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我计划基于PSoC 5LP制作一个手持式LCR表(加上更多)。我想使用升压转换器,让我有效地把它从2个AA细胞。
然而,该装置的本质是它进行灵敏的模拟测量。在ESR模式中,例如,它产生大约100mV的波形,并且必须精确地测量衰减。当测量电感或电容时,它同样需要产生和精确测量波形,频率从几千赫到大约1MHz。 我会看到从升压转换器的噪声耦合到我正在测量的模拟信号吗?我可以采取什么措施来防止它,并且在合理的成本约束下,将噪声消除到手持式应用程序中的可接受程度是切实可行的吗?版面推荐如何? 以上来自于百度翻译 以下为原文 I'm planning to make a handheld LCR meter (plus more) based on the PSoC 5LP. I'd like to use the boost converter to allow me to power it efficiently off 2 AA cells. However, the nature of the device is that it does sensitive analog measurements. In ESR mode, for instance, it generates a waveform at around 100mV, and has to accurately measure the attenuation. When measuring inductance or capacitance, it likewise has to generate and accurately measure waveforms, at frequencies from a few kilohertz up to about 1MHz. Will I see significant coupling of noise from the boost converter into the analog signals I'm measuring? What steps can I take to prevent it - and is it practical to eliminate the noise to an acceptable degree in a handheld application with a reasonable cost constraint? How about layout recommendations? |
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这可能有帮助
CyPress公司 注意其他AP笔记底部的附加链接。 我建议用启动原和频谱分析仪进行一些工作。 看看你从PSRR上获得了多少OPAMP和一般 布局问题。 在这个环节,他们提到升压转换器050 -套件,但不加入它。 前面讨论了20位性能。除了A/D行为之外 以升压开关频率为特征,所以不确定我们能推断多少。 从20位演出… CyPress公司 CyPress公司 问候,Dana。 以上来自于百度翻译 以下为原文 This might help - www.cypress.com/ Notice additional links at bottom for other ap notes. I would advise some work with a starting proto and a spectrum analyzer to see how much clk feedthru you get from PSRR on OpAmps and general layout issues. In this link they mention boost converter for -050 kit, but do not join it with 20 bit performance discussed earlier. Besides the A/D behaviour not characterized at boost switching frequencies, so not sure we can infer much from 20 bit performance....... www.cypress.com/ www.cypress.com/ Regards, Dana. |
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我认为MHz的性能可能是有争议的,没有PSRR曲线,
如果你在PGA中看到G=16(只是为了得到一个想法),你就下降了20分贝。 从G=16直流值。没有多少BW离开。用于OPAP的GBW为8兆赫。 TYP,只是为了一个量规。 问候,Dana。 以上来自于百度翻译 以下为原文 I would think Mhz performance might be at issue, there are no PSRR curves, and if you look at a G = 16 in a PGA (just to get an idea) you are down 20 db from the G = 16 DC value. Not much BW left. GBW for the OpAmps is 8 Mhz typ, just for a gauge. Regards, Dana. |
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谢谢,这张便条很有用。我希望这是塞浦路斯已经考虑过的,但是,因为芯片结合了升压转换器和敏感的模拟电子,这似乎是一个自然匹配!
