power supply circuit

Abstract

The application relates to a power supply circuit, which comprises a positive line, a negative line, a voltage reference unit, a current sampling unit and a feedback unit. The current sampling unit is arranged on the negative line. Two input ends of the feedback unit are connected to the negative line and are arranged on the two sides of the current sampling unit respectively. A first input end of the voltage reference unit is connected to an output end of the feedback unit. A second input end of the voltage reference unit is connected to the positive line. A third input end of the voltage reference unit is connected to the negative line. An output end of the voltage reference unit is connected to the positive line. The application can solve the problem of voltage drop after the power supply is loaded, and has the advantages of simple structure, low cost and good adaptability.

Description

Technical Field

[0001] This application relates to the field of power supply technology, and in particular to a power supply circuit. Background Technology

[0002] In DC power supply systems, a drop in output voltage after the power supply is under load is a common problem. The root cause is the voltage drop due to the resistance between the power supply line and the load. Furthermore, the larger the load current or the longer and smaller the wire diameter of the power supply line, the more pronounced the voltage drop problem becomes.

[0003] Traditional solutions primarily involve increasing the wire diameter to reduce resistance or shortening the power cord length to decrease voltage drop. However, increasing the wire diameter leads to thicker wires, more difficult wiring, and increased costs, while shortening the power cord is difficult to implement in space-constrained applications. In other words, these methods are poorly suited for compact, lightweight, or low-cost designs. Utility Model Content

[0004] To address the shortcomings of the prior art, this application provides a power supply circuit that can solve the voltage drop problem after the power supply is under load, and has a simple structure, low cost, and good adaptability.

[0005] This application provides a power supply circuit, including a positive line, a negative line, a voltage reference unit, a current sampling unit, and a feedback unit. The current sampling unit is disposed on the negative line. The two input terminals of the feedback unit are connected to the negative line and are respectively disposed on both sides of the current sampling unit. The first input terminal of the voltage reference unit is connected to the output terminal of the feedback unit, the second input terminal of the voltage reference unit is connected to the positive line, the third input terminal of the voltage reference unit is connected to the negative line, and the output terminal of the voltage reference unit is connected to the positive line.

[0006] In the power supply circuit of this application, the load current signal is acquired through a current sampling unit (located on the negative line). Simultaneously, the two input terminals of the feedback unit are connected across the current sampling unit to extract the line loss voltage difference signal. This signal is input to the voltage reference unit, which can dynamically adjust its internal reference voltage, causing the reference of the output voltage feedback loop to rise as the load current increases, directly offsetting the voltage drop caused by line resistance. This allows for automatic compensation of the output voltage drop caused by increased load current while maintaining the physical parameters of the output conductors. It also reduces structural limitations associated with increasing wire diameter or shortening wire length, significantly lowering costs and improving adaptability.

[0007] In some embodiments, the voltage reference unit includes a first resistor, a second resistor, and a Zener diode. The first resistor and the second resistor are connected in series. The first resistor is connected to the positive line, and the second resistor is connected to the negative line. The first input terminal of the Zener diode is connected to the output terminal of the feedback unit, the second input terminal of the Zener diode is connected between the first resistor and the second resistor, and the output terminal of the Zener diode is connected to the positive line.

[0008] In some embodiments, the power supply circuit is connected to the load to supply power to the load, and the current sampling unit includes a third resistor, which is disposed on the negative line near the load side.

[0009] In some embodiments, the feedback unit includes an operational amplifier, a fourth resistor, a fifth resistor, and a sixth resistor. The non-inverting input of the operational amplifier is connected to the negative line of the third resistor on the side closer to the load via the fourth resistor. The inverting input of the operational amplifier is connected to the negative line of the third resistor on the side farther from the load via the fifth resistor. The output of the operational amplifier is connected to the first input of the voltage reference unit. The output of the operational amplifier and the inverting input of the operational amplifier are connected via the sixth resistor.

[0010] In some embodiments, the power supply circuit further includes a resistor-capacitor (RC) buffer unit, one end of which is connected between the first resistor and the second resistor, and the other end of which is connected to the output terminal of the voltage reference unit.

