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| 型号： | MAX8760ETL+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 29/39页 |
| 文件大小： | 0K |
| 描述： | IC CNTRLR QUICK PWM 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，6 位 VID AMD 移动式 Turion? |
| 输入电压： | 4 V ~ 28 V |
| 输出数： | 2 |
| 输出电压： | 0.38 V ~ 1.55 V |
| 工作温度： | 0°C ~ 85°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
Mobile Turion 64 CPU Core Power Supplies
Low-Power Pulse Skipping
During pulse-skipping override mode ( SKIP = REF or
GND, Table 7), the multiphase Quick-PWM controllers
use an automatic pulse-skipping control scheme. When
? i
? t
=
V BATT - V OUT
L
I PEAK
SKIP is pulled low, the controller uses the automatic
pulse-skipping control scheme, overriding forced-PWM
operation, and blanks the upper VROK threshold.
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 LOAD = I PEAK /2
When driven to GND, the multiphase Quick-PWM
0
ON-TIME
TIME
controller disables the secondary phase (DLS = PGND
and DHS = LXS) and the primary phase uses the auto-
matic 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.
Automatic Pulse-Skipping Switchover
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 switch-
Figure 7. Pulse-Skipping/Discontinuous Crossover Point
I PEAK
I LOAD
I LIMIT
over. 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 thresh-
old (see the Electrical Characteristics table), the com-
parator forces DL low (Figure 5). This mechanism causes
0
I LIMIT(VALLEY) = I LOAD(MAX)
TIME
(
2 - LIR
2 η
)
I LOAD ( SKIP ) = η TOTAL ? OUT ? ? IN OUT ?
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
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
duty cycles. The total load current at the PFM/PWM
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
Figure 8. “Valley” Current-Limit Threshold Point
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.
Current-Limit Circuit
The current-limit circuit employs a unique “valley” current-
sensing algorithm that uses current-sense resistors
between the current-sense inputs (C_P to C_N) as the cur-
rent-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 controller 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 |
|---|---|
| MAX8760ETL+ | 功能描述:电流型 PWM 控制器 Dual-Phase Quick PWM Controller RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX8760ETL+T | 功能描述:电流型 PWM 控制器 Dual-Phase Quick PWM Controller RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX8760ETL-T | 功能描述:电流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX8760EVKIT | 功能描述:电流型 PWM 控制器 Evaluation Kit for the MAX8760 RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX8761ETG+ | 功能描述:LCD 驱动器 Linear-Regulator LCD Panel Power Supply RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
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