Advantages of Module Power Supplies, Applications of Module Power Supplies, Installation and Maintenance of Module Power Supplies

1. Overview

The design of today’s power supply systems poses significant challenges for electronic designers. They must utilize limited resources and space to design flexible, efficient, reliable, and competitive power supply systems in a short time. Module power supplies (or power modules) are currently the best choice for designers. Replacing discrete component designs with modular power supplies is like using microprocessors instead of integrated circuit blocks, allowing for more flexible and faster system development, thereby shortening the time spent on development or design changes, saving labor and technical investment.2. Advantages of Module Power SuppliesModule power supplies have the following advantages:　　　　　●Simple design. Only one power module, along with a few discrete components, is needed to obtain a power supply.　　　　　　●Shortened development cycle. Module power supplies generally come with multiple input and output options. Users can also stack or cross-stack them to form modular combinations, achieving multiple inputs and outputs, greatly reducing prototype development time.　　　　　　●Flexible modifications. If product design needs to be changed, simply switch or parallel another suitable power module.　　　　　　●Low technical requirements. Module power supplies are generally equipped with standardized front-ends, highly integrated power modules, and other components, making power supply design simpler.　　　　　　●The module power supply casing has a three-in-one structure of heat sink, radiator, and housing, achieving a conduction cooling method for the module power supply, bringing the temperature value close to the minimum. At the same time, it gives the module power supply an attractive appearance.　　　　　　●High quality and reliability. Module power supplies are generally produced fully automated and equipped with high-tech production techniques, ensuring stable and reliable quality.　　●Wide applications: Module power supplies can be widely used in aerospace, locomotives and ships, military weapons, power generation and distribution, postal and telecommunications, metallurgy and mining, automatic control, household appliances, instruments and meters, and various fields of social production and life, especially playing an irreplaceable important role in high reliability and high-tech fields.3. Applications of Module Power Supplies3.1 Adjustment of Output Voltage For module power supply products with TRIM or ADJ (adjustable) output pins, the output voltage can be adjusted within a certain range through resistors or potentiometers, generally within ±10%.　　 For TRIM output pins, connect the center of the potentiometer to TRIM, and connect the other two ends to the +S and -S pins of the module. If there are no +S and -S pins, connect both ends to the corresponding positive and negative terminals of the main circuit (connect +S to +Vin and -S to -Vin), then adjust the potentiometer. The resistance value of the potentiometer is generally selected to be 5 to 10 kΩ.　　 For ADJ output pins, there are input side adjustment and output side adjustment. The output side adjustment is the same as the adjustment method for the TRIM pin. The input side adjustment can only increase the output voltage; in this case, connect one end of the potentiometer to the center and the other end to the input ground.　　3.2 Input Protection Circuit Generally, module power supply products have built-in filters that can meet the requirements of general power supply applications. If higher requirements are needed for the power supply system, an input filter network should be added. LC or π-type networks can be used, but it is advisable to choose smaller inductance and larger capacitance.　　 To prevent transient high voltage from damaging the module power supply, it is recommended that users connect a transient suppression diode at the input and use a fuse to ensure the module operates within a safe input voltage range. To reduce common-mode noise, Y (Cy) capacitors can be added, typically selecting several nF high-frequency capacitors. R is the fuse, D1 is the protection diode, and D2 is the transient suppression diode (P6KE series).　　3.3 Remote Control On/Off Circuit The remote control operation of the module power supply is done through the REM terminal. There are generally two control methods:　　　(1) Connect REM to -VIN (reference ground) to remotely turn off, requiring VREF<0.4V. If REM is floating or connected to +VIN, the module works, requiring VREM>1V.　　　　　　(2) Connect REM to VIN to remotely turn off, requiring VREM<0.4V. Connect REM to +VIN, and the module works, requiring VREM>1V. If REM is floating, it will turn off remotely, known as “floating off” (-R).　　If isolation from the input side is required, an optocoupler can be used to transmit the control signal.　