| 在线座谈主题：飞思卡尔以太网供电器件满足您的供电需求 |
| [ 问题 1 ] |
DC/DC的输出电压如何调节？通过改变开关频率吗？调节是否方便？ |
| [ 答案 1 ] |
要调整 DC-DC 的输出电压您可以调整变压器的电压比例, 用來很方便, 小的调整,可以调整feedback potential divider 的比例, 詳情可參閱AN3279. |
| [ 问题 2 ] |
DC/DC 输出可调范围为多少？ |
| [ 答案 2 ] |
DC/DC 的输出范围是没有规定,可依您的设计而定。 |
| [ 问题 3 ] |
Demo 板的供应以及技术支持情况如何？ |
| [ 答案 3 ] |
Our products and boards are readily available. Pls approach our Freescale sales office or Distributors in your region. |
| [ 问题 4 ] |
End-Point POE 是否只支持数据线上供电？ |
| [ 答案 4 ] |
End-Point PoE 支持数据线队供电，也支持空余线队供电。 但是目前 Endpoint 方式采用数据线队供电。 在 midspan 方式中，必须使用空余线对。 |
| [ 问题 5 ] |
飞思卡尔的 PD 器件能提供的端口数最高能达到多少? |
| [ 答案 5 ] |
MC34670 supports only one PD device. |
| [ 问题 6 ] |
飞思卡尔在 POE 方面与 Powerdsine，LT，等厂商相比有哪些优势和劣势？我希望听到一个客观公正的评价，谢谢！ |
| [ 答案 6 ] |
You need to distinguish PD from PSE. Our part is the PD, client end. Apart from Freescale being very competitive on price, our device can yield a very efficient design in terms of power conversion efficiency. We are able to achieve close to 88% or better. Also our MC34670 has very useful features like Leading Edge Blanking and Adjustable Oscillator. |
| [ 问题 7 ] |
MCZ34670 都有哪些封装形式? |
| [ 答案 7 ] |
MCZ34670 采用 SOIC 20 引脚的封装形式，具体尺寸请参考数据手册。
|
| [ 问题 8 ] |
MCZ34670 和其他厂家的 PoE 产品如 SI3400, Isl6844 相比有什么特点和优势吗？ |
| [ 答案 8 ] |
Apart from Freescale MCZ34670 being very competitive in price (depending on quantity), our device can yield a very efficient design in terms of power conversion efficiency. We are able to achieve close to 88% or better. Also our MC34670 has very useful features like Leading Edge Blanking and Adjustable Oscillator. |
| [ 问题 9 ] |
MCZ34670 评估板有些什么功能? 价格如何? |
| [ 答案 9 ] |
评估板 KIT34670EVB。 可以验证 MCZ34670 的主要特性。 它提供符合 IEEE802.3af 规范的受电设备 PD 接口；5V 隔离电压输出； 可调节浪涌电流； 欠压监控调节； 可配置设备类型为 0 到 4 类设备等。
关于价格，请和我们销售代表和我们的代理商联系。 联系方式在我们的中文网页上。 http://www.freescale.com.cn/others/wheretobuy/index.asp
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| [ 问题 10 ] |
MCZ34670 是供电芯片, 那么, 设备受电由专门的电路要求吗? 即由专门的芯片吗? |
| [ 答案 10 ] |
MCZ34670 is POE powered device, that is to say MCZ34670 will get power from PSE equipment by Ethernet cable. |
| [ 问题 11 ] |
MCZ34670 有 5v 系列的芯片吗，再有封装有几种? |
| [ 答案 11 ] |
MCZ34670 是用支援 IEEE802.3af (是 48V input) 所以沒有 5V, 目前封裝只有一種。 如果您所说的是输出电压的话那 MCZ34670 是没有限制输出电压的。 |
| [ 问题 12 ] |
MCZ34670 有没有瞬态过电压保护？如果没有, 如何考虑在 PD 端加上瞬态过电压保护功能？ |
| [ 答案 12 ] |
MCZ34670 有瞬态过压保护功能，当输入电压高于 65V 左右时，过压保护功能会起作用。另外需要外加 TVS 作保护。 |
| [ 问题 13 ] |
MCZ34670 有那些功能? 是否具有 ESD 保护功能? |
| [ 答案 13 ] |
本次座谈的主要目的是向各位介绍 MCZ34670 的功能和使用。
它具有 ESD 保护功能，＋/-2000V （Human Body model）。+/-200V (Machine Model) |
| [ 问题 14 ] |
MCZ34670 中 DC/DC 的输出为可调吗？ |
| [ 答案 14 ] |
因为 MCZ34670 是一个 DC-DC 控制器所以 DC-DC 的输出电压可以透过调整外部器件调整。可参阅问题1。 |
| [ 问题 15 ] |
PD 的分类是依据什么进行? 是电压还是电流还是别的什么? |
| [ 答案 15 ] |
The PD classification allows the PSE to identify four different (power) classes depending on the required power that the PD will draw during normal operation.
