Programmable current limited regulated output circuit and control method

Abstract

The application discloses a programmable current-limiting regulating output circuit and a control method, and belongs to the field of electronic measurement circuits. The application comprises a power supply end, a reference voltage input end, a digital-to-analog converter, a sampling resistor, a comparator, a first triode, a second triode, an output control transistor and a voltage output end; the base of the first triode is connected to the output end of the digital-to-analog converter, the emitter is connected to the power supply end, and the collector is connected to the first input end of the comparator; the second input end of the comparator is connected to the voltage output end through the sampling resistor; the output end of the comparator is connected to the base of the second triode; the collector of the second triode is connected to the reference voltage input end, the emitter is connected to the voltage output end; the gate of the output control transistor is connected to the reference voltage input end, the drain is connected to the power supply end, and the source is connected to the voltage output end.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic measurement circuit, and particularly relates to a programmable current-limiting regulating output circuit and a control method. BACKGROUND

[0002] In the production and testing process of electronic display devices, especially in the aging test link of cells, stable control of power supply current is one of the key factors to ensure the quality of screen body and production efficiency. In the cell aging process, the screen body needs to withstand a certain current to simulate the actual use condition, and excessive current can cause the screen body to overheat or even burn, thereby seriously affecting product quality and production yield.

[0003] In the traditional screen body aging test, in order to avoid damage to the screen body due to overcurrent, a fixed upper limit current limiting card control combined with software overcurrent detection is usually used. However, the maximum current value that can be withstood by different models and specifications of screen bodies is different, and the fixed upper limit current limiting card control cannot flexibly adapt to such differences, resulting in that the current limiting value is set too high or too low in some cases, and the screen body cannot be effectively protected. On the other hand, although software overcurrent detection can provide a certain degree of protection, due to the delay of software processing, when overcurrent is detected, the screen body has been damaged to a certain extent. Especially in the face of sudden large current impact, the reaction speed of software card control is far from enough to avoid the risk of screen body burn. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a programmable current-limiting regulating output circuit and a control method.

[0005] The technical solutions provided by the present application are described as follows:

[0006] The present application provides a programmable current-limiting regulating output circuit, which comprises:

[0007] a power supply end (VCC), a reference voltage input end (IN_REF), a digital-to-analog converter (DAC), a sampling resistor (R1), a comparator (U1), a first triode (Q2), a second triode (Q3), an output control transistor (Q1), and a voltage output end (V_out);

[0008] The base of the first triode (Q2) is connected to the output of the digital-to-analog converter (DAC), the emitter is connected to the power supply end, and the collector is connected to the first input of the comparator (U1). The second input of the comparator (U1) is connected to the voltage output end (V_out) through the sampling resistor (R1). The output of the comparator (U1) is connected to the base of the second triode (Q3). The collector of the second triode (Q3) is connected to the reference voltage input end (IN_REF), and the emitter is connected to the voltage output end. The gate of the output control transistor (Q1) is connected to the reference voltage input end (IN_REF), the drain is connected to the power supply end (VCC), and the source is connected to the voltage output end (V_out). When the voltage at the first input of the comparator (U1) is lower than the voltage at the second input, the second triode (Q3) is turned on, so that the voltage at the reference voltage input end (IN_REF) pulls down the voltage control at the gate of the output control transistor (Q1) to limit the conduction degree of the output control transistor (Q1), and outputs voltage to the voltage output end (V_out) through the second triode (Q3).

[0009] Optionally, the digital-to-analog converter (DAC) is connected to the power supply end (VCC) through a second resistor (R2).

[0010] Optionally, the digital-to-analog converter (DAC) is connected to the voltage output end (V_out) through a third resistor (R3).

[0011] Optionally, the reference voltage input end (IN_REF) is connected to the voltage output end (V_out) through a fourth resistor (R4).

[0012] Optionally, the reference voltage input end (IN_REF) is connected to the voltage output end (V_out) through a fifth resistor (R5).