3.4 Module Combination 　(1) Parallel Expansion. By paralleling the output terminals of the same module, the output capacity can be enhanced, but the output voltages of the parallel modules must be adjusted to be relatively consistent to ensure current sharing and avoid unnecessary oscillations. For modules with larger output currents, lead resistances can be carefully designed to achieve current sharing. It is not advisable to parallel more than 2 modules using this method. Moreover, if one of the modules fails, the entire system will not function properly. The connection circuit RL for parallel expansion is the load.　　(2) Redundant Hot Backup Parallel. By paralleling the output terminals of the same module through diodes, the output capacity can be enhanced to improve the reliability of the power supply system. In principle, if paired with corresponding output alarm circuits, the modules can be placed on a removable bus, allowing for timely replacement of failed modules. There is no limit on the number of modules paralleled using this method. D is generally a Schottky diode.　　(3) Series Expansion. By connecting the output terminals of the same module in series, the output voltage can be doubled, and the power will increase accordingly, while diodes must be connected at the series output terminals for protection.　3.5 Bell Current Backup Usage The bell current generator is mainly used to provide ringing for telephone users in a telephone exchange, generally used in a biased state. The bias can be divided into positive and negative bias. To improve the reliability of the bell current system, backup for the bell current is needed. Below is a recommended backup method (taking negative bias as an example).　　 This plan uses the output after the bell current starts, prohibiting the backup bell current through the REM control terminal. During the startup process, the faster starting bell current will operate. A simple delay circuit can prevent two bell currents from starting simultaneously, causing a dual-pass situation. As shown in Figure 8, the bell currents A and B and their peripheral circuits can be placed on different bell current boards of the same bus. Thus, if one of the bell currents fails, it can be replaced without affecting the normal operation of the system. RCA and RCB are necessary connections for the two bell current boards.4. Installation and Maintenance of Module Power Supplies Due to the numerous categories, series, and specifications of module power supplies produced by various companies, their functional and physical characteristics vary. Therefore, the installation, use, and maintenance aspects also differ, but attention should be paid to the following points:　　(1) After opening the package, carefully check whether the terminal markings match the instructions provided and whether they comply with the requirements specified in the order contract. If not, immediately contact the production or sales unit to discuss solutions.　　　　(2) As the first step of installation, the metal casing of the module power supply must be reliably grounded to ensure safety, but do not mistakenly connect the casing to the neutral line.　　(3) Before powering on after installation, check and verify the connections at each terminal again, ensuring that the input and output, AC and DC, single-phase and multi-phase, positive and negative, voltage values, and current values are all correct to prevent reverse or incorrect connections.　　　　(4) For high-power power supplies, there are generally two or more “+” output terminals and “-” output terminals. In fact, they all belong to one output electrode, but they are internally connected together for user convenience.　　　　(5) Module power supplies should not be operated at full load for extended periods. The usage rate of linear power supplies should be kept within 60%; for switching power supplies, it should be kept within 80%, otherwise, it may lead to premature failure of the module power supply.　　　　(6) For module power supplies, some manufacturers may have a fixed resistor at the adjustable terminal (ADJ) when leaving the factory. Users must supply the corresponding resistance potentiometer to replace the fixed resistor. However, it is important to note that when the adjustable terminals are open, loading is absolutely not allowed.　　　　(7) To achieve sufficient heat dissipation, module power supplies should be installed in locations with good air circulation. Generally, if the working current of linear power supplies is above 4A or the working current of switching power supplies is above 7A, forced air cooling should be added. Additionally, no other objects should be placed on the module power supply casing.　　　　(8) Module power supplies are generally suitable for resistive loads. If they need to be applied to capacitive or inductive loads, this should be specified in the order contract for custom manufacturing.　　　　(9) For high-voltage module power supplies, it is prohibited to touch the high-voltage danger zone within 10 minutes after use and after power failure.　　　　(10) Principles for selecting module power supplies: Generally, larger power supplies should choose switching power supplies, while smaller power supplies should choose linear supplies.　　　　(11) Module power supplies should not be forcibly disassembled, as forceful disassembly will damage them.