EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: i509VCB on August 27, 2024, 07:14:48 pm
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Hi I am working on a project which has dual role power. For the output path, I have the following:
[attach=1]
I believe this output path is fine. The input path I am less sure about. The VIN is provided by a diode ORing of a barrel jack, another USB-C port, this USB-C port or the USB 2.0 connection from the MCU (not related to power delivery, I disable power to the USB-C ports with only the MCU connected):
[attach=2]
Where my confusion comes in is that for a different PD controller, the TPS65988, it's EVM shows a load switch on both the sink and source paths. If I do not include the load switch on the input path, is there a potential issue with the diode ORing that could result in the buck converter trying to power itself?
[attach=3]
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I think you need to clarify if you actually need dual role, and why. And if you want to meet USB spec.
If you do, you'll use something like that TPS65988 (https://www.ti.com/lit/ds/symlink/tps65988.pdf), which will communicate over the CC lines, and switch voltages depending on what it sees.
https://www.reddit.com/r/AskElectronics/comments/1dv1mbk/usbc_dualrole/ (https://www.reddit.com/r/AskElectronics/comments/1dv1mbk/usbc_dualrole/)
https://www.ti.com/lit/ml/slyp807/slyp807.pdf (https://www.ti.com/lit/ml/slyp807/slyp807.pdf)
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I think you need to clarify if you actually need dual role, and why. And if you want to meet USB spec.
If you do, you'll use something like that TPS65988 (https://www.ti.com/lit/ds/symlink/tps65988.pdf), which will communicate over the CC lines, and switch voltages depending on what it sees.
https://www.reddit.com/r/AskElectronics/comments/1dv1mbk/usbc_dualrole/ (https://www.reddit.com/r/AskElectronics/comments/1dv1mbk/usbc_dualrole/)
https://www.ti.com/lit/ml/slyp807/slyp807.pdf (https://www.ti.com/lit/ml/slyp807/slyp807.pdf)
Dual role power yes. Dual role USB would be nice but I need to fight the N100 on the LattePanda Mu for that and probably for another day. I also don't necessarily need to comply with the standard on paper.
I have looked at the TPS65988 before. However I've decided against it because it effectively requires me to go 6 layers (TI suggests 8 layers). I chose to go with one of the bigger STM32G0B1 since I already need a microcontroller for something else, it's cheap enough and it has 2 USB-C PD phys. ST does have a middleware library for implementing the standard.
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If you want to use the STM32 then you can see the schematic of their EV boards:
https://www.st.com/en/ecosystems/x-nucleo-drp1m1.html (https://www.st.com/en/ecosystems/x-nucleo-drp1m1.html)
https://www.st.com/en/evaluation-tools/stm32g0c1e-ev.html?icmp=tt21847_gl_pron_jun2021 (https://www.st.com/en/evaluation-tools/stm32g0c1e-ev.html?icmp=tt21847_gl_pron_jun2021)
Where TCPP03 provides the same hardware switching functionality.
https://www.st.com/en/protections-and-emi-filters/tcpp03-m20.html (https://www.st.com/en/protections-and-emi-filters/tcpp03-m20.html)