During classification probing by the PSE, the PD applies the appropriate load current onto the line. The PSE measures the load current and can determine the classification. |
| [ 问题 16 ] |
POE 采用直流供电, 在直流电源注入不支持 PoE 的设备时是不是会发生不安全问题? |
| [ 答案 16 ] |
No, it should be safe to plug in non-compliant PoE PD because in the IEEE802.3af standard, there is a signature resistor detection feature, during signature detection phase the Power Sourcing Equipment (PSE) applies a voltage in the range 2.7 V - 10.1 V on the PI connector and looks for the 25k ohm signature resistor. If 25k ohm signature resistor is not presented (case for non-compliant PoE PD), PSE will terminate the power supply to the PD. |
| [ 问题 17 ] |
POE 的供电距离有没有限制? 是多少？它和那些因素有关? |
| [ 答案 17 ] |
PoE 供电距离是 100m, 这和电缆的品質有关，但是按规定用 CAT5, CAT5-E, CAT6 就应该没有问题。 |
| [ 问题 18 ] |
POE 的最大供电功率 15W 是对全体 PD 还是单个 PD 而言?
|
| [ 答案 18 ] |
是针对一个 PD 受电设备的。我们介绍了 MCZ34670 可以设置 Rclass 分类电阻，以便让 PSE 端对之进行分类识别。 |
| [ 问题 19 ] |
POE 对短路或过载保护的能力如何? 响应时间有多快? |
| [ 答案 19 ] |
There are in-rush current limit, over current and over-voltage protection functions in MC34670. The response time will be much under 1ms. |
| [ 问题 20 ] |
POE 供电的通路是否有限? 如果采用这种网络功率截取方法的设备过多，能否对网络的稳定运行构成威胁？ |
| [ 答案 20 ] |
POE only provides 350mA/15W maximum power to a network equipment. The PSE will limit connected PD devices to meet the POE spec. So it will not be influenced to network stability. |
| [ 问题 21 ] |
POE 是否也需要加 ESD 保护? |
| [ 答案 21 ] |
根据您产品使用环境要求，我们的 MCZ34670 提供 ＋/-2000VESD 保护功能。 |
| [ 问题 22 ] |
POE 中使用直流供电, 为什么还需要桥式整流器? 它起什么样作用?
|
| [ 答案 22 ] |
请您观看我们本次座谈的材料，其中我们讨论了全桥整流器的作用。 |
| [ 问题 23 ] |
PSE 能否对受电设备有软起动功能以减小浪涌电流? |
| [ 答案 23 ] |
飞思卡尔的 MCZ34670 是提供多种智能方式的 PD 芯片，MCZ34670 可以通过调节外部电阻值来设置浪涌电流的门限值。 当设置为较小值时， 受电设备就可以对 PSE 端索取较小少的电流。 以减少浪涌。并且 MCZ34670 芯片又提供软起动功能。 |
| [ 问题 24 ] |
RJ-45 中信号传输对 POE 的影响有多大? 所引起的噪音能占多大的比例? 如何进行避免?
|
| [ 答案 24 ] |
RJ45 信号线上的信号对 POE 供电的影响不大，因为电源可在空余线对上传输，当电源在数据线上传输时数据的电压会通过 PD 稳压电路把数据电压波过滤。 |
| [ 问题 25 ] |
Why 48v not 24v DC?
|
| [ 答案 25 ] |
34670 fully supports the IEEE802.3af standard which is for 48V. The input range is governed by this standard and is in the range of 37V to 57V for the PD end. |
| [ 问题 26 ] |
从开始对 PD 进行检测到 48V 正常供电, 这个过程有多长时间?
|
| [ 答案 26 ] |
The maximum detection time is 500ms,
the maximum power turn on time is 400ms.
