Adjustable electronic load circuit

Abstract

The utility model relates to an adjustable electronic load circuit, which comprises a filtering module, a power supply module, a current control module, a current and voltage detection module, a work indication module and an input slow start module, wherein the filtering module is coupled between an input voltage VIN of a power supply end and a power ground GND; the power supply module is used for converting an input voltage VIN into a working voltage VCC and providing the working voltage VCC to the current control module and the current and voltage detection module; the current control module is used for adjusting the loop current and providing the loop current to the current and voltage detection module; the current and voltage detection module is used for monitoring input voltage VIN and loop current; the working indication module is used for indicating the working state of the adjustable electronic load circuit; and the input slow start module is used for controlling the on-off of the work indication module. The technical problem that in the prior art, when a plurality of resistors are used at the same time, the current of a loop where each resistor is located cannot be monitored is solved, and the technical effect of ensuring the stability of the current of the loop is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of integrated circuits, and more particularly to an adjustable electronic load circuit. Background Art

[0002] In the prior art, high-power resistors are often used as loads. However, due to their large volume, small adjustable resistance value, and large resistance span between electrodes, they have problems such as small applicable space, high heat dissipation requirements, heat concentration, and inability to accurately adjust the loop current. Moreover, when multiple resistors are used simultaneously, since the loop current of each resistor circuit cannot be monitored, the stability of the loop current cannot be guaranteed, and thus the current balance cannot be ensured. Summary of the Utility Model

[0003] To solve the above problems, an embodiment of the present application provides an adjustable electronic load circuit, including a filtering module, a power supply module, a current control module, a current and voltage detection module, a working indication module, and an input soft start module: The filtering module is coupled between the input voltage VIN of the power supply terminal and the power supply ground GND; the power supply module is used to convert the input voltage VIN into a working voltage VCC and supply it to the current control module and the current and voltage detection module; the current control module is used to adjust the loop current and supply the loop current to the current and voltage detection module; the current and voltage detection module is used to monitor the input voltage VIN and the loop current; the working indication module is used to indicate the working state of the adjustable electronic load circuit; the input soft start module is used to control the on-off of the working indication module.

[0004] Preferably, the filtering module includes resistors R19 - R24 and capacitors C7 - C11; the resistor R19 and the resistor R20 are in parallel with the input voltage VIN, and the capacitor C10 is connected in series between the common terminal of the resistor R19 and the resistor R20 and the power supply ground GND; the input voltage VIN and the ground terminal are respectively connected in series with the resistor R21 and the capacitor C11, the resistor R22 and the capacitor C7 in sequence; the power supply ground GND and the ground terminal are respectively connected in series with the resistor R23 and the capacitor C8, the resistor R24 and the capacitor C9 in sequence.

[0005] Preferably, the power supply module includes chip U4, diode D1, reference chip Q3, inductor L1, capacitors C1 - C3, capacitor C5, resistors R10, R12, and R13; the negative electrode of the diode D1 is sequentially connected in series with the inductor L1 and the capacitor C3, the positive electrode of the diode D1 and the capacitor C3 are both grounded, and the common terminal of the inductor L1 and the capacitor C2 is connected to the operating voltage VCC; between the operating voltage VCC and the ground terminal, the resistor R13 and the resistor R12 are sequentially connected in series, and the capacitor C5 is connected in parallel across the resistor R13; the chip U4 has a VIN pin connected to the input voltage VIN, a GND pin for grounding, a BST pin and a SW pin connected in parallel with the capacitor CI, an FB pin connected to the common terminal of the resistor R12 and the resistor R13, and an EN pin connected to the first pin of the reference chip Q3; the resistor R10 and the reference chip Q3 are sequentially connected in series between the input voltage VIN and the ground terminal, the second pin of the reference chip Q3 is connected in series with the resistor R10, and the third pin of the reference chip Q3 is grounded.

[0006] Preferably, the current control module includes a sampling unit and a control unit; the sampling unit is connected to the power supply ground GND, outputs a sampling voltage, and provides it to the control unit; the control unit is used to adjust the loop current according to the sampling voltage and the reference voltage VREF.

