VCore Rail on Turing GPUs Explained

VCore Rail on Turing GPUs Explained
Type	Circuit
Device(s)	RTX 2060, RTX 2070, RTX 2080, RTX 2080Ti
Difficulty	◉◉◌◌ Medium

Everything you need to know about VCore on Turing GPUs from a repair perspective.

The Controller Circuit

Most of the time, high end Turing cards (2070-2080Ti) use UP9512P or the MP2886a 8-phase buck controllers (full datasheet is unavailable publicly).

Some low end cards (such as the 2060) use a different variant of the UP9512, the UP9512s (also has no public datasheet) shown in figure 3.

Vcore controller (UP9512P) location on a reference RTX 2080 (Figure 1).

Schematic view of the Vcore circuit (UP9512P) (Figure 2).

Schematic view of the Vcore circuit (UP9512s) (Figure 3).

Vcore enable signal schematic view (Figure 4).

Markings on the schematic and board could differ from GPU model to another but the circuit is almost always the same.

V_CC is provided to the controller by 5V Rail on Turing GPUs through a 2 ohm resistor on pin 12 for the P and MP2886a variants and pin 10 on the S variant.

P_GOOD signal from the controller then goes to enable PEX and VMem.

Usage

VCore, as the name suggests, powers on the core. It is the most powerful and most power hungry rail on the card.

The controller generates PWM signals regulating the voltage going to the core depending on the load.

Common Problems

No VCore Voltage

In this case, check if the controller has 5V or 3.3V on its V_CC, and 3V on EN. If one of them is missing trace their respective circuits and check for broken, knocked off, or defective components

If both are present but no output, measure the V_ref pin. It should be 2V if not, the controller is faulty.

No P_GOOD Signal

If the controller isn't outputting P_GOOD but VCore is present then it's highly likely the controller itself is faulty.

Short on VCore

By design, VCore has low resistance to GND (less than 1 Ω), so using a low-end multimeter won't be able to measure it accurately. Often times, the short happens on one of the VRMs. How to find them is explained here Base Voltage Rail Short on Turing GPUs.