[0013] Optionally, the digital-to-analog converter (DAC) is connected to the base of the first triode (Q2) through a sixth resistor (R6).

[0014] Optionally, the connection point between the second input of the comparator (U1) and the sampling resistor (R1) is a first sampling point (V1), and the first sampling point (V1) is used to collect the load voltage of the sampling resistor (R1).

[0015] Optionally, the connection point between the first input of the comparator (U1) and the third resistor (R3) is a second sampling point (V2), and the second sampling point (V2) is used to collect the load voltage of the third resistor (R3).

[0016] The second aspect of the present application provides a control method of a programmable current-limiting regulating output circuit, the control method comprising:

[0017] setting a preset current value I through the digital-to-analog converter (DAC);

[0018] collecting the load voltage of the second collection point (V2) through the first input end of the comparator (U1) and collecting the voltage of the first sampling point (V1) through the second input end of the comparator (U1);

[0019] comparing the voltage of the first input end and the voltage of the second input end through the comparator (U1);

[0020] if the voltage of the second input end is greater than the voltage of the first input end;

[0021] then the output end of the comparator (U1) controls the second triode (Q3) to be turned on, and the output control transistor (Q1) is disconnected through the reference voltage input end (IN_REF). Optionally, before the comparator (U1) compares the voltage of the first input end and the voltage of the second input end, comprising:

[0022] performing digital filtering processing on the voltage of the first input end and the voltage of the second input end to filter out high-frequency noise interference.

[0023] From the above technical solutions, the present application has the following advantages: the dynamic setting of the current-limiting value is realized through the digital-to-analog converter (DAC), and the high-precision comparator (U1) is combined to monitor the voltage across the sampling resistor (R1) in real time, which can reflect the load current state and ensure that the output current is always controlled within the preset safe threshold range. When the load current fluctuates due to abnormal conditions, it can quickly respond, adjust the output state through the output control transistor (Q1), timely limit the current, and prevent the load device from being damaged. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 An embodiment schematic diagram of a programmable current-limiting regulating output circuit provided by the present application;

[0025] Figure 2 An embodiment schematic diagram of a control method of a programmable current-limiting regulating output circuit provided by the present application. DETAILED DESCRIPTION

[0026] In order to solve the above technical problems, the application provides a programmable current limiting regulation output circuit and a control method, which are used in the field of electronic measurement circuit, and the dynamic setting of the current limiting value is realized through a digital-to-analog converter (DAC), and the voltage at both ends of a sampling resistor (R1) is monitored in real time through a high-precision comparator (U1), so that the load current state can be reflected, and it is ensured that the output current is always controlled within the preset safe threshold range. When the load current fluctuates due to abnormal conditions, it can quickly respond, adjust the output state through an output control transistor (Q1), and timely limit the current to prevent the load device from being damaged. In the application, the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "transverse" and "longitudinal" are based on the directions or positional relationships shown in the drawings, and are only used to illustrate the relative positional relationships between the components or constituent parts, and do not particularly limit the specific mounting directions of the components or constituent parts.

[0027] In addition, in addition to being used to indicate the directions or positional relationships, the above-mentioned terms can also be used to indicate other meanings, for example, the term "upper" can also be used to indicate a certain dependent relationship or connection relationship in some cases. Those skilled in the art can understand the specific meanings of these terms in the application according to the specific circumstances.

[0028] In addition, the terms "mounting", "setting", "provided with", "connection", "connected" should be understood broadly. For example, it can be fixed connection, detachable connection, or integral structure; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium, or internal communication between two devices, elements or constituent parts. Those skilled in the art can understand the specific meanings of the above-mentioned terms in the application according to the specific circumstances.

[0029] In addition, the structures, proportions, sizes, etc. shown in the drawings in the application are only used to cooperate with the disclosed content in the specification, to enable those skilled in the art to understand and read, and do not have technical significance, and any modification of the structure, change of the proportional relationship or adjustment of the size, which does not affect the effects and purposes that can be achieved by the application, still falls within the scope of the technical content disclosed by the application.

