Line loss voltage compensation circuit

Abstract

The utility model provides a kind of line loss voltage compensation circuit, it includes: load current detection circuit, signal amplification circuit, error current detection circuit and voltage compensation circuit;Wherein, the load current detection circuit, signal amplification circuit, error current detection circuit, compensation control unit are connected in turn, and the voltage compensation circuit is simultaneously connected power management chip.The circuit structure of the present application is simple, without voltage sampling to remote port voltage by sampling line, can automatically calculate compensation voltage, and the automatic high-precision compensation of voltage is realized by power management chip, to offset line loss influence, ensure that load end voltage is stable.

Description

Technical Field

[0001] This utility model relates to the field of circuit design technology, and in particular to a line loss voltage compensation circuit. Background Technology

[0002] With the continuous development of electronic technology, electronic products are becoming increasingly diversified and their performance is constantly improving. Therefore, a more stable power supply is needed. However, due to the resistance of the power supply line, line loss occurs during the current transmission process, which further leads to unstable voltage at both ends of the load module and affects the power supply of the equipment. Therefore, line loss compensation function is needed to ensure voltage stability.

[0003] The existing line loss compensation schemes have complex structural designs. For example, the technical solution with application number 202110767861.2 and patent name "line loss compensation module, switching power supply chip and system" involves dozens of electronic components. The technical solution with application number 202010258150.8 and patent name "a line loss compensation circuit and control method for a low dropout linear voltage regulator circuit" requires the setting of multiple PMOS transistors and NMOS transistors, which also leads to complex structural designs. Utility Model Content

[0004] The voltage compensation circuit in this invention has a simple structure design. It does not require sampling the voltage at the remote port through a sampling line. It can automatically calculate the compensation voltage and achieve automatic high-precision voltage compensation through a power management chip to offset the influence of line loss and ensure the stability of the load voltage.

[0005] This utility model provides a line loss voltage compensation circuit, which includes: a load current detection circuit, a signal amplification circuit, an error current detection circuit, and a voltage compensation circuit.

[0006] The load current detection circuit, signal amplification circuit, error current detection circuit, and compensation control unit are connected in sequence, and the voltage compensation circuit is also connected to the power management chip.

[0007] The load current detection circuit includes a sampling unit for outputting the load current value I in the main circuit. out The power management chip calculates the load current value I in the main circuit based on the voltage drop generated when the sampled unit flows through it. out ;

[0008] The signal amplification circuit is connected to the load current detection circuit and is used to amplify the voltage signal output by the load current detection circuit to obtain an amplified error voltage signal.

[0009] The error current detection circuit is connected to the signal amplification circuit and is used to generate a voltage drop signal when current flows through it. The power management chip calculates the error current value Ierr based on the main circuit preset voltage, the error voltage signal, and the voltage drop signal generated when current flows through the error current detection circuit.

[0010] The voltage compensation circuit is connected to both the error current detection circuit and the power management chip, and the power management chip calculates the compensation voltage V based on the error current value Ierr. com And according to the compensation voltage V com Control the voltage output of the voltage compensation circuit.

[0011] Preferably, the load current detection circuit further includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first operational amplifier;

[0012] The first resistor R1 and the second resistor R2 are respectively connected to one end of the sampling unit, and the first resistor is also connected to the inverting input terminal of the first operational amplifier, and the second resistor R2 is also connected to the non-inverting input terminal of the first operational amplifier.

[0013] The third resistor R3 is connected to the first resistor R1 and the output terminal of the first operational amplifier, and the fourth resistor R4 is connected to the second resistor R2 and ground.

[0014] Preferably, the sampling unit includes a sampling resistor R. sense Or current transformer.

[0015] Preferably, the signal amplification circuit includes: a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a second operational amplifier;

[0016] The fifth resistor R5 is connected to the output terminal of the first operational amplifier and the inverting input terminal of the second operational amplifier, respectively.

[0017] The sixth resistor R6 is connected to the non-inverting input terminal of the second operational amplifier 3 and the reference voltage Vpos, respectively.

[0018] The seventh resistor R7 is connected to the non-inverting input terminal of the second operational amplifier and ground, and the eighth resistor R8 is connected to the inverting input terminal and the output terminal of the second operational amplifier.

[0019] Preferably, the error current detection circuit includes a ninth resistor R9 and a diode D1, wherein the ninth resistor R9 is connected to the output terminal of the second operational amplifier and the negative terminal of the diode D1, respectively.

[0020] Preferably, the voltage compensation circuit includes a tenth resistor R10 and an eleventh resistor R11, wherein the tenth resistor R10 and the eleventh resistor R11 are both connected to the positive terminal of diode D1, and the tenth resistor R10 is also connected to the compensation voltage output terminal Vout+, and the eleventh resistor R11 is grounded.

