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| TWS Earbuds XYT-T62C circuit board with IP5403 Power IC, L120 Charging IC, boost coil and important repair points. |
TWS Earbuds XYT-T62C Circuit Details and Repair Guide.
The XYT-T62C is a compact TWS earbuds charging and power-management board designed around a rechargeable lithium battery system, Bluetooth-based wireless operation, charging control, battery indication, and power conversion.
This article explains the available board specifications, important ICs, charging section, boost circuit, display section, and practical circuit repair methods. The goal is to make the board easier to understand for electronics technicians, students, and anyone troubleshooting a TWS charging case.
The board information discussed here is based on the identified component markings and the measurements supplied with the device. Some component functions, especially the unidentified 16-pin IC and the exact display-driving method, should be confirmed from the original schematic or datasheet before making a board-level modification.
TWS Earbuds Basic Specifications.
The main specifications provided for this TWS device are:
Bluetooth Version: V5.3
Charging Input: 5V
Input Current Rating: 1-3A
Charging Connector: Micro USB
Reported Standby Time: Up to 480 hours
Earbud Battery: 30mAh
Charging Case Battery: 1200mAh
Board Number: XYT-T62C
Seven-Segment Display: 1 unit, 6 pins
Identified IC Quantity: 3
Bluetooth Core Specification 5.3 introduced improvements aimed at reliability, energy efficiency, and user experience in supported implementations. The exact performance of an individual TWS product, however, depends on its Bluetooth chipset, firmware, antenna design, and implementation rather than the version number alone.
The 5V figure represents the USB charging input. It should not automatically be treated as the lithium battery's charging voltage. A typical single-cell lithium battery uses a charging termination voltage around 4.2V, while the charging circuit regulates the battery charging process.
How This TWS Circuit Works.
A TWS charging case is more than a simple battery holder. It combines several power and control functions into a very small PCB.
When a 5V supply is connected through the Micro USB port, the charging section receives the input and controls current going toward the rechargeable battery. The stored battery energy is then distributed to the earbuds through their charging contacts.
The board also contains a boost conversion section. This allows the lower battery voltage to be converted into a higher regulated output when the case provides an external USB power output or power-bank function.
The complete power path can be understood approximately as:
Micro USB 5V Input → Charging/Power Management → Case Battery → Boost Converter → 5V Output
At the same time, the case provides controlled power to the two earbuds through their charging contacts.
XYT-T62C PCB and Internal Circuit Structure.
The board number printed on the PCB is XYT-T62C. The board contains three identified integrated circuits in the supplied configuration, together with a six-pin seven-segment display, charging components, boost coil, LEDs, battery connections, USB connector, and supporting passive components.
The three important IC markings are:
IP5403 - 234400DA
16-pin IC - marking not identified
L120
The IP5403 is documented as an integrated mobile power-supply SoC with charging and discharging functions, including a boost section. Its published pin description includes battery, VIN, boost switching, 5V output, LED and control connections.
Power IC: IP5403 - 234400DA.
Main Function of the IP5403.
The IP5403 is one of the most important components in this board because it manages a major part of the power-management system.
The identified package uses 8 pins, and the available technical information describes the IP5403 as a highly integrated mobile power-supply SoC with approximately 1A charging and 1A discharging capability. It also includes a boost converter section for generating a higher output from the battery.
In practical TWS case circuitry, this type of IC can handle functions such as:
Battery charging management
Battery-powered output control
Boost conversion
LED indication
Power-path control
System power management
The exact circuit configuration depends on how the XYT-T62C PCB designer connected the IC.
Why the Power IC Is Important for Repair.
If the IP5403 section fails, several different symptoms may appear at the same time.
For example, the charging case may refuse to charge, the battery may not provide output power, the display may remain inactive, or the external 5V boost output may disappear.
Because the IC is connected to several parts of the power path, a technician should not replace it immediately after seeing a no-power symptom. Shorted capacitors, damaged coils, bad batteries, broken tracks, or connector faults can produce the same result.
16-Pin Analogue and Digital Conversion Section.
What Is Known About the 16-Pin IC.
The supplied board information identifies a 16-pin IC as an ADC or analogue-to-digital conversion device, but its exact part number is not available.
An ADC converts an analogue electrical quantity into digital information that another circuit can process. Battery voltage is a common quantity that may be measured in portable electronics.
However, the statement that this particular IC definitely converts charging voltage directly into the seven-segment display cannot be confirmed from the provided information alone.
The display may instead be controlled by another integrated section, a microcontroller, or a dedicated display-driver circuit depending on the actual board design.
Therefore, during repair, the safest approach is to trace the PCB connections rather than assuming the exact internal function of the 16-pin device.
Six-Pin Seven-Segment Display.
The board uses one seven-segment display with six pins.
Its purpose is likely to provide a visual indication related to battery or charging status. Depending on the firmware and circuit design, a TWS charging case can use a segment display to show battery percentage, charging information, or another power-related indication.
