A current sharing circuit and a lamp

Abstract

This utility model discloses a current sharing circuit and a lighting fixture. The circuit includes: a power input module, a load balancing circuit, a comparison feedback circuit, a first feedback circuit, and a second feedback circuit. The power input module generates a drive current. The load balancing circuit distributes the drive current into a first current and a second current. The first current acts on a first load, and the second current acts on a second load. The first feedback circuit feeds back the first voltage formed after the first current passes through the first load. The second feedback circuit feeds back the second voltage formed after the second current passes through the second load. The comparison feedback circuit compares the first voltage and the second voltage and transmits the comparison result to the load balancing circuit. The load balancing circuit adjusts the first current and the second current according to the comparison result to achieve current sharing between the first current and the second current. This utility model improves response speed and reduces hardware costs. It is applicable to the field of lighting fixture technology.

Description

Technical Field

[0001] This utility model relates to the field of lighting fixture technology, specifically to a current sharing circuit and a lighting fixture. Background Technology

[0002] In output circuits for LED light bulb loads, if two strings of LEDs are connected in parallel, a failure of one LED in one string can cause a large current flow in the other string, leading to bulb burnout or inconsistent brightness between the two strings. A common solution is a controller (MCU) to handle dynamic current changes and output, ensuring consistent brightness between the two strings. However, this approach introduces control devices, resulting in higher overall cost and complexity. Therefore, the technical problems in this area urgently need to be addressed by the industry. Utility Model Content

[0003] This utility model provides a current sharing circuit and a lamp to solve one or more technical problems existing in the prior art, and at least provides a beneficial option or creates conditions.

[0004] This invention provides a current sharing circuit, comprising: a power input module, a load balancing circuit, a comparison feedback circuit, a first feedback circuit, and a second feedback circuit; the power input module generates a drive current; the load balancing circuit distributes the drive current into a first current and a second current; the first current acts on an external first load, and the second current acts on an external second load; the first feedback circuit provides feedback on a first voltage formed after the first current passes through the first load; the second feedback circuit provides feedback on a second voltage formed after the second current passes through the second load; the comparison feedback circuit compares the first voltage and the second voltage and transmits the comparison result to the load balancing circuit; the load balancing circuit adjusts the first current and the second current according to the comparison result to achieve current sharing between the first current and the second current.

[0005] Furthermore, the load balancing circuit includes a first switching module, a second switching module, and a third switching module. The third switching module is used to control its own on / off state according to the comparison result, so as to control the on / off state of the second switching module and thereby adjust the second current. The first switching module is used to maintain the on state when the power input module generates the driving current, so as to keep the first current constant.

[0006] Furthermore, the input terminal of the third switch module is connected to the control terminal of the second switch module and the output terminal of the power input module. The output terminal of the third switch module is grounded. The output terminal of the comparison feedback circuit is connected to the control terminal of the third switch module and the control terminal of the first switch module. The first load is connected to the second feedback circuit through the second switch module, and the second load is connected to the second feedback circuit through the first switch module. When the first voltage is greater than the second voltage, the third switch module is turned on, causing the second switch module to be turned off. When the first voltage is less than the second voltage, the third switch module is turned off, causing the second switch module to be turned on.

[0007] Furthermore, the first switching module includes: a first transistor and a sixth resistor; the second switching module includes: a MOSFET, a first diode and a fifth resistor; the third switching module includes: a third transistor, a seventh resistor and an eighth resistor; The gate of the MOS transistor and the collector of the third transistor are respectively connected to the positive terminal of the power input module, the drain of the MOS transistor is connected to the cathode of the first load, and the source of the MOS transistor is connected to the cathode of the first diode and the first feedback circuit. The base of the first transistor is connected to one end of the sixth resistor, the collector of the first transistor is connected to the cathode of the second load, and the emitter of the first transistor is connected to the second feedback circuit. The anode of the first diode is connected to one end of the fifth resistor, and the other end of the fifth resistor is connected to the other end of the sixth resistor and one end of the eighth resistor, respectively. The other end of the eighth resistor is connected to one end of the seventh resistor and the base of the third transistor, respectively. The emitter of the third transistor and the other end of the seventh resistor are connected to the ground terminal.

