Where is the power controller in Xiaomi? Mi5: diagram, photo and diagnosis

Xiaomi Mi5 — The legendary smartphone, Released in 2016, is still in use by many users, but as you get older, even the most reliable technology starts to malfunction, and one of the most common problems is power failure. Mi5 suddenly stopped charging, turned off at low charge or does not respond at all to the charger, the culprit may be the power controller (PMIC — Power Management Integrated Circuit).

In this article, we will not only show you where the power controller in Xiaomi is located. Mi5, But we'll also figure out how to check it out, what symptoms indicate a breakdown, and what to do if it's out of order, and you'll get a step-by-step instruction with board pictures, circuits, and tips from the repairmen. And if you plan to repair the device yourself - pay attention to the critical nuances of soldering chips in the Mi5, Who often ignore newcomers.

What is a power controller and why it is needed in a smartphone

The power controller (or PMIC — Power Management IC) — It's the chip that controls all the power in the smartphone:

• 🔋 Battery charging (current and voltage control).
• ⚡ Power distribution between components (processor, screen, communication modules).
• 🔄 Switching power sources (from battery to charger and back).
• 🛡️ Protection against overheating, short circuit and overvoltage.

Xiaomi. Mi5 Qualcomm controller is used PMI8994 (family PMIC It's a highly integrated chip that combines multiple functions in a single chip. If it fails, the smartphone can:

• 🚫 Stop completely switching on (even on charging).
• 🔌 Charge extremely slowly or only when turned off.
• 💥 Turn off when connected to charging or when loaded.
• 🔥 Overheat in the lower part of the body.

It is important to understand that the symptoms of a malfunctioning PMIC This often coincides with battery or charging port problems, so other possible causes must be ruled out before you sin on the controller.

Where is the power controller in Xiaomi? Mi5: photograph

Xiaomi. Mi5 power-train PMI8994 It's located on the motherboard on the back side (the one you can't see when you remove the back cover:

• 📍 Next to the charging connector (USB Type-C).
• 🔍 Under a metal screen (must be removed to access).
• 🔧 Marking on the board: usually marked as U3001 or PMI8994.

Below is the layout scheme (reference point – charging connector at the bottom of the board):

For clarity, we will give a photo of the board Mi5 with the designation of the controller (clickable in enlarged form):

⚠️ Warning: If you have never soldered BGA-components, do not try to replace them PMIC This chip has ball-point conclusions (BGA), And it requires professional equipment to dismantle/install it (infrared soldering station, solder stencils, high-quality flux) and improper soldering will damage the board tracks or adjacent components.

Signs of failure of the power controller in Mi5

How to tell a breakdown PMIC from other nutritional problems? Here are the key symptoms:

• 🔌 The smartphone does not charge from either the original or third-party charger (including through Power Bank).
• 🔋 Charging is only in the off state, but stops when turned on.
• ⚡ Fast battery discharge (from 100% to 0% in 1-2 hours) even without active use.
• 💥 The smartphone turns off when connecting to a charger or when trying to turn it on on a charger.
• 🔥 Overheating in the lower part of the case (especially when connected to the network).
• 🛑 Cyclical reboot at low charge (e.g. 10-15%).

However, these same symptoms may indicate other malfunctions:

• 🔋 Battery wear (checked by replacement for known serviceable).
• 🔌 Breakdown of the charging port (oxidation of contacts, breakage of tracks).
• 🔧 Firmware problems (for example, after a failed update).
• ⚡ Short circuit on board (often after falling or getting moisture).

To accurately diagnose PMIC, You'll need a multimeter and voltage checks at key points on the board.

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If the smartphone does not turn on at all (even on charging), first check the battery and charging port.

How to check the power controller Xiaomi Mi5: step-by-step

For diagnosis. PMIC You'll need it:

• 🔧 Multimeter (preferably digital, with a mode of measuring constant voltage).
• 🔍 Loop or microscope (to inspect the charge for damage).
• 🔌 Correct charger (5V/2A or original from Xiaomi).
• 🔋 Charging cable with verified contacts (preferably a new one).

⚠️ Warning: All measurements are taken on the smartphone turned off! connect the charger only after connecting the multimeter probes to avoid short circuit.

Remove the back cover and battery|Check the fee for visible damage|Connect the charger to the smartphone|Set the multimeter to the constant voltage measurement mode (DCV, 20V)|Check voltage at key payment points-->

Step 1: Check the voltage on the battery

Connect the multimeter probes to the battery contacts (red plus, black minus).

• 🔋 3.7–4.2V — battery.
• 🔋 2.5–3.5V — It's discharged, but it can still charge.
• 🔋 Below. 2.5V — deep discharge, requires a "booster" to start charging.
• 🔋 0V — breakage inside the battery or controller failure.

Step 2: Check the voltage on the charging connector

Connect the charger and measure the voltage on the contacts USB Type-C:

• 🔌 5V ± 0.2V — standard (standard charger).
• 🔌 9V/12V — fast charging (if supported).
• 🔌 0V or jumping values - a problem in the charging port or cable.

Step 3: Checking the output chains PMIC

This will require a Xiaomi payment scheme Mi5. Key points for measurement (reference point – marking next to the PMIC):

• 📍 VCC_MAIN — The main meal of the fee (should be) 3.8–4.2V battery-operated).
• 📍 VCC_1V8 — Logic nutrition (should be) 1.8V).
• 📍 VCC_3V3 — The peripheral nutrition (should be) 3.3V).