Therefore it can take up to 900ms from
the moment PD start to get into detection phase
till 48V is applied
|
| [ 问题 27 ] |
大家都知道 DC 的掉电检测在低功耗的应用是可能会误判断为设备移除，请问贵公司是怎样解决这个问题的？ |
| [ 答案 27 ] |
PSE will issue a signature detection voltage to detect PD device existed or not, so there will always be minimal current drawn. So there is no problem for the function. The signature detection is defined in the POE spec, IEEE 802.3af. |
| [ 问题 28 ] |
当供电距离较远时，需要加入中继器。那中继器也是PoE吗？应该不是吧。 |
| [ 答案 28 ] |
This would depends if the repeater has PSE inserted. Normally, if it is not specified then it is not. PoE is a capability added, not the repeater itself. |
| [ 问题 29 ] |
电流是多少？供电距离最大是多少？对网线有何要求？ |
| [ 答案 29 ] |
您的问题不太清楚一般来说 IEEE802.3af 规定 PD 功率在 13 瓦以下供电距离是 100m 按规定 cable 用 CAT5, CAT5-E, CAT6 就可以。 |
| [ 问题 30 ] |
对 PSE 电源有特殊要求吗? 使用普通的 48V 电源是否可以给 PD 供电? |
| [ 答案 30 ] |
You would be able to do this providing that the inrush current, OVLO, over voltage are not violated with the settings and the device limits as transients and surges could be very high. However, we do not recommend doing this as this would not comply to the PoE IEEE 802.3af standard, and this standard mandates cable requirements and safety issues. So it is recommended that you use the PD with a PSE. |
| [ 问题 31 ] |
隔离变压器的设计有什么要求？有参考资料吗？ |
| [ 答案 31 ] |
您是指那个变压器？如果是 LAN side 请按 IEEE802.3。如果是 DC-DC 方面就跟你 DC-DC 有关。 |
| [ 问题 32 ] |
功率分级是怎样分级的？请问 PD 是否要加一个分级电阻？ |
| [ 答案 32 ] |
There are 4 levels for PD classification, 0 for 0.44-12.95W(, 1 for 0.44 to 3.84W, 2 for 3.84 to 6.49W, 3 for 6.49 to 12.95W. The classification resistors is 4.42Kohm(0), 475ohms(1), 261ohms(2) and 169ohms(3). You could see the details in MC34670 datasheet. |
| [ 问题 33 ] |
既然 MCZ34670 兼容非标准设备，那非标准的供电设备输出电压是否有要求? |
| [ 答案 33 ] |
PD input voltage is limited from 37 to 57V. |
| [ 问题 34 ] |
加上偏置磁圈之后可以使效率提高到 80+，这个偏置磁圈是什么？
|
| [ 答案 34 ] |
In cases where the external MOSFET gate drive pulls more than 5.0 mA, an auxiliary winding is needed to reduce the power dissipation in the internal high voltage LDO. The internal high voltage regulator of the 34670 regulates from the input voltage across VPWR and VIN down to the VDD voltage. During start-up the high voltage regulator provides the necessary voltage for the internal gate driver to commence switching. If the external MOSFET gate drive pulls less than 3.0 mA under all circumstances, an auxiliary transformer winding that usually provides the bias voltage for the chip and the gate driver is not required.
