Large-current constant-current control circuit based on multiple triodes

Abstract

The utility model discloses a large-current constant-current control circuit based on multiple triodes, and relates to the field of constant-current control, in which a reference voltage generation module is used for accessing a direct-current power supply output by a power supply protection module, setting a constant current value and generating a reference voltage based on the constant current value; the constant current control module is used for accessing the direct current power supply output by the power supply protection module and adjusting the working state of each triode control unit connected in parallel according to a set reference voltage so as to share the required total current load; compared with additional peripheral elements required by using a DCDC chip, the circuit mainly depends on basic electronic elements such as the triodes, the resistors and the capacitors, and the components are generally lower in price and easier to obtain, so that the overall material cost is effectively reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of constant current control especially relates to a big current constant current control circuit based on multichannel triode. BACKGROUND

[0002] In the current technical application, adopting DC-DC converter (referred to as DCDC chip) to realize constant current scheme has the advantage of high circuit integration, which makes the circuit design more compact and efficient. However, this scheme is not without drawbacks, specifically, it has the following main problems:

[0003] High cost: the scheme using DCDC chip usually needs higher component cost. In addition to the price of DCDC chip itself, in order to ensure its normal work, a series of peripheral elements such as inductance, capacitance, resistance and possibly needed heat dissipation device need to be additionally configured. These additional components not only increase the material cost, but also increase the design complexity and the space requirement of PCB board.

[0004] EMC radiation problem is significant: since DCDC chip is essentially realized by high-frequency switching to adjust voltage or current, this process will produce electromagnetic interference (EMC radiation). Especially when operating at high frequency, the generated EMC radiation may interfere with the surrounding electronic equipment, affecting their working performance. In order to solve this problem, engineers have to spend a lot of time and effort to optimize circuit layout, select appropriate filter elements, carry out shielding design, etc. to meet the strict electromagnetic compatibility standards. This undoubtedly prolongs the development cycle of the product, and may increase the overall cost of the project.

[0005] Design complexity and challenge: although DCDC chip can provide efficient power management solution, its complex internal structure and working principle also bring challenges to circuit design. For example, maintaining stable output under different load conditions, avoiding voltage drop or overshoot phenomenon, requires designers to have deep professional knowledge and rich practical experience. In addition, for some noise-sensitive application scenarios, how to reduce the noise brought by DCDC chip is also a problem to be considered.

[0006] In summary, although DCDC chip has obvious advantages in realizing constant current control, its high cost, serious EMC radiation problem and relatively complex design challenge make many engineers seek more optimized alternative solutions in practical application. INVENTION CONTENTS

[0007] In order to solve the above technical problems and realize low-cost large current constant current control, the utility model provides a kind of big current constant current control circuit based on multichannel triode, comprising:

[0008] a power protection module, configured to receive an external power input and process the external power input to output a stable direct current power;

[0009] a reference voltage generation module, configured to access the direct current power output by the power protection module and set a constant current value, and generate a reference voltage based on the constant current value;

[0010] a constant current control module including a plurality of parallelly connected triode control units, configured to access the direct current power output by the power protection module and adjust the working state of each parallelly connected triode control unit according to the set reference voltage to share a total current load required by the load; wherein the total current load represents a working current required by the load.

[0011] Further, the power protection module includes:

[0012] a rectification unit, configured to perform rectification processing on the external power to convert alternating current into direct current;

[0013] a filter unit, configured to perform filtering processing on the rectified direct current power to remove voltage fluctuation and noise and provide a stable direct current power;

[0014] an overvoltage protection unit, configured to protect the circuit from transient voltage spikes.

[0015] Further, the rectification unit includes:

[0016] a first diode D1; a positive terminal of the first diode D1 is connected to one end of a twenty-fifth resistor R25 and one end of a first capacitor C1 in sequence and then connected to a positive power supply B+; a negative terminal of the first diode D1 is connected to the overvoltage protection unit; the other end of the first capacitor C1 is connected to one end of a sixth capacitor C6; the other end of the sixth capacitor C6 is grounded.

[0017] Further, the overvoltage protection unit includes:

[0018] a transient voltage suppressor TVS1; one end of the transient voltage suppressor TVS1 is connected to the negative terminal of the first diode D1 and one end of the filter unit at the same time, the other end of the transient voltage suppressor TVS1 is connected to the other end of the twenty-fifth resistor R25 and then grounded, and the other end of the transient voltage suppressor TVS1 is also connected to the other end of the filter unit.