A display that remains completely off does not necessarily mean that the display itself is defective. The fault can come from the power supply, driver circuit, PCB track, control IC, or a missing ground connection.
When troubleshooting, first confirm that the display receives the required supply and ground connections before replacing it.
L120 Charging IC and Charging Section.
Role of the L120 IC.
The supplied circuit information identifies L120 as the charging IC.
Its reported function is to control the charging path from the Micro USB input toward the battery system and provide charging-status indication through an LED.
The supplied measurements show:
Reported charging-related voltage: 4.2-5V
Reported charging current/load: 0.35A
Measured load voltage: 4.77V
Reported charging time: 30-40 minutes
Charging indicator: Green LED
One important distinction is necessary here: 4.77V is an input/load-side measurement and should not automatically be considered the lithium battery terminal charging voltage. A single-cell Li-ion or Li-Po battery normally requires a controlled charge profile with a final battery voltage around 4.2V.
The actual battery terminal voltage should therefore be measured directly across the battery and compared with the charging behaviour of the particular circuit.
Understanding the 30-40 Minute Charging Figure.
The supplied script states a 30-40 minute charging time. That figure should be treated as a board-specific observed or quoted value rather than a universal charging time for the complete 1200mAh case battery.
For example, charging a 1200mAh battery from empty at only 0.35A would theoretically require several hours even before accounting for charging losses and the constant-voltage phase.
Therefore, the 30-40 minute value may refer to a particular operating condition, the earbuds themselves, or a partial charging interval. It should not be used as a guaranteed full-charge time for every XYT-T62C board.
Charging and Boost Coil Section.
The charging and boost section is one of the most important areas of the PCB.
The external 5V USB input enters the power-management circuitry, while the stored battery energy can later be converted back to a regulated higher voltage through the boost converter.
A boost coil, also called an inductor, works together with the switching converter. The switching IC rapidly controls current through the coil and uses the stored magnetic energy to generate a higher output voltage.
This is especially useful when the TWS charging case also provides a power-bank style output.
How the Boost Circuit Produces 5V.
A single lithium battery operates at a much lower voltage than 5V. The boost converter therefore increases the battery voltage to produce a suitable regulated output.
In simple terms:
Battery Voltage → Boost Coil and Switching Circuit → Higher DC Output
The IP5403 is documented as having a boost function and 5V output-related circuitry, which makes it suitable for power-bank style designs.
A damaged boost coil, shorted output capacitor, failed switching IC, or broken PCB track can prevent the 5V output from appearing.
TWS Earbuds Charging Contacts.
The charging case transfers electrical power to the left and right earbuds through metal charging contacts.
Each earbud contains its own small rechargeable battery and internal charging/control circuitry. The case therefore has to provide a stable charging supply while maintaining safe contact with both earbuds.
Dirty or oxidised charging pins can create a misleading circuit fault. If one earbud does not charge while the other works correctly, the first checks should include the spring contacts, earbud contact pads, physical alignment, and the corresponding PCB tracks.
TWS Circuit Repair Guide.
Problem: TWS Case Is Completely Dead.
Start by checking the Micro USB connector.
Measure the voltage directly at the USB input pins. A stable USB source should normally provide approximately 5V under the intended operating conditions.
Next, check whether that input voltage reaches the charging section.
If 5V is present at the connector but disappears before reaching the charging IC, inspect:
Broken Micro USB solder joints
Damaged PCB tracks
Open protection components
Shorted capacitors
Corroded board areas
Cracked solder joints
If the input reaches the power section but the board remains dead, check the battery voltage and the IP5403 power-management section.
Problem: Charging LED Does Not Turn On.
First confirm that the USB input is present.
Then check the battery voltage and the voltage around the L120 charging section.
A missing LED indication can result from a failed LED, open resistor, incorrect charging conditions, damaged charging IC, or a broken PCB track.
Do not replace the IC simply because the LED is not glowing. Voltage measurements should identify whether the problem is on the input side, charging-control side, or indicator side.
Problem: Battery Is Not Charging.
Disconnect the battery from the circuit only when it is safe and appropriate for the board design.
Measure the battery terminal voltage. If the battery is deeply discharged, physically swollen, damaged, or showing abnormal resistance, it should not be forced into charging.
With a normal battery connected, verify whether the charging circuit receives the 5V input and whether the charging voltage rises appropriately toward the battery's regulated charge voltage.
A charging fault can be caused by the L120 section, the battery itself, a connector problem, a damaged protection component, or an open PCB trace.
Problem: Earbuds Are Not Charging Inside the Case.
If the case itself powers on but the earbuds do not charge, inspect the charging contacts first.
Clean the contact surfaces carefully and check whether the spring-loaded pins move freely.
Measure the voltage at the earbud charging contacts while the earbuds are correctly seated.
If the voltage is missing on one side only, trace the PCB path from the charging-control section toward that side. An open resistor, damaged transistor, broken track, or bad spring contact can isolate one earbud from the charging supply.
Problem: One Earbud Charges but the Other Does Not.
This is often a contact or mechanical problem rather than a main power IC failure.
