
proper voltage-positioned slope. Select the positive
input summing resistors so R FBS = R F and R A = R B .
Minimum Input Voltage Requirements
and Dropout Performance
The nonadjustable minimum off-time one-shot and the
number of phases restrict the output voltage adjustable
range for continuous-conduction operation. For best
dropout performance, use the slower (200kHz) on-time
settings. When working with low input voltages, the
duty-factor limit must be calculated using worst-case
values for on- and off-times. Manufacturing tolerances
and internal propagation delays introduce an error to
the TON K factor. This error is greater at higher fre-
quencies (Table 6). Also, keep in mind that transient
response performance of buck regulators operated too
close to dropout is poor, and bulk output capacitance
must often be added (see the V SAG equation in the
Design Procedure section).
The absolute point of dropout is when the inductor cur-
rent ramps down during the minimum off-time ( ? I DOWN )
as much as it ramps up during the on-time ( ? I UP ). The
ratio h = ? I UP / ? I DOWN is an indicator of the ability to
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1544ETL+ | 功能描述:电压模式 PWM 控制器 Dual-Phase Quick-PWM Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1544ETL+T | 功能描述:电压模式 PWM 控制器 Dual-Phase Quick-PWM Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1544ETL+TG075 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX1544ETL-T | 功能描述:电压模式 PWM 控制器 RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX1544EVKIT | 制造商:Maxim Integrated Products 功能描述:DUAL-PHASE, QUICK-PWM CONTROLLER FOR AMD HAMM - Bulk |
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