[0007] Preferably, the sampling unit includes sampling resistors R1, R2, R3, and R5 connected in parallel.

[0008] Preferably, the control unit includes chip U3, field - effect transistor Q1, resistors R6, R9, and switch S2;

[0009] The resistor R6 and the resistor R9 are sequentially connected in series between the operating voltage VCC and the ground terminal;

[0010] The chip U3 has a first pin connected to the gate of the field - effect transistor Q1, a second pin for grounding, a third pin connected to the reference voltage VREF, a fourth pin connected to the sampling unit, a fifth pin connected to the common terminal of the resistor R6 and the resistor R9 through the switch S2, and a sixth pin connected to the operating voltage VCC; the source of the field - effect transistor Q4 is coupled to the drain of the field - effect transistor Q1.

[0011] Preferably, the current and voltage detection module includes a current and voltage detection chip U1. The current and voltage detection chip U1 includes a first pin connected to the input voltage VIN, a second pin connected to the operating voltage VCC, a third pin for grounding, a fourth pin connected to the sampling unit, and a fifth pin connected to the source electrode of the field effect transistor Q1.

[0012] Preferably, the input soft start module includes a negative temperature coefficient resistor RT1. The negative temperature coefficient resistor RT1 is connected in series between the input voltage VIN and the operating indication module.

[0013] Preferably, the operating indication module includes a switch S1, a resistor R15, and an LED indicator D3. The switch S1, the resistor R15, and the LED indicator D3 are connected in series in sequence between the negative temperature coefficient resistor RT1 and the ground terminal.

[0014] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages: By setting up a current and voltage detection module to monitor the input voltage VIN and the loop current in real time and sending the monitoring results to the current control module, the current control module can adjust the loop current in real time according to the monitoring results, ensuring the stability of the current at the load end. It solves the technical problem in the prior art that when multiple resistors are used simultaneously, the loop current of each resistor cannot be monitored, and achieves the technical effect of ensuring the stability of the loop current. Description of the Drawings

[0015] Figure 1 Shows a circuit block diagram of an adjustable electronic load circuit provided by an embodiment of the present application;

[0016] Figure 2 Shows a circuit schematic diagram of a filtering module provided by an embodiment of the present application;

[0017] Figure 3 Shows a circuit schematic diagram of a power supply module provided by an embodiment of the present application;

[0018] Figure 4 Shows a circuit schematic diagram of a current control module and a current and voltage detection module provided by an embodiment of the present application;

[0019] Figure 5 Shows a circuit schematic diagram of an input soft start module provided by an embodiment of the present application;

[0020] Figure 6 Shows a circuit schematic diagram of an operating indication module provided by an embodiment of the present application. Detailed Embodiments

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the following will clearly and completely describe the technical solutions of the embodiments of the present disclosure in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts belong to the scope of protection of the present disclosure.

[0022] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should have the ordinary meaning understood by those of ordinary skill in the art to which the present disclosure pertains. The "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" mean that the elements or items appearing before this term cover the elements or items listed after this term and their equivalents, without excluding other elements or items. The terms such as "upper", "lower", "left", "right", etc. are only used to represent relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0023] Figure 1 The circuit block diagram of an adjustable electronic load circuit provided by an embodiment of the present application is shown. As Figure 1 shown, the present utility model provides an adjustable electronic load circuit, including a filtering module 100, a power supply module 200, a current control module 300, a current-voltage detection module 400, a working indication module 500, and an input soft-start module 600: The filtering module 100 is coupled between the input voltage VIN at the power supply terminal and the power supply ground GND; the power supply module 200 is used to convert the input voltage VIN into a working voltage VCC and supply it to the current control module 300 and the current-voltage detection module 400; the current control module 300 is used to adjust the loop current and supply the loop current to the current-voltage detection module 400; the current-voltage detection module 400 is used to monitor the input voltage VIN and the loop current; the working indication module 500 is used to indicate the working state of the adjustable electronic load circuit; the input soft-start module 600 is used to control the on-off of the working indication module 500.