[0019] Further, the filter unit includes:

[0020] The third capacitor C3, the fourth capacitor C4 and the fifth capacitor C5; one end of the fifth capacitor C5 is connected with one end of the twenty-fourth resistor R24, and is sequentially connected with one end of the fourth capacitor C4, one end of the third capacitor C3 and one end of the transient voltage suppressor TVS1; the other end of the fifth capacitor C5 is connected with one end of the second capacitor C2, and is sequentially connected with the other end of the fourth capacitor C4, the other end of the third capacitor C3 and the other end of the transient voltage suppressor TVS1; the other end of the twenty-fourth resistor R24 is connected with the other end of the second capacitor C2 and one end of the first resistor R1, and is connected with the positive voltage input pin IN in the load.

[0021] Further, the reference voltage generation module comprises:

[0022] A constant current value setting unit is configured to set a constant current value by adjusting the resistance value of the resistor.

[0023] A reference voltage generation unit is configured to generate a reference voltage based on the constant current value.

[0024] Further, the constant current value setting unit comprises:

[0025] The twelfth resistor R12 and the thirteenth resistor R13; one end of the thirteenth resistor R13 is sequentially connected with one end of the twelfth resistor R12, one end of the eighth capacitor C8 and the reference voltage generation unit while being grounded; the other end of the thirteenth resistor R13 is connected with the constant current control module while being sequentially connected with the other end of the twelfth resistor R12 and one end of the twenty-first resistor R21; the other end of the twenty-first resistor R21 is connected with the other end of the eighth capacitor C8 and then connected to the reference voltage generation unit.

[0026] The constant current value setting unit is specifically configured to set the constant current value by adjusting the resistance value of the twelfth resistor R12 and the thirteenth resistor R13.

[0027] Further, the reference voltage generation unit comprises:

[0028] The eighth transistor Q8; the emitter of the eighth transistor Q8 is connected with one end of the eighth capacitor C8 and grounded, the base is sequentially connected with the other end of the eighth capacitor C8 and the other end of the twenty-first resistor R21, and the collector is connected with the constant current control module and then connected with the other end of the first resistor R1.

[0029] Further, each of the triode control units comprises a power triode, a current-limiting resistor, a filter capacitor and a bias resistor; the base of the power triode is connected with one end of the filter capacitor and one end of the current-limiting resistor in sequence, the collector is connected to the negative voltage output pin OUT in the load through the output pin OUT, and the emitter is connected with one end of the bias resistor; the other end of the bias resistor is connected with the other end of the thirteenth resistor R13 in the constant current value setting unit; the other end of the filter capacitor is grounded; the other end of the current-limiting resistor is connected with one end of the nineteenth capacitor C19, and simultaneously connected with the other end of the first resistor R1 and the collector of the eighth triode Q8; the other end of the nineteenth capacitor C19 is grounded.

[0030] Further, the load is an LED module; the total current load is shared by a plurality of triode control units connected in parallel, and each triode control unit allocates the total current load according to a preset proportion.

[0031] Compared with the prior art, the utility model at least has the following beneficial effects:

[0032] (1) In the utility model, the reference voltage generation module is used for connecting the DC power supply output by the power protection module, and setting a constant current value, and simultaneously generating a reference voltage based on the constant current value; the constant current control module is used for connecting the DC power supply output by the power protection module, and adjusting the working state of each parallel triode control unit according to the set reference voltage to share the required total current load; compared with the additional peripheral elements (such as inductance, capacitance and the like) required by the DCDC chip, the utility model mainly depends on basic electronic elements such as triodes, resistors and capacitors, and these components are generally cheaper and easier to obtain, thereby effectively reducing the overall material cost.

[0033] (2) Since the DCDC chip adjusts voltage or current by high-frequency switching, this can cause significant electromagnetic compatibility (EMC) problems, and the utility model utilizes the triode control unit to distribute current, avoiding the EMC radiation caused by high-frequency switching, and reducing the design complexity and the need for additional shielding measures.

[0034] (3) The solution proposed by the utility model has lower design complexity compared with the DCDC chip solution, and it does not need complex PCB layout to deal with the problem of high-frequency signal processing, so that the circuit design is more direct and easy to implement.

[0035] (4) The utility model can effectively disperse heat and reduce the risk of overheating of a single component by using a plurality of parallelly connected triode control units to share the total current load, thereby improving the stability and long-term reliability of the entire circuit.

[0036] (5) The utility model allows flexibly adjusting the current proportion borne by each triode control unit according to actual demand, which provides greater flexibility and adaptability for different application scenarios.