The aux winding has an higher output voltage than the LDO and delivers all the current to drive the gate.
|
| [ 问题 35 ] |
兼容非标准供电是否指非标准的 48V 供电设备？
|
| [ 答案 35 ] |
能兼容以前非标准的 48V 供电设备的。
|
| [ 问题 36 ] |
每一片芯片, 只能实现向一条网线供电吗?
|
| [ 答案 36 ] |
我对您的问题的理解是 MCZ34670 只能向一个 PD 设备提供电源。是的，MCZ34670 是向 PD 受电设备提供电源并且符合 IEEE802.3af 规范的要求。
|
| [ 问题 37 ] |
目前国际上有没有超过 350mA 的 POE 的供电标准，如 500mA 或 1A？
|
| [ 答案 37 ] |
At this moment the answer is no based on the current IEEE802.3af specification. However, the upcoming new IEEE802.3at standard is expected to supply 30W power which in turn should be able to support higher current.
|
| [ 问题 38 ] |
目前来说, 以太网供电 (POE) 所存在的主要问题是什么? 有什么解决方案?
|
| [ 答案 38 ] |
您的问题范围指向不明确。
如果从市场发展的角度讲，它是比较新的技术，需要大家的接受和认同。成本，方便性，实用性等等。
从技术角度讲，PSE 端的设计相对 PD 端较复杂，但是使用中跨方式可以分担其的负荷。POE 设计的灵活性可以提供不同的手段达到目的。
|
| [ 问题 39 ] |
能否详细介绍如何对 PD 进行检测? 包括那些内容?
|
| [ 答案 39 ] |
首先，PSE 向 PD 发送 2-10v 的检测电压，用来检测 PD 端的特征电阻是否是标准规定的 25Kohm。如果检测到是符合标准的 PD 设备后，PSE 会加大功率，发送 15-20V 的检测电压，以便对 PD 设备的功率进行分类。
本次座谈中向大家介绍了对 PD 检测的方式，请您观看我们的座谈材料。或查看我们产品的数据手册。
|
| [ 问题 40 ] |
你好，802.3af 与普通的以太网一样吗？如果能用到普通的以太网上，能提供多大的功率或电流输出，谢谢！
|
| [ 答案 40 ] |
802.3af 是一个基于普通的以太网的规范, 功率可参阅问题32。
|
| [ 问题 41 ] |
请问, 与别的 POE 方案相比, MCZ34670 的最大的优势是什么?
|
| [ 答案 41 ] |
Apart from our MCZ34670 being very competitive on price (depending on qty), our device can yield a very efficient design in terms of power conversion efficiency. We are able to achieve close to 88% or better.Also our MCZ34670 has very useful features like Leading Edge Blanking and Adjustable Oscillator.
|
| [ 问题 42 ] |
请问 MCZ34670 有没有热保护和热插拔功能?
|
| [ 答案 42 ] |
MCZ34670 是有热保护和热插拔功能的。
|
| [ 问题 43 ] |
请问 MCZ34670 支持哪一种掉电检测方式？是直流掉电检测还是交流掉电检测，或者是两者都支持？
|
| [ 答案 43 ] |
For power cut or drop, the testing is not done by the PD. Whenever the power is drop, the PSE will need to re-estabilsh that the device is PoE compliant again (ie signiture detection). What happens is that the PD will shut down when the presented power, or voltage rather is below the ULVO threshold. You can utilize the under voltage lock out pin by means of 2 resistors on MCZ34670 to set this threshold. |
| [ 问题 44 ] |
请问多少钱?
|
| [ 答案 44 ] |
We offer very competitive pricing for sizeable volumes. Please approach Freescale sales representative in your region.
|
| [ 问题 45 ] |
请问该器件是否能采用非隔离输出？以减低成本。
|
| [ 答案 45 ] |
是可以的。
|
| [ 问题 46 ] |
请问供货周期多长？飞思卡尔是否提供相应的交换机方案？
|
| [ 答案 46 ] |
If the switch scheme is relating PoE operation, we do not, else you can approach our networking product sales group within your region to enquire about our Switch products. For leadtime, it depends on your volume, please approach our sales representative in your region.
|
| [ 问题 47 ] |
请问飞思卡尔有 PSE 的集成解决方案吗？
|
| [ 答案 47 ] |
Currently we do not have PSE solutions for our general product offering.
|
| [ 问题 48 ] |
请问网络变压器应该如何选择？谢谢！
|
| [ 答案 48 ] |
Base on the IEEE 802.3af specification requirement to choose the isolation transformer.