[0030] The technical solutions in the application will be described clearly and completely in the following combined with the drawings in the application. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application.

[0031] Referring to Figure 1 The first aspect of the present application provides a programmable current-limiting regulating output circuit, an embodiment of which comprises:

[0032] a power supply end (VCC), a reference voltage input end (IN_REF), a digital-to-analog converter (DAC), a sampling resistor (R1), a comparator (U1), a first transistor (Q2), a second transistor (Q3), an output control transistor (Q1), and a voltage output end (V_out);

[0033] The base of the first transistor (Q2) is connected to the output end of the digital-to-analog converter (DAC), the emitter is connected to the power supply end, and the collector is connected to the first input end of the comparator (U1). The second input end of the comparator (U1) is connected to the voltage output end (V_out) through the sampling resistor (R1). The output end of the comparator (U1) is connected to the base of the second transistor (Q3). The collector of the second transistor (Q3) is connected to the reference voltage input end (IN_REF), and the emitter is connected to the voltage output end. The gate of the output control transistor (Q1) is connected to the reference voltage input end (IN_REF). The drain is connected to the power supply end (VCC), and the source is connected to the voltage output end (V_out). When the voltage at the first input end of the comparator (U1) is lower than the voltage at the second input end, the second transistor (Q3) is turned on, so that the voltage at the reference voltage input end (IN_REF) pulls down the voltage control at the gate of the output control transistor (Q1) to limit the degree of conduction of the output control transistor (Q1), and the voltage is output to the voltage output end (V_out) through the second transistor (Q3).

[0034] The programmable current limiting regulation output circuit provided in the application comprises a power supply end (VCC), a reference voltage input end (IN_REF), a digital-to-analog converter (DAC), a sampling resistor (R1), a comparator (U1), a first transistor (Q2), a second transistor (Q3), an output control transistor (Q1), and a voltage output end (V_out). A preset voltage corresponding to a preset current value is set by the DAC, and the voltage signal is transmitted to the base of the first transistor (Q2). In a normal working state, the first transistor (Q2) controls the collector current thereof according to the voltage output by the DAC, thereby affecting the voltage at the first input end of the comparator (U1). The second input end of the comparator (U1) is connected to the voltage output end (V_out) through the sampling resistor (R1), and the load current is monitored in real time. When the load current is small, the voltage drop on the sampling resistor (R1) is small, and the voltage at the second input end of the comparator (U1) is lower than the voltage at the first input end. Since the voltage at the second input end is lower than the voltage at the first input end, the output end of the comparator (U1) remains at a low level, and the second transistor (Q3) is in a closed state. The voltage at the reference voltage input end (IN_REF) remains at a set value, the output control transistor (Q1) is turned on, and the voltage at the power supply end (VCC) is normally output to the voltage output end (V_out) through the output control transistor (Q1). When the external load is increased, causing the load current to exceed the preset current value, the voltage drop on the sampling resistor (R1) is increased, and the voltage at the second input end of the comparator (U1) is increased. When the voltage at the second input end exceeds V2, the output end of the comparator (U1) becomes high, triggering the second transistor (Q3) to be turned on. After the second transistor (Q3) is turned on, the voltage at the reference voltage input end (IN_REF) is pulled low, thereby affecting the gate voltage of the output control transistor (Q1). After the gate voltage of the output control transistor (Q1) is pulled low, the degree of conduction of the output control transistor (Q1) is limited, causing the voltage output to the voltage output end (V_out) to be reduced, thereby realizing current limiting protection.

[0035] In the embodiment, the dynamic setting of the current limiting value is performed by the digital-to-analog converter (DAC), which can adapt to the differences in current bearing capacity of different models and specifications of screen bodies. The comparator (U1) monitors the voltages at the first input end and the second input end, which can reflect the load current state, ensuring that the output current is controlled within a preset safe threshold range. When the voltage at the second input end is lower than the voltage at the first input end and exceeds the preset threshold, the output state is adjusted by the output control transistor, the current is timely limited, the load equipment is prevented from being damaged due to overcurrent, and the defective product rate in the production process is reduced.

