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--- lm317 [2016/06/02 14:24]
admin 创建
+++ lm317 [2016/06/02 21:22] (当前版本)
gongyu
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-LM317是非常常用的可调输出线性稳压器。 is a popular adjustable linear voltage regulator. It was designed by Robert C Dobkin in 1976 while he worked at National Semiconductor.
+LM317是非常常用的可调输出线性稳压器，由美国国家半导体公司的Robert C Dobkin于1976设计的一颗经典器件，与LM317输出正电压相对应的是能够输出负电压的线性稳压器LM337由Robert "Bob" Pease设计
+{{ :lm317picture.jpg |}}
+<WRAP centeralign> LM317 </WRAP>
-The LM337 (a negative complement to the LM317) regulates voltages below, rather than above, the reference. It was designed by Robert "Bob" Pease (1940 – 2011).
+====规格====
-Specifications[edit]
+^符号	|参数	|值	|单位   |
+^Vout		|1.25   |– 37	|V
+^Vin            |– Vout	|差别	|3  – 40	V
+^TJ	|工作结温范围	|0 – 125	|°C |
+^IO(MAX)	|最大输出电流	|1.5	|A|
+^IL(MIN)	|最小负载电流	|3.5 mA typical, 12 mA maximum	||
+^PD	|功率消耗	|内部限制	|W [1]|
+^RθJA	|结到环境热阻	|80	|°C/W |
+^RθJC	|结壳热阻	        |5	|°C/W |
-Part pinout of LM317T showing its constant voltage reference. Package is TO-220.
-Symbol	Parameter	Value	Unit
-Vout		1.25  – 37	V
-Vin – Vout	difference	3  – 40	V
-TJ	Operating junction temperature range	0 – 125	°C [1]
-IO(MAX)	Maximum output current	1.5	A
-IL(MIN)	Minimum load current	3.5 mA typical, 12 mA maximum	[1]
-PD	Power dissipation	Internally Limited	W [1]
-RθJA	Thermal resistance, Junction to ambient	80	°C/W [1]
-RθJC	Thermal resistance, Junction to case	5	°C/W [1]
 Without a heat sink with an ambient temperature at 50 ⁰C such as on a hot summer day inside a box, a maximum power dissipation of (TJ-TA)/RθJA = ((125-50)/80) = 0.98 W can be permitted. (A piece of shiny sheet metal of Aluminum with the dimensions 6 x 6 cm and 1.5 mm thick, results in a thermal resistance that permits 4.7 W of heat dissipation[2][3]).
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 For a constant current mode with an input voltage source at VIN at 12 V and a forward voltage drop of VF=3.6 V, the maximum output current will be PMAX / (VI - VF) = 0.98 / (12-3.6) = 112 mA.
-Operation[edit]
+{{ :lm317_block.gif |}}
-Main article: Linear regulator
+<WRAP centeralign> LM317内部功能框图 </WRAP>
+====工作====
+{{ :lm317_front.png |}}
 As linear regulators, the LM317 and LM337 are used in DC to DC converter applications.
@@ 行 28: / 行 32: @@
 In packages with a heat-dissipating mounting tab, such as TO-220, the tab is connected internally to the output pin which may make it necessary to electrically isolate the tab or the heat sink from other parts of the application circuit. Failure to do this may cause the circuit to short.
-Voltage regulator[edit]
+====稳压====
+{{ :577px-lm317_typical_schematic.svg.png |}}
-Schematic of LM317 in a typical voltage regulator configuration, including decoupling capacitors to address input noise and output transients.
+<WRAP centeralign> Schematic of LM317 in a typical voltage regulator configuration, including decoupling capacitors to address input noise and output transients.</WRAP>
 The LM317 has three pins: INput, OUTput, and ADJustment. The device is conceptually an op amp with a relatively high output current capacity. The inverting input of the amp is the adjustment pin, while the non-inverting input is set by an internal bandgap voltage reference which produces a stable reference voltage of 1.25 V.
