35W switching power supply circuit having a set-top box output of 5

A 35W switching power supply circuit designed for a set-top box output is depicted in Figure 5. It features five distinct voltage outputs: Uo1 (+30V, 100mA), Uo2 (+18V, 550mA), Uo3 (+5V, 2.5A), Uo4 (+3.3V, 3A), and Uo5 (-5V, 100mA). The +5V and +3.3V outputs serve as the main outputs, while the others provide supplementary power. When the AC input voltage is 220V (±15%), the total output power of the switching power supply reaches 38.5W. It operates effectively across a wide input voltage range of 85V to 265V, with total output power decreasing to 25W under lower voltage conditions. This power supply is suitable for various applications, including set-top boxes, video recorders (VCRs), camcorders (CVCRs), and DVD players. The efficiency of the set-top box switching power supply exceeds 77% and includes protections for under-voltage and over-voltage conditions.

The 35W switching power supply circuit is a versatile power management solution, particularly tailored for consumer electronic devices such as set-top boxes and multimedia equipment. The circuit's design incorporates a switching regulator topology, which enhances efficiency by minimizing power loss during voltage regulation. The five output voltages allow for a range of device compatibility, ensuring that the power supply can cater to different operational requirements.

The main outputs, +5V and +3.3V, are critical for powering digital circuits in devices like set-top boxes and VCRs, where stable voltage levels are essential for reliable operation. The additional outputs provide flexibility for other components that may require different voltage levels, thereby reducing the need for multiple power supplies in a single device.

The power supply's ability to function across a wide input voltage range (85V to 265V) makes it suitable for global applications, accommodating variations in mains voltage. This feature is particularly beneficial for devices intended for international markets, ensuring consistent performance regardless of the local power grid conditions.

Efficiency is a significant consideration in the design of this power supply, with an efficiency rating exceeding 77%. This not only reduces energy consumption but also minimizes heat generation, which is critical for maintaining the longevity and reliability of electronic components. The inclusion of under-voltage and over-voltage protection mechanisms enhances the safety of the circuit, safeguarding both the power supply and the devices it powers from potential damage due to voltage fluctuations.

Overall, the 35W switching power supply circuit represents a well-engineered solution for powering a variety of electronic devices, combining efficiency, versatility, and safety features in a compact design.35W switching power supply circuit having a set-top box output is shown in Figure 5. The five-way voltage respectively: Uo1 (+ 30V, 100mA), Uo2 (+ 18V, 550mA), Uo3 (+ 5V, 2.5A) , Uo4 (+ 3.3V, 3A), Uo5 (-5V, 100mA). Wherein, + 5V and + 3.3V as the main output, the rest are supplemented by output from various quarters. When the AC input voltage u 220 (1 15%) V, the switching power supply total output power of 38.5W, the use of a wide range of input voltage (u 85 ~ 265V), the total output power is reduced 25W.

Can be used as set-top boxes (Set Top Box), video recorder (VCR), camcorder (CVCR) and DVD player in the switching power supply. The set-top boxes switching power supply efficiency above 77%, with under-voltage and over-voltage protection.