Power supplies convert AC from the power grid to DC for charging mobile phones. They also control the frequency of the current-carrying conductors. They must follow international safety standards like IEC 60065 to provide insulation and isolation, restrict voltage and current, and avoid fire. This verified design uses TI devices to monitor current, voltage and power on a bus that carries -48 V. It uses the INA226 device to make these measurements and an ISO1541 to translate them into I2C-compatible signals.
AC-Based Power Supply
The AC power supply is one of the most important parts of a telecom system. The power supply must provide enough power to meet the demands of the load without dropping output voltage, which can cause hardware damage. It should also be able to deliver a constant power output. In addition, the AC power supply must compensate for voltage drop due to long wires. It can be achieved by using shielded cables and following cable layout protocols. The alternating current (AC) is the flow of electricity that changes its direction and polarity periodically. It is the opposite of a direct current, which stays constant in both directions. AC power is commonly found in outlets, batteries, and electric motors. It can also simulate power line disturbances, such as surges, sags, and spikes, for immunity tests.
Moreover, AC-based power supplies have many advantages over DC ones. These include a wider range of input voltages and the ability to sustain high inrush currents. In addition, they can reduce noise and have better regulation. AC power sources also have different levels of efficiency and cooling technologies. For example, linear power supplies are less complex and cheaper but create more heat than switched-mode ones.
DC-Based Power Supply
The power supply is one of the most important components in electronic and electrical systems. Choosing the right type of power supply for a particular project or task is essential. But what is telecom power supplies? It must meet various criteria, including voltage and current limits, efficiency, noise immunity, and physical size. It should also be easy to use and safe to operate.
There are many different types of power supplies available in the market. Some are used for small projects, and others have a larger output. Some of these supplies include unregulated, regulated, and switched modes. Unregulated power supplies have little control circuits and do not stabilize the work. They typically consist of a transformer, a rectifier, and a filter. They are unsuitable for most electronics because they produce small variations in the output, known as a ripple voltage. These variations cause electronic noise and can damage the circuits.
Regulated power supplies have a built-in regulator that controls the power supply’s output. It is useful for applications that require clean DC power. The regulator reduces the ripple voltage, stabilizing the power supply over various load conditions. These power supplies can be either linear or switching, each having advantages and disadvantages. Linear power supplies have simple, straightforward operation methods that reduce ripple voltage and electronic noise. Switched mode power supplies (SMPS) have a more complex design but are smaller and cooler than linear supplies. They also have a higher power density and can operate in a wider range of polarities than linear power supplies.
Rack Power
Telecom power supplies provide regulated DC output voltages fed from the base of telecom towers to DC devices at the top. They also support fault management to stop power flow when a cable or terminal is faulty (or even when a technician comes in contact with it).
In addition to regulating the output, rack PDUs can display energy usage at the outlet level and over a secure network. This feature lets users quickly identify where energy is consumed and reveals locations with spare capacity. Outlet-level metering also helps reduce the risk of accidental plug disconnects, which can cause unintentional data loss and reduce costs by allowing IT managers to turn off unneeded equipment. While the traditional AC (alternating current) power supply can deliver enough energy for most telecom applications, new 5G infrastructure demands are driving the need for more efficient rectifiers and higher-voltage DC outputs. These higher-voltage DC supplies can reduce cabling costs, improve safety, and reduce voltage drop along cables. Another key benefit of a DC-DC converter is that it can provide backup power for longer periods than traditional batteries. Since most of the telecom gear at the top of a macro cell tower requires 48V DC input, it’s important to ensure that this power can be delivered for extended periods.
Ringing Power
A ringing power supply is the main DC voltage conversion source for 3.3V, 5V and 12V telecom integrated circuits. The power supply is commonly designed using a flyback topology with a leakage inductor, which generates primary-side ringing. The resulting ringing can generate high transient voltages that damage the MOSFETs. Consequently, it is important to design the MOSFETs and the transformer with a control strategy to reduce ringing. Ringing is a parasitic effect in switching power supplies that produces an unwanted current oscillation or ringing in the output inductor and the power switch. It can occur when the power switch is on or off, and the output inductor is ‘dry’ (i.e., operating in discontinuous conduction mode). It is also more common when the output inductor is ‘dry’ than when it is ‘wet’ or in the continuous conduction mode.
Ringing can cause various problems, including increased EMI that radiates and conducts across the ground plane. It can also increase current flow and produce excessive heating of the components, which decreases performance. Additionally, ringing can increase the voltage induced in vias and PCB pads that connect the IC to the ground plane. The result is a significant decrease in throughput, responsivity and signal quality. Decoupling capacitors can reduce ringing by providing a charge reservoir to compensate for the transient current in the power bus. However, they are only effective if the target impedance of the PDN is lower than the currents drawn by the switching ICs.