[0037] To sum up, the multi-channel triode-based large-current constant current control circuit not only solves the problems of high cost and serious EMC radiation caused by the use of DCDC chips in the prior art, but also provides advantages such as simplified design, enhanced circuit stability and flexibility, and the like. These improvements help to reduce development difficulty and cost. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is a multi-channel triode-based large-current constant current control circuit diagram;

[0039] Figure 2 It is a circuit diagram of an LED module. DETAILED DESCRIPTION

[0040] The following is a specific embodiment of the present application and further describes the technical solutions of the present application in conjunction with the drawings, but the present application is not limited to these embodiments.

[0041] In order to realize large-current constant current control at low cost, as shown in the prior art, Figure 1 The utility model discloses a multi-channel triode-based large-current constant current control circuit, which comprises:

[0042] A power protection module is used to receive external power input and process it to output stable DC power.

[0043] The power protection module comprises:

[0044] A rectifier unit is used to rectify the external power and convert AC power into DC power.

[0045] The rectifier unit comprises:

[0046] A first diode D1; the anode of the first diode D1 is connected to one end of a twenty-fifth resistor R25 and one end of a first capacitor C1 in sequence and then connected to a positive power supply B+; the cathode of the first diode D1 is connected to an overvoltage protection unit; the other end of the first capacitor C1 is connected to one end of a sixth capacitor C6; the other end of the sixth capacitor C6 is grounded.

[0047] An overvoltage protection unit is used to protect the circuit from transient voltage spikes.

[0048] The overvoltage protection unit comprises:

[0049] A transient voltage suppressor TVS1; one end of the transient voltage suppressor TVS1 is connected with the negative end of the first diode D1 and one end of the filter unit, and the other end is connected with the other end of the twenty-fifth resistor R25 and then grounded, and also connected with the other end of the filter unit.

[0050] A filter unit for filtering the rectified direct current power supply, removing voltage fluctuation and noise, and providing stable direct current power supply.

[0051] The filter unit comprises:

[0052] A third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5; one end of the fifth capacitor C5 is connected with one end of the twenty-fourth resistor R24, and in turn connected with one end of the fourth capacitor C4, one end of the third capacitor C3 and one end of the transient voltage suppressor TVS1; the other end of the fifth capacitor C5 is connected with one end of the second capacitor C2, and in turn connected with the other end of the fourth capacitor C4, the other end of the third capacitor C3 and the other end of the transient voltage suppressor TVS1; the other end of the twenty-fourth resistor R24 is connected with the other end of the second capacitor C2 and one end of the first resistor R1, and then connected with the positive voltage input pin IN in the load.

[0053] A reference voltage generation module for accessing the direct current power supply output by the power supply protection module, setting a constant current value, and generating a reference voltage based on the constant current value.

[0054] The reference voltage generation module comprises:

[0055] A constant current value setting unit for setting a constant current value by adjusting the resistance value.

[0056] The constant current value setting unit comprises:

[0057] A twelfth resistor R12 and a thirteenth resistor R13; one end of the thirteenth resistor R13 is in turn connected with one end of the twelfth resistor R12, one end of the eighth capacitor C8 and the reference voltage generation unit while being grounded; the other end of the thirteenth resistor R13 is in turn connected with the other end of the twelfth resistor R12 and one end of the twenty-first resistor R21 while being connected with the constant current control module; the other end of the twenty-first resistor R21 is connected with the other end of the eighth capacitor C8 and then connected with the reference voltage generation unit.

[0058] The constant current value setting unit is specifically configured to set a constant current value by adjusting the resistance value of the twelfth resistor R12 and the thirteenth resistor R13.

[0059] A reference voltage generation unit for generating a reference voltage based on the constant current value.

[0060] The reference voltage generating unit comprises:

[0061] The eighth transistor Q8 has its emitter connected to one end of an eighth capacitor C8 and grounded, its base connected to the other end of the eighth capacitor C8 and the other end of a twenty-first resistor R21 in sequence, and its collector connected to the constant current control module and then to the other end of the first resistor R1.

[0062] The constant current control module comprises a plurality of parallelly connected triode control units, which are used to access the direct current power output by the power protection module and adjust the working state of each parallelly connected triode control unit according to the set reference voltage, so as to share the total current load required by the load. The total current load represents the working current required by the load. In this way, the constant current control module ensures that the working current is stably and accurately controlled to the LED module.

[0063] Each of the triode control units comprises a power triode, a current-limiting resistor, a filter capacitor and a bias resistor. The base of the power triode is connected to one end of the filter capacitor and one end of the current-limiting resistor in sequence, the collector is connected to the negative voltage output pin OUT in the load through the output pin OUT, and the emitter is connected to one end of the bias resistor. The other end of the bias resistor is connected to the other end of a thirteenth resistor R13 in the constant current value setting unit. The other end of the filter capacitor is grounded. The other end of the current-limiting resistor is connected to one end of a nineteenth capacitor C19, and then connected to the other end of the first resistor R1 and the collector of the eighth transistor Q8. The other end of the nineteenth capacitor C19 is grounded.