|
| [ 问题 49 ] |
请问我们是不是可以这样简单的理解，MCZ34670 是支持标准的 PD 再加入了一个 DC/DC？
|
| [ 答案 49 ] |
简单地说是可以这样理解。
|
| [ 问题 50 ] |
请问用 MCZ34670 开发一个输出 5V 的 PD 估计需要多少成本？器件占用面积大约为多少？这个在实际应用时比较重要。
|
| [ 答案 50 ] |
我们提供了一个评估板套件，还有 MCZ34670 数据手册中给出了应用连接图。 您可以参考这些来估算成本。 关于器件的尺寸，也在数据手册中列出了。 关于产品的价格，请和我们的销售和代理商联系。
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| [ 问题 51 ] |
软件的开发环境为何? 是否有提供简易发展版做测试?
|
| [ 答案 51 ] |
For our PD device, no programming is needed. The settings are accomplished by resistor settings. But for the PSE, this would depend on which devices you are using.
|
| [ 问题 52 ] |
什么是以太网在线供电 (PoE)? 对用户来说，哪种方式最合适呢？它适合什么环境？
|
| [ 答案 52 ] |
PoE 是一种电源管理技术，可作为设备端直接嵌入交换机中，或是独立的中继集线器。IEEE 于 2003 年中正式核准了 802.3af 标准，802.3af 标准规定路由器、交换机与集线器，经由以太网络电缆径向 VOIP、WLAN AP（Access Point）等供电方式。 |
| [ 问题 53 ] |
实现 802.3af 标准的 POE, 是否意味要更换新的交换机?
|
| [ 答案 53 ] |
有两种选择
a. 可以不必换现有的交换机 只需加装一台Power injection将讯号与电源 一起注入网络传输线
b. 换一台有POE功能的交换机
|
| [ 问题 54 ] |
使用 MCZ34670 设计，产品的总的额外成本大约多少？
|
| [ 答案 54 ] |
This would depends on the topology (isolated/non isolated/flyback/forward) of your DC-Dc needs, transformer costs etc. But for our device, it would be marginal cost to your BOM. Pls approach Freescale sales office or support group in your region for pricing. |
| [ 问题 55 ] |
使用 POE 后，隔离变压器要调整吗? |
| [ 答案 55 ] |
是的。请看我们的应用笔记 AN3279，它详细的介绍了变压器部分的使用。
No modification to the isolation transformer is needed if power is supplied by spare pair. If power is supplied by data pair then you need an isolation transformer capable of allowing the DC to pass through |
| [ 问题 56 ] |
我的设备网速要求不高，所以网线长度大于 100m 也没有问题，所以我更关心这个芯片可以正常供电的最大长度，要大于100m的极限值。
|
| [ 答案 56 ] |
MCZ34670 的欠压锁闭（UVLO）功能要求您输入电压不小于 34V。所以只要保证供电电压稳定，可以适当的增加传输距离。 |
| [ 问题 57 ] |
我是个入门者, 请问 PD 和 PSE 通过 RJ-45 传输的 TX 发送和接收 RX 信息是个什么样的信号? 发送和接收是否需要同步? 它对变压器有什么特别的要求?
|
| [ 答案 57 ] |
It is Ethernet protocol signal. It is not necessary for synchronization. No need to modify transformer circuits for POE application. |
| [ 问题 58 ] |
我一直在从事这方面的设计，建议是不是能把整流桥集成到 PD 中，这样即能达到极性保护的作用也可以缩小布板面积?
|
| [ 答案 58 ] |
We have road maps for these devices and features. Your suggestion is more of a trade off between cost and integration for which we value with much.