[0021] The beneficial effects of this utility model are:

[0022] The line loss voltage compensation circuit in this invention has a simple design. It does not require voltage sampling at the remote port via a sampling line; it only needs its own load current detection circuit to obtain the load current value I in the main circuit. out The error voltage is used as the reference voltage for power loop control, and the compensation voltage is automatically calculated. Finally, the power management chip realizes automatic high-precision voltage compensation to offset the influence of line loss and ensure the stability of the load voltage. Attached Figure Description

[0023] Figure 1 This is a structural diagram of the line loss voltage compensation circuit in this utility model. Detailed Implementation

[0024] The following are merely preferred embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the scope of protection of this utility model. The embodiments described below are only for explaining this utility model and should not be construed as limiting this utility model. The scope of protection of this utility model should be determined by the scope of the claims. The embodiments of this utility model are described in detail below. In order to facilitate the description of this utility model and simplify the description, the technical terms used in the specification of this utility model should be interpreted broadly, including but not limited to conventional alternatives not mentioned in this application, as well as direct and indirect implementation methods.

[0025] Example 1

[0026] This embodiment discloses a line loss voltage compensation circuit, such as Figure 1 As shown, it includes: a load current detection circuit 100, a signal amplification circuit 200, an error current detection circuit 300, and a voltage compensation circuit 400.

[0027] The load current detection circuit 100, signal amplification circuit 200, error current detection circuit 300, and voltage compensation circuit 400 are connected in sequence, and the voltage compensation circuit 400 is also connected to the power management chip U. The connection includes an electrical connection.

[0028] The load current detection circuit 100 includes a sampling unit 1 for outputting the load current value I in the main circuit. out (Right now Figure 1 The voltage drop generated when the current i) flows through the sampling unit 1 is used by the power management chip U to calculate the load current I in the main circuit based on the voltage drop. out ;

[0029] The signal amplification circuit 200 is connected to the load current detection circuit 100 and is used to amplify the voltage signal output by the load current detection circuit 100 (i.e., the voltage drop generated when flowing through the sampling unit 1) to obtain the amplified error voltage signal and output it to the power management chip U.

[0030] The error current detection circuit 300 is connected to the signal amplification circuit 200 and is used to generate a voltage drop signal when current flows through it. The power management chip U calculates the error current value Ierr based on the main circuit preset voltage Vref, the error voltage signal, and the voltage drop signal generated when current flows through the error current detection circuit 300.

[0031] The voltage compensation circuit 400 is connected to the error current detection circuit 300 and the power management chip U, respectively, and the power management chip U calculates the compensation voltage V based on the error current value Ierr. com And according to the compensation voltage V com The voltage output of the control voltage compensation circuit 400 is controlled so that the difference between the load voltage and the target voltage is within a preset range, thereby achieving line loss compensation.

[0032] Specifically, the load current detection circuit 100 includes: a sampling unit 1, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first operational amplifier 2;

[0033] The sampling unit 1 is connected in series in the main circuit. In this embodiment, the sampling unit 1 includes a sampling resistor R. sense Or current transformer;

[0034] The first resistor R1 and the second resistor R2 are respectively connected to one end of the sampling unit 1, and the first resistor R1 is also connected to the inverting input terminal of the first operational amplifier 2, and the second resistor R2 is also connected to the non-inverting input terminal of the first operational amplifier 2.

[0035] The third resistor R3 is connected to the first resistor R1 and the output terminal of the first operational amplifier 2, and the fourth resistor R4 is connected to the second resistor R2 and ground.

[0036] In this embodiment, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, and the first operational amplifier 2 can form a differential amplifier circuit, which can obtain the load current I in the main circuit. out (Right now Figure 1 The voltage drop generated when the current i) flows through the sampling unit 1 is obtained, and the current value flowing through the load in the main circuit is obtained based on the voltage drop.

[0037] For example, in this embodiment, it is known that sampling unit 1 is a sampling resistor R. sense And R sense =0.01Ω, R1=R2=1000Ω, R3=10kΩ, the voltage drop V at the output of the first operational amplifier 2. diff =1V, since the formula V holds true. sense =I out* R sense V diff = V sense *R3 / R2, where V sense If the sampling voltage is at sampling unit 1, then the power management chip U can be determined according to formula V. sense =I out* R sense V diff = V sense * Solve for V using R3 / R2 respectively. sense =0.1V, I out =10A.

