To understand the power supply, start with the physical diagram of the power supply's internal structure!
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This post was last edited by alan000345 on 2019-2-20 10:32 The power supply is not like a processor, where you can know the performance by looking at the specifications; nor is the power supply like a graphics card, where the grade is determined by a key GPU. In addition to meeting the power requirements, a good power supply must also consider factors such as stability, energy saving, quietness, and safety. In the absence of professional equipment for testing, we can only understand the power supply at a glance if we understand some basic principles and component knowledge of the power supply. Grasp the key and stop feeling dizzy From the outside, the power supply is only slightly larger than a "brick", but it has a lot of stuff in its "belly". When we remove the outer shell, we can see hundreds of various electronic components and complex and crisscrossed cables, which can't help but make people dizzy. As the saying goes, "to catch a thief, first catch the king". When observing the power supply, we should also pay attention to the following parts. The internal structure diagram of a power supply. Numbers 1 to 6 respectively identify the parts that everyone should pay attention to. 1. Primary and secondary EMI filter circuits. The function of this part is to filter the AC power entering the external power grid and obtain relatively pure AC power for subsequent use. 2. PFC circuit. Its function is to reduce harmonics in the process of converting AC power into DC power, reduce interference to the indoor power grid and the AC power grid, and reduce AC power loss. 3. High-voltage filter capacitor. Its function is to purify high-voltage DC power and provide relatively "pure" current for subsequent high-to-low voltage conversion. 4. Power supply topology. Topology refers to the overall structure of the power supply, which directly affects the conversion efficiency of the power supply. 5. The inductor of the low-voltage filter circuit. Its function is to stabilize the voltage and current at the output end, which is directly related to the stable use of the computer hardware system. 6. Heat sink. When the transformer and switch circuit perform voltage conversion, a large amount of heat will be generated, so a heat sink is needed to quickly transfer the heat. First and second level EMI filter circuits The national 3C certification requires that the power supplies on the market must pass the EMI anti-electromagnetic radiation certification. Therefore, qualified power supplies should have EMI filter circuits. [font=Arial, The first-level EMI filter circuit is located at the power interface. The circuit with better workmanship also has an independent PCB board and inductor coil. The second-level EMI filter circuit is usually on the main PCB board of the power supply and is composed of components such as inductor coils and capacitors. The secondary EMI filter circuit on a low-quality power supply sang the "empty city plan" However, low-end power supplies often only have one level of EMI filter circuits, and slightly better power supplies should have complete primary and secondary EMI filter circuits. PFC circuit PFC circuits are divided into passive and active types. Most power supplies now use active PFC. Passive PFC uses this "big head" inductor The inductor coil of active PFC is often located in front of the high-voltage filter capacitor. The power factor of passive PFC is generally around 0.7, while the power factor of active PFC is as high as 0.9 or above, which is significantly better than passive PFC. It is also quite easy to distinguish between the two. High-voltage filter capacitors What are high-voltage filter capacitors? It's simple. The highest and largest capacitors in the power supply are (1 to 2). When comparing capacitors, in principle, they can only be compared with power supplies of the same type, because at the same power, the capacitance required for passive PFC power supplies is larger than that for active ones. When comparing at the same level, we can see the capacity, withstand voltage and temperature resistance of the high-voltage filter capacitor. In theory, the larger the values of these three items, the better. The power supply adopts active PFC, so a high-voltage filter capacitor with a capacity of 330μF can meet the demand. The withstand voltage of the capacitor is 400V and the temperature resistance is 85℃. Power supply topology To put it simply, in the past few years, power supply topologies can be divided into two types: half-bridge and forward. Now the forward type is the main one. The half-bridge type is a traditional power supply structure, which usually has a low conversion efficiency; while the forward structure conversion efficiency can easily reach more than 80%. Traditional Half-Bridge Topology Forward topology helps improve conversion efficiency When distinguishing, we might as well use the elimination method: in the center of the half-bridge power supply, there must be three transformers, one large and two small, arranged in a straight line; if your power supply is not of this structure, then congratulations, this is most likely a forward power supply. Inductor coil of low-voltage filter circuit In the low-voltage filter circuit part, we mainly look at the size, number of turns and color of the inductor coil. Naturally, the larger the coil and the more turns, the better; as for the color, theoretically from best to worst, they are gray, black, light green and yellow, and the better the inductance, the smaller the loss. The low-voltage filter circuit mainly depends on the inductor coil. Heat sink The role of the heat sink is needless to say. Switching tubes and Schottky tubes that generate more heat are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks have fins. In theory, the more fins, the better. Passive PFC all use this "big head" inductor Passive PFC all use this "big head" inductor [p=22, 2, The inductor of active PFC is often located in front of the high-voltage filter capacitor. The power factor of passive PFC is generally