PSoC 5LP ADC上升到1MHz,因此它肯定在400 KHz升压调节器产生的频率范围内进行采样。 以上来自于百度翻译 以下为原文 Thanks, that appnote will be very useful. I'm hoping this is something Cypress have considered, though, since the chip combines the boost converter and sensitive analog electronics, this seems like a natural matchup! The PSoC 5LP ADC goes up to 1MHz, so it's definitely sampling in the range of frequencies produced by the 400KHz boost regulator. |
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当你不需要完整的采样率时,你总是可以进行过采样/平均。尤其是后者,你可以跳过平均窗口中最高和最低的样本,这会使它更有效。
你也可以使用数字滤波器来减少噪音。 以上来自于百度翻译 以下为原文 When you don't need the full sample rate, you can always do oversampling / averaging. Esp. with the latter, you can skip the highest and lowest samples in your averaging window, which should make it more effective. You also can use the digital filter to reduce noise. |
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顺便问一下:根据数据表(HTTP://www. CyPress)COM/?RES= 72824)PSoC5LP可以以低至1.8V的电源电压运行。所以对于两个单元,根本不需要升压转换器。
此外,模拟铁芯有自己的电压调节器,所以它可能不会受到升压转换器的影响(它似乎位于芯片的另一侧,从引脚判断)。 以上来自于百度翻译 以下为原文 btw: according to the data sheet (http://www.cypress.com/?rID=72824 ) the PSoC5LP can run with a supply voltage as low as 1.8V. So for two cells, you won't need the boost converter at all. Also, the analog core has its own voltage regulator, so it might not be affected as much by the boost converter (which seems to be located on the opposite side of the chip, judging from the pinout). |
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当然,W/O升压转换器的模拟规格和动态范围也减少了,
所以小心LV的影响。 为什么我们不能一无所获,这是工程的祸根? 问候,Dana。 以上来自于百度翻译 以下为原文 Of course w/o a boost converter analog specifications and dynamic range are reduced, so beware of LV affects. Why can we not get something for nothing, the bane of engineering ? Regards, Dana. |
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不幸的是,我与3.3或5V的设备接口,我需要比1.8V允许更多的空间。此外,LDO在过滤高频开关噪声方面也不是很好。
此外,虽然有一个单独的内部模拟调节器,AppNoX仍然建议单独的主调节器用于数字和模拟。我想我可以设置升压调节器的最大- 5.5伏特-然后使用两个单独的LDO数字和模拟,以及大量的解耦帽和一些铁氧体。我很乐观,这就足够了。 以上来自于百度翻译 以下为原文 @hli: Unfortunately, I'm interfacing with devices that are 3.3 or 5v. And I need more headroom for analog applications than 1.8v allows. Also, LDOs aren't very good at filtering out high frequency switching noise. Also, although there's a separate internal analog regulator, the appnote still recommends separate main regulators for digital and analog. I'm thinking I may set the boost regulator to the max - 5.5 volts - then use two separate LDOs for digital and analog, along with plenty of decoupling caps and perhaps some ferrites. I'm optimistic that will be sufficient. |
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研究使用聚合物钽,以及01和1陶瓷。这个
聚合物的ESR比传统钽好10倍。 ASP-Eng/ErFrqExpRealPurras.ASP-NPC www. NICCOF/CONTER/TECHNFO/ESR FRQYTC-NSPE-H-NACY-0809PDF 问候,Dana。 以上来自于百度翻译 以下为原文 Look into using Polymer Tantalums, along with .01 and .1 ceramic. The polymers are ~ 10 x better esr than traditional tantalums. www.low-esr.com/esrfreqperfcurves.asp#NPC www.niccomp.com/help/techinfo/ESR-Freq_TC-NSPE-H-NACY-0809.pdf Regards, Dana. |
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你没有提到任何外围设备。我假设这个想法是把任何东西放进PSoC(尤其是当在DP上阅读这个建议)。
如果你真的关心模拟性能,使用外部升压转换器可能是个好主意。这使得解耦变得更容易,因为在PSOC核心内部没有开关电路。你也可以选择一个转换器,为你的预期负载产生更少的涟漪和噪音。 以上来自于百度翻译 以下为原文 You didn't mention any peripherals. I was assuming that the idea was to put anything inside the PSoC (esp. when reading the proposal over at DP) If you really care about analog performance, it might be a good idea to use an external boost converter. This makes decoupling easier, since then there is no switching circuit inside of the PSoC core. You also could select a converter which generates less ripple and noise for your intended load. |
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其中一个“纹波器”电路能清除开关噪声。
以上来自于百度翻译 以下为原文 would one of those "ripple eater" circuits clean up the switching noise. |
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不确定你在看什么,“波纹电路”,但3终端
作为一类,调节器拒绝在AOL减少误差的涟波。 用于调节器。其他技术,在更高的频率,通过使用 相移,像全通滤波器,和反馈可以帮助拒绝一些。 相关信号 问候,Dana。 以上来自于百度翻译 以下为原文 Not sure what you are looking at, "ripple eate circuits", but 3 terminal regulators, as a class, reject ripple at ~ Aol reduction of the error amp used in regulator. Other techniques, at higher frequencies, via use of phase shift, like all pass filter, and feedback can aid in rejecting some correlated signals. Regards, Dana. |
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