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| 型号： | MAX17007GTI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 20/35页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR QPWM GRAPHICS 28TQFN |
| 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： | 电源 |
| 电流 - 电源： | 1.7mA |
| 电源电压： | 4.5 V ~ 26 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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Dual and Combinable QPWM Graphics
Core Controllers for Notebook Computers
Switching Frequency
The MAX17007/MAX17008 feature independent resis-
tor-programmable switching frequencies for each
SMPS, providing flexibility for applications where one
SMPS operates at a lower switching frequency when
connected to a high-voltage input rail while the other
SMPS operates at a higher switching frequency when
connected to a lower voltage rail as a second-stage
regulator. Connect a resistor (R TON ) between TON and
V IN to set the switching period T SW = 1/f SW :
T SW1 = C TON (R TON1 + 6.5k ? )
T SW2 = C TON (R TON2 + 6.5k ? )
where C TON = 16.26pF. A 97.5k ? to 302.5k ? corre-
sponds to switching periods of 1.67μs (600kHz) to 5μs
(200kHz) for SMPS1 and SMPS2. High-frequency
(600kHz) 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 volt-
age supply. Low-frequency (200kHz) operation offers
the best overall efficiency at the expense of component
size and board space.
For continuous conduction operation, the actual switching
frequency can be estimated by:
Combined-Mode Current Balance
In combined mode, the one-shot for SMPS2 varies the
on-time in response to the input voltage and the differ-
ence between the SMPS1 and SMPS2 inductor cur-
rents. The SMPS1 one-shot in combined mode behaves
the same way as it does in separate mode. As such,
SMPS2 regulates the current balance, while SMPS1
regulates the voltage.
Two identical transconductance amplifiers integrate the
difference between SMPS1 and SMPS2 current-sense
signals. The summed output is internally connected to
CCI, allowing adjustment of the integration time con-
stant with a compensation network (usually a capacitor)
connected between CCI and the output.
The resulting compensation current and voltage are
determined by the following equations:
I CCI = G m [(V CSH1 - V CSL1 ) - (V CSH2 - V CSL2 )]
V CCI = V OUT + I CCI Z CCI
where Z CCI is the impedance at the CCI output. The
SMPS2 on-time one-shot uses this integrated signal
(V CCI ) to set the SMPS2 high-side MOSFETs on-time.
When SMPS1 and SMPS2 current-sense signals
(V CSH1 - V CSL1 and V CSH2 - V CSL2 ) become unbal-
anced, the transconductance amplifiers adjust the
SMPS2 on-time, which increases or decreases the
f SW =
V OUT + V DIS
t ON ( V IN + V CHG )
SMPS2 inductor current until the current-sense signals
are properly balanced. In combined mode, the SMPS2
on-time is given by:
where V DIS is the sum of the parasitic voltage drops in
the inductor discharge path, including synchronous
rectifier, inductor, and printed-circuit board (PCB)
resistances; V CHG is the sum of the resistances in the
charging path, including the high-side switch, inductor,
and PCB resistances; and t ON is the on-time calculated
by the on-time block.
When operating in separate mode, it is recommended
that both SMPS switching frequencies be set apart by
10% to 30% to prevent the two sides from beating
against each other.
Combined-Mode On-Time One-Shot
In combined mode (FB2 = V CC ), TON1 sets the on-
time, and hence the switching frequency, for both SMPS.
The on-time is programmed using the TON1 equation,
which sets the switching frequency per phase. The
effective switching frequency as seen on the input and
output capacitors is twice the per-phase frequency.
SMPS2 On-Time t ON2 = T SW2 (V CCI /V IN )
SMPS Enable Controls (EN1, EN2)
EN1 and EN2 provide independent control of output
soft-start and soft-shutdown. This allows flexible control
of startup and shutdown sequencing. The outputs can
be started simultaneously, sequentially, or indepen-
dently. To provide sequential startup, connect EN of
one regulator to PGOOD of the other. For example, with
EN1 connected to PGOOD2, OUT1 soft-starts after
OUT2 is in regulation.
When configured in separate mode, the two outputs are
independent. A fault at one output does not trigger
shutdown of the other.
When configured in combined mode (FB2 = V CC ), EN1
is the master control input that enables/disables the
combined output, while EN2 has no function and must
be connected to GND. The startup slew rate follows
that of SMPS1.
Toggle EN low to clear the overvoltage, undervoltage,
and thermal-fault latches.
20
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX17008GTI+ | 功能描述:电压模式 PWM 控制器 QPWM Graphics Core 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 |
| MAX17008GTI+T | 功能描述:电压模式 PWM 控制器 QPWM Graphics Core 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 |
| MAX17009GTL+ | 功能描述:其他电源管理 AMD Dual-Phase CPU Controller RoHS:否 制造商:Texas Instruments 输出电压范围: 输出电流:4 mA 输入电压范围:3 V to 3.6 V 输入电流: 功率耗散: 工作温度范围:- 40 C to + 110 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-48 封装:Reel |
| MAX17009GTL+T | 功能描述:其他电源管理 AMD Dual-Phase CPU Controller RoHS:否 制造商:Texas Instruments 输出电压范围: 输出电流:4 mA 输入电压范围:3 V to 3.6 V 输入电流: 功率耗散: 工作温度范围:- 40 C to + 110 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-48 封装:Reel |
| MAX1700EEE | 功能描述:直流/直流开关转换器 1-3 Cell 1A Step-Up DC/DC Converters RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
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