Sony KLV-40W652D 5 Volt Power Supply Guide
To understand the Sony Bravia 5V Power Supply Detail, we will first take a closer look at the 5-volt power supply used in the Sony Bravia model KLV-40W652D. In this model, the 5V power supply plays an important role on the main board, as it provides a stable voltage required for the proper operation of different circuits on the board. The buck converter IC used in this section is AOZ1236QI-01, which is responsible for converting and regulating the voltage to generate a stable 5-volt power rail. In this article, we will also discuss this IC, its role in the circuit, and how it operates as a buck converter to produce the required 5V supply. Since the 5-volt buck converter power supply is a very important section of this board, we will also publish a series of articles explaining the other buck converter power supplies used on the same board.
AOZ1236QI-01 Buck Converter IC
The AOZ1236QI-01 is a 23-pin, 4mm × 4mm QFN buck converter IC used on the Sony KLV-40W652D main board to generate a regulated 5-volt power supply. In this circuit, the IC receives approximately 19V as the input supply and efficiently converts it into a stable 5V output required by different sections of the board. As a switching buck converter, this IC regulates the output voltage through its feedback control system. The output level is determined by the feedback network, where two voltage-divider resistors (R1 and R2) are connected to the feedback pin. These resistors set the reference level and define the correct ratio that allows the IC to maintain a stable 5V output during normal operation. You can also see R1 and R2 clearly in the section image shown below, which illustrates how the feedback network sets the required output voltage.
5V Rail Distribution & Key Circuits
In the Sony Bravia 5V Power Supply Detail section of the Sony KLV-40W652D main board, the 5-volt rail plays a very important role because it is distributed to several critical circuits. This 5V line is used as the input supply for two 3.3V regulators, and it also feeds the 1.2V regulator used by the main processing section. In addition, the 1.8V buck converter used for the tuner section also receives its input from the same 5V rail. There is also another 1.1V regulator on the board that operates from this 5V supply. Apart from these regulators, this 5V line is also used to provide USB power, supplying current to the USB ports, and it also powers the Wi-Fi IC on the board. From this distribution, it is clear that the 5V voltage regulator section is one of the most important power sources on this board, because several other voltage rails and functional sections depend on this single supply line.
AOZ1236QI-01 Pin Configuration
Pin 1: PGOOD
This pin outputs the Power Good (PGOOD) signal, which indicates whether the 5V output of the AOZ1236QI-01 buck converter IC is within the specified regulation range. When the output voltage reaches the correct level, this pin goes high to notify the system that the power supply is stable and safe for the connected circuits. If the voltage is out of range, the pin remains low, signaling a fault or startup condition.
Pin 2: EN
The Enable (EN) pin controls the operation of the AOZ1236QI-01 buck converter IC. When this pin is driven high, the IC is enabled and begins switching to regulate the 5V output. Driving this pin low disables the IC, stopping the output and placing the device in a low-power shutdown mode. This pin allows the system to turn the 5V power supply on or off as needed, providing control for power sequencing and energy-saving operations.
Pin 3: PFM
The PFM (Pulse-Frequency Modulation) pin allows the AOZ1236QI-01 IC to operate in PFM mode, optimizing efficiency at light load conditions. When this pin is configured, the IC adjusts the switching frequency dynamically to reduce power loss, minimize heat generation, and improve overall efficiency. This pin is important for low-current operation, ensuring that the 5V output remains stable while consuming minimal power from the input supply.
Pin 4: AGND
The Analog Ground (AGND) pin provides a reference ground for the internal control circuitry of the AOZ1236QI-01 IC. It is separated from the power ground to minimize noise interference from the high-current switching paths. Proper connection of AGND is critical for accurate voltage regulation, stable operation of the 5V output, and reliable performance of the feedback and control circuits.
Pin 5: FB
The Feedback (FB) pin is used by the AOZ1236QI-01 IC to monitor the output voltage and regulate the 5V supply. The voltage at this pin is compared internally to a reference voltage to control the switching of the buck converter. By connecting a resistor voltage-divider network (R1 and R2) to this pin, the IC determines the correct output voltage and maintains stable regulation under varying load conditions. This pin is essential for precise and reliable 5V output performance.
Pin 6: TON
The TON pin sets the on-time of the internal power switch in the AOZ1236QI-01 buck converter IC. By controlling the duration of each switching cycle, this pin helps regulate the 5V output voltage and affects the operating frequency of the converter. Proper configuration of TON ensures stable voltage regulation, efficient power conversion, and optimal performance under different load conditions.
Pin 7: AIN
The AIN (Analog Input) pin is used to provide an external analog control voltage to the AOZ1236QI-01 IC. This input can adjust the operation of the buck converter, such as modifying the output voltage or regulating current limits, depending on the design. Proper connection to AIN allows precise control over the 5V output and ensures stable performance of the power supply under varying operating conditions.
Pin 8: IN
The IN pin is the main input voltage pin for the AOZ1236QI-01 buck converter IC. It receives the higher voltage supply (approximately 19V in the Sony KLV-40W652D board) and feeds the internal power stage. Proper connection of this pin is crucial, as it provides the energy that the IC converts into a stable 5V output. Any fluctuation or disconnection at the IN pin can directly affect the 5V power supply and the operation of downstream circuits.
Pin 9: IN
The IN pin (Pin 9), like Pin 8, serves as an additional input voltage connection for the AOZ1236QI-01 IC. It helps supply the internal power stage with the input voltage (approximately 19V on the Sony KLV-40W652D board) to ensure sufficient current for the 5V output. Having multiple IN pins allows better current handling, reduces voltage drop, and ensures stable operation of the IC under varying load conditions.