[0036] Please refer to Figure 1 , in combination with Embodiment 1, in an optional embodiment, the digital-to-analog converter (DAC) is connected with the power supply end (VCC) through a second resistor (R2).

[0037] Digital-to-analog converter (DAC) is one of the core components in the circuit, responsible for converting digital signals into analog voltage signals.

[0038] In this circuit, the digital-to-analog converter (DAC) is used to set a preset current value corresponding to the voltage signal, which will serve as the reference for current limiting control. The digital-to-analog converter (DAC) is connected to the power supply terminal (VCC) through the second resistor (R2), ensuring that the digital-to-analog converter (DAC) can obtain voltage from the power supply terminal. The second resistor (R2) plays a role in limiting current and dividing voltage, protecting the digital-to-analog converter (DAC) from excessive current impact. The digital-to-analog converter (DAC) will output the corresponding analog voltage signal according to the set digital signal, and the voltage signal is transmitted to the base of the first transistor (Q2) through the second resistor (R2). The voltage signal at the base of the first transistor (Q2) controls the conduction degree of the first transistor (Q2), which in turn affects the voltage at the first input terminal of the comparator (U1). The comparator (U1) compares the voltage at the first input terminal and the second input terminal to determine whether the load current exceeds the preset current value. When the load current exceeds the preset current value, the voltage drop on the sampling resistor (R1) increases, causing the voltage at the second input terminal of the comparator (U1) to rise. After the comparator detects that the voltage at the second input terminal is lower than the voltage at the first input terminal, it outputs a control signal to turn on the second transistor (Q3), which in turn lowers the voltage at the reference voltage input terminal (IN_REF), limiting the conduction degree of the output control transistor (Q1) and reducing the voltage output to the voltage output terminal (V_out), achieving current limiting protection.

[0039] In this embodiment: The digital-to-analog converter (DAC) realizes dynamic adjustment of the current limiting value, which can adapt to the current demand of different screens and improve the universality and adaptability of the circuit. The dynamic adjustment capability avoids the defect that the traditional fixed current limiting value circuit cannot adapt to variable load conditions. The circuit uses a hardware comparator (U1) to monitor the load current in real time, and can quickly cut off or limit the output current once an overcurrent condition is detected, preventing the load from being damaged due to overcurrent and shortening the overcurrent protection time, thereby improving the safety of the circuit. The digital-to-analog converter (DAC) and comparator (U1) cooperate to ensure the stability of the current limiting value, so that the circuit can maintain accurate current control under different load conditions, which helps to improve the quality and performance of the product.

[0040] Please refer to Figure 1 , in combination with embodiment 1, in an optional embodiment, the digital-to-analog converter (DAC) is connected to the voltage output terminal (V_out) through the third resistor (R3).

[0041] The digital-to-analog converter (DAC) is responsible for converting digital signals into analog voltage signals, which represent the preset current limit value. The digital-to-analog converter (DAC) is connected to the voltage output terminal (V_out) through a third resistor (R3). The third resistor (R3) plays a role in voltage division and current limiting, ensuring that the voltage signal output by the digital-to-analog converter (DAC) will not be directly loaded onto the voltage output terminal, but will be divided by an appropriate resistance value, thereby protecting the digital-to-analog converter (DAC) and subsequent circuits from excessive voltage or current. During current limit control, the voltage signal output by the digital-to-analog converter (DAC) is compared with the voltage on the sampling resistor (R1). When the load current changes, the voltage on the sampling resistor (R1) will also change accordingly, which is detected by the comparator (U1). Assuming that the digital-to-analog converter (DAC) is set to output a voltage signal representing a specific current limit value. When the load current connected to the voltage output terminal (V_out) is within the normal range, the comparator will not trigger the current limit protection. When the load current exceeds the preset current limit value, the voltage on the sampling resistor (R1) will rise accordingly, exceeding the corresponding value of the digital-to-analog converter (DAC) output voltage divided by the third resistor (R3), and the comparator detects this difference and triggers the current limit protection mechanism.

