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IDProjectCategoryView StatusLast Update
0000500T99X171.00 SKB EagleHWpublic2019-04-22 10:03
Reporter(SW) Jacky Chiang Assigned To(HW) Sean Chiang Due Date
PrioritynormalSeveritys2-severeReproducibilityhave not tried
Status closedResolutionfixed 
Summary0000500: Eagle B'd can run without power adaptor. It just connected console Board or HDMI or USB.
DescriptionEagle B'd can run without power adaptor.
It just connected console Board or HDMI or USB.
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Users monitoring this issue

User List (ALTech) Philip , (ALTech) SB Park , (HW) Jim Liang , (HW) Sean Chiang , (RD) Fu-chiang Young

Activities

(ALTech) SY Yoon

2019-02-27 00:24

developer   ~0001214

We connected USB cable from PC to Eagle to upgrade SW.
Before connect USB cable, we pull out the adaptor plug and wait for more than 2 min.
And connect USB cable from PC to Eagle. Then Eagle boot and show live channel.
Sean said that Eagle cannot boot with USB/UART/HDMI power. But USB can boot Eagle without Power adapter.
I think it should be prepared any isolation.

(HW) Sean Chiang

2019-03-04 21:00

developer   ~0001305

Hi Mr. Yoon,
We have verified a couple of pieces of boards in our side but we can't duplicate the same symptom as you mentioned above. Can you confirm the boards in your hand can boot only from USB cable (USB connect from PC to Eagle)?

(ALTech) SY Yoon

2019-03-05 09:16

developer   ~0001312

Hi Mr. Sean Chiang,

Mr. Kerwin Chen also saw it when he stay in Korea last week. As you know, we use USB cable for SW upgrade by AML tool, "USB_burning_tool".
We just connect that cable. But Eagle boot and show the AV without any trouble.
I use LG notebook 13ZD970.

Today, I tested 2 times. First it doesn't work after plug out Adaptor and plug in USB port. But 2nd time it works.
I'm not sure. Our test sequence is as follows :
1. Boot normal and wait when we can watch Live channel.
2. Plug out Adaptor
3. Wait for more than 2 min.
4. Plug in USB Port that is connected with PC.

I tried again with above sequence. Eagle boot normally.
I'm not the difference between first trial and 2nd/3rd trials.
Could you check with our sequence ? I checked another STB with that sequence. It works well.

(ALTech) SB Park

2019-03-05 10:10

developer   ~0001314

Hi Sean
I add my comment

1. U902 is power switch of USB? pin1 is 5v in and pin6 is 5v out? (I cannot see your schematic, and I just guess)
2. when eagle board turn on at Only USB and No adapter, the U902 is also turn no. and the USB voltage can supply to eagel through U902
    when eagle board does not turn on at Only USB and No adapter, the U902 also does not turn no. and the USB voltage can Not supply to eagel through U902
3. when eagle board turn on at Only USB, No adapter, the USB voltage is not 5V
    I measured it about 4.7~4.8V (the voltage is changabe by Ext USB source)
    I think it is abnormal state

(HW) Sean Chiang

2019-04-04 14:02

developer   ~0001878

Hi SB,
Here are my comment for the load switch design of USB and HDMI interface in our eagle board.
1. The load switch we used in Eagle board has a enable pin which used to turn on/off the load switch by external signal. And the current design to turn on the load switch is to add a pull-high resistor and connected directly to enable pin and DC_5V which means that when we plug in the 5V adapter to system and the load switch will be turned-on simultaneously.
2. Based on this concept, we can confirmed that if user do not plug in 5V adapter to the product, the load switch can not be turned on through external 5V supply from USB or HDMI port.
3. Also, based on this design concept, as you know that if user plug in 5V adapter first and then plug external 5V supply from USB or HDMI. When user plug out the 5V adapter suddenly, since the time period is too short and the load switch would not able to be turned-off in such short period, the system may still actives which be supplied through the external USB or HDMI 5V. But as I mentioned to Mr. Philip and you, this is not a normal use case and we didn't received this kindly of complaint from user or existing worldwide Customers.
4. Finally, we also aware that if user plug in the external 5V from USB or HDMI when DC adapter is not plug in system. The load switch might have the risk if there is no reserve voltage/ current protection in load switch. So, we already consider this condition in our design and already use the load switch which has reverse current/voltage protection in it.

Please let me know if you have any questions for this issue.

Issue History

Date Modified Username Field Change
2019-02-22 11:32 (SW) Jacky Chiang New Issue
2019-02-27 00:20 (ALTech) SY Yoon Issue Monitored: (ALTech) SB Park
2019-02-27 00:24 (ALTech) SY Yoon Note Added: 0001214
2019-03-01 14:47 (ALTech) SY Yoon Assigned To => (HW) Sean Chiang
2019-03-01 14:47 (ALTech) SY Yoon Status new => assigned
2019-03-01 14:47 (ALTech) SY Yoon Issue Monitored: (ALTech) Philip
2019-03-04 18:17 (HW) Sean Chiang Issue Monitored: (HW) Jim Liang
2019-03-04 18:17 (HW) Sean Chiang Issue Monitored: (HW) Sean Chiang
2019-03-04 18:17 (HW) Sean Chiang Issue Monitored: (RD) Fu-chiang Young
2019-03-04 21:00 (HW) Sean Chiang Note Added: 0001305
2019-03-05 09:16 (ALTech) SY Yoon Note Added: 0001312
2019-03-05 10:10 (ALTech) SB Park Note Added: 0001314
2019-04-04 14:02 (HW) Sean Chiang Note Added: 0001878
2019-04-22 10:03 (ALTech) SB Park Status assigned => closed
2019-04-22 10:03 (ALTech) SB Park Resolution open => fixed