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| 型号： | MAX17409GTI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 22/32页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR NVIDIA CPU 28-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 系列： | Quick-PWM™ |
| 应用： | 处理器 |
| 电流 - 电源： | 1.5mA |
| 电源电压： | 4.5 V ~ 5.5 V |
| 工作温度： | -40°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（4x4） |
| 包装： | 带卷 (TR) |
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1-Phase Quick-PWM GPU Controller
Forced-PWM Operation (Normal Mode)
During soft-shutdown and normal operation—when the
CPU is actively running (SKIP = low, Table 3) — the
MAX17409 operates with the low-noise, forced-PWM
control scheme. Forced-PWM operation disables the
zero-crossing comparator, forcing the low-side gate-
drive waveforms to constantly be the complement of
the high-side gate-drive waveforms. This keeps the
switching frequency constant and allows the inductor
current to reverse under light loads, providing fast,
accurate negative-output-voltage transitions by quickly
discharging the output capacitors.
Forced-PWM operation comes at a cost: the no-load
+5V bias supply current remains between 10mA to
Once V LX drops below the zero-crossing comparator
threshold (see the Electrical Characteristics table), the
comparator forces DL low (Figure 2). This mechanism
causes the threshold between pulse-skipping PFM and
nonskipping-PWM operation to coincide with the
boundary between continuous and discontinuous induc-
tor-current operation. The PFM/PWM crossover occurs
when the load current is equal to 1/2 the peak-to-peak
ripple current, which is a function of the inductor value
(Figure 5). For a 7V to 20V battery input range, this
threshold is relatively constant, with only a minor depen-
dence 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:
50mA, depending on the external MOSFETs and
switching frequency. To maintain high efficiency under
light-load conditions, the processor might switch the
I LOAD ( SKIP ) =
? ? ? ?
2 ? L ? ? V IN ?
1 ? t SW V OUT ? ? V IN - V OUT ?
controller to a low-power pulse-skipping control
scheme after entering suspend mode. The MAX17409
automatically uses pulse-skipping operation during
soft-start, regardless of the SKIP configuration.
Light-Load Pulse-Skipping Operation
During soft-start and sleep states —SKIP is pulled
high—the MAX17409 operates in pulse-skipping mode.
The pulse-skipping mode enables the driver’s zero-
crossing comparator, so the controller pulls DL low
when its current-sense inputs detect “zero” inductor
current. This keeps the inductor from sinking current
and discharging the output capacitors and forces the
controller to skip pulses under light-load conditions to
avoid overcharging the output.
Upon entering pulse-skipping operation, the controller
The switching waveforms might 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. Trade-offs between
PFM noise and light-load efficiency are made by varying
the inductor value. Generally, low inductor values pro-
duce 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 volt-
age ripple. Penalties for using higher inductor values
include larger physical size and degraded load-tran-
sient response, especially at low input-voltage levels.
temporarily blanks the upper PWRGD thresholds, and
sets the OVP threshold to 1.80V to prevent false OVP
faults when the transition to pulse-skipping operation
coincides with a VID DAC code. The MAX17409 auto-
matically uses forced-PWM operation during soft-shut-
? I
? t
=
V BATT - V OUT
L
I PEAK
down, regardless of the SKIP configuration.
Automatic Pulse-Skipping Switchover
In skip mode (SKIP = high), an inherent automatic
switchover to PFM takes place at light loads. This
switchover is affected by a comparator that truncates
I LOAD = I PEAK /2
the low-side switch on-time at the inductor current’s
0
ON-TIME
TIME
zero crossing. The zero-crossing comparator senses
the inductor current across the low-side MOSFETs.
Figure 5. Pulse-Skipping/Discontinuous Crossover Point
22
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1740EUB | 功能描述:转换 - 电压电平 Integrated Circuits (ICs) RoHS:否 制造商:Micrel 类型:CML/LVDS/LVPECL to LVCMOS/LVTTL 传播延迟时间:1.9 ns 电源电流:14 mA 电源电压-最大:3.6 V 电源电压-最小:3 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MLF-8 |
| MAX1740EUB+ | 功能描述:转换 - 电压电平 SIM/Smart Card Level Translator RoHS:否 制造商:Micrel 类型:CML/LVDS/LVPECL to LVCMOS/LVTTL 传播延迟时间:1.9 ns 电源电流:14 mA 电源电压-最大:3.6 V 电源电压-最小:3 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MLF-8 |
| MAX1740EUB+T | 功能描述:转换 - 电压电平 SIM/Smart Card Level Translator RoHS:否 制造商:Micrel 类型:CML/LVDS/LVPECL to LVCMOS/LVTTL 传播延迟时间:1.9 ns 电源电流:14 mA 电源电压-最大:3.6 V 电源电压-最小:3 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MLF-8 |
| MAX1740EUB-T | 功能描述:转换 - 电压电平 RoHS:否 制造商:Micrel 类型:CML/LVDS/LVPECL to LVCMOS/LVTTL 传播延迟时间:1.9 ns 电源电流:14 mA 电源电压-最大:3.6 V 电源电压-最小:3 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:MLF-8 |
| MAX17410EVKIT+ | 功能描述:电源管理IC开发工具 MAX17410 Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
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