@@ 行 41: / 行 45: @@
 To make the output more stable, the device is designed to keep the quiescent current at or below 100µA, making it possible to ignore the error term in nearly all practical cases.[4]
-Current regulator[edit]
+====稳流====
+{{ :640px-lm317_1a_constcurrent.svg.png |}}
-A constant current source circuit constructed with LM317
+<WRAP centeralign> A constant current source circuit constructed with LM317 </WRAP>
 The device can be configured to regulate the current to a load, rather than the voltage, by replacing the low-side resistor of the divider with the load itself. The output current is that resulting from dropping the reference voltage across the resistor. Ideally, this is:
@@ 行 50: / 行 54: @@
 Iout = (Vref/RH) + IQ
-LM317 can also be used to design various other circuits like 0 V to 30 V regulator circuit, adjustable regulator circuit with improved ripple rejection, precision current limiter circuit, tracking pre-regulator circuit, 1.25 V to 20 V regulator circuit with minimum program current, adjustable multiple on-card regulators with single control, battery charger circuit, 50 mA constant current battery charger circuit, slow turn-on 15 V regulator circuit, ac voltage regulator circuit, current-limited 6 V charger circuit, adjustable 4 V regulator circuit, high-current adjustable regulator circuit and many more. [5]
+LM317 can also be used to design various other circuits like 0 V to 30 V regulator circuit, adjustable regulator circuit with improved ripple rejection, precision current limiter circuit, tracking pre-regulator circuit, 1.25 V to 20 V regulator circuit with minimum program current, adjustable multiple on-card regulators with single control, battery charger circuit, 50 mA constant current battery charger circuit, slow turn-on 15 V regulator circuit, ac voltage regulator circuit, current-limited 6 V charger circuit, adjustable 4 V regulator circuit, high-current adjustable regulator circuit and many more.
-Compared to 78xx/79xx[edit]
+====同78xx/79xx系列比较====
 The LM317 is an adjustable analogue to the popular 78xx fixed regulators. Like the LM317, each of the 78xx regulators is designed to adjust the output voltage until it is some fixed voltage above the adjustment pin (which in this case is labeled "ground").
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 The LM337 relates in the same way to the fixed 79xx regulators.
-See also[edit]
+====相关文档====
-Bandgap voltage reference
+  * {{:lm317.pdf|LM317数据手册，PDF格式}}
-Brokaw bandgap reference
+  * {{:lm337.pdf|LM337数据手册，PDF格式}}
-List of LM-series integrated circuits
-References[edit]
-^ Jump up to: a b c d e LM317.pdf Archived August 22, 2014, at the Wayback Machine.
-Jump up ^ "Calculating heat sinks". November 2013. Retrieved 2016-04-16.
-Jump up ^ Nuova Elettronica. Accidenti come scotta questo transistor. 1978, volume 11, pages 58-102
-Jump up ^ "LM117/LM317A/LM317-N 3-Terminal Adjustable Regulator" (PDF). 2004 May, Revised 2013 August. Retrieved 2013-10-02. Check date values in: |date= (help)
-Jump up ^ "LM317 3-Terminal Adjustable Regulator" (PDF). Texas Instruments. October 2014. pp. 11–16. Archived from the original (PDF) on 31 March 2015. Retrieved 31 March 2015.
-Jump up ^ "LM340-N/LM78XX Series 3-Terminal Positive Regulators" (PDF). 2000 February, Revised 2013 March. Retrieved 2013-10-02. Check date values in: |date= (help)
-External links[edit]
-LM317 Circuit Schematics and Pinouts
-Online calculator to pick resistors for LM317 circuit
-Band-Gap
-The Design of Band-Gap Reference Circuits: Trials and Tribulations – Robert Pease, National Semiconductor (shows LM317 design in Figure 4: LM117)
-LM317 Bandgap Voltage Reference Example (ECE 327) – Brief explanation of the temperature-independent bandgap reference circuit within the LM317.
-IC Datasheets
-Voltage Regulator Databook (Historical 1980), National Semiconductor
-LM317 (positive), LM350 (3 Amp), Texas Instruments (TI acquired National Semiconductor)
-LM317 (positive), LM350 (3 Amp), ON Semiconductor
-LM317 (positive), STMicroelectronics
-LM337 (negative), Texas Instruments