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README.md
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README.md
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these are the hardware design files for **insert project name here**.
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the PD blocker removes Power Delivery (PD) capabilities from USB-C connections
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purpose
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purpose
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=======
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some USB-C devices do not require the Power Delivery features available on the connector, mainly higher voltage and current.
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the device might not even be rated for higher voltages.
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mischievous eMarked cables (with PD-capable chips built in) or chargers might raise the voltage without the device requesting it.
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the higher voltage could then damage the device.
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the PD blocker protects your [expensive] USB-C device from such damages.
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usage
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usage
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=====
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insert the PD blocker in line between the power source (e.g. charger or host computer) and the cable connecting your device.
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this is the ideal position to also safeguard against mischievous eMarked cables, still being able to use them.
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else you can also insert the PD blocker between your device and the cable or power source.
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your device will still be protected against mischievous eMarked cables, but you won't be able to use them.
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all other features of USB-C are preserved (e.g. USB2, USB3, USB4, SBU, orientation detection)
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some alternate modes requiring PD communication will not work anymore though.
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mode of operation
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=================
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to prevent PD communication, capacitors are placed on the CC lines.
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they smooth out the 300 Kbps BMC signal used for PD communication.
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it still allows the identification of Rp, Rd, and Ra used for orientation and role detection.
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an additional circuit will cut the power when VBUS exceeds 5.5V (on either side of the PD blocker).
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warning
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=======
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the PD blocker can block up to 36V.
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PD rev 2.0 specifies voltages up to 20V.
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PD rev 3.0 specifies voltages up to 48V, but I haven't seen any power source using this new capability yet.
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