: You should find a reading between 3.7V and 5V . Any value above 0V proves the USB controller IC detected the cable and is actively trying to turn on the primary charging path. If it reads a flat 0V, the IC is dead or lacks its baseline power supply rails. Diagnostic Measurement Expected Value Interpretation Action Required RVP Resistor (Pad 1) Upstream USB power is functional. Proceed to check downstream. RVP Resistor (Pad 2) Resistor is intact and passing voltage. Check validation signals. RVP Resistor (Pad 2) 0V (Pad 1 is 5V) Open/Blown Resistor or downstream short. Replace 10-Ohm Resistor / Clear Short. Power Gate Enable Pin 3.7V - 5.0V USB IC is operational and validating cable. Trace faults closer to the main PMIC. 5. Professional Repair Tips
: Variable (indicating the voltage fluctuates depending on the connected charger or negotiate state).
While it is a technical label typically used in schematics and board repair, pp-var-usb-rvp
: Once the USB controller senses the steady 5V coming from PP_VAR_USB_RVP , it asserts a validation signal ( PWR_GATE_EN_VBUS_1_VALID ). This flips open the main charging gate, allowing current to flow into the primary charging IC (such as the Tigris or Rubicon chips) to safely charge the battery. Diagnostics & Common Point of Failures
When you find a string like this in a project: : You should find a reading between 3
The inclusion of RVP indicates that the device is designed with safety in mind. Reverse voltage can damage electronic components, and the RVP feature helps protect against such risks, ensuring the longevity and reliability of the device.
The power rail (often fully designated as PP_VAR_USB_RVP_TIGRIS_R ) is a critical voltage line responsible for USB cable validation and reverse voltage protection in modern Apple devices. When an iPhone or iPad refuses to charge despite a pristine lightning port or USB-C assembly, component-level microsoldering technicians look directly at this circuit to isolate the fault. Check validation signals
: Raw voltage enters via the charging port flex cable onto the main board as PP_VBUS_USB .
Upstream failure. Power is not entering from the charging port or the Hydra/Tigris IC is not initiating. Check flex cable, charging port, or main VBUS. 2. Verify USB IC Activation Status
: Commonly stands for Power Profile or Peripheral Protocol .