[0024] In this embodiment, by setting the current-voltage detection module 400 to monitor the input voltage VIN and the loop current in real time and sending the monitoring results to the current control module 300, the current control module 300 adjusts the loop current in real time according to the monitoring results, ensuring the stability of the current at the load end. This solves the technical problem in the prior art that when multiple resistors are used simultaneously, the loop current of each path where the resistor is located cannot be monitored, and achieves the technical effect of ensuring the stability of the loop current.

[0025] Figure 2 The circuit schematic diagram of a filtering module provided by an embodiment of the present application is shown. As Figure 2 shown, the filtering module 100 includes resistors R19 - R24 and capacitors C7 - C11; the resistor R19 and the resistor R20 are in parallel with the input voltage VIN, and the capacitor C10 is connected in series between the common terminal of the resistor R19 and the resistor R20 and the power ground GND; between the input voltage VIN and the ground terminal, the resistor R21 and the capacitor C11, and the resistor R22 and the capacitor C7 are connected in series in sequence; between the power ground GND and the ground terminal, the resistor R23 and the capacitor C8, and the resistor R24 and the capacitor C9 are connected in series in sequence.

[0026] In this embodiment, the filtering module 100 is used to prevent the adjustable electronic load circuit from generating an oscillating voltage due to the current control module 300, and further avoid damage to the load or circuit components. Among them, the resistor R21 and the capacitor C11, and the resistor R21 and the capacitor C11 play the roles of absorbing overvoltage in the peak state, consuming voltage energy, suppressing circuit oscillation, filtering high-frequency noise, and limiting the over-inductance current. The resistor R23 and the capacitor C8, and the resistor R24 and the capacitor C9 play the roles of filtering high-frequency noise and interference. The resistors R23 and R24 can limit the flow of current, thereby suppressing the oscillation caused in the circuit; the resistors R19 and R20 can suppress the inrush current at startup, and reduce and maintain the voltage to the required voltage level. When the input voltage VIN fluctuates greatly instantaneously, the voltage fluctuation is reduced. The capacitor C10 can filter high-frequency noise, prevent the noise from spreading through the power supply loop, thereby reducing the interference to the circuit, and can also realize functions such as bypass and decoupling, further reducing the high-frequency interference impedance between the input voltage VIN and the power ground GND.

[0027] Figure 3 The circuit schematic diagram of a power supply module provided by an embodiment of the present application is shown. As Figure 3As shown in the figure, the power supply module 200 includes chip U4, diode D1, reference chip Q3, inductor L1, capacitors C1 - C3, capacitor C5, resistors R10, R12, and R13; the negative electrode of diode D1 is successively connected in series with inductor L1 and capacitor C3, the positive electrode of diode D1 and capacitor C3 are both grounded, and the common terminal of inductor L1 and capacitor C2 is connected to the working voltage VCC; a resistor R13 and a resistor R12 are successively connected in series between the working voltage VCC and the ground terminal, and capacitor C5 is connected in parallel across resistor R13; chip U4 has a VIN pin connected to the input voltage VIN, a GND pin for grounding, a BST pin and a SW pin connected in parallel with capacitor CI, an FB pin connected to the common terminal of resistor R12 and resistor R13, and an EN pin connected to the first pin of reference chip Q3; resistor R10 and reference chip Q3 are successively connected in series between the input voltage VIN and the ground terminal, the second pin of reference chip Q3 is connected in series with resistor R10, and the third pin of reference chip Q3 is grounded.

[0028] In this embodiment, chip U4 is a BUCK chip, which is used to convert the input voltage VIN into the working voltage VCC. Specifically, the voltage range that chip U4 can convert is DC28V to DC30V. The reference chip Q3 is used to provide an enable signal to chip U4 to enable chip U4 to enter the normal working state.

[0029] Figure 4 The circuit schematic diagram of a current control module and a current - voltage detection module provided by an embodiment of the present application is shown. As Figure 1 and Figure 4 shown, the current control module 300 includes a sampling unit and a control unit; the sampling unit is connected to the power supply ground GND, outputs a sampling voltage, and provides it to the control unit; the control unit is used to adjust the loop current according to the sampling voltage and the reference voltage VREF.

[0030] As Figure 4 shown, the sampling unit includes sampling resistors R1, R2, R3, and R5 connected in parallel.