[0038] Furthermore, the signal amplification circuit 200 includes: a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a second operational amplifier 3;

[0039] The fifth resistor R5 is connected to the output terminal of the first operational amplifier 2 and the inverting input terminal of the second operational amplifier 3, respectively.

[0040] The sixth resistor R6 is connected to the non-inverting input terminal of the second operational amplifier 3 and the reference voltage Vpos (in this embodiment, Vpos = 5V).

[0041] The seventh resistor R7 is connected to the non-inverting input terminal of the second operational amplifier 3 and ground, and the eighth resistor R8 is connected to the inverting input terminal and the output terminal of the second operational amplifier 3.

[0042] For example, in this embodiment, if R6 = 1kΩ and R7 = 380Ω are known, the power management chip calculates the error voltage Verr based on the error voltage signal output by the second operational amplifier 3 as follows: Verr = (R7 * (V pos -V diff)) / R6=(380Ω*(5V-1V)) / 1kΩ=1.52V.

[0043] Therefore, the signal amplification circuit 200 can amplify the output voltage (i.e., V) of the first operational amplifier 2. diff ) and reference voltage V pos The output voltage of the second operational amplifier 3 is amplified based on the difference between the two to obtain the amplified error voltage Verr, which is convenient for subsequent calculation of the compensation voltage.

[0044] The error current detection circuit 300 includes a ninth resistor R9 and a diode D1, wherein the ninth resistor R9 is connected to the output terminal of the second operational amplifier 3 and the negative terminal of the diode D1, respectively.

[0045] For example, in this embodiment, if R9 = 20kΩ, the voltage drop of diode D1 Vf = 0.5V, and the preset voltage of the main circuit Vref = 2.4V, then the power management chip U calculates the error current value Ierr according to the following formula: Ierr = (Vref - Vf - Verr) / R9 = (2.4V - 0.5V - 1.52V) / 20kΩ = 19μA.

[0046] The voltage compensation circuit 400 includes a tenth resistor R10 and an eleventh resistor R11, wherein the tenth resistor R10 and the eleventh resistor R11 are both connected to the positive terminal of diode D1, and the tenth resistor R10 is also connected to the compensation voltage output terminal Vout+, and the eleventh resistor R11 is also grounded.

[0047] For example, in this embodiment, if R10 = 20kΩ is known, the power management chip U calculates the compensation voltage V according to the following formula. com Compensation voltage V com =Ierr*R10=19μA*20kΩ=0.38V.

[0048] Furthermore, the power management chip U adjusts the compensation voltage V according to... com Adjust the voltage at the compensation voltage output terminal Vout+ so that the difference between the load voltage and the target voltage is within a preset range, thereby compensating for line loss.

[0049] In this embodiment, the power management chip U can be an existing product, which includes:

[0050] The PWM controller 402 and / or MOSFET switch 403 can adjust the voltage at the power supply output terminal by adjusting the PWM duty cycle of the PWM controller 402 or the switching frequency of the MOSFET switch 403, and output the voltage change at the power supply output terminal Vout+, such that the change in voltage at the power supply output terminal Vout+ is related to the compensation voltage V.com This ensures that the voltage output at the voltage output terminal Vout+ is the same as the target voltage.

[0051] In addition, error amplifier 401 is used to amplify the voltage difference signal between the voltage output at voltage output terminal Vout+ and the target voltage, so as to ensure that the voltage difference signal can effectively drive the execution of subsequent voltage compensation steps and further improve the voltage compensation accuracy.

[0052] Specifically, increasing the duty cycle of the PWM or decreasing the switching frequency of the MOSFET will increase the voltage output at the voltage output terminal Vout+, and the amount of voltage increase will be equal to the compensation voltage V. com Ultimately, the load voltage (i.e., the voltage output at the Vout terminal + the output voltage) will equal the target voltage.

[0053] Decreasing the duty cycle of the PWM or increasing the switching frequency will reduce the voltage output at the voltage output terminal Vout+, and the amount of voltage reduction will be equal to the compensation voltage V. com Ultimately, the load voltage will equal the target voltage.

[0054] In this embodiment, the cross-sectional area S of the output cable (copper wire) is known. wire =2.5mm 2 Output cable length L wire =5500mm, resistivity ρ of copper wire cu =1.72*10 -8 *Ω*m, then the output cable resistance R wire for:

[0055] R wire =(ρ cu* L wire ) / S wire =(1.72*10 -8 (*Ω*m*5500mm) / 2.5mm 2 =0.038Ω, further according to V wire =I out * R wire Calculate the line loss voltage drop when current flows through the output cable. Tables 1-1 and 1-2 show the load current value I in the main circuit. out The line loss voltage drop V when the current flows through the output cable at currents of 1-20A. wire and compensation voltage V com .