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| [ 问题 59 ] |
现在 30W 的标准也即将出来了，也有公司退出了支持 30W 功率的兼容 PD，比如美信公司，请问 MCZ34670 既然支持非标准的供电设备， 是否可以通过外围电路设计来增加供电的功率超过 13W, 能不能达到 30W？
|
| [ 答案 59 ] |
MCZ34670 use external power MOSFET configuration. If input voltage range is within specification, theoretically is possible to change those external component eg. MOSFET, transformer ... to increase the system output power.
|
| [ 问题 60 ] |
演讲中曾经提到 PD 端电压受线缆影响，所以需要低电压保护，这个最低电压是 37 还是 42？
|
| [ 答案 60 ] |
The Default Turn-Off Voltage (UVLO = VIN) is min. 30. Also there is an external UVLO Programming function by external resistor value. The programming range is 25V - 50V.
|
| [ 问题 61 ] |
一般以太网供电, 其用电设备电流应该控制在多大的范围内合适?
|
| [ 答案 61 ] |
IEEE802.3af 规定 PD 功率在 13 瓦以下。 |
| [ 问题 62 ] |
已经建设的以太网能向网络终端提供电源吗？如果不能，如何改造? |
| [ 答案 62 ] |
The midspan PSE and Endpoint PSE could solve the problem.
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| [ 问题 63 ] |
以太网在线供电 (PoE) 有些什么好处? |
| [ 答案 63 ] |
优点如下:
不需加一个AC/DC adaptor安装Access pioint, web cam, IP phone等 不需另外拉AC电安装方便
可以经由UPS 在PSE 端 增加系统可靠性等
|
| [ 问题 64 ] |
由何处理 EMC 带来的问题?
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| [ 答案 64 ] |
EMC 是一个非常复杂的问题，它和产品设计使用的芯片，功能，电路板布局，走线方式，等等有关。您可以参考有关 EMC 的专著来降低 EMC 问题。 当产品发现 EMC 问题后，需要使用专门的设备进行分析（扫频），然后定位问题芯片，引脚，或其他，再具体加以分析。找出解决方法。
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| [ 问题 65 ] |
有人说 PoE 能促进网络的聚合, 你认为如何? POE 的生命力或前景如何?
|
| [ 答案 65 ] |
POE 有很的潜力 将来的 IP Phone, web cam, Access point 会逐渐转换为支持 POE。
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| [ 问题 66 ] |
有时候 PSE 需要提供更高的电压，比如 120V，飞思卡尔半导体公司有没有解决方案？
|
| [ 答案 66 ] |
34670 design support the IEEE802.3af standard and the input voltage of 34670 supporting range now is over IEEE802.3af to max. 80V.
|
| [ 问题 67 ] |
与 Silicon 的 SI3400 相比，MCZ34670 有什么优势？
|
| [ 答案 67 ] |
Apart from MCZ34670 being very competitive on price (depending on quantity), our device can yield a very efficient design in terms of power conversion efficiency. We are able to achieve close to 88% or better. Also our MCZ34670 has very useful features like Leading Edge Blanking and Adjustable Oscillator.
|
| [ 问题 68 ] |
在 POE 上, 如何解决脉冲和辐射保护问题？ |
| [ 答案 68 ] |
在 PD 端的变压器上要注意绕线部份尽量降低杂散电感及安装接地遮蔽以降低幅射 PCB layout 要注意到 Power 部份与讯号部份做清楚的隔离。 |
| [ 问题 69 ] |
在那里可以找到 MCZ34670 的规格书？
|
| [ 答案 69 ] |
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MC34670&nodeId=0174400719
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| [ 问题 70 ] |
在上电检测期间，因为要检测特征电阻，怎样估计整流桥在检测期间的影响？
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| [ 答案 70 ] |
您的问题非常好。 我们提供了针对 MCZ34670 特征电子检测的一个计算公式，请您参考我们的应用笔记 （Application Notes）AN3279，获得详细的信息。 |
| [ 问题 71 ] |
在以太网供电 (POE)，电源噪声会不会对数据传输有影响？如果有影响, 如何避免它对数据传输的影响? |
| [ 答案 71 ] |
在 IEEE802.3af 电源噪声对 PSE 的电源噪声有规定所以只要 PSE 符合这个规定应该对数据传输的影响有限。
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| [ 问题 72 ] |
这个芯片可以定到样片吗？ |
| [ 答案 72 ] |
Yes, this product is launched and we do provide sampling, please approach Freescale sales representative in your region. |
| [ 问题 73 ] |
中跨和端跨 POE 在供电上有何不同? 为什么?
|
| [ 答案 73 ] |
Mid span and end span are quite different. For End span, this would be the switch end where the power would be inserted by the PSE via either the spare pairs or the data pairs. For mid span, this would be a hub to extend the network wanting to use PoE but the switch does not provide such capability. The mid span inserts the power using the spare pairs only. Midspan PSE allows for the power to be supplied external to the ethernet. This provides both data and power on the twisted pair link segment without burdening each port of the Ethernet equipment when you need to provide power.
