From 0c4987cd210bb629ddd4fdd80934298208c09b0e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?King=20K=C3=A9vin?= Date: Mon, 14 Nov 2022 23:40:17 +0100 Subject: [PATCH] doc: overall improvement --- README.md | 43 +++++++++++++++++++++++-------------------- 1 file changed, 23 insertions(+), 20 deletions(-) diff --git a/README.md b/README.md index ebf80a5..7d38fe2 100644 --- a/README.md +++ b/README.md @@ -1,4 +1,4 @@ -the PD blocker removes Power Delivery (PD) capabilities from USB-C connections +The PD blocker removes Power Delivery (PD) capabilities from USB-C connections and provides over-voltage protection. @@ -6,41 +6,44 @@ the PD blocker removes Power Delivery (PD) capabilities from USB-C connections purpose ======= -some USB-C devices do not require the Power Delivery features available on the connector, mainly higher voltage and current. -the device might not even be rated for higher voltages. -mischievous eMarked cables (with PD-capable chips built in) or chargers might raise the voltage without the device requesting it. -the higher voltage could then damage the device. +Some USB-C devices do not require the Power Delivery features available on USB-C, mainly higher voltage and current. +The device could not even be rated for higher voltages. +But chargers might be stuck at higher voltage, or mischievous eMarked cables (with PD-capable chips built in) could raise the voltage, permanently damaging it. -the PD blocker protects your [expensive] USB-C device from such damages. +The PD blocker protects your [expensive] USB-C device from such damages. usage ===== -insert the PD blocker in line, between the power source (e.g. charger or host computer), cable, and your device. -it can be inserted between any two of these components, and will work the same. -plug and receptacle can be either side, and it is reversible along the axis of the connectors (like normal USB-C connectors). +Insert the PD blocker in line, between the power source (e.g. charger or host computer), cable, and your device. +It can be inserted between any two of these components, and will work the same. +Plug and receptacle can be either side, and it is reversible along the axis of the connectors (like normal USB-C connectors). -PD communication is completely block. -when over-voltage is detected (Vbus > 5.5V), power is cut and an OVP LED indicating the culprit side lights up. +The PD blocker will prevent any Power Delivery communication, such as raising the voltage. +And when over-voltage is detected (Vbus > 5.5V), power is cut and an OVP LED indicating the culprit side lights up. +Connect the PD blocker before the target device for the protection to take effect before it can reach it. -all other features of USB-C are preserved (e.g. USB2, USB3, USB4, SBU, orientation detection) -some alternate modes requiring PD communication will not work anymore though. +All other features of USB-C are preserved (e.g. USB2, USB3, USB4, SBU, orientation detection) +Some alternate modes requiring PD communication will not work anymore though. mode of operation ================= -to prevent PD communication, capacitors are placed on the CC lines. -they smooth out the 300 Kbps BMC signal used for PD communication. -it still allows the identification of Rp, Rd, and Ra used for orientation and role detection. +To prevent PD communication, capacitors are placed on the CC lines. +They smooth out the 300 Kbps BMC signal used for PD communication. +It still allows the identification of Rp, Rd, and Ra used for orientation and role detection. -additionally there is an over-voltage protection circuit. +Additionally there is an over-voltage protection circuit. VBUS (on either side) is compared to a reference voltage. -when VBUS is below 5.5V, p-channel MOSFETs are switched on, and allow VBUS going from one side to the other. -when VBUS is above 5.5V, the p-channel MOSFETs are switched off, and prevent VBUS interconnection, cutting the power. +When VBUS is below 5.5V, p-channel MOSFETs are switched on, and allow VBUS going from one side to the other. +When VBUS is above 5.5V, the p-channel MOSFETs are switched off, and prevent VBUS interconnection, cutting the power. warning ======= -the PD blocker can block up to 36V. +The PD blocker can block up to 36V. PD rev 2.0 specifies voltages up to 20V. PD rev 3.0 specifies voltages up to 48V, but I haven't seen any power source using this new capability yet. + +The PD blocker can take a seconds (at 5.6V) until the over-voltage protection take effect. +Connect the PD blocker before the target device for the protection to take effect before it can reach it.