I have found this thead in a TI forum. They explain the purpose of both capacitors C_GS and C_GD.
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C_GD is the capacitance between the gate and drain. This capacitance and the combined total gate capacitance (C_G) must be fully charged for the MOSFET to switch on.
The significance of this is that the charge pump on ACDRV has a limit of 60 uA. By keeping the gate capacitance or gate charge low, you can reduce your turn on time.
"
[URL]https://e2e.ti.com/support/power-management-group/power-management/f/power-management-forum/945449/bq24171-acfet-and-rbfet[/URL]...
DavidRM
Member
Last Activity: 12-13-2024, 04:55 PM
Joined: 09-15-2024
Location: Madrid
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MOSFETs have been replaced but ACDREV does not have proper voltage. VCC and ACDET are OK.
To summarize the overall problem, there is not current in PQ21's gate.
Which is the purpose of PC180 and PC181?...Leave a comment:
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Yes, I will recieve MOSFETs on Wednesday. I know that we have to solve charging issues first.
However I want to know if I can check that PCH and EC are not damaged....Leave a comment:
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Is there a way to check if that ec chip (it is the ITE8987E) is damaged?
How can I check if PCH has been damaged?...Leave a comment:
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Thanks it was a check to see it was worth to continue or not.
The reason is that I have placed a MOSFET whose source and drain were shorted in PQ21. Since I was working fine before and I thought that there was no problem. But I have read that there is the risk of feeding the CPU with 19V, burning it.
Apart of that, with that defective MOSFET in PQ21 and a good MOSFET in PQ22 my laptop was able to power on.
However now it does not. Since the topic is related with a laptop that can work like a desktop but it does not charge the battery (or the case in which...Leave a comment:
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Also i have checked that +VCC_CORE is shorted to GND, it is means that the CPU is dead? Resistance is 4.5 ohmLeave a comment:
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I have replaced DCin MOSFETs with the initial ones (one with source and drain sorted and the other seems ok). Then REGN value is 6.8, ACDRV is 19.8. Also PQ23 has been replaced with a bad mosfet. I think that I am going to buy new ones to repeat all the measures properly.Leave a comment:
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I use different probes with resisiance of 0.5 ohms
ACN 3 drops to 0
ACP 3 drops to 0
CMSRC 0.02
ACDRV 0
ACOK 0
ACDET 2,6
IADP 0
IDCHG 0
PMON 0
PROCHOT 0
SDA 0
SCL 0
CMPIN 0
CMPOUT 0
BATPRES 0
TB_STAT 0
BATSRC 0
BATDRV 0
SRN 0
SRP 0
ILIM 0
GND 0
LODRV 0
REGN 2 drops to 0
BOOT 0
HIDRV 0
PHASE 0
VCC 19.6...Leave a comment:
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I have replaced IC charger, there were some shorts
I have repeated all the measurements:
PR198 removed and voltage remains 0
ACN ACP 0.5 ohm
ACN GND 1M ohm (changes depending on the scale)
PQ21
D: 19,95 V 75kohm to gnd
S: 0 V 2.4 Mohm
G: 0 V very high
PQ22
D: 0 V 300 kohm
S: 0 V 2.4 Mohm
G: 0 V very highLeave a comment:
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ACN GND 12 Mohm
ACN ACP 1.3 Mohm
PQ21
source / drain 1.6M
source / gate 1.6M
gate / drain 1.4M
PQ22
[B]source / drain [/B]1.8M
[B]source / gate[/B] 1.6M
[B]gate / drain[/B] 1.4MACN GND 12 Mohm
ACN ACP 1.3 Mohm
PQ21
source / drain 1.6M
source / gate 1.6M
gate / drain 1.4M
PQ22
[B]source / drain [/B]1.8M
[B]source / gate[/B] 1.6M
[B]gate / drain[/B] 1.4MACN GND 12 Mohm
ACN ACP 1.3 Mohm
PQ21
source / drain 1.6M
source / gate 1.6MLeave a comment:
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Voltage in REGN is 6.6 V(you can see it in my first message).
Charger is correct I have another one from MSI which can be suitable in this case. Both have same polarity.
My board does not have Reverse Input Voltage Protection circuit.
I do not have any problem to remove that resistor but as my laptop does not have that protection that I mention I pretty sure that the problem has a different origin.
I can try but I have measure ACDRV-1 (before resistor and it is the same)
Thanks...Leave a comment:
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Hi all
I have followed this topic because I have the same problem.
Laptop can work without battery as desktop computer.
If I connect the battery and I plug the AC adapter, power supply overpower protections triggers and the voltage from the AC adapter drops from 19V to 0V.
I turn on my computer with the battery and If I plug AC adapter it is not detected, but it can be detected sometimes without any reason. When It was detected It worked properly
My board is DABKLGMB8D0 REV D
I have replaced PQ21 because source, drain and gate were...Leave a comment:
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Hi
I'm David. I have worked as engineer in different quantitative fields focused on the mathematical models, software and hardware. Apart of that I have different hobbies related with electronics that let me learn how to build and repair circuits. I have always tried to repair my own computers but now that I have more advanced equipment I want try to repair directly the components instead of replace them.
I have followed some threads very helpful.Leave a comment:
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