[0008] Furthermore, the current sharing circuit also includes a protection circuit; the protection circuit is used to stabilize the input of the third switching module, filter the third switching module, and limit the conduction speed of the third switching module.

[0009] Furthermore, the protection circuit includes: a Zener diode, a ninth resistor, and a first capacitor; the cathode of the Zener diode is connected to one end of the ninth resistor and one end of the first capacitor, respectively, and the anode of the Zener diode, the other end of the ninth resistor, and the other end of the first capacitor are connected to the ground terminal, respectively; the Zener diode is used to stabilize the input of the third switching module, and the ninth resistor and the first capacitor are used to: filter the third switching module and limit the conduction speed of the third switching module.

[0010] Furthermore, the comparison feedback circuit includes: a third resistor, a fourth resistor, a comparator, and a driving module; the driving module is used to provide drive to the comparator. One end of the third resistor is connected to the first feedback circuit, and the other end of the third resistor is connected to one input terminal of the comparator. One end of the fourth resistor is connected to the second feedback circuit, and the other end of the fourth resistor is connected to the other input terminal of the comparator. The output terminal of the comparator is connected to the other end of the eighth resistor and one end of the sixth resistor, respectively.

[0011] Furthermore, the first feedback circuit includes: a first resistor; one end of the first resistor is connected to the source of the MOS transistor and one end of the third resistor, respectively, and the other end of the first resistor is connected to the ground terminal.

[0012] Furthermore, the second feedback circuit includes: a second resistor; one end of the second resistor is connected to the emitter of the first transistor and one end of the fourth resistor, respectively, and the other end of the second resistor is connected to the ground terminal.

[0013] On the other hand, a lamp is provided that integrates the current sharing circuit described in any one of the above technical solutions.

[0014] This invention has at least the following advantages: By constructing a load balancing circuit, a comparison feedback circuit, a first feedback circuit, and a second feedback circuit, this invention avoids the need for a programmable MCU to collect AD values ​​and perform code calculations. Adjusting the dynamic current through hardware improves response speed and reduces hardware costs. This invention is primarily applicable to the field of lighting fixture technology. Attached Figure Description

[0015] The accompanying drawings are provided to further understand the technical solution of this utility model and constitute a part of the specification. They are used together with the embodiments of this utility model to explain the technical solution of this utility model, and do not constitute a limitation on the technical solution of this utility model.

[0016] Figure 1 This is a schematic diagram of the current sharing circuit. Figure 2 This is a schematic diagram of the circuit module connection structure of the current sharing circuit; Figure 3 These are simulation results of the actual operation of the current sharing circuit. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this utility model and are not intended to limit this utility model.

[0018] It should be noted that although functional modules are divided in the system diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the system or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0019] refer to Figure 1 , Figure 2 and Figure 3 , Figure 1 This is a schematic diagram of the current sharing circuit. Figure 2 This is a schematic diagram of the circuit module connection structure of the current sharing circuit; Figure 3 These are simulation results of the actual operation of the current sharing circuit.

[0020] The purpose of this invention is to provide a suitable circuit structure to achieve current sharing without relying on an active control chip, thereby improving the response speed of current sharing.

[0021] To achieve this technical goal, this application discloses a current sharing circuit, including: a power input module 100, a load balancing circuit 200, a comparison feedback circuit 300, a first feedback circuit 401, and a second feedback circuit 402.

[0022] The power input module 100 generates a drive current. The load balancing circuit 200 distributes the drive current into a first current and a second current; the first current acts on an external first load 101, and the second current acts on an external second load 102; the first feedback circuit 401 provides feedback on the first voltage formed after the first current passes through the first load 101; the second feedback circuit 402 provides feedback on the second voltage formed after the second current passes through the second load 102; the comparison feedback circuit 300 compares the first voltage and the second voltage and transmits the comparison result to the load balancing circuit 200; the load balancing circuit 200 adjusts the first current and the second current according to the comparison result to achieve current sharing between the first current and the second current.

[0023] The load balancing circuit includes a first switch module, a second switch module, and a third switch module. The third switch module controls its own on / off state according to the comparison result to control the on / off state of the second switch module, thereby adjusting the second current. The first switch module remains on when the power input module generates a drive current, so that the first current remains unchanged.