So this offers a way to allow PoE to be added to older systems without replacing the switch hubs (with newer, PoE enabled units). |
| [ 问题 74 ] |
中跨馈电支持什么样的网络? 端跨馈电技术呢?
|
| [ 答案 74 ] |
The Midspan PSE is located between the network switch/hub and the PoE Terminal(PD). The advantage of the standalone Midspan PSE is the simple extension of the existing network infrastructure. The Endpoint PSE equipment is integrated in the network switch/hub.
|
| [ 问题 75 ] |
34670 是否可以支持 IEEE802.3AF PLUS? |
| [ 答案 75 ] |
No |
| [ 问题 76 ] |
飞思卡尔有 PSE 的解决方案吗？
|
| [ 答案 76 ] |
For PSE, currently we do not for our general product offering. |
| [ 问题 77 ] |
I am using the 34670 Evaluation Board that is currently available, the it is fixed to 5V i want to have it to 3.3V is this possible? Where can i find this information?
|
| [ 答案 77 ] |
It is possible, yet it cannot be done by simply changing the resistor divider, since the transformer turn ratio primarily sets the output voltage.
change the following components on the EVB to generate 3.3V:
T1: POE13P_33B (Coilcraft)
C10: 47nF
R10: 470Ohm
R13: 1.5k
R9: 120Ohm
C9: 4.7nF
|
| [ 问题 78 ] |
PSE 可提供 15.4W 的功率, 而 PD 只能接受 12.95W, 是否意味 POE 的效率一般只有 80% 左右?
|
| [ 答案 78 ] |
The 2.4W power difference is the margin for the cable power loss not the efficiency of the PD.
|
| [ 问题 79 ] |
贵公司有 PSE 端的芯片吗? 是什么型号? |
| [ 答案 79 ] |
For PSE, currently we do not for our general product offering. |
| [ 问题 80 ] |
目前飞思卡尔的 POE 解决方案是什么样的？ 芯片量产了吗？ |
| [ 答案 80 ] |
We have MCZ34670 as our current PoE solution and is in mass production already.
|
| [ 问题 81 ] |
目前对于 POE 供电有没有超过 350mA 的国际标准？如500mA, 1A...
|
| [ 答案 81 ] |
At this moment the answer is no based on the current IEEE802.3af specification. However, the upcoming new IEEE802.3at standard is expected to supply 30W power which in turn should be able to support higher current.
|
| [ 问题 82 ] |
请问可以支持 CISCO 的 POE 标准么?
|
| [ 答案 82 ] |
Yes
|
| [ 问题 83 ] |
请问哪里有卖?
|
| [ 答案 83 ] |
Please contact Freescale local sales office or our web site for detials http://www.freescale.com.cn/products/powermanagement/mc34670.asp
|
| [ 问题 84 ] |
确切的讲在 POE 中，PSE 要比 PD 实现的难度大，现在市场上 PD 的集成实现方案比较多，贵公司也提出了自己的方案，但 PSE 的实现方案倒相对比较少？请问贵公司对 PSE 的集成解决方案有什么规划？
|
| [ 答案 84 ] |
For PSE, currently we do not for our general product offering.
|
| [ 问题 85 ] |
一般以太网供电, 其用电设备电流应该控制在多大的范围内合适?
|
| [ 答案 85 ] |
PD power is limited to 12.95W according to IEEE802.3af.
|
| [ 问题 86 ] |
以太网在线供电是如何工作? 一般来说, 有几种工作方式?
|
| [ 答案 86 ] |
You can go through our presentation again and check IEEE802.3af for details.
|