[0011] In some embodiments, the RC buffer unit includes a seventh resistor, a first capacitor, and a second capacitor. The seventh resistor and the first capacitor are connected in series. One end of the seventh resistor and one end of the second capacitor are connected together to the output terminal of the voltage reference unit. One end of the first capacitor and the other end of the second capacitor are connected together between the first resistor and the second resistor.

[0012] In some embodiments, the power supply circuit further includes an overvoltage indicator unit, and the voltage reference unit is connected to the positive line via the overvoltage indicator unit, wherein the positive terminal of the overvoltage indicator unit is connected to the positive line, and the negative terminal of the overvoltage indicator unit is connected to the output terminal of the voltage reference unit.

[0013] In some embodiments, the overvoltage indication unit includes a light-emitting diode, an eighth resistor, and a ninth resistor. The positive terminal of the light-emitting diode is connected to the positive line through the eighth resistor, the negative terminal of the light-emitting diode is connected to the output terminal of the voltage reference unit, and the ninth resistor is connected in parallel with the light-emitting diode.

[0014] In some embodiments, the power supply circuit further includes a power supply connected to the positive and negative lines, a voltage reference unit disposed near the power supply, and a current sampling unit disposed near the load.

[0015] In some embodiments, the power supply circuit further includes a third capacitor, which is connected to the positive and negative lines and disposed near the power supply side. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure and electrical principle of the power supply circuit according to the first embodiment of this application.

[0017] Figure 2 This is a schematic diagram of the structure and electrical principle of the power supply circuit according to the second embodiment of this application.

[0018] Figure 3 This is a schematic diagram of the structure and electrical principle of the power supply circuit according to the third embodiment of this application.

[0019] Explanation of key component symbols:

[0020] 1. Power supply circuit; 2. Load; 11. Positive line; 12. Negative line; 13. Voltage reference unit; 14. Current sampling unit; 15. Feedback unit; 16. RC buffer unit; 17. Overvoltage indicator unit; 18. Power supply; R1, first resistor; R2, second resistor; U1, Zener diode; R3, third resistor; U2, operational amplifier; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor; R7, seventh resistor; C1, first capacitor; C2, second capacitor; D1, light-emitting diode; R8, eighth resistor; R9, ninth resistor; C3, third capacitor.

[0021] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0022] In the description of the embodiments in this application, the words "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of the words "exemplary," "or," and "for example" is intended to present the relevant concepts in a specific manner.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used in this application's specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. It should be understood that, unless otherwise stated, " / " in this application means "or". For example, A / B can mean A or B. "And / or" in this application is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. "At least one" refers to one or more. "More than one" refers to two or more. For example, at least one of a, b, or c can represent: a, b, c, a and b, a and c, b and c, and a, b, and c (seven cases).

[0024] It should also be noted that the terms "first" and "second" in the specification, claims and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence.

[0025] In DC power supply systems, the actual output voltage of the power supply device often drops compared to its no-load state when operating under load. This problem stems from the non-negligible resistance (commonly referred to as line loss Rline) of the connecting wires between the power supply output and the receiving device. According to physical laws, when current flows through a resistive wire, a voltage drop proportional to its resistance and current magnitude will inevitably occur (ΔU=I*Rline). Furthermore, the voltage drop becomes particularly pronounced when increased load power consumption leads to a significant increase in output current, or when longer, thinner power cables are used due to application requirements, increasing the wire resistance.

[0026] Traditionally, addressing voltage drop caused by line loss primarily relies on increasing the conductivity of the physical cable or shortening the transmission distance. The most direct approach is to use conductors with larger diameters and lower resistivity to reduce Rline, or to shorten the conductor length as much as possible within the limits of system design space.