[0031] As Figure 4 shown, the control unit includes chip U3, field - effect transistor Q1, resistors R6, R9, and switch S2; resistors R6 and R9 are successively connected in series between the working voltage VCC and the ground terminal; chip U3 has a first pin connected to the gate of field - effect transistor Q1, a second pin for grounding, a third pin connected to the reference voltage VREF, a fourth pin connected to the sampling unit, a fifth pin connected to the common terminal of resistor R6 and resistor R9 through switch S2, and a sixth pin connected to the working voltage VCC; the source of field - effect transistor Q4 is coupled to the drain of field - effect transistor Q1.

[0032] AsFigure 4 As shown, the current and voltage detection module includes a current and voltage detection chip U1, which includes a first pin connected to an input voltage VIN, a second pin connected to an operating voltage VCC, a third pin for grounding, a fourth pin connected to a sampling unit, and a fifth pin connected to a source of a field effect transistor Q1.

[0033] In this embodiment, the chip U3 obtains the reference voltage VREF through the third pin, obtains the sampling voltage of the sampling unit through the fourth pin, and after calculation, controls the field effect tube Q1 to enter the linear state through the first pin, so that the voltage of the third pin and the fourth pin of the chip U3 are equal, which is equivalent to adjusting the voltage across the resistors R1, R2, R3, R4, and R5, so that the current changes. When the reference voltage VREF is a fixed value, the current value flowing through the field effect tube Q1 is a constant value, realizing the closed-loop control of the loop current. Specifically, the field effect tube Q4 is used to share the voltage of the field effect tube Q1, which can increase the overall power capacity and increase the power of the whole machine to 300W.

[0034] Figure 5 FIG. 1 shows a circuit diagram of an input slow start module provided in an embodiment of the present application. Figure 4 As shown, the input slow start module 600 includes a negative temperature coefficient resistor RT1 , and the negative temperature coefficient resistor RT1 is connected in series between the input voltage VIN and the work indication module 500 .

[0035] In this embodiment, when the load is suddenly connected, the loop of the adjustable electronic load circuit generates a surge current. At this time, the negative temperature coefficient resistor RT1 is in a cold state and has a large internal resistance, so it can limit the loop current. As the temperature of the negative temperature coefficient resistor RT1 gradually increases, the internal resistance decreases, and the loop current returns to a normal value, forming a slow start.

[0036] Figure 6 FIG. 1 shows a circuit diagram of a work indication module provided in an embodiment of the present application. Figure 5 As shown, the work indication module 500 includes a switch S1, a resistor R15 and an LED indicator D3; the switch S1, the resistor R15 and the LED indicator D3 are sequentially connected in series between the negative temperature coefficient resistor RT1 and the ground terminal.

[0037] In this embodiment, the LED indicator light D3 is used to indicate that the entire circuit has entered a working state. The switch S1 is a load switch. When the switch S1 is turned on, the LED indicator light D3 lights up.

[0038] It should be noted that the components among the various embodiments of the present disclosure can be interchangeable as long as they can play the corresponding roles.

[0039] There are a few points to note:

[0040] (1) Unless otherwise defined, in the embodiments of the present disclosure and the accompanying drawings, the same reference numerals represent the same meanings.

[0041] (2) In the accompanying drawings of the embodiments of the present disclosure, only the structures related to the embodiments of the present disclosure are involved, and other structures can refer to the general design.

[0042] (3) For clarity, in the accompanying drawings used to describe the embodiments of the present disclosure, components or regions are enlarged. It can be understood that when an element is referred to as being "on" or "under" another element, the element can be "directly" on or under the other element, or there may be intermediate elements.

[0043] As described above, the above are only the specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present disclosure can easily think of changes or substitutions, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

Claims

1. An adjustable electronic load circuit, characterized in that: It includes filter module, power supply module, current control module, current and voltage detection module, work indication module and input slow start module: A filter module is coupled between an input voltage VIN of a power supply end and a power ground GND; A power supply module, used for converting an input voltage VIN into an operating voltage VCC, and providing the voltage to the current control module and the current and voltage detection module; A current control module, used for adjusting the loop current and providing the loop current to the current and voltage detection module; The current and voltage detection module is used to monitor the input voltage VIN and the loop current; A working indication module, used for indicating the working state of the adjustable electronic load circuit; The input slow start module is used to control the on and off of the work indication module.