[0024] The input terminal of the third switch module is connected to the control terminal of the second switch module and the output terminal of the power input module. The output terminal of the third switch module is grounded. The output terminal of the comparison feedback circuit is connected to the control terminal of the third switch module and the control terminal of the first switch module. The first load is connected to the second feedback circuit through the second switch module, and the second load is connected to the second feedback circuit through the first switch module. When the first voltage is greater than the second voltage, the third switch module is turned on, causing the second switch module to be turned off. When the first voltage is less than the second voltage, the third switch module is turned off, causing the second switch module to be turned on.

[0025] This invention avoids the need for a programmable MCU (active control chip) to collect AD values ​​and perform code calculations by constructing a load balancing circuit 200, a comparison feedback circuit 300, a first feedback circuit 401, and a second feedback circuit 402. By adjusting the dynamic current in hardware, it improves response speed and reduces hardware costs.

[0026] To more clearly describe the technical solution of this application, the following description uses a specific circuit structure.

[0027] The load balancing circuit 200 includes: a first transistor Q1, a MOSFET Q2, a third transistor Q3, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a tenth resistor R10, an eleventh resistor R11, and a first diode D1.

[0028] The protection circuit includes: a ninth resistor R9, a Zener diode D2, and a first capacitor C1.

[0029] In this module, the first transistor Q1 and the sixth resistor R6 form the first switching module, the MOSFET Q2, the first diode D1 and the fifth resistor R5 form the second switching module, and the third transistor Q3, the seventh resistor R7 and the eighth resistor R8 form the third switching module.

[0030] The comparison feedback circuit 300 includes: a third resistor R3, a fourth resistor R4, a comparator X1, and a drive module V1. The first feedback circuit 401 includes: a first resistor R1. The second feedback circuit 402 includes: a second resistor R2.

[0031] The positive terminal of the power input module 100 is connected to the anode of the first load module 101, the anode of the second load module 102, and one end of the eleventh resistor R11.

[0032] The drain of the MOS transistor Q2 is connected to the cathode of the first load module 101, and the gate of the MOS transistor Q2 is connected to the other end of the eleventh resistor R11, the cathode of the Zener diode D2, one end of the ninth resistor R9, one end of the first capacitor C1, and one end of the tenth resistor R10.

[0033] The other end of the tenth resistor R10 is connected to the collector of the third transistor Q3, and the base of the third transistor Q3 is connected to one end of the seventh resistor R7 and one end of the eighth resistor R8.

[0034] The source of the MOS transistor Q2 is connected to one end of the first resistor R1, one end of the third resistor R3, and the cathode of the first diode D1. The anode of the first diode D1 is connected to one end of the fifth resistor R5, and the other end of the fifth resistor R5 is connected to the output of the comparator X1, one end of the sixth resistor R6, and the other end of the eighth resistor R8.

[0035] The other end of the sixth resistor R6 is connected to the base of the first transistor Q1, and the collector of the first transistor Q1 is connected to the cathode of the second load module 102.

[0036] The other end of the third resistor R3 is connected to the non-inverting input of comparator X1, the inverting input of comparator X1 is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the emitter of the first transistor Q1 and one end of the second resistor R2 respectively; the driving module V1 is used to drive comparator X1.

[0037] The other end of the first resistor R1, the other end of the second resistor R2, the emitter of the third transistor Q3, the other end of the seventh resistor R7, the other end of the first capacitor C1, the other end of the ninth resistor R9, the anode of the Zener diode D2, and the negative terminal of the power input module 100 are respectively connected to the ground terminal.

[0038] When this circuit is in operation, the power input module 100 generates a drive current, which acts on the load balancing circuit 200. At this time, since MOSFET Q2 is connected in series with the first load 101, and the first transistor Q1 is connected in series with the second load 102, the load balancing circuit 200 distributes the first current flowing through the first load 101 through MOSFET Q2 and the second current flowing through the second load 102 through the first transistor Q1. The path of the first current is: through the first load 101, MOSFET Q2, and first resistor R1 in sequence. The path of the second current is: through the second load 102, first transistor Q1, and second resistor R2 in sequence.