[0027] However, these methods only focus on reducing line impedance at the physical level to decrease line voltage drop. Such solutions based on modifying physical cables have significant limitations. For example, thicker and stiffer cables lead to bending difficulties in confined spaces, making wiring challenging, complicating connector selection and matching, and significantly increasing the overall weight and volume of the wiring. Furthermore, using larger gauge conductors or advanced low-resistance materials inevitably increases raw material and processing costs. In applications where compact, lightweight design and cost control are extremely stringent (such as consumer electronics, portable devices, and distributed power systems), this approach, primarily based on physically replacing conductors, often exhibits poor structural adaptability and low economic efficiency.

[0028] Therefore, this application provides a power supply circuit that can solve the voltage drop problem under load, and has a simple structure, low cost, and good adaptability. Some embodiments will be described below with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0029] Figure 1 This is a schematic diagram of the structure and electrical principle of the power supply circuit 1 according to the first embodiment of this application.

[0030] like Figure 1 As shown, an embodiment of this application provides a power supply circuit 1, which may include a positive line 11, a negative line 12 (ground line), a voltage reference unit 13, a current sampling unit 14, and a feedback unit 15. The current sampling unit 14 may be disposed on the negative line 12, and the current signal of the load 2 is obtained through the current sampling unit 14 (which is disposed on the negative line 12). The two input terminals of the feedback unit 15 may be connected to the negative line 12 and may be respectively disposed on both sides of the current sampling unit 14, that is, the two input terminals of the feedback unit 15 are connected across both sides of the current sampling unit 14 to extract the line loss voltage difference signal. The first input terminal of the voltage reference unit 13 can be connected to the output terminal of the feedback unit 15, the second input terminal of the voltage reference unit 13 can be connected to the positive line 11, the third input terminal of the voltage reference unit 13 can be connected to the negative line 12, and the output terminal of the voltage reference unit 13 can be connected to the positive line 11. Thus, the voltage reference unit 13 can receive the aforementioned line loss voltage difference signal and dynamically adjust its internal reference voltage, causing the reference of the output voltage feedback loop to rise as the current of the load 2 increases, directly offsetting the voltage drop caused by the line resistance. In this case, it is possible to automatically compensate for the output voltage drop caused by the increase of the load 2 current while keeping the physical parameters of the output conductor unchanged, and it also reduces the structural limitations of increasing wire diameter or shortening wire length, significantly reducing costs and improving adaptability.

[0031] Figure 2 This is a schematic diagram of the structure and electrical principle of the power supply circuit 1 according to the second embodiment of this application.

[0032] In some embodiments, such as Figure 2As shown, the voltage reference unit 13 may include a first resistor R1, a second resistor R2, and a Zener diode U1. The first resistor R1 and the second resistor R2 are connected in series. The first resistor R1 is connected to the positive line 11, and the second resistor R2 is connected to the negative line 12. The first input terminal (i.e., the common terminal) of the Zener diode U1 is connected to the output terminal of the feedback unit 15, the second input terminal of the Zener diode U1 is connected between the first resistor R1 and the second resistor R2, and the output terminal of the Zener diode U1 is connected to the positive line 11. In this configuration, an initial reference is established by the voltage division of the first resistor R1 and the second resistor R2. The Zener diode U1 dynamically adjusts the voltage at the voltage division point through the compensation signal (i.e., the line loss voltage difference signal) output by the feedback unit 15. When the compensation signal raises the potential at the input terminal of the Zener diode U1, it forces a synchronous change in the potential at its cathode (output terminal), thereby altering the reference value of the voltage loop of the power supply 18. Therefore, by utilizing the synergistic effect of a simple voltage divider network and Zener diode U1, dynamic adjustment of the voltage reference can be achieved, ensuring that the compensation action is strictly synchronized with the load current 2, while maintaining the stability of the reference voltage.

[0033] In some embodiments, the Zener diode U1 is also called a voltage regulator, which can be an adjustable output voltage regulator. That is, the output voltage can be set (within the specification range) by connecting an external voltage divider consisting of two resistors, such as the first resistor R1 and the second resistor R2 in the embodiments of this application. In addition, the voltage regulator can also be connected to an additional external feedback terminal, such as the feedback unit 15 in the embodiments of this application.