around 0.7, while the power factor of active PFC is as high as 0.9 or more, which is significantly better than passive PFC. It is also quite easy to distinguish between the two. High-voltage filter capacitor. "]Which are the high-voltage filter capacitors? It's very simple. The highest and largest capacitors in the power supply are (1 to 2). When comparing capacitors, in principle, they can only be compared with power supplies of the same type, because at the same power, the passive PFC power supply requires a larger capacitor capacity than the active one. When comparing at the same level, we can see the capacity, withstand voltage and temperature resistance of the high-voltage filter capacitor. In theory, the larger the values of these three items, the better. The power supply adopts active PFC, so a high-voltage filter capacitor with a capacity of 330μF can meet the needs. The capacitor has a withstand voltage of 400V and a temperature resistance of 85℃. Power supply topology To put it simply, in the past few years, the topology of power supplies can be divided into half-bridge and forward types. Now the forward type is basically the main one. The half-bridge type is a traditional power supply structure, and the conversion efficiency is usually not high; while the forward structure conversion efficiency can easily reach more than 80%. Traditional Half-Bridge Topology Forward topology helps improve conversion efficiency When distinguishing, we might as well use the elimination method: in the center of the half-bridge power supply, there must be three transformers, one large and two small, arranged in a straight line; if your power supply is not of this structure, then congratulations, this is most likely a forward power supply. Inductor coil of low-voltage filter circuit In the low-voltage filter circuit part, we mainly look at the size, number of turns and color of the inductor coil. Naturally, the larger the coil and the more turns, the better; as for the color, theoretically from best to worst, they are gray, black, light green and yellow, and the better the inductance, the smaller the loss. The low-voltage filter circuit mainly depends on the inductor coil. Heat sink The role of the heat sink is needless to say. Switching tubes and Schottky tubes that generate more heat are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks have fins. In theory, the more fins, the better. Passive PFC all use this "big head" inductor Passive PFC all use this "big head" inductor [p=22, 2, The inductor of active PFC is often located in front of the high-voltage filter capacitor. The power factor of passive PFC is generally around 0.7, while the power factor of active PFC is as high as 0.9 or more, which is significantly better than passive PFC. It is also quite easy to distinguish between the two. High-voltage filter capacitor. "]Which are the high-voltage filter capacitors? It's very simple. The highest and largest capacitors in the power supply are (1 to 2). When comparing capacitors, in principle, they can only be compared with power supplies of the same type, because at the same power, the passive PFC power supply requires a larger capacitor capacity than the active one. When comparing at the same level, we can see the capacity, withstand voltage and temperature resistance of the high-voltage filter capacitor. In theory, the larger the values of these three items, the better. The power supply adopts active PFC, so a high-voltage filter capacitor with a capacity of 330μF can meet the needs. The capacitor has a withstand voltage of 400V and a temperature resistance of 85℃. Power supply topology To put it simply, in the past few years, the topology of power supplies can be divided into half-bridge and forward types. Now the forward type is basically the main one. The half-bridge type is a traditional power supply structure, and the conversion efficiency is usually not high; while the forward structure conversion efficiency can easily reach more than 80%. Traditional Half-Bridge Topology Forward topology helps improve conversion efficiency When distinguishing, we might as well use the elimination method: in the center of the half-bridge power supply, there must be three transformers, one large and two small, arranged in a straight line; if your power supply is not of this structure, then congratulations, this is most likely a forward power supply. Inductor coil of low-voltage filter circuit In the low-voltage filter circuit part, we mainly look at the size, number of turns and color of the inductor coil. Naturally, the larger the coil and the more turns, the better; as for the color, theoretically from best to worst, they are gray, black, light green and yellow, and the better the inductance, the smaller the loss. The low-voltage filter circuit mainly depends on the inductor coil. Heat sink The role of the heat sink is needless to say. Switching tubes and Schottky tubes that generate more heat are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks have fins. In theory, the more fins, the better. Passive PFC all use this "big head" inductor The inductor coil of active PFC is often located in front of the high voltage filter capacitor The power factor of passive PFC is generally around 0.7, while the power factor of active PFC is as high as 0.9 or above, which is significantly better than passive PFC. It is also quite easy to distinguish between the two. High-voltage filter capacitor What are the high-voltage filter capacitors? It's very simple. The highest and largest capacitor in the power supply is (1 to 2). When comparing capacitors, in principle, they can only be compared with power supplies of the same type, because at the same power, the capacitance required for passive PFC power supplies is larger than that of active ones. When comparing at the same level, we can see the capacity, withstand voltage and temperature resistance of the high-voltage filter capacitor. In theory, the larger the values of these three items, the better. The power supply adopts active PFC, so a high-voltage filter capacitor with a capacity of 330μF can meet the demand. The withstand voltage of the capacitor is 400V and the temperature resistance