[0042] In this embodiment: the digital-to-analog converter (DAC) is connected to the voltage output terminal through a third resistor (R3), and the analog voltage signal output by the digital-to-analog converter (DAC) serves as a reference for current limit control, which is compared with the voltage on the sampling resistor (R1), helping to improve the accuracy of current limit control and ensure that the current fluctuates within the preset safe range. The third resistor (R3) plays a role in voltage division and current limiting, protecting the digital-to-analog converter (DAC) and subsequent circuits from excessive voltage or current, helping to improve system stability and reduce system failures caused by voltage or current fluctuations. By adjusting the output voltage of the digital-to-analog converter (DAC), different current limit values can be set to meet the current demand under different load conditions, making the circuit widely applicable to various scenarios requiring accurate current control, improving the versatility and adaptability of the circuit. When the load current exceeds the preset current limit value, the voltage on the sampling resistor (R1) will rise accordingly, and after comparison with the output voltage of the digital-to-analog converter (DAC), the comparator (U1) can quickly detect the difference and trigger the current limit protection mechanism, improving system safety. Through the programmable current limit adjustment output circuit, it ensures that the screen body will not be damaged due to overcurrent during the aging test process, thereby reducing the defective rate and improving production efficiency.

[0043] Please refer to Figure 1 , in combination with embodiment 1, in an optional embodiment, the reference voltage input terminal (IN_REF) is connected to the voltage output terminal (V_out) through a fourth resistor (R4).

[0044] The reference voltage input terminal (IN_REF) is connected to the voltage output terminal (V_out) through the fourth resistor (R4). The fourth resistor (R4) functions as a voltage divider and current limiter, ensuring that voltage fluctuations at the voltage output terminal (V_out) are not directly transmitted to the reference voltage input terminal (IN_REF), but are divided by an appropriate resistance value. During current limit control, when the load current changes cause voltage fluctuations at the voltage output terminal (V_out), they are transmitted to the reference voltage input terminal (IN_REF) through the fourth resistor (R4). Assuming that the reference voltage input terminal (IN_REF) is set to a stable voltage value as the basis for current limit control, the voltage at the voltage output terminal remains stable when the load current is within the normal range, and the voltage fluctuations transmitted to the reference voltage input terminal (IN_REF) through the fourth resistor (R4) are small enough not to affect current limit control. When the load current exceeds the preset current limit value, the voltage on the sampling resistor (R1) rises accordingly, and after comparing it with the output voltage of the digital-to-analog converter (DAC), the comparator (U1) detects the difference and triggers the current limit protection mechanism.

[0045] In this embodiment, the reference voltage input terminal (IN_REF) is connected to the voltage output terminal (V_out) through the fourth resistor (R4), which ensures the stability of the reference voltage. The fourth resistor (R4) functions as a current limiter and voltage divider, protecting the reference voltage source from excessive voltage or current at the voltage output terminal (V_out). By providing a stable reference voltage reference, it helps to improve the stability and reliability of the circuit.

[0046] Please refer to Figure 1 , in combination with embodiment 1, in an alternative embodiment, the reference voltage input terminal (IN_REF) is connected to the voltage output terminal (V_out) through the fifth resistor (R5).

[0047] The reference voltage input terminal (IN_REF) is connected to the voltage output terminal (V_out) through the fifth resistor (R5). The fifth resistor (R5) functions as a voltage divider and current limiter. When the load current connected to the voltage output terminal (V_out) is within the normal range, the voltage at the voltage output terminal (V_out) remains stable, and the voltage fluctuations transmitted to the reference voltage input terminal (IN_REF) through the fifth resistor (R5) will not affect the current limit control. When the load current exceeds the preset current limit value, the voltage on