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| 型号： | MAX17409GTI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 16/32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
t ( V + 0 . 075 V )
Detailed Description
Free-Running, Constant On-Time PWM
Controller with Input Feed-Forward
The Quick-PWM control architecture is a pseudo-fixed-
frequency, constant-on-time, current-mode regulator
with voltage feed-forward (Figure 2). This architecture
relies on the output filter capacitor’s ESR to act as the
current-sense resistor, so the output ripple voltage pro-
vides the PWM ramp signal. The control algorithm is
simple: the high-side switch on-time is determined solely
by a one-shot whose period is inversely proportional to
input voltage, and directly proportional to output volt-
age (see the On-Time One-Shot section). Another one-
shot sets a minimum off-time. The on-time one-shot
triggers when the error comparator goes low, the induc-
tor current is below the valley current-limit threshold,
and the minimum off-time one-shot times out.
+5V Bias Supply (V CC and V DD )
The Quick-PWM controller requires an external +5V
bias supply in addition to the battery. Typically, this
+5V bias supply is the notebook’s 95% efficient +5V
system supply. Keeping the bias supply external to the
IC improves efficiency and eliminates the cost associat-
ed with the +5V linear regulator that would otherwise be
needed to supply the PWM circuit and gate drivers. If
stand-alone capability is needed, the +5V bias supply
can be generated with an external linear regulator.
The +5V bias supply must provide V CC (PWM con-
troller) and V DD (gate-drive power), so the maximum
current drawn is:
I BIAS = I CC + f SW ( Q G ( LOW ) + Q G ( HIGH ) )
where I CC is provided in the Electrical Characteristics
table, f SW is the switching frequency, and Q G(LOW) and
Q G(HIGH) are the MOSFET data sheet ’s total gate-
charge specification limits at V GS = 5V.
V IN and V DD can be connected together if the input
power source is a fixed +4.5V to +5.5V supply. If the
+5V bias supply is powered up prior to the battery sup-
ply, the enable signal ( SHDN going from low to high)
must be delayed until the battery voltage is present to
ensure startup.
Switching Frequency (TON)
Connect a resistor (R TON ) between TON and V IN to set
the switching period (t SW = 1/f SW ):
t SW = 16.3pF x (R TON + 6.5k ? )
A 96.75k ? to 303.25k ? corresponds to switching peri-
ods of 167ns (600kHz) to 500ns (200kHz), respectively.
High-frequency (600kHz) operation optimizes the appli-
cation for the smallest component size, trading off effi-
ciency due to higher switching losses. This might be
acceptable in ultra-portable devices where the load
currents are lower and the controller is powered from a
lower voltage supply. Low-frequency (200kHz) opera-
tion offers the best overall efficiency at the expense of
component size and board space.
On-Time One-Shot
The core contains a fast, low-jitter, adjustable one-shot
that sets the high-side MOSFET’s on-time. The one-shot
varies the on-time in response to the input and feed-
back voltages. The main high-side switch on-time is
inversely proportional to the input voltage as measured
by the R TON input, and proportional to the feedback
voltage (V FB ):
t ON ( MAIN ) = SW FB
V IN
where the switching period (t SW = 1/f SW ) is set by the
resistor at the TON pin and 0.075V is an approximation
to accommodate the expected drop across the low-
side MOSFET switch.
This algorithm results in a nearly constant switching fre-
quency and balanced inductor currents despite the lack
of a fixed-frequency clock generator. The benefits of a
constant switching frequency are twofold: first, the fre-
quency can be selected to avoid noise-sensitive
regions such as the 455kHz IF band; second, the induc-
tor ripple-current operating point remains relatively con-
stant, resulting in easy design methodology and
predictable output-voltage ripple. The on-time one-
shots have good accuracy at the operating points
specified in the Electrical Characteristics table. On-
times at operating points far removed from the condi-
tions specified in the Electrical Characteristics table
can vary over a wider range.
On-times translate only roughly to switching frequen-
cies. The on-times guaranteed in the Electrical
Characteristics table are influenced by switching
delays in the external high-side MOSFET. Resistive
losses, including the inductor, both MOSFETs, output
capacitor ESR, and PCB copper losses in the output
and ground tend to raise the switching frequency at
higher output currents. Also, the dead-time effect
increases the effective on-time, reducing the switching
frequency. It occurs only during forced-PWM operation
and dynamic output-voltage transitions when the induc-
tor current reverses at light or negative load currents.
With reversed inductor current, the inductor ’s EMF
causes LX to go high earlier than normal, extending the
16
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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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