[SOLVED] Host_client usb-header-load switching

Host_client usb header load switching

Hello everyone,

Kindly help me in the following circuit to understand the action,:thinker:

This is a header circuit to make a bridge between device and host.



This is a header circuit to make a bridge between device and host.
Lets say Magconn connector( https://www.hackster.io/OscarSeo/getting-started-with-magconn-6ecbd3 ) is Device-A and CN1 is Device-B.
When the 2 devices are connected, VBUS would be same on both side ( no matter VUSB is comming from device -B).
At this time ID signal from device-A will be floating in host mode. Not sure ID signal from CN1 will be floating or grounded!

Question arises in my mind,

1. CN1 connector is a micro usb male, which connect my device to the one side of header.
2. Transistor Q3 is responsible for turning ON the MOSFET Q1, that is been biased from +usb 5V. :bsdetector:
3. Not sure why extra 1-7 wire is connected afetr Q1, then U1 active high IC is powered by VBUS ?
4. Not sure how the M_SIG signal is used here, the magconn connector connect with just a magconn header with host. Kindly explain it in detail.
5. By the U3 IC, how the active load is acting ?(NO datasheet found)
6. If the host is not connected I think VBUS will be not available in P+ test point, right?
7. Do you think, D+,D-,ID signals can be show in scope, if both device are connected?

Help me please.

Re: Host_client usb header load switching

Hi,

2)
Q1 isnormally ON to supply the device with power.
Q3 is NOT responsible fir turning Q1 ON...instead it is responsible to turn Q1 OFF in case on input overvoltage.
--> It is an overvoltage protection circuit.

"Active high" is not a device name, it's just an explanation of the circuit SLG49M1448.
SLG49M1448 is a power switch with reverse current protection. ON/OFF is controlled by the SLG4R4918..
I don't know the function of SLG4R4918 ....contact silego.com for datasheets.

Klaus

Re: Host_client usb header load switching

KlausST said:

Hi,

2)
Q1 isnormally ON to supply the device with power.
Q3 is NOT responsible fir turning Q1 ON...instead it is responsible to turn Q1 OFF in case on input overvoltage.
--> It is an overvoltage protection circuit.

"Active high" is not a device name, it's just an explanation of the circuit SLG49M1448.
SLG49M1448 is a power switch with reverse current protection. ON/OFF is controlled by the SLG4R4918..
I don't know the function of SLG4R4918 ....contact silego.com for datasheets.

Klaus

Click to expand...

Thank you for your response.
Yes, I might be wrong. Q1 will be turned ON here.
Can you explain number 4 and 6 questions ?