[0064] As shown in Figure 1 The embodiment reduces the power consumption of a single power triode and improves the stability and reliability of the circuit by connecting multiple power triodes (Q1 to Q7) in parallel to share the total current load. Each triode control unit contains a power triode, a current-limiting resistor, a filter capacitor and a bias resistor, which work together to ensure that the total current load is evenly distributed. Specifically, Figure 1 The triode control unit corresponding to the power triode Q1 is composed of the power triode Q1, the current-limiting resistor R14, the filter capacitor C7 and the bias resistor R4. The triode control unit corresponding to the power triode Q2 is composed of the power triode Q2, the current-limiting resistor R15, the filter capacitor C9 and the bias resistor R5. The composition of the remaining triode control units is shown in Figure 1 .

[0065] In addition, the eighth transistor Q8 in the reference voltage generation module has a relatively stable base-emitter (BE) voltage drop, which is usually maintained at around 0.6V. By adjusting the resistance values of the twelfth resistor R12 and the thirteenth resistor R13, the required constant current value can be accurately set. Specifically, the twelfth resistor R12 and the thirteenth resistor R13 form a constant current value setting unit that is commonly grounded, and by adjusting the resistance values of these two resistors, the output of the reference voltage generation unit can be adjusted, thereby controlling the operating state of each parallel power transistor and ensuring that the LED module is provided with stable and accurately controlled operating current.

[0066] It needs to be explained that, Figure 1 With Figure 2 T1 to T21 in the figure represent test points.

[0067] The load is an LED module as shown in Figure 2 The total current load is shared by multiple transistor control units connected in parallel, and each transistor control unit allocates the total current load according to a predetermined proportion.

[0068] In different current demand situations, the number of power transistors or transistor control units required for use will be different. Specifically, the number of power transistors needs to be determined according to the actual current demand of the input (IN) and output (OUT) parts. For example, in the application of driving an LED module, if the total current required is large, more power transistors need to be connected in parallel to share the current load, so as to avoid overloading or overheating of a single power transistor, and to ensure the stability and reliability of the circuit.

[0069] For an example in a specific application, assume that the total current demand is 770mA, and each power transistor can safely carry about 110mA of current. In this case, in order to meet the total current demand of 770mA (total current load), 7 power transistors (Q1 to Q7) need to be connected in parallel. This configuration not only effectively disperses the current load and reduces the power consumption of individual transistors, but also improves the overall stability of the circuit by the joint work of multiple power transistors.

[0070] In addition, each transistor control unit contains a power transistor, a current limiting resistor, a filter capacitor, a bias resistor and other components inside, which work together to ensure that each power transistor can share the total current load according to the predetermined proportion. For example, under the total current demand of 770mA, each transistor control unit can be designed to carry about 110mA of current. By reasonably selecting the parameters of the current limiting resistor and other related elements, the operating state of each transistor can be accurately controlled to ensure that it can operate efficiently within the specified current range.

[0071] It is worth noting that when the current demand in actual application changes, such as the total current increases to a higher value or decreases to a lower value, the corresponding number of triode control units also needs to be adjusted. For example, if the total current demand increases to 1A, 9 or more triode control units may be needed to work in parallel; on the contrary, if the total current demand decreases to 550mA, only 5 triode control units may be needed to meet the requirements. Therefore, flexible adjustment of the number of parallel triode control units according to the specific current demand is one of the key factors to realize efficient and stable constant current control.

[0072] In this way, the utility model provides a flexible and scalable solution, which can dynamically adjust the circuit configuration according to the requirements of different application scenarios, both ensures the effective management of large current, and realizes the maximization of cost benefit. At the same time, the design also significantly reduces the EMC radiation problem, and simplifies the circuit design and implementation process.

[0073] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, motion condition, etc. between the components in a certain posture (as shown in the drawings), if the specific posture changes, the directional indications also change accordingly.

[0074] In addition, the description such as "first", "second", "one" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "first", "second" can be explicitly or implicitly included at least one of the features. In the description of the present application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0075] In the present application, unless otherwise specifically defined and limited, the terms "connection", "fixation" and the like should be understood broadly, for example, "fixation" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically limited. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0076] In addition, the technical solutions of each embodiment of the present application can be combined with each other, but it must be based on the realization of ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, also not within the scope of protection required by the present application.