[0056] Table 1-1 Load Current Values ​​I out Line loss voltage drop V when 1-10A wire and compensation voltage V com

[0057]

[0058] Table 1-2 Load Current Values ​​I out Line loss voltage drop V at 11-20A wire and compensation voltage V com

[0059]

[0060] As can be seen from Tables 1-1 and 1-2, when the load current value I... out For the range of 1-20A, the line loss voltage drop V wire and compensation voltage V com They are essentially equal, with an error of less than 10mV. Therefore, the compensation control unit 400 determines the compensation based on the compensation voltage V. com Adjust the voltage at the power supply output terminal so that the change in voltage at the power supply output terminal Vout+ is related to the compensation voltage V. com This ensures that the voltage output at the voltage output terminal Vout+ is the same as the target voltage, thereby achieving high-precision compensation for output line loss voltage.

[0061] It should also be noted that the load current value I in this embodiment is... out Error voltage Verr, error current Ierr, compensation voltage V com The calculations are all based on Ohm's law, which is common knowledge in this field.

[0062] In summary, the line loss voltage compensation circuit structure in this application is extremely simple. It eliminates the need for voltage sampling at the remote port via a sampling line, saving on sampling lines and the difficulty of laying cables. The load current value I in the main circuit can be obtained solely through its own load current detection circuit. out The error voltage is used as the reference voltage for power loop control, and the compensation voltage is automatically calculated. Finally, the power management chip realizes automatic high-precision voltage compensation to offset the influence of line loss and ensure the stability of the load voltage.

[0063] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A line loss voltage compensation circuit, characterized in that, include: Load current detection circuit, signal amplification circuit, error current detection circuit, and voltage compensation circuit; The load current detection circuit, signal amplification circuit, error current detection circuit, and compensation control unit are connected in sequence, and the voltage compensation circuit is also connected to the power management chip. The load current detection circuit includes a sampling unit for outputting the load current value I in the main circuit. out The power management chip calculates the load current value I in the main circuit based on the voltage drop generated when the sampled unit flows through it. out ; The signal amplification circuit is connected to the load current detection circuit and is used to amplify the voltage signal output by the load current detection circuit to obtain an amplified error voltage signal. The error current detection circuit is connected to the signal amplification circuit and is used to generate a voltage drop signal when current flows through it. The power management chip calculates the error current value Ierr based on the main circuit preset voltage, the error voltage signal, and the voltage drop signal generated when current flows through the error current detection circuit. The voltage compensation circuit is connected to both the error current detection circuit and the power management chip, and the power management chip calculates the compensation voltage V based on the error current value Ierr. com And according to the compensation voltage V com Control the voltage output of the voltage compensation circuit.

2. The line loss voltage compensation circuit as described in claim 1, characterized in that, The load current detection circuit further includes: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, and a first operational amplifier; The first resistor R1 and the second resistor R2 are respectively connected to one end of the sampling unit, and the first resistor is also connected to the inverting input terminal of the first operational amplifier, and the second resistor R2 is also connected to the non-inverting input terminal of the first operational amplifier. The third resistor R3 is connected to the first resistor R1 and the output terminal of the first operational amplifier, and the fourth resistor R4 is connected to the second resistor R2 and ground.

3. The line loss voltage compensation circuit as described in claim 1, characterized in that, The sampling unit includes a sampling resistor R. sense Or current transformer.

4. The line loss voltage compensation circuit as described in claim 1, characterized in that, The signal amplification circuit includes: a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, and a second operational amplifier; The fifth resistor R5 is connected to the output terminal of the first operational amplifier and the inverting input terminal of the second operational amplifier, respectively. The sixth resistor R6 is connected to the non-inverting input terminal of the second operational amplifier 3 and the reference voltage Vpos, respectively. The seventh resistor R7 is connected to the non-inverting input terminal of the second operational amplifier and ground, and the eighth resistor R8 is connected to the inverting input terminal and the output terminal of the second operational amplifier.

5. The line loss voltage compensation circuit as described in claim 4, characterized in that, The error current detection circuit includes a ninth resistor R9 and a diode D1, wherein the ninth resistor R9 is connected to the output terminal of the second operational amplifier and the negative terminal of the diode D1.

6. The line loss voltage compensation circuit as described in claim 5, characterized in that, The voltage compensation circuit includes a tenth resistor R10 and an eleventh resistor R11, wherein the tenth resistor R10 and the eleventh resistor R11 are both connected to the positive terminal of diode D1, and the tenth resistor R10 is also connected to the compensation voltage output terminal Vout+, and the eleventh resistor R11 is grounded.

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