[0034] In some embodiments, such as Figure 2 As shown, the power supply circuit 1 can be connected to the load 2 to supply power to the load 2. The current sampling unit 14 can include a third resistor R3 (also called a sampling resistor), which can be placed close to the load 2 on the negative line 12. In this case, the current sampling unit 14 is arranged close to the load 2 terminal on the negative line 12, so that the third resistor R3 is directly connected in series in the line. The voltage difference (ΔU=Iout×(R3+Rline)) generated by the load 2 current (Iout) flowing through the sampling resistor can reflect the complete loop impedance characteristics, including the wire resistance (Rline). A more realistic line loss related signal can be captured at the closest point to the load 2, thereby reducing the interference of parasitic impedance on the power supply 18 side and ensuring that the compensation result strictly corresponds to the actual voltage drop at the load 2 terminal.

[0035] In some embodiments, the load 2 may include, but is not limited to, at least one of the following electrical devices: consumer electronics (such as laptops), portable devices (such as mobile phones), and terminal devices of the distributed power supply system (such as servers).

[0036] In some embodiments, such as Figure 2As shown, the feedback unit 15 may include an operational amplifier U2, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The non-inverting input of operational amplifier U2 can be connected to the negative line 12 of the third resistor R3 near the load 2 via the fourth resistor R4. The inverting input of operational amplifier U2 can be connected to the negative line 12 of the third resistor R3 away from the load 2 via the fifth resistor R5. The output of operational amplifier U2 can be connected to the first input of the voltage reference unit 13, and the output of operational amplifier U2 can be connected to its inverting input via the sixth resistor R6. In this scenario, operational amplifier U2 can acquire the voltage across the third resistor R3 via the fourth resistor R4 and the fifth resistor R5, respectively. The closed-loop gain (K) can be set using the sixth resistor R6. Operational amplifier U2 can then amplify the voltage difference (ΔU) on both sides and output a compensation signal. The output value can satisfy the formula: K=(ΔU·Gv) / (Iout×R3). Through the resistor network (i.e., the aforementioned voltage divider), a mathematical relationship can be constructed between the output voltage detection voltage division ratio (Gv=R2 / (R1+R2)) and the line loss compensation amount. Thus, the theoretical compensation model can be implemented with a pure hardware circuit, thereby reducing the voltage difference error between the voltage detection point and the two ends of the load.

[0037] It is understood that in the power supply circuit 1 of this application embodiment, the resistance values ​​of the first resistor R1, the second resistor R2 and the third resistor R3 are all fixed values. Therefore, by detecting the load current and line loss resistance, the resistance values ​​of the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6 can be determined through the above mathematical relationship. Thus, resistors with more suitable resistance values ​​can be selected to match different load 2 conditions and improve the compensation accuracy.

[0038] Figure 3 This is a schematic diagram of the structure and electrical principle of the power supply circuit 1 according to the second embodiment of this application.

[0039] In some embodiments, such as Figure 3 As shown, the power supply circuit 1 may further include a resistor-capacitor (RC) buffer unit 16. In the power supply circuit 1 of this embodiment, one end of the RC buffer unit 16 can be connected between the first resistor R1 and the second resistor R2, and the other end of the RC buffer unit 16 can be connected to the output terminal of the voltage reference unit 13. In this case, the RC buffer unit 16 is connected across the voltage divider point and the output terminal of the voltage reference unit 13 to form a low-pass filter network, which filters out the high-frequency fluctuation components in the feedback compensation signal. This can reduce the instantaneous jump in the reference voltage caused by sudden changes in the load 2 or noise, thereby maintaining the stability of the voltage loop reference, avoiding the risk of overcompensation or oscillation, and improving the system's anti-interference capability.