is 85℃. Power supply topology To put it simply, in the past few years, power supply topologies can be divided into two types: half-bridge and forward. Now the forward type is the main one. The half-bridge type is a traditional power supply structure, which usually has a low conversion efficiency; while the forward structure conversion efficiency can easily reach more than 80%. Traditional Half-Bridge Topology Forward topology helps improve conversion efficiency When distinguishing, we might as well use the elimination method: in the center of the half-bridge power supply, there must be three transformers, one large and two small, arranged in a straight line; if your power supply is not of this structure, then congratulations, this is most likely a forward power supply. Inductor coil of low-voltage filter circuit In the low-voltage filter circuit part, we mainly look at the size, number of turns and color of the inductor coil. Naturally, the larger the coil and the more turns, the better; as for the color, theoretically from best to worst, they are gray, black, light green and yellow, and the better the inductance, the smaller the loss. The low-voltage filter circuit mainly depends on the inductor coil. Heat sink The role of the heat sink is needless to say. Switching tubes and Schottky tubes that generate more heat are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks have fins. In theory, the more fins, the better. Passive PFC all use this "big head" inductor The inductor coil of active PFC is often located in front of the high voltage filter capacitor The power factor of passive PFC is generally around 0.7, while the power factor of active PFC is as high as 0.9 or above, which is significantly better than passive PFC. It is also quite easy to distinguish between the two. High-voltage filter capacitor What are the high-voltage filter capacitors? It's very simple. The highest and largest capacitor in the power supply is (1 to 2). When comparing capacitors, in principle, they can only be compared with power supplies of the same type, because at the same power, the capacitance required for passive PFC power supplies is larger than that of active ones. When comparing at the same level, we can see the capacity, withstand voltage and temperature resistance of the high-voltage filter capacitor. In theory, the larger the values of these three items, the better. The power supply adopts active PFC, so a high-voltage filter capacitor with a capacity of 330μF can meet the demand. The withstand voltage of the capacitor is 400V and the temperature resistance is 85℃. Power supply topology To put it simply, in the past few years, power supply topologies can be divided into two types: half-bridge and forward. Now the forward type is the main one. The half-bridge type is a traditional power supply structure, which usually has a low conversion efficiency; while the forward structure conversion efficiency can easily reach more than 80%. Traditional Half-Bridge Topology Forward topology helps improve conversion efficiency When distinguishing, we might as well use the elimination method: in the center of the half-bridge power supply, there must be three transformers, one large and two small, arranged in a straight line; if your power supply is not of this structure, then congratulations, this is most likely a forward power supply. Inductor coil of low-voltage filter circuit In the low-voltage filter circuit part, we mainly look at the size, number of turns and color of the inductor coil. Naturally, the larger the coil and the more turns, the better; as for the color, theoretically from best to worst, they are gray, black, light green and yellow, and the better the inductance, the smaller the loss. The low-voltage filter circuit mainly depends on the inductor coil. Heat sink The role of the heat sink is needless to say. Switching tubes and Schottky tubes that generate more heat are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks have fins. In theory, the more fins, the better. The power factor of passive PFC is generally around 0.7, while the power factor of active PFC is as high as 0.9 or above, which is significantly better than passive PFC. It is also quite easy to distinguish between the two.High-voltage filter capacitor What are high-voltage filter capacitors? It's very simple. The highest and largest capacitor in the power supply is (1 to 2). When comparing capacitors, in principle, they can only be compared with power supplies of the same type, because at the same power, the capacitance required for passive PFC power supplies is larger than that of active ones. When comparing at the same level, we can see the capacity, withstand voltage and temperature resistance of the high-voltage filter capacitor. In theory, the larger the values of these three items, the better. The power supply adopts active PFC, so a high-voltage filter capacitor with a capacity of 330μF can meet the demand. The withstand voltage of this capacitor is 400V and the temperature resistance is 85℃. Power supply topology "]To put it simply, in the past few years, the power supply topology can be divided into half-bridge and forward types. Now the forward type is the main one. The half-bridge type is a traditional power supply structure, which usually has a low conversion efficiency; while the forward structure conversion efficiency can easily reach more than 80%. Traditional half-bridge topology In distinguishing, we might as well use the method of elimination: in the center of the half-bridge power supply, there must be three transformers, one large and two small, arranged in a straight line; if your power supply is not of this structure, then congratulations, it is most likely a forward power supply. Inductor of low voltage filter circuit In the low voltage filter circuit, we mainly look at the size, number of turns and color of the inductor. Naturally, the larger the coil and the more turns, the better; as for the color, theoretically from best to worst, they are gray, black, light green and yellow. The better the inductance, the smaller the loss. The low-voltage filter circuit mainly depends on the inductor coil Heat sink The role of the heat sink