https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945999#M3733 <P>1：Allan能帮忙分析这个问题就可以了，我还是想知道客户是通过哪种方法下电的？</P> <P>2：我想知道客户的10块板子用的料都是一模一样的吗？ FS26有很多个part number</P> <P>3：客户有没有做过交叉测试就是用好板子上的fs26换到坏板子上情况有所改善吗？能排除是PCB焊接的问题吗？这个可能需要很久的时间做这些测试</P> <P>&nbsp;</P> Tue, 03 Sep 2024 07:26:32 GMT guoweisun 2024-09-03T07:26:32Z https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945743#M3725 <P>Hi NXP support team:</P><P>Recently we encountered a tricky problem that when we removed the wakeup source for&nbsp; FS26 it cannot power off occasionally. We found the VBOS voltage was quite weird. Compared to the normal situation VBOS voltage jumpped to about 5V and quickly went down. I post the capture of&nbsp; measurement for these signals from logistic analyzer. Please refer to this and help us analyze this problem. In the below picture FS0B_VBOS is the voltage of VBOS&nbsp; there is a&nbsp; wave after FS26 enter into LPOFF status than all the other voltage that supplied by FS26 go wrong and FS26 cannot control the system power on again. I want to know the reason why VBOS act like this ?</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="tianxing_0-1725326767772.png" style="width: 587px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/296697iFD1220E24FF77BFE/image-dimensions/587x394?v=v2" width="587" height="394" role="button" title="tianxing_0-1725326767772.png" alt="tianxing_0-1725326767772.png" /></span></P><P>Below picture is the wave that FS26 powered down in a right sequence. All the voltages were normal ,VBOS voltage didn't jump and the system went power down smoothly.</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="tianxing_1-1725327035064.png" style="width: 568px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/296701i3B45B6FE350725C5/image-dimensions/568x465?v=v2" width="568" height="465" role="button" title="tianxing_1-1725327035064.png" alt="tianxing_1-1725327035064.png" /></span></P><P>&nbsp;</P><P>&nbsp;</P><P>&nbsp;&nbsp;</P> Tue, 03 Sep 2024 01:38:49 GMT https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945743#M3725 tianxing 2024-09-03T01:38:49Z https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945870#M3726 <P>HI</P> <P>没太看懂您写的英文，能都用中文描述下问题多谢！</P> Tue, 03 Sep 2024 04:05:34 GMT https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945870#M3726 guoweisun 2024-09-03T04:05:34Z https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945910#M3727 <P>FS26 下电异常时发现VBOS 的电压有波动，会下调到一个比较低的幅值然后再上调。 但正常下电时没有这样的波动，我们想知道VBOS发生这种异常的原因，请您帮忙看看，谢谢 下图是正常下电时的状态，FS0B_VBOS是逻辑分析仪测量的VBOS电压状态，此时VBOS从4.99下降到4.6V左右然后一致保持这个电压，系统顺利下电了。</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="tianxing_0-1725342540245.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/296741i1FE2B2FE8FA92E64/image-size/medium?v=v2&amp;px=400" role="button" title="tianxing_0-1725342540245.png" alt="tianxing_0-1725342540245.png" /></span></P><P>下图是<SPAN>&nbsp;</SPAN>异常下电时的波形，可以看到红色框里面的VBOS电压下调到4.38V左右然后又上调到5.18V然后再下降到4.99V此时系统不能正常下电，在所有这些现象出现时，</P><P>&nbsp;</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="tianxing_1-1725342602776.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/296742i12AE8D5B8B4FA870/image-size/medium?v=v2&amp;px=400" role="button" title="tianxing_1-1725342602776.png" alt="tianxing_1-1725342602776.png" /></span></P><P>VBOS是最先出现异常的，不知道是什么原因导致的。</P><P>&nbsp;</P><P>&nbsp;</P><P>&nbsp;</P><P>&nbsp;</P> Tue, 03 Sep 2024 05:51:18 GMT https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945910#M3727 tianxing 2024-09-03T05:51:18Z https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945925#M3728 <P>1：客户是哪种用发VBOST&nbsp;&nbsp; ---&gt; back-end regulator OR Front-end regulator?</P> Tue, 03 Sep 2024 06:18:00 GMT https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945925#M3728 guoweisun 2024-09-03T06:18:00Z https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945948#M3730 <P>您好，我们是<SPAN>back-end regulator&nbsp;</SPAN></P> Tue, 03 Sep 2024 06:43:34 GMT https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945948#M3730 tianxing 2024-09-03T06:43:34Z https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945968#M3731 <P>1:客户下电是通过哪种途径实现的？</P> <P>2：客户有没有实际测试过VBOS的电压在示波器上</P> <P>3：正常下电跟非正常下电，客户有做了哪些不同的操作？还是说这个不正常下电是偶然发生的并无规律可言</P> Tue, 03 Sep 2024 06:58:54 GMT https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945968#M3731 guoweisun 2024-09-03T06:58:54Z https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945993#M3732 测试过VBOS的电压，正常下电和非正常下电是同一个操作。<BR />不正常下电是偶然发生，10块板子现象都不一样，有些比较严重每次都不正常，有些就需要10次左右出来一次，目前天津这边的安工也在帮忙分析这个问题 Tue, 03 Sep 2024 07:19:34 GMT https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945993#M3732 tianxing 2024-09-03T07:19:34Z https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945999#M3733 <P>1：Allan能帮忙分析这个问题就可以了，我还是想知道客户是通过哪种方法下电的？</P> <P>2：我想知道客户的10块板子用的料都是一模一样的吗？ FS26有很多个part number</P> <P>3：客户有没有做过交叉测试就是用好板子上的fs26换到坏板子上情况有所改善吗？能排除是PCB焊接的问题吗？这个可能需要很久的时间做这些测试</P> <P>&nbsp;</P> Tue, 03 Sep 2024 07:26:32 GMT https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1945999#M3733 guoweisun 2024-09-03T07:26:32Z https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1946009#M3734 <P>1.是通过移除唤醒源下电的 wake1 脚的唤醒源被拿掉后 触发FS26执行下电，这时VSUP是一直在的</P><P>2.10块板子用料是一样的而且是同批生产</P><P>3.没有做过这样的交换</P><P>目前有一块现象严重的板子（每次下电都发生异常），我们去掉了 VCORE和VPRE 后端的负载（两个电容）下电异常的现象就不出现了，我们想知道为什么这样修改异常现象就消失了，还想知道这样修改是否可行，能否彻底解决这个问题？</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="tianxing_0-1725348724770.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/296763i8C9E5F0CC48D9C56/image-size/medium?v=v2&amp;px=400" role="button" title="tianxing_0-1725348724770.png" alt="tianxing_0-1725348724770.png" /></span></P><P>修改电路后的下电时序图</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="tianxing_1-1725348786358.png" style="width: 400px;"><img src="https://community.nxp.com/t5/image/serverpage/image-id/296764i503D53E2BAAF94C9/image-size/medium?v=v2&amp;px=400" role="button" title="tianxing_1-1725348786358.png" alt="tianxing_1-1725348786358.png" /></span></P><P>&nbsp;</P><P>&nbsp;</P> Tue, 03 Sep 2024 07:34:26 GMT https://community.nxp.com/t5/Power-Management/FS26-VBOS-voltage-abnormal/m-p/1946009#M3734 tianxing 2024-09-03T07:34:26Z