[0040] In some embodiments, such as Figure 3As shown, the RC buffer unit 16 may include a seventh resistor R7, a first capacitor C1, and a second capacitor C2. The seventh resistor R7 can be connected in series with the first capacitor C1. One end of the seventh resistor R7 and one end of the second capacitor C2 can be connected together to the output terminal of the voltage reference unit 13. One end of the first capacitor C1 and the other end of the second capacitor C2 can be connected together between the first resistor R1 and the second resistor R2. In this case, the seventh resistor R7 and the first capacitor C1 can form the main body of the RC filter, and the second capacitor C2 connected in parallel can provide high-frequency bypass. This can jointly attenuate the AC component in the compensation signal, that is, the transient response characteristics of the reference voltage can be optimized through the dual filtering structure, and the influence of high-frequency interference on the voltage loop reference can be further isolated, thereby ensuring that the compensation process is smooth and without overshoot.

[0041] In some embodiments, such as Figure 3 As shown, the power supply circuit 1 may further include an overvoltage indicator unit 17. In the power supply circuit 1 of this embodiment, the voltage reference unit 13 can be connected to the positive line 11 via the overvoltage indicator unit 17. The positive terminal of the overvoltage indicator unit 17 can be connected to the positive line 11, and the negative terminal of the overvoltage indicator unit 17 can be connected to the output terminal of the voltage reference unit 13. In this case, the overvoltage indicator unit 17 is connected between the output terminal of the reference unit and the positive line 11. When overcompensation causes an abnormal rise in the reference voltage, this unit triggers a protection action, thereby increasing the safety redundancy of the compensation mechanism, providing visual / electrical protection in case of circuit failure or parameter drift, and reducing damage to the load 2 equipment caused by overcompensation.

[0042] In some embodiments, such as Figure 3 As shown, the overvoltage indicator unit 17 may include a light-emitting diode (LED) D1, an eighth resistor R8, and a ninth resistor R9. The positive terminal of LED D1 can be connected to the positive line 11 through the eighth resistor R8, and the negative terminal of LED D1 can be connected to the output terminal of the voltage reference unit 13. The ninth resistor R9 can be connected in parallel with LED D1. In this case, the eighth resistor R8 can be used to limit current to protect LED D1 from overcurrent burnout. Under normal conditions, LED D1 is conducting and emitting light (the voltage on the positive line 11 is greater than the reference voltage). When the compensation voltage exceeds the threshold, LED D1 is turned off due to the rise in the negative terminal potential (the reference voltage is greater than the voltage on the positive line 11). The ninth resistor R9 can provide a leakage current bypass path, thereby providing an intuitive light signal to indicate the overvoltage risk. The parallel ninth resistor R9 can also reduce false triggering to ensure the sensitivity of the protection action, achieving low-cost and high-reliability safety protection.

[0043] In some embodiments, the power supply circuit 1 may further include a power supply 18. In the power supply circuit 1 of this application embodiment, the power supply 18 may be connected to the positive line 11 and the negative line 12, the voltage reference unit 13 may be disposed close to the power supply 18, and the current sampling unit 14 may be disposed close to the load 2. In this case, the voltage reference unit 13 is disposed close to the power supply 18 to reduce its own voltage drop error, and the current sampling unit 14 is disposed close to the load 2 to obtain the most accurate current-voltage difference signal. Through this physical layout optimization, the influence of path parasitic parameters on sampling accuracy and reference stability can be minimized, ensuring the overall compensation accuracy of the power supply circuit 1 of this application embodiment.

[0044] In some embodiments, such as Figure 3 As shown, the power supply circuit 1 may also include a third capacitor C3. In the power supply circuit 1 of this embodiment, the third capacitor C3 may be connected to the positive line 11 and the negative line 12 and disposed near the power supply 18. In this case, by placing the input capacitor (i.e., the third capacitor C3) near the power supply 18, the high-frequency ripple on the power supply 18 side is directly absorbed, and external interference can be reduced at the power supply 18 inlet. This prevents input noise from affecting the detection path at the load 2 end through the compensation loop, thereby ensuring the purity and accuracy of the compensation signal.

