Power Supplies in Controlled Digital Systems

Power Supply Quality Standards

Until recently, the quality of power supplies was primarily assessed based on manufacturer data characteristics such as power density, efficiency, compliance certifications, warranty duration, and price. Recently, an additional parameter of controlled digital management over the supply has been introduced. The traditional controlled management until now was analog control, which had the advantage of rapid control of the supply at low costs through a simple control circuit. This was suitable for applications in relatively simple systems with a specific goal, such as remote control without reading data from the supply.

Today, systems are becoming increasingly intelligent, necessitating advancements in the control and management of power supplies, leading to the emergence of digital control. This allows the system designer to receive real-time information and accordingly perform programmed control and management of the supply. The objective for the designer is to optimize the process against the required outcome to manage the process effectively. A microprocessor is used to decode the dynamic system requirements, which are constantly changing, and through software, ensure the desired outcome.

Digitally controlled power supplies can be divided into two categories: the first category includes analog power supplies with digital communication interfaces such as PMBus and I2C, where the basic operations these interfaces can handle are controlling the output voltage of the supply, and more advanced operations also allow for data reading from the supply.

The second category consists of 100% digital control via:

• System-on-a-chip (SDP)
• Microcontroller (MCU)
• FPGA usage

In practice, SDP, MCU, or FPGA can process the information and correspondingly send a signal to the supply, which reacts to the signal and performs the required action, thereby controlling the supply. For the supply to be monitored as well, data must be read from the supply and transmitted to the processor, which will then send a command back to the supply.

The power supply company MEAN WELL, officially represented in Israel by Advice Electronics Ltd., offers a wide range of controlled supplies for various fields: drivers for LEDs, industrial supplies, communication supplies, and medical supplies.

Recently, MEAN WELL launched its series of modular medical supplies, the NMP series, available in two different power options:

• NMP650 with a total power of 650W and 4 SLOTS
• NMP12K with a total power of 1200W and 6 SLOTS

The two aforementioned power supplies allow for control of each module individually or all modules simultaneously, including control over voltage and current, Inhibit, and DC O.K. signals for each module.

The available modules support voltages of 5V, 12V, 24V, and 48V, with a maximum power output of 240W for each module.

The modules can be controlled analogically, enabling the adjustment of the output voltage of the module and also allowing for the limitation of the output current of each module.

The supplies also include an internal auxiliary (AUX) voltage of 5VDC, providing 1.5A for the 650W model and 2A for the 1200W model.

This auxiliary voltage can be used for control applications or to power a programmed controller from which commands will be received for control purposes.

In recent years, controlled management has almost entirely shifted to the field of LED lighting, where control until recently primarily relied on analog management based on current. Current control results in dimming of the lighting and is accomplished through three main options:

1. Dimming via an external analog voltage called 0~10VDC
2. Dimming via a signal known as PWM
3. Dimming via a resistance known as Resistance

In the example before us, the ELG-150 driver from MEAN WELL is presented. This driver includes the above options:

In addition to the three analog options, another control method has been added: digital control known as DALI (Digital Addressable Lighting Interface). This control allows for the simultaneous connection of multiple lighting fixtures, with each fixture assigned its own address. The DALI communication comes from a programmed controller that sends commands to a specific address, thereby controlling the dimming of the driver connected to the LED lighting. Once each driver has an address, dimming can be performed differently at each point according to the requirements. Another advantage of DALI communication is its communication range; since commands from the controller are transmitted via an RJ45 cable, distances of up to 50 meters can be achieved from the controller to the point where the driver is connected.

Numerous communication protocols are also found in other smart systems, such as the TN-3000 solar inverter from MEAN WELL. This inverter is capable of operating directly from battery voltage or from a direct connection to solar panels, including charging the batteries from the solar panels. This inverter can be interfaced with a computer for data reading and remote control as needed.

In summary, it is clear that the traditional world is changing rapidly, and as time goes by, systems are becoming smarter and more efficient, all in order to meet new needs with minimal effort and maximum efficiency.

By: Rami Menuch, Advice Electronics Ltd.

For more information: 03-9000910, rami@advice.co.il, 052-2880463