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| 型号： | LM2794EVAL |
| 厂商： | National Semiconductor |
| 文件页数： | 16/23页 |
| 文件大小： | 0K |
| 描述： | BOARD EVALUATION LM2794 |
| 标准包装： | 1 |
| 电流 - 输出 / 通道： | 80mA |
| 输出及类型： | 4，非隔离 |
| 输出电压： | 4V |
| 特点： | 充电泵 |
| 输入电压： | 2.7 ~ 5.5 V |
| 已供物品： | 板 |
| 已用 IC / 零件： | LM2794 |
| 相关产品： | LM2794TLX/NOPB-ND - IC LED DRVR WHT BCKLT 14USMD LM2794BLDKR-ND - IC LED DRVR WHT BCKLT 14USMD LM2794TL/NOPBCT-ND - IC LED DRVR WHT BCKLT 14MICROSMD LM2794TL/NOPBTR-ND - IC LED DRVR WHT BCKLT 14MICROSMD LM2794BLCT-ND - IC LED DRVR WHT BCKLT 14USMD LM2794BLTR-ND - IC LED DRVR WHT BCKLT 14USMD |
SNVS168L – JANUARY 2002 – REVISED MAY 2013
POWER EFFICIENCY
Figure 27 shows the efficiency of the LM2794/5. The change in efficiency shown by the graph comes from the
transition from Pass Mode to a gain of 1.5.
Efficiency (E) of the LM2794/5 is defined here as the ratio of the power consumed by LEDs (P LED ) to the power
drawn from the input source (P IN ). In the equations below, I Q is the quiescent current of the LM2794/5, I LED is the
current flowing through one LED, V LED is the forward voltage at that LED current, and N is the number of LEDs
connected to the regulated current outputs. In the input power calculation, the 1.5 represents the switched
capacitor gain configuration of the LM2794/5.
P LED = N × V LED × I LED
P IN = V IN × I IN
P IN = V IN × (1.5 × N × I LED + I Q )
E = (P LED ÷ P IN )
(9)
(10)
(11)
(12)
Efficiency, as defined here, is in part dependent on LED voltage. Variation in LED voltage does not affect power
consumed by the circuit and typically does not relate to the brightness of the LED. For an advanced analysis, it is
recommended that power consumed by the circuit (V IN x I IN ) be evaluated rather than power efficiency. Figure 28
shows the power consumption of the LM2794/5 Typical Application Circuit.
Figure 27. Efficiency vs V IN
4 LEDs, V LED = 3.6V, I LED = 15mA
450
430
410
390
370
350
330
310
290
3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
V IN (V)
Figure 28. P IN vs V IN
4 LEDs, 2.5 ≤ V DX ≤ 3.9V, I DX = 15mA
16
Product Folder Links: LM2794 LM2795
Copyright ? 2002–2013, Texas Instruments Incorporated
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| LM2794TL | 功能描述:IC LED DRVR WHT BCKLT 14MICROSMD RoHS:否 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压（升压），切换式电容器（充电泵） 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C |
| LM2794TL/NOPB | 功能描述:LED照明驱动器 RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
| LM2794TLX | 功能描述:IC LED DRVR WHT BCKLT 14USMD RoHS:否 类别:集成电路 (IC) >> PMIC - LED 驱动器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- 恒定电流:- 恒定电压:- 拓扑:升压（升压），切换式电容器（充电泵） 输出数:1 内部驱动器:是 类型 - 主要:背光 类型 - 次要:白色 LED 频率:625kHz ~ 875kHz 电源电压:2.7 V ~ 5.3 V 输出电压:5V 安装类型:表面贴装 封装/外壳:10-TFSOP，10-MSOP（0.118"，3.00mm 宽） 供应商设备封装:10-µMAX 包装:带卷 (TR) 工作温度:-40°C ~ 85°C |
| LM2794TLX/NOPB | 功能描述:LED照明驱动器 RoHS:否 制造商:STMicroelectronics 输入电压:11.5 V to 23 V 工作频率: 最大电源电流:1.7 mA 输出电流: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:SO-16N |
| LM2795 | 制造商:未知厂家 制造商全称:未知厂家 功能描述: |
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