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| 型号： | MAX1544ETL+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 29/42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
SKIP is a three-level logic input — GND, REF, or high.
This input is intended to be driven by a dedicated
open-drain output with the pullup resistor connected
either to REF (or a resistive divider from V CC ) or to a
logic-level high-bias supply (3.3V or greater).
? i
? t
=
V BATT - V OUT
L
I PEAK
When driven to GND, the multiphase Quick-PWM con-
troller disables the secondary phase (DLS = PGND and
DHS = LXS) and the primary phase uses the automatic
pulse-skipping control scheme. When pulled up to REF,
the controller keeps both phases active and uses the
automatic pulse-skipping control scheme — alternating
between the primary and secondary phases with each
cycle.
I LOAD = I PEAK /2
Automatic Pulse-Skipping Switchover
0
ON-TIME
TIME
In skip mode ( SKIP = REF or GND), an inherent automatic
switchover to PFM takes place at light loads (Figure 7). A
comparator that truncates the low-side switch on-time at
the inductor current ’ s zero crossing affects this
switchover. The zero-crossing comparator senses the
inductor current across the current-sense resistors. Once
V C _ P - V C _ N drops below the zero crossing comparator
threshold (see the Electrical Characteristics ), the com-
parator forces DL low (Figure 5). This mechanism causes
the threshold between pulse-skipping PFM and nonskip-
ping PWM operation to coincide with the boundary
between continuous and discontinuous inductor-current
operation. The PFM/PWM crossover occurs when the
Figure 7. Pulse-Skipping/Discontinuous Crossover Point
I PEAK
I LOAD
I LIMIT
load current of each phase is equal to 1/2 the peak-to-
peak ripple current, which is a function of the inductor
value (Figure 7). For a battery input range of 7V to 20V,
this threshold is relatively constant, with only a minor
dependence on the input voltage due to the typically low
0
I LIMIT(VALLEY) = I LOAD(MAX)
TIME
(
2 - LIR
2 η
)
duty cycles. The total load current at the PFM/PWM
I LOAD ( SKIP ) = η TOTAL ? OUT ? ? IN OUT ?
crossover threshold (I LOAD(SKIP) ) is approximately:
? V K ? ? V - V ?
? L ? ? V IN ?
where η TOTAL is the number of active phases, and K is
the on-time scale factor (Table 6).
The switching waveforms may appear noisy and asyn-
chronous when light loading activates pulse-skipping
operation, but this is a normal operating condition that
results in high light-load efficiency. Varying the inductor
value makes trade-offs between PFM noise and light-load
efficiency. Generally, low inductor values produce a
broader efficiency vs. load curve, while higher values
result in higher full-load efficiency (assuming that the coil
resistance remains fixed) and less output voltage ripple.
Penalties for using higher inductor values include larger
physical size and degraded load-transient response,
especially at low input voltage levels.
Figure 8. “ Valley ” Current-Limit Threshold Point
Current-Limit Circuit
The current-limit circuit employs a unique “ valley ” cur-
rent-sensing algorithm that uses current-sense resistors
between the current-sense inputs (C_P to C_N) as the
current-sensing elements. If the current-sense signal of
the selected phase is above the current-limit threshold,
the PWM controller does not initiate a new cycle
(Figure 8) until the inductor current of the selected
phase drops below the valley current-limit threshold.
When either phase trips the current limit, both phases
are effectively current limited since the interleaved con-
troller does not initiate a cycle with either phase.
______________________________________________________________________________________
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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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