is self-explanatory. Switch tubes and Schottky tubes with large heat generation are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks are equipped with fins. In theory, the more fins, the better. The power factor of passive PFC is generally around 0.7, while the power factor of active PFC is as high as 0.9 or above, which is significantly better than passive PFC. It is also quite easy to distinguish between the two.High-voltage filter capacitor What are high-voltage filter capacitors? It's very simple. The highest and largest capacitor in the power supply is (1 to 2). When comparing capacitors, in principle, they can only be compared with power supplies of the same type, because at the same power, the capacitance required for passive PFC power supplies is larger than that of active ones. When comparing at the same level, we can see the capacity, withstand voltage and temperature resistance of the high-voltage filter capacitor. In theory, the larger the values of these three items, the better. The power supply adopts active PFC, so a high-voltage filter capacitor with a capacity of 330μF can meet the demand. The withstand voltage of this capacitor is 400V and the temperature resistance is 85℃. Power supply topology "]To put it simply, in the past few years, the power supply topology can be divided into half-bridge and forward types. Now the forward type is the main one. The half-bridge type is a traditional power supply structure, which usually has a low conversion efficiency; while the forward structure conversion efficiency can easily reach more than 80%. Traditional half-bridge topology In distinguishing, we might as well use the method of elimination: in the center of the half-bridge power supply, there must be three transformers, one large and two small, arranged in a straight line; if your power supply is not of this structure, then congratulations, it is most likely a forward power supply. Inductor of low voltage filter circuit In the low voltage filter circuit, we mainly look at the size, number of turns and color of the inductor. Naturally, the larger the coil and the more turns, the better; as for the color, theoretically from best to worst, they are gray, black, light green and yellow. The better the inductance, the smaller the loss. The low-voltage filter circuit mainly depends on the inductor coil Heat sink The role of the heat sink is self-explanatory. Switch tubes and Schottky tubes with large heat generation are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks are equipped with fins. In theory, the more fins, the better. 2, left]Power supply topologyTo put it simply, in the past few years, power supply topologies can be divided into two types: half-bridge and forward. Now the forward type is the main one. The half-bridge type is a traditional power supply structure, which usually has a low conversion efficiency; while the forward type structure can easily achieve a conversion efficiency of more than 80%. Traditional Half-Bridge Topology Forward topology helps improve conversion efficiency When distinguishing, we might as well use the elimination method: in the center of the half-bridge power supply, there must be three transformers, one large and two small, arranged in a straight line; if your power supply is not of this structure, then congratulations, this is most likely a forward power supply. Inductor coil of low-voltage filter circuit In the low-voltage filter circuit part, we mainly look at the size, number of turns and color of the inductor coil. Naturally, the larger the coil and the more turns, the better; as for the color, theoretically from best to worst, they are gray, black, light green and yellow, and the better the inductance, the smaller the loss. The low-voltage filter circuit mainly depends on the inductor coil. Heat sink The role of the heat sink is needless to say. Switching tubes and Schottky tubes that generate more heat are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks have fins. In theory, the more fins, the better. 2, left]Power supply topologyTo put it simply, in the past few years, power supply topologies can be divided into two types: half-bridge and forward. Now the forward type is the main one. The half-bridge type is a traditional power supply structure, which usually has a low conversion efficiency; while the forward type structure can easily achieve a conversion efficiency of more than 80%. Traditional Half-Bridge Topology Forward topology helps improve conversion efficiency When distinguishing, we might as well use the elimination method: in the center of the half-bridge power supply, there must be three transformers, one large and two small, arranged in a straight line; if your power supply is not of this structure, then congratulations, this is most likely a forward power supply. Inductor coil of low-voltage filter circuit In the low-voltage filter circuit part, we mainly look at the size, number of turns and color of the inductor coil. Naturally, the larger the coil and the more turns, the better; as for the color, theoretically from best to worst, they are gray, black, light green and yellow, and the better the inductance, the smaller the loss. The low-voltage filter circuit mainly depends on the inductor coil. Heat sink The role of the heat sink is needless to say. Switching tubes and Schottky tubes that generate more heat are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks have fins. In theory, the more fins, the better. [left]Heat sink The role of the heat sink is self-explanatory. Switch tubes and Schottky tubes with large heat generation are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks are equipped with fins. In theory, the more fins, the better. [left]Heat sink The role of the heat sink is self-explanatory. Switch tubes and Schottky tubes with large heat generation are often installed on heat sinks. Currently, commercially available power supplies generally use aluminum heat sinks, and the thicker the better. At the same time, in order to expand the heat dissipation area within a limited space, most heat sinks are equipped with fins. In theory, the more fins, the better.
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