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| 型号： | MAX17528GTJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 21/41页 |
| 文件大小： | 0K |
| 描述： | IC PWM CTRLR STP-DWN 32TQFN-EP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 系列： | Quick-PWM™ |
| 应用： | 控制器，Intel IMVP-6.5? GMCH |
| 输入电压： | 4.5 V ~ 5.5 V |
| 输出数： | 1 |
| 输出电压： | 0.01 V ~ 1.5 V |
| 工作温度： | -40°C ~ 105°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
| 包装： | 管件 |
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1-Phase Quick-PWM
Intel IMVP-6.5/GMCH Controllers
t ON SW ? FB ?
= t
Detailed Description
Free-Running, Constant On-Time
Controllers 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 3). This architecture
relies on the output filter capacitor’s ESR and the load
regulation to provide the proper current-mode compen-
sation, so the resulting feedback ripple voltage provides
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 the feedback 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 feed-
back voltage drops below the target voltage), the
inductor current is below the valley current-limit thresh-
old, 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 sup-
ply. Keeping the bias supply external to the IC improves
efficiency and eliminates the cost associated 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 gen-
erated 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
A 96.75k ? to 303.25k ? corresponds to switching peri-
ods of 1.67μs (600kHz) to 5μs (200kHz), respectively.
High-frequency (over 500kHz) operation optimizes the
application for the smallest component size, trading off
efficiency due to higher switching losses. This may be
acceptable in ultra-portable devices where the load
currents are lower and the controller is powered from a
lower voltage supply. Low-frequency (under 300kHz)
operation offers the best overall efficiency at the
expense of component size and board space.
TON Open-Circuit Fault Protection
The TON input includes open-circuit protection to avoid
long, uncontrolled on-times that could result in an over-
voltage condition on the output. The MAX17528 detects
an open-circuit fault if the TON current drops below
10μA for any reason —the TON resistor (R TON ) is
unpopulated, a high resistance value is used, the input
voltage is low, etc. Under these conditions, the
MAX17528 stops switching (DH and DL pulled low) and
immediately sets the fault latch. Toggle SHDN or cycle
the V CC power supply below 0.5V to clear the fault latch
and reactivate the controller.
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 feedback
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 ):
? V ?
? V IN ?
current drawn is:
I BIAS = I CC + f SW ( Q G ( LOW ) + Q G ( HIGH )
)
where the switching period (t SW = 1/f SW ) is set by the
resistor between V IN and TON.
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 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 supply, 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 ? )
This algorithm results in a nearly constant switching fre-
quency despite the lack of a fixed-frequency clock
generator. The benefits of a constant switching fre-
quency are twofold: first, the frequency can be select-
ed to avoid noise-sensitive regions, such as the 455kHz
IF band; second, the inductor ripple-current operating
point remains relatively constant, 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 conditions specified in the Electrical
Characteristics table can vary over a wider range.
______________________________________________________________________________________
21
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX17528GTJ+ | 功能描述:电流型 PWM 控制器 1-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 |
| MAX17528GTJ+T | 功能描述:电流型 PWM 控制器 1-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 |
| MAX17535ETG+ | 功能描述:电池管理 High Frequency SMBus Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX17535ETG+T | 功能描述:电池管理 High Frequency SMBus Charger RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
| MAX17535EVKIT+ | 功能描述:电池管理 EVKIT RoHS:否 制造商:Texas Instruments 电池类型:Li-Ion 输出电压:5 V 输出电流:4.5 A 工作电源电压:3.9 V to 17 V 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装 / 箱体:VQFN-24 封装:Reel |
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