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参数资料
| 型号： | MAX5975AETE+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 15/20页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR FLYBK ISO CM 16TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 600kHz |
| 占空比： | 84% |
| 降压： | 无 |
| 升压： | 无 |
| 回扫： | 是 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 16-WFQFN 裸露焊盘 |
| 包装： | 管件 |
Current-Mode PWM Controllers with Frequency
Dithering for EMI-Sensitive Power Supplies
Frequency Foldback for High-Efficiency
Light-Load Operation
The frequency foldback threshold can be programmed
from 0 to 20% of the full load current using a resistor from
FFB to GND.
Figure 4 shows device operation in frequency foldback
mode. Calculate the value of R FFB as follows:
where R SS is the resistor connected between SS and
GND, and I SS-CH is the current sourced from SS to R SS
(10 F A typ).
DCLMP
To set D MAX using supply voltage feed forward, connect
a resistive divider between the supply voltage, DCLMP,
and GND as shown in the Typical Applications Circuits.
R FFB =
10 × I LOAD(LIGHT) × R CS
I FFB
This feed-forward duty-cycle clamp ensures that the
external n-channel MOSFET is not stressed during sup-
ply transients. V DCLMP is calculated as follows:
V DCLMP =
× V S
whereR FFB istheresistorconnectedtoFFB,I LOAD(LIGHT)
is the current at light-load conditions that triggers fre-
quency foldback, R CS is the value of the sense resistor
connected between CS and PGND, and I FFB is the cur-
rent sourced from FFB to R FFB (30 F A typ).
Duty-Cycle Clamping
The maximum duty cycle is determined by the lowest
of three voltages: 2V, the voltage at SS (V SS ), and the
voltage (2.43V - V DCLMP ). The maximum duty cycle is
calculated as:
R DCLMP2
R DCLMP1 + R DCLMP2
where R DCLMP1 and R DCLMP2 are the resistive divider
values shown in the Typical Applications Circuits and V S
is the input supply voltage.
Oscillator Synchronization
The internal oscillator can be synchronized to an exter-
nal clock by applying the clock to SYNC/DITHER direct-
ly. The external clock frequency can be set anywhere
D MAX =
V MIN
2.43V
between 1.1x to 2x the internal clock frequency.
Using an external clock increases the maximum duty
where V MIN = minimum (2V, V SS , 2.43V - V DCLMP ).
SS
By connecting a resistor between SS and ground, the
voltage at SS can be made to be lower than 2V. V SS is
calculated as follows:
cycle by a factor equal to f SYNC /f SW . This factor should
be accounted for in setting the maximum duty cycle
using any of the methods described in the Duty-Cycle
Clamping section. The formula below shows how the
maximum duty cycle is affected by the external clock
frequency:
× SYNC
V CSAVG
FFB
NDRV
V SS = R SS × I SS ? CH
D MAX =
V MIN f
2.43V f SW
t SW
t SW X 2
t SW X 2
COMP
Figure 4. Entering Frequency Foldback
15
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PDF描述 |
|---|---|
| MAX5974BETE+ | IC REG CTRLR FLYBACK PWM 16-TQFN |
| MAX5068BAUE+ | IC REG CTRLR FLYBK ISO 16-TSSOP |
| MAX5068EAUE+ | IC REG CTRLR FLYBK ISO 16-TSSOP |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX5975AETE+ | 功能描述:电流型 PWM 控制器 Current-Mode 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 |
| MAX5975AETE+T | 功能描述:电流型 PWM 控制器 Current-Mode 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 |
| MAX5975BETE+ | 功能描述:电流型 PWM 控制器 Current-Mode 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 |
| MAX5975BETE+T | 功能描述:电流型 PWM 控制器 Current-Mode 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 |
| MAX5975CETE+ | 制造商:Maxim Integrated Products 功能描述:CURRENT-MODE PWM CONTROLLERS WITH FREQUENCY DITHERING FOR EM - Rail/Tube |
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