[0039] A first current flows through a first resistor R1 and generates a first voltage across it. A second current flows through a second resistor R2 and generates a second voltage across it. The first voltage reflects the condition of the first current, and the second voltage reflects the condition of the second current.

[0040] The first voltage is input to one input terminal of comparator X1 through the third resistor R3, and the second voltage is input to the other input terminal of comparator X1 through the fourth resistor R4. Comparator X1 compares the first and second voltages to obtain an adjustment signal, which is input to the load balancing circuit 200. In the load balancing circuit 200, the adjustment signal controls the first transistor Q1 through the sixth resistor R6, thereby adjusting the second current. This adjustment signal controls the third transistor Q3 through the eighth resistor R8, and the third transistor Q3 controls the MOSFET Q2, thereby adjusting the first current. Through this adjustment method, the first and second currents are balanced to achieve the target value.

[0041] To ensure the stability of the load balancing circuit 200, the load balancing circuit 200 further includes: a Zener diode D2, the cathode of which is connected to the other end of the eleventh resistor R11, the gate of the MOSFET Q2, one end of the ninth resistor R9, one end of the first capacitor C1, and one end of the tenth resistor R10; the anode of the Zener diode D2 is connected to the ground terminal.

[0042] In the overall circuit structure, transistor Q1 and MOSFET Q2 form a mirror image for current conduction. Comparator X1 mainly performs the functions of receiving, comparing, amplifying, and outputting. Transistor Q3 mainly controls the current conduction; Zener diode D2 maintains a stable input, thus counteracting the output voltage of comparator X1. When the input voltage across resistor R3 is greater than the input voltage across resistor R4, comparator X1 outputs positive feedback. Transistor Q3 conducts, de-conducting MOSFET Q2. When the input voltage across resistor R4 is greater than the input voltage across resistor R3, comparator X1 outputs negative feedback, de-conducting transistor Q3 and turning on MOSFET Q2.

[0043] The ninth resistor R9 and the first capacitor C1 limit the conduction speed and filter the circuit. On the other hand, the first diode D1 can be considered a bypass diode for MOSFET Q2, preventing voltage input to comparator X1, the third transistor Q3, and the first transistor Q1 when MOSFET Q2 outputs from its source, thus preventing system failure. It can also be considered together with the source of MOSFET Q2 as the base-circuit junction of a transistor, further mirroring the output of the first transistor Q1 and improving current sharing accuracy. The driver module V1 drives the output adjustment of comparator X1; the eleventh resistor R11 and the eighth resistor R8 perform current sharing sampling; the fifth resistor R5 and the sixth resistor R6 perform mirror biasing; the third resistor R3 and the fourth resistor R4 provide voltage follower feedback and voltage division; the first resistor R1 and the second resistor R2 divide the voltage and draw out the total load current.

[0044] refer to Figure 3 Based on the actual simulation results, in this specific embodiment, with both loads operating normally, it can be seen that the current value of the first load 101 is approximately 249.5mA, and the current value of the second load 102 is approximately 250.2mA. This achieves current sharing for both the first load 101 and the second load 102.

[0045] In some further specific embodiments, the MOS transistor Q2 is an N-type MOS transistor, and the first transistor Q1 is an NPN type transistor.

[0046] On the other hand, a lamp is also provided, which integrates the current sharing circuit described in any of the above specific embodiments. Although the description of this application has been quite detailed and particularly focused on several described embodiments, it is not intended to limit itself to any of these details or embodiments or any particular embodiment. Rather, it should be considered as effectively covering the intended scope of this application by referring to the appended claims and taking into account the broad possible interpretations of these claims provided by the prior art. Furthermore, the foregoing description of this application with respect to embodiments foreseeable by the inventor is intended to provide a useful description, and non-substantial modifications to this application that have not yet been foreseen may still represent equivalent modifications.

Claims

1. A current sharing circuit, characterized in that, include: The system includes a power input module, a load balancing circuit, a comparison feedback circuit, a first feedback circuit, and a second feedback circuit; the power input module is used to generate drive current. The load balancing circuit is used to distribute the drive current into a first current and a second current; the first current acts on an external first load, and the second current acts on an external second load; The first feedback circuit is used to provide feedback on the first voltage formed after the first current passes through the first load; The second feedback circuit is used to provide feedback on the second voltage formed after the second current passes through the second load; The comparison feedback circuit is used to compare the first voltage and the second voltage, and transmit the comparison result to the load balancing circuit. The load balancing circuit adjusts the first current and the second current according to the comparison result to achieve current sharing between the first current and the second current.

