数字电位器怎么连接到VCC？

你必须确保电位器身腿的电压不会超过或低于电源。连接电源的锅，而Vdd的控制器不存在，你违反这个规则。如果POTS电压高于VDD或低于VSS，则没有绝缘。如果POTS电压在功率范围之内，一切都正常。



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    You must ensure the voltages of potentiometers body legs will not go over or below the power supply. Connecting power to the pots while Vdd of the controller is absent you're violating this rule. There is none insulation if pots voltage going upper than Vdd or lower than Vss. If pots voltages are inside power limits all is OK.

这听起来是个好主意。我去试试，谢谢。你知道数字隔离器吗？那也行吗？HTTP//www.类比.COM/MENTA/Eng/TealTea/Deas-SeaTss/AdUM1200，1201.PDFI不想把B端接上，但除非我这样做，否则100K壶永远不会比50K高。我不知道为什么会这样，是吗？



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    that sounds like a good idea. I'll give it a go, thanks. Do you know anything about digital isolators. Would that also work?
http://www.analog.com/media/en/technical-documentation/data-sheets/ADuM1200_1201.pdf
 
I did not want to ground the B end, but unless I did that, the 100K pot would never go higher than about 50K. I don't know why that was, do you?

相关内容：http://www. McCux.com／…/M101054 7.ASPX第1010547页



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    related:
http://www.microchip.com/.../m1010547.aspx#1010547

参考MCP431数据表第3页，它表示-& GT；注意：在“MaximumRatings”下列出的那些应力可能会对设备造成永久性损坏。这只是一个应力等级，并且在本说明书的操作清单中指出的那些或任何其他条件的设备的功能操作并没有被暗示。对于延长的周期的最大额定条件的暴露可能影响设备可靠性，但是数据表也说。VDD相对于VSS的电压……-0.6V至+7.0V电压在CS、SCK、SDI、SDI/SDO、WP和复位方面相对于VSS。在所有其他引脚（PXA、PXW、PXB、ANDSDO）上，相对于VSS…-0.3V到VDD+0.3V输入钳位电流，IIK（VI和LT；0，VI & GT；VDD，VI & GT；高压引脚上的VPP）…±20 MAX钳位电流，IOK（VO和LT；0或VO & Gt；VDD）±20 Maso，这意味着电流限制在20mA，THE。E可以实际上是大于VDD两端的电压锅两端，不会有损坏？



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    referring to MCP4341 datasheet page 3, it says ->
 
† Notice: Stresses above those listed under “Maximum
Ratings” may cause permanent damage to the device. This is
a stress rating only and functional operation of the device at
those or any other conditions above those indicated in the
operational listings of this specification is not implied.
Exposure to maximum rating conditions for extended periods
may affect device reliability
 
but the datasheet also says
Voltage on VDD with respect to VSS ................ -0.6V to +7.0V
Voltage on CS, SCK, SDI, SDI/SDO, WP, and
RESET with respect to VSS ................................... -0.6V to 12.5V
Voltage on all other pins (PxA, PxW, PxB, and
SDO) with respect to VSS ............................ -0.3V to VDD + 0.3V
Input clamp current, IIK
(VI < 0, VI > VDD, VI > VPP ON HV pins) ......................±20 mA
Output clamp current, IOK
(VO < 0 or VO > VDD) ..................................................±20 mA
 
So, does that mean that provided the current is limited to 20mA, there can actually be voltages greater than VDD across the pot ends, and there will not be damage?

我认为将电流限制在20毫安的最大值比在电路断电时简单地去除外部电源是困难的。你可能还想把一个肖特基二极管从“A”罐端放到Vdd，以确保在上电或关机期间电压差保持在0.3V以下，直到断开装置工作。没有参考，它们将漂浮在Vdd和VSS之间。你可以将一个电阻从VSS连接到外部电源，而不是一个固态接地。此外，你的反向极性二极管D4应该直接在输入端，电容器应该直接在调节器输入端。



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    I think it would be more difficult to limit the current to the maximum of 20 mA, than to simply remove the external source electrically when the circuit powers off. You might also want to put a Schottky diode from the "A" pot ends to Vdd to assure that the voltage difference remains below 0.3V during power-up or shut-down, until the disconnect device operates.
 
You need to have some sort of ground reference for the "B" pot ends. Without a reference, they will float between Vdd and Vss. You may be able to connect a resistor from Vss to the external source low side instead of a solid ground.
 
Also, your reverse polarity diode D4 should be directly at the input, and the capacitor should be directly on the regulator input.

“W”结束了吗？



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What about "W" ends ?

嗯，我在事物的末尾，没有很多时间来增加设计。最大的电压，将永远连接到锅从外部设备将是10伏。所以，如果我把一个1K电阻器串联在A端和外部设备上，那就应该这样做。你怎么认为？



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    hmmm, i am at the tail end of things, and don't have a lot of time to be adding to the design. The maximum voltage that will ever be connected across the pot from an external device will be 10 volts. So, if I put a 1k resistor in series with the A end and the external device, that should do it. what do you think?

这实际上是一个5伏的部分，所以它可能不会正常工作在7伏特的绝对极限，远低于10伏特。有一个高电压版本好10-36伏，但只有一个通道：http://www. McCys.com /www/eN/Eng/MCP41HV51，目前还不清楚你需要做什么。如果您只想通过PIC控制可变输出电压，还有许多其他方法来实现这一点。



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    This is really a 5 volt part, so it will likely not work properly at its absolute limit of 7 volts, much less 10 volts. There is a high voltage version good from 10-36 volts, but only single channel:
 
http://www.microchip.com/wwwproducts/en/MCP41HV51
 
It's unclear just what you need to do. If you just want a variable output voltage controlled by the PIC there are many other ways to accomplish this.

建议在应用程序和示意图之间使用所谓的光隔离放大器。



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    suggestion is to use a so called optical isolation amplifier between your application and the schematic provided