Compare the left and right charging contact voltages.
If one side has a normal charging voltage and the other side does not, inspect the corresponding track and components.
If both sides have a charging supply but one earbud still remains dead, the fault may be inside that earbud, including its battery, charging circuit, connector, or internal PCB.
Problem: Seven-Segment Display Is Blank.
Check the display supply and ground first.
Next, inspect the six display pins for cracked solder joints or damaged tracks.
If power is present but the display does not respond, the fault may be in the control circuit or display-driving section.
Because the exact 16-pin IC and its internal connection are not identified, it is safer to trace the PCB electrically before replacing this IC.
Problem: TWS Case Does Not Produce 5V Output.
This problem points toward the boost or output section.
Check the battery voltage first. A boost converter cannot generate a stable 5V output if the battery is disconnected or severely discharged.
Then inspect the boost coil for an open winding, damaged solder joint, or physical cracking.
After that, check the switching section around the IP5403 and the output capacitors.
The IP5403 documentation identifies its boost converter and 5V output functions, so this IC and the surrounding inductor/capacitor network are important diagnostic points.
Problem: TWS Gets Hot During Charging.
Abnormal heating should never be ignored.
Disconnect the charger and inspect the battery for swelling, leakage, physical damage, or unusual temperature.
A shorted capacitor, damaged charging IC, faulty battery, or PCB short can cause excessive current.
Measure resistance to ground on important power rails only after safely removing the power source. A very low resistance does not automatically prove that the IC is defective because some converter circuits naturally contain low-resistance paths.
Practical Voltage Testing Procedure.
For technicians working on this type of TWS circuit, a multimeter is the most useful starting tool.
Step 1: Check USB Input.
Measure the voltage between the Micro USB 5V line and ground.
A normal USB supply should be close to 5V.
Step 2: Check Battery Voltage.
Measure directly across the case battery terminals.
A healthy single-cell rechargeable battery should normally be somewhere within its expected operating range. A battery reading near zero, a rapidly collapsing voltage, or visible physical damage requires special attention.
Step 3: Check the Charging Path.
With the charger connected, compare the voltage before and after the relevant charging components.
A large unexpected voltage drop may indicate a damaged component, poor solder joint, or excessive load.
Step 4: Check the Boost Output.
If the design provides an external power output, measure the output with the device operating normally.
A missing 5V output with a healthy battery should direct troubleshooting toward the boost converter, coil, switching components, or output capacitors.
Step 5: Check the Charging Contacts.
Measure the voltage delivered to the left and right earbud charging contacts.
The two sides should be examined under the same operating condition because comparison testing is often faster than trying to diagnose a single side in isolation.
Important Safety Points During TWS Circuit Repair.
Lithium batteries can deliver very high current from a small package. A short circuit can create heat, smoke, fire, or permanent battery damage.
Never short the battery terminals with a multimeter probe, wire, screwdriver, or other conductive object.
Do not continue charging a swollen, punctured, leaking, or unusually hot battery.
Do not assume that every 5V measurement on the PCB is a direct battery-charging voltage.
Avoid replacing an unknown IC simply by matching the number of pins. Board markings, package versions, pin assignments, and circuit configurations must be confirmed before substitution.
Key Circuit Specifications at a Glance.
The XYT-T62C TWS board combines a Micro USB input, rechargeable battery system, power-management IC, charging IC, display section, boost coil, and earbud charging outputs.
The supplied board configuration identifies the IP5403 - 234400DA as the principal power-management IC and L120 as the charging IC. The IP5403 is documented as a charging/discharging power-supply SoC with an integrated boost section.
The reported earbud battery capacity is 30mAh, while the charging case battery is listed as 1200mAh. The supplied board measurements also report approximately 4.77V at the charging/load side and 0.35A under the stated test condition.
These values are useful for diagnosis, but they should be treated as measurements from this particular board rather than universal specifications for every TWS product.
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| IP5403 - 234400DA TWS Main Board IC Images |
What Makes This Circuit Useful for Repair Work.
The most useful aspect of the XYT-T62C board is that several common TWS problems can be isolated by following the power path instead of replacing components randomly.
Start from the USB input, move to the charging section, verify the battery, inspect the power-management stage, and finally check the boost and earbud charging outputs.
This approach makes troubleshooting more systematic and reduces unnecessary IC replacement.
For board-level repair, the combination of a digital multimeter, controlled 5V power source, good lighting, a microscope or magnifier, and careful continuity testing is often more useful than immediately replacing expensive components.
Note: The IC markings and measured values in this article apply to the supplied XYT-T62C board information. Confirm the actual PCB revision, component markings, and circuit connections before performing a repair.
Disclaimer: This article is prepared for educational and electronics-repair reference purposes. Some functions of the unidentified 16-pin IC, the exact display-driving method, and certain charging-time figures cannot be independently confirmed from a complete manufacturer schematic. Do not rely on unverified measurements when working with lithium batteries or live charging circuits. The official Bluetooth technology reference for Core Specification information is Bluetooth SIG — bluetooth.com.