2. The current sharing circuit according to claim 1, characterized in that, The load balancing circuit includes a first switch module, a second switch module, and a third switch module. The third switch module is used to control its own on / off state according to the comparison result, so as to control the on / off state of the second switch module and thereby adjust the second current. The first switch module is used to maintain the on state when the power input module generates the drive current, so as to keep the first current constant.

3. A current sharing circuit according to claim 2, characterized in that, The input terminal of the third switch module is connected to the control terminal of the second switch module and the output terminal of the power input module. The output terminal of the third switch module is grounded. The output terminal of the comparison feedback circuit is connected to the control terminal of the third switch module and the control terminal of the first switch module. The first load is connected to the second feedback circuit through the second switch module, and the second load is connected to the second feedback circuit through the first switch module. When the first voltage is greater than the second voltage, the third switch module is turned on, causing the second switch module to be turned off. When the first voltage is less than the second voltage, the third switch module is turned off, causing the second switch module to be turned on.

4. A current sharing circuit according to claim 3, characterized in that, The first switching module includes: a first transistor and a sixth resistor; the second switching module includes: a MOSFET, a first diode and a fifth resistor; the third switching module includes: a third transistor, a seventh resistor and an eighth resistor; The gate of the MOS transistor and the collector of the third transistor are respectively connected to the positive terminal of the power input module, the drain of the MOS transistor is connected to the cathode of the first load, and the source of the MOS transistor is connected to the cathode of the first diode and the first feedback circuit. The base of the first transistor is connected to one end of the sixth resistor, the collector of the first transistor is connected to the cathode of the second load, and the emitter of the first transistor is connected to the second feedback circuit. The anode of the first diode is connected to one end of the fifth resistor, and the other end of the fifth resistor is connected to the other end of the sixth resistor and one end of the eighth resistor, respectively. The other end of the eighth resistor is connected to one end of the seventh resistor and the base of the third transistor, respectively. The emitter of the third transistor and the other end of the seventh resistor are connected to the ground terminal.

5. A current sharing circuit according to claim 2, characterized in that, Also includes: Protection circuit; the protection circuit is used to stabilize the input of the third switching module, filter the third switching module, and limit the conduction speed of the third switching module.

6. A current sharing circuit according to claim 5, characterized in that, The protection circuit includes: a Zener diode, a ninth resistor, and a first capacitor; the cathode of the Zener diode is connected to one end of the ninth resistor and one end of the first capacitor, respectively, and the anode of the Zener diode, the other end of the ninth resistor, and the other end of the first capacitor are connected to the ground terminal, respectively; the Zener diode is used to stabilize the input of the third switching module, and the ninth resistor and the first capacitor are used to: filter the third switching module and limit the conduction speed of the third switching module.

7. A current sharing circuit according to claim 4, characterized in that, The comparison feedback circuit includes: a third resistor, a fourth resistor, a comparator, and a driver module; the driver module is used to provide drive to the comparator. One end of the third resistor is connected to the first feedback circuit, and the other end of the third resistor is connected to one input terminal of the comparator. One end of the fourth resistor is connected to the second feedback circuit, and the other end of the fourth resistor is connected to the other input terminal of the comparator. The output terminal of the comparator is connected to the other end of the eighth resistor and one end of the sixth resistor, respectively.

8. A current sharing circuit according to claim 7, characterized in that, The first feedback circuit includes: a first resistor; one end of the first resistor is connected to the source of the MOSFET and one end of the third resistor, and the other end of the first resistor is connected to the ground terminal.

9. A current sharing circuit according to claim 7, characterized in that, The second feedback circuit includes: a second resistor; one end of the second resistor is connected to the emitter of the first transistor and one end of the fourth resistor, respectively, and the other end of the second resistor is connected to the ground terminal.

10. A lamp, characterized in that, The device integrates the current sharing circuit as described in any one of claims 1 to 9.

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