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| 型号： | TLV431AFTA |
| 厂商： | Diodes Inc |
| 文件页数： | 8/14页 |
| 文件大小： | 0K |
| 描述： | IC VREF SHUNT ADJ SOT-23 |
| 标准包装： | 1 |
| 基准类型： | 分流器，可调式 |
| 输出电压： | 1.24 V ~ 18 V |
| 容差： | ±1% |
| 输入电压： | 最高 18V |
| 通道数： | 1 |
| 电流 - 阴极： | 100µA |
| 电流 - 输出： | 15mA |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | TO-236-3，SC-59，SOT-23-3 |
| 供应商设备封装： | SOT-23-3 |
| 包装： | 标准包装 |
| 其它名称： | TLV431AFTADKR |
A Product Line of
Diodes Incorporated
TLV431
Application Notes
In a conventional shunt regulator application (Figure 1), an external series resistor (R 3 ) is connected between the supply voltage, V IN , and the
TLV431.
R 3 determines the current that flows through the load (I L ) and the TLV431 (I K ). The TLV431 will adjust how much current it sinks or “shunts” to
maintain a voltage equal to V REF across its feedback pin. Since load current and supply voltage may vary, R 3 should be small enough to supply
at least the minimum acceptable I KMIN to the TLV431 even when the supply voltage is at its minimum and the load current is at its maximum
value. When the supply voltage is at its maximum and I L is at its minimum, R 3 should be large enough so that the current flowing through the
TLV431 is less than 15mA.
R 3 is determined by the supply voltage, (V IN ), the load and operating current, (I L and I K ), and the TLV431’s reverse breakdown voltage, V KA .
R 3 =
V IN ? V KA
I L + I K
V KA = V REF × ? ? 1 +
R 1 ?
R 2 ? ?
?
where
?
?
?
and V KA = V OUT
Figure 1
The values of R1 and R2 should be large enough so that the current flowing through them is much smaller than the current through R3 yet not
too large that the voltage drop across them caused I REF affects the reference accuracy.
The most frequent application of the TLV431 is in isolated low output voltage power supplies where the regulated output is galvanically isolated
from the controller. As shown in Figure 2 the TLV431 drives current, I F , through the opto-coupler’s LED which in turn drives the isolated transistor
which is connected to the controller on the primary side of the power supply.
This completes the feedback path through the isolation barrier and ensures that a stable isolated supply is maintained.
Assuming a forward drop of 1.4V across the opto-coupler diode allows output voltages as low as 2.7V to be regulated.
Regulated Supply
To controller
To controller
Optocoupler
I F
Regulated Supply
V OUT = V REF ? 1 +
?
R3
R1
?
?
R1 ?
R 2 ?
TLV431 ?
V OUT ? 2 .7
I F (min)
> R 3 ≥
V OUT (max) ? 2. 7
15 mA
R2
GND
Figure 2. Using the TLV431 as the Regulating Element in an Isolated PSU
TLV431
Document number: DS32088 Rev. 6 - 2
8 of 14
October 2012
? Diodes Incorporated
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相关代理商/技术参数 |
参数描述 |
|---|---|
| TLV431AH6TA | 功能描述:基准电压& 基准电流 1.24V 1% V-REF ADJ RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
| TLV431AID | 功能描述:基准电压& 基准电流 LV Adj Prec Shunt RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel |
| TLV431AID | 制造商:Texas Instruments 功能描述:IC SM SHUNT REGULATOR ADJ +2.5/36V |
| TLV431AID | 制造商:Texas Instruments 功能描述:SHUNT REG ADJ +2.5/36V SOIC8 431 |
| TLV431AIDBV | 制造商:TI 制造商全称:Texas Instruments 功能描述:LOW-VOLTAGE ADJUSTABLE PRECISION SHUNT REGULATORS |
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