2. The adjustable electronic load circuit according to claim 1, characterized in that: The filtering module includes resistors R19-R24 and capacitors C7-C11; The resistor R19 and the resistor R20 are connected in parallel with the input voltage VIN, and the capacitor C10 is connected in series between a common end of the resistor R19 and the resistor R20 and the power ground GND; The resistor R21 and the capacitor C11, the resistor R22 and the capacitor C7 are connected in series in sequence between the input voltage VIN and the ground terminal; The resistor R23 and the capacitor C8, and the resistor R24 ​​and the capacitor C9 are connected in series in sequence between the power ground GND and the ground terminal.

3. The adjustable electronic load circuit according to claim 2, characterized in that: The power supply module includes a chip U4, a diode D1, a reference chip Q3, an inductor L1, capacitors C1-C3, a capacitor C5, a resistor R10, a resistor R12, and a resistor R13; The cathode of the diode D1 is connected in series with the inductor L1 and the capacitor C3 in sequence, the anode of the diode D1 and the capacitor C3 are both grounded, and the common end of the inductor L1 and the capacitor C2 is connected to the working voltage VCC; The resistor R13 and the resistor R12 are connected in series between the working voltage VCC and the ground terminal, and the capacitor C5 is connected in parallel at both ends of the resistor R13; The chip U4 has a VIN pin connected to the input voltage VIN, a GND pin for grounding, a BST pin and a SW pin connected in parallel with the capacitor CI, an FB pin connected to the common end of the resistor R12 and the resistor R13, and an EN pin connected to the first pin of the reference chip Q3; The resistor R10 and the reference chip Q3 are connected in series between the input voltage VIN and the ground terminal in sequence, the second pin of the reference chip Q3 is connected in series with the resistor R10, and the third pin of the reference chip Q3 is grounded.

4. The adjustable electronic load circuit according to claim 3, characterized in that: The current control module includes a sampling unit and a control unit; The sampling unit is connected to the power ground GND, outputs a sampling voltage, and provides it to the control unit; The control unit is used to adjust the loop current according to the sampling voltage and the reference voltage VREF.

5. The adjustable electronic load circuit according to claim 4, characterized in that: The sampling unit includes a sampling resistor R1, a sampling resistor R2, a sampling resistor R3, and a sampling resistor R5 connected in parallel.

6. The adjustable electronic load circuit according to claim 5, characterized in that: The control unit includes a chip U3, a field effect transistor Q1, a field effect transistor Q4, a resistor R6, a resistor R9 and a switch S2; The resistor R6 and the resistor R9 are connected in series between the working voltage VCC and the ground terminal; The chip U3 has a first pin connected to the gate of the field effect transistor Q1, a second pin for grounding, a third pin connected to the reference voltage VREF, a fourth pin connected to the sampling unit, a fifth pin connected to the common end of the resistor R6 and the resistor R9 through the switch S2, and a sixth pin connected to the working voltage VCC; The source of the field effect transistor Q4 is coupled to the drain of the field effect transistor Q1 .

7. The adjustable electronic load circuit according to claim 6, characterized in that: The current and voltage detection module includes a current and voltage detection chip U1, and the current and voltage detection chip U1 includes a first pin connected to the input voltage VIN, a second pin connected to the working voltage VCC, a third pin for grounding, a fourth pin connected to the sampling unit, and a fifth pin connected to the source of the field effect transistor Q1.

8. The adjustable electronic load circuit according to claim 7, characterized in that: The input slow start module includes a negative temperature coefficient resistor RT1, and the negative temperature coefficient resistor RT1 is connected in series between the input voltage VIN and the work indication module.

9. The adjustable electronic load circuit according to claim 8, characterized in that: The work indication module includes a switch S1, a resistor R15 and an LED indicator light D3; The switch S1, the resistor R15 and the LED indicator D3 are sequentially connected in series between the negative temperature coefficient resistor RT1 and the ground terminal.

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