Pin 10: LX
The LX pin is the switching node output of the AOZ1236QI-01 buck converter IC. This pin connects to the inductor and is the point where the high-speed switching occurs to convert the input voltage (≈19V) down to a regulated 5V output. Proper layout and connection of the LX pin are crucial for efficient energy transfer, minimal noise, and stable 5V power supply operation across the board.
Pin 11: LX
Similar to Pin 10, the LX pin (Pin 11) serves as an additional switching node connection in the AOZ1236QI-01 buck converter IC. It connects to the inductor and handles the high-speed switching necessary to convert the input voltage to a stable 5V output. Using multiple LX pins helps share the current load, reduces voltage stress on individual pins, and ensures efficient operation of the 5V power rail on the Sony KLV-40W652D main board.
Pin 12, 13, 14, 15: PGND
Short Description: These pins serve as the Power Ground (PGND) connections for the AOZ1236QI-01 buck converter IC. They provide the return path for high-current switching from the LX nodes and output capacitors back to the input source. Having multiple PGND pins ensures better current handling, reduces voltage drops, and minimizes switching noise. Proper layout of PGND pins is essential for stable 5V output and reliable operation of the IC, while keeping the analog control circuitry isolated from high-current paths.
Pin 16, 17, 18: XL
Pins XL (16, 17, and 18) serve as switching node connections for the AOZ1236QI-01 buck converter IC. They connect to the inductor(s) and handle the high-speed switching necessary to step down the input voltage (≈19V) to a stable 5V output. Using multiple XL pins allows better current sharing, reduces voltage stress on individual pins, and ensures efficient energy transfer. Proper layout and connection of these pins are essential for stable 5V output and minimizing switching noise across the board.
Pin 19: PGND
The PGND (Power Ground) pin provides a return path for high-current switching from the LX nodes and output capacitors. Proper connection of this pin ensures stable 5V output, minimizes voltage drops, and reduces switching noise. This pin, along with the other PGND pins, isolates high-current paths from the sensitive analog control circuitry, allowing accurate voltage regulation by the AOZ1236QI-01 IC.
Pin 20: BST
The BST (Bootstrap) pin provides the necessary gate drive voltage for the high-side MOSFET in the AOZ1236QI-01 buck converter IC. By connecting a bootstrap capacitor between the BST pin and the LX pin, the IC can fully enhance the high-side switch, enabling efficient voltage conversion from the input (≈19V) to a regulated 5V output. Proper connection of the BST pin is essential for stable switching operation and maintaining optimal efficiency of the 5V power supply.
Pin 21: VCC
The VCC pin provides the supply voltage for the internal control circuitry of the AOZ1236QI-01 buck converter IC. This voltage powers the internal reference, error amplifier, and logic circuits that regulate the 5V output. Proper connection to VCC is critical for stable operation of the IC, ensuring accurate feedback control and reliable power conversion performance on the Sony KLV-40W652D main board.
Pin 22: IN
The IN pin (Pin 22) serves as an additional input voltage connection for the AOZ1236QI-01 IC. It supplies the internal power stage with the input voltage (≈19V on the Sony KLV-40W652D board), ensuring sufficient current for the 5V output. Proper connection of this pin is essential for stable 5V power supply operation and efficient energy conversion, supporting the overall performance of the IC under varying load conditions.
Pin 23: SS
The SS (Soft-Start) pin controls the soft-start function of the AOZ1236QI-01 buck converter IC. By connecting an external capacitor to this pin, the IC gradually ramps up the output voltage when powered on, preventing inrush current and reducing stress on the 5V output components. Proper use of the SS pin ensures a smooth startup, protects downstream circuits, and enhances the reliability of the 5V power supply on the Sony KLV-40W652D board.
AOZ1236QI-01 Layout and Feedback Network
Below, you can see the layout image of the AOZ1236QI-01 IC on the Sony KLV-40W652D main board. This image highlights the feedback network, including the R1 and R2 voltage-divider resistors, which determine the regulated 5V output. The layout clearly shows how the IC is connected to the surrounding components, including the inductor, capacitors, and power ground pins, giving a complete view of its position and interaction on the board. From this image, you can understand how the feedback mechanism works to maintain a stable 5V supply across different load conditions, making it an essential part of the board’s power regulation.
Technical Advice for Technicians
Based on practical experience with the Sony KLV-40W652D main board, here are some technical tips for technicians working with the AOZ1236QI-01 buck converter IC. Always ensure that the feedback resistors R1 and R2 are correctly soldered and securely connected, as they directly influence the 5V output stability. Check the PGND and AGND connections to prevent noise interference and voltage fluctuations. When probing the 5V rail, use proper measuring techniques to avoid false readings caused by the high-speed switching at the LX pins. Proper layout inspection and careful handling of these pins can prevent common faults and ensure long-term reliability of the power supply section.
Conclusion
the Sony Bravia 5V Power Supply Detail of the KLV-40W652D model demonstrates the critical role of the AOZ1236QI-01 buck converter IC in providing a stable 5V output for multiple regulators, USB power, and other key circuits. Understanding the pin configuration, feedback network (R1 and R2), and layout is essential for both troubleshooting and optimizing the performance of the main board. By following the detailed explanations and technical advice provided, technicians can ensure reliable operation and prevent common faults in the 5V power rail. This comprehensive overview highlights the importance of the 5V supply and its impact on the overall functionality of the Sony Bravia main board.
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Shaukat Ali has over 30 years of experience in LED TV repair, specializing in chip-level repair work. He is an expert in Sony LED TVs, and also repairs other major brands like Samsung, TCL, Orient, and Haier. His expertise includes display panel faults, motherboard issues, power supply circuits, T-Con, and HDMI faults. Based in Lahore, he shares real-time fault finding cases from daily repair work to help technicians and learners with practical experience.
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