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参数资料
| 型号： | MAX5974EETE+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 18/22页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR FLYBACK PWM 16-TQFN |
| 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： | 82% |
| 降压： | 无 |
| 升压： | 无 |
| 回扫： | 是 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 16-WFQFN 裸露焊盘 |
| 包装： | 管件 |
MAX5974E/MAX5974F
Current-Mode PWM Controllers for
Low-Cost Flyback Supplies
V CSBL
(BLANKED CS
V CS-PEAK
(400mV)
VOLTAGE)
HICCUP
DISCHARGE WITH I SS-DH
V SS-HI
SOFT-START
VOLTAGE,
V SS
t SS
t RSTRT
V SS-DTH
Figure 6. Hiccup Mode Timing Diagram
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.
When V CSAVG falls below V FFB , the device folds back
the switching frequency to 1/2 the original value to
reduce switching losses and increase the converter effi-
ciency. Calculate the value of R FFB as follows:
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:
V SS
= R SS × I SS-CH
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).
R FFB =
10 × I LOAD(LIGHT) × R CS
I FFB
DCLMP
To set D MAX using supply voltage feed-forward, connect
a resistive divider between the supply voltage, DCLMP,
where R FFB is the resistor between FFB and GND,
I LOAD(LIGHT) is the current at light-load conditions that
triggers frequency foldback, R CS is the value of the
sense resistor connected between CS and PGND, and
and GND as shown in the Typical Application Circuit.
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:
I FFB is the current sourced from FFB to R FFB (30 F A typ).
Duty-Cycle Clamping
The maximum duty cycle is determined by the lowest
V DCLMP
=
R DCLMP2
R DCLMP1 + R DCLMP2
× V S
of three voltages: 2V, the voltage at SS (V SS ), and the
voltage (2.43V - V DCLMP ). The maximum duty cycle is
calculated as:
where R DCLMP1 and R DCLMP2 are the resistive divider
values shown in the Typical Application Circuit and V S is
the input supply voltage.
D MAX =
V MIN
2.43V
The maximum duty cycle is then set to:
where V MIN = minimum (2V, V SS , 2.43V - V DCLMP ).
18
D MAX = 1 ?
D CLMP
2.43
Maxim Integrated
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX5974EETE+ | 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 |
| MAX5974EETE+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 |
| MAX5974EEVKIT# | 功能描述:电流型 PWM 控制器 MAX5974E Eval Kit 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 |
| MAX5974FETE+ | 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 |
| MAX5974FETE+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 |
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