[0045] In summary, in the power supply circuit 1 of this application embodiment, the current signal of the load 2 is obtained through the current sampling unit 14 (which is disposed on the negative line 12). At the same time, the two input terminals of the feedback unit 15 are connected across the two sides of the current sampling unit 14 to extract the line loss voltage difference signal. After this signal is input to the voltage reference unit 13, the voltage reference unit 13 can dynamically adjust its internal reference voltage, so that the reference of the output voltage feedback loop rises as the current of the load 2 increases, directly offsetting the voltage drop caused by the line resistance. Thus, it can automatically compensate for the output voltage drop caused by the increase of the current of the load 2 without changing the physical parameters of the output conductor, and can also reduce the structural limitations of increasing the wire diameter or shortening the wire length, significantly reducing costs and improving adaptability.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A power supply circuit, characterized in that, It includes a positive line, a negative line, a voltage reference unit, a current sampling unit, and a feedback unit. The current sampling unit is disposed on the negative line. The two input terminals of the feedback unit are connected to the negative line and are respectively disposed on both sides of the current sampling unit. The first input terminal of the voltage reference unit is connected to the output terminal of the feedback unit. The second input terminal of the voltage reference unit is connected to the positive line. The third input terminal of the voltage reference unit is connected to the negative line. The output terminal of the voltage reference unit is connected to the positive line.

2. The power supply circuit according to claim 1, characterized in that, The voltage reference unit includes a first resistor, a second resistor, and a Zener diode. The first resistor and the second resistor are connected in series. The first resistor is connected to the positive line, and the second resistor is connected to the negative line. The first input terminal of the Zener diode is connected to the output terminal of the feedback unit, the second input terminal of the Zener diode is connected between the first resistor and the second resistor, and the output terminal of the Zener diode is connected to the positive line.

3. The power supply circuit according to claim 1, characterized in that, The power supply circuit is connected to the load to supply power to the load, and the current sampling unit includes a third resistor, which is disposed on the negative line near the load.

4. The power supply circuit according to claim 3, characterized in that, The feedback unit includes an operational amplifier, a fourth resistor, a fifth resistor, and a sixth resistor. The non-inverting input of the operational amplifier is connected to the negative line of the third resistor on the side closer to the load through the fourth resistor. The inverting input of the operational amplifier is connected to the negative line of the third resistor on the side farther from the load through the fifth resistor. The output of the operational amplifier is connected to the first input of the voltage reference unit. The output of the operational amplifier and the inverting input of the operational amplifier are connected through the sixth resistor.

5. The power supply circuit according to claim 2, characterized in that, The power supply circuit also includes a resistor-capacitor (RC) buffer unit, one end of which is connected between the first resistor and the second resistor, and the other end of which is connected to the output terminal of the voltage reference unit.

6. The power supply circuit according to claim 5, characterized in that, The RC buffer unit includes a seventh resistor, a first capacitor, and a second capacitor. The seventh resistor is connected in series with the first capacitor. One end of the seventh resistor and one end of the second capacitor are connected together to the output terminal of the voltage reference unit. One end of the first capacitor and the other end of the second capacitor are connected together between the first resistor and the second resistor.

7. The power supply circuit according to claim 1, characterized in that, The power supply circuit also includes an overvoltage indicator unit. The voltage reference unit is connected to the positive line via the overvoltage indicator unit, wherein the positive terminal of the overvoltage indicator unit is connected to the positive line, and the negative terminal of the overvoltage indicator unit is connected to the output terminal of the voltage reference unit.

8. The power supply circuit according to claim 7, characterized in that, The overvoltage indicator unit includes a light-emitting diode, an eighth resistor, and a ninth resistor. The positive terminal of the light-emitting diode is connected to the positive line through the eighth resistor, and the negative terminal of the light-emitting diode is connected to the output terminal of the voltage reference unit. The ninth resistor is connected in parallel with the light-emitting diode.

9. The power supply circuit according to claim 3, characterized in that, The power supply circuit also includes a power source connected to the positive line and the negative line. The voltage reference unit is located near the power source, and the current sampling unit is located near the load.

10. The power supply circuit according to claim 9, characterized in that, The power supply circuit also includes a third capacitor, which is connected to the positive line and the negative line and is located close to the power supply side.

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