If the voltage on these lines is absent or greatly underestimated, with high probability defective. PMIC severance.

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If you don’t have a payment scheme, you can find it in the service manuals for Xiaomi. Mi5 on the GSMArena forums or 4PDA. They are usually covered in topics related to repairs.

What to do if the power controller burned: repair or replacement

If the diagnosis confirmed the malfunction PMI8994, You have two options:

1. 🔧 Replacement of the power controller (requires professional equipment).
2. 💻 Replacement of the entire motherboard (expensive but reliable).

Let us consider both options in more detail.

Option 1: Replacement PMIC (only for experienced craftsmen!)

For replacement PMI8994 need:

• 🔥 Infrared soldering station (e.g. Quicko) T12 Lukey. 858D).
• 🔍 Microscope (magnification) ×10–×20).
• 🧲 Stencil for BGA (flat-sweeten).
• 🔧 High quality flux (e.g. Amtech) NC-559).
• 🔋 New PMIC (You can order on AliExpress or in specialized stores).

Replacement process:

1. Remove the metal screen from PMIC (carefully so as not to damage the neighbouring components).
2. Heat the board to the melting point of the solder (~220–240°C) and remove the old chip.
3. Clear the contact area from solder residues (use the brazing and flux).
4. Apply a new solder through the stencil and install a new one PMIC.
5. Check the absence of short circuits with a multimeter before turning on.

⚠️ Even experienced masters do not always take up replacement PMIC Xiaomi Mi5, Because the board of this smartphone is multilayered, and when you overheat, you can peel off the internal tracks.

Option 2: Replacement of motherboard

If a replacement PMIC too risky or impractical (for example, the fee already has other damage), you can consider the option of buying a used or a new motherboard:

• 💰 B/y fee - from 1500 to 3000 rubles (depending on the condition).
• 💰 New fee - from 5000 rubles (rarely found on sale).

When buying a used fee, pay attention to:

• 🔍 Condition of connectors (especially charging and antenna).
• 🔋 Level of wear of contacts (oxidation, blackening).
• 📱 IMEI (lock-in IMEI better not).

After the replacement fee will require a transfer IMEI (if it is tied to the old board) and configure the smartphone from scratch.

Frequent reasons for failure of the power controller in Mi5

PMIC Xiaomi Mi5 It doesn't just fail, but here's the main reason:

• ⚡ Use of low-quality chargers (especially with higher output voltage) 5V).
• 🔥 Overheating of a smartphone (for example, during long games or charging under the sun).
• 💧 Moisture infestation (even if the smartphone worked after that, corrosion could damage the tracks).
• 🔌 Short circuit in the charging port (for example, after a fall or sloppy soldering).
• 🔋 Deep battery discharge (if the smartphone has been lying discharged for a long time, PMIC could have gone out).
• ⚡ Power surges in the network (for example, when charging from an unstable source).

⚠️ Attention: One of the most common causes of death PMIC into Mi5 — Use of cheap Power Bank with higher output voltage 5.2V. Many Chinese external batteries are available to 5.5V, Over time, the power controller will be destroyed.

To extend life PMIC, follow simple rules:

• 🔌 Use only original or certified chargers.
• 🔋 Do not allow a deep discharge of the battery (charge at 10-15%).
• 🔥 Avoid overheating (do not play heavy games while charging).
• 💧 Do not leave your smartphone in wet rooms (bathroom, kitchen).

Alternative ways to resuscitate the smartphone, if PMIC burnt-out

If a replacement PMIC If you don't have a board, or you don't have a board, because it's expensive, you can try workarounds, and they won't restore full functionality, but they will allow you to use your smartphone temporarily.

Method 1: Nutrition through USB-OTG (power-user)

If PMIC burned, but the fee is otherwise good, you can feed power directly to the battery through USB-OTG adapter:

1. Take the smartphone apart and disconnect the battery.
2. Connect to the battery contacts a stabilized 3.7 power source–4.2V (For example, from a laboratory power supply unit).
3. Connect your smartphone to your PC through USB And try to turn it on.

⚠️ Attention: This method is extremely dangerous! If you don't connect properly, you can burn the board or cause a fire. Use it only if you understand what you're doing.

Method 2: Using wireless charging (if supported)

Xiaomi Mi5 It does not have built-in wireless charging, but you can install an external Qi receiver (for example, from Nokia). DT-900). For that:

1. Stick the Qi receiver to the back cover (over the battery).
2. Sell his contacts to + and--the battery.
3. Place your smartphone on a wireless charging station.

This method won't restore PMIC, But it will allow you to charge the smartphone without connecting to USB-port.

Method 3: Flashing (if the problem is a software failure)

Sometimes the symptoms of a burnt-out" PMIC It could be caused by a firmware failure:

1. Install the smartphone in Fastboot mode (clamp Volume down) + Nutrition).
2. Connect to the PC and flash through the Mi Flash Tool official firmware.
3. If your smartphone doesn’t respond, try flashing through EDL-Mode (requires an authorized Xiaomi account).

If after flashing the problem remained - it is definitely in the iron.

FAQ: Frequent questions about Xiaomi’s power controller Mi5