Claims

1. A multi-path triode-based high current constant current control circuit, characterized by, The application relates to a power protection module, a reference voltage generation module and a constant current control module. The power protection module is used for receiving external power input and processing the same to output stable direct current power. The reference voltage generation module is used for accessing the direct current power output by the power protection module and setting a constant current value, and generating a reference voltage based on the constant current value. The constant current control module comprises a plurality of parallelly connected triode control units, and is used for accessing the direct current power output by the power protection module and adjusting the working state of each parallelly connected triode control unit according to the set reference voltage to share the total current load required by the load.

2. A multi-transistor based high current constant current control circuit as claimed in claim 1, wherein, The power protection module comprises: The rectification unit is used for rectifying the external power to convert alternating current into direct current. The filter unit is used for filtering the rectified direct current power to remove voltage fluctuation and noise and provide stable direct current power. The overvoltage protection unit is used for protecting the circuit from transient voltage spikes.

3. A multi-transistor based high current constant current control circuit as claimed in claim 2, wherein, The rectification unit comprises: The positive electrode end of the first diode D1 is connected with one end of the twenty-fifth resistor R25 and one end of the first capacitor C1 in sequence and then connected with the positive electrode power B+.

4. A multi-transistor based high current constant current control circuit as claimed in claim 3, wherein, The negative electrode end of the first diode D1 is connected with the overvoltage protection unit. The other end of the sixth capacitor C6 is grounded.

5. A multi-transistor based high current constant current control circuit as claimed in claim 4, wherein, The overvoltage protection unit comprises: The transient voltage suppressor TVS1 is connected with the negative electrode end of the first diode D1 and one end of the filter unit in sequence and connected with the other end of the twenty-fifth resistor R25 and then grounded.

6. A multi-transistor based high current constant current control circuit as claimed in claim 5, wherein, The filter unit comprises: The third capacitor C3, the fourth capacitor C4 and the fifth capacitor C5 are connected with each other in sequence. The other end of the fifth capacitor C5 is connected with one end of the second capacitor C2 and then connected with the other end of the fourth capacitor C4, the other end of the third capacitor C3 and the other end of the transient voltage suppressor TVS1 in sequence.

7. A high current constant current control circuit based on multiple transistors as claimed in claim 6, wherein, The other end of the twenty-fourth resistor R24 is connected with the other end of the second capacitor C2 and one end of the first resistor R1 and then connected with the positive electrode voltage input pin IN in the load. The reference voltage generation module comprises: The constant current value setting unit is used for setting the constant current value by adjusting the resistance value. The reference voltage generation unit is used for generating a reference voltage based on the constant current value. The constant current value setting unit comprises: Twelfth resistor R12 and thirteenth resistor R13; one end of the thirteenth resistor R13 is connected to one end of the twelfth resistor R12, one end of the eighth capacitor C8 and the reference voltage generating unit while being grounded; the other end of the thirteenth resistor R13 is connected to the constant current control module while being connected to the other end of the twelfth resistor R12 and one end of the twenty-first resistor R21; the other end of the twenty-first resistor R21 is connected to the other end of the eighth capacitor C8 and then connected to the reference voltage generating unit; The constant current value setting unit is specifically used for setting the constant current value by adjusting the resistance values of the twelfth resistor R12 and the thirteenth resistor R13.

8. A multi-transistor based high current constant current control circuit as claimed in claim 7, wherein, The reference voltage generating unit comprises: The eighth transistor Q8; the emitter of the eighth transistor Q8 is connected to one end of the eighth capacitor C8 and grounded, the base is connected to the other end of the eighth capacitor C8 and the other end of the twenty-first resistor R21, and the collector is connected to the constant current control module and then connected to the other end of the first resistor R1.

9. A multi-transistor based high current constant current control circuit as claimed in claim 8, wherein, Each of the triode control units comprises a power triode, a current-limiting resistor, a filter capacitor and a bias resistor; the base of the power triode is connected to one end of the filter capacitor and one end of the current-limiting resistor, the collector is connected to the negative voltage output pin OUT in the load through the output pin OUT, and the emitter is connected to one end of the bias resistor; the other end of the bias resistor is connected to the other end of the thirteenth resistor R13 in the constant current value setting unit; the other end of the filter capacitor is grounded; the other end of the current-limiting resistor is connected to one end of the nineteenth capacitor C19 and then connected to the other end of the first resistor R1 and the collector of the eighth transistor Q8; the other end of the nineteenth capacitor C19 is grounded.

10. A multi-transistor based high current constant current control circuit as claimed in claim 9, wherein, The load is an LED module; the total current load is shared by a plurality of triode control units connected in parallel, and each triode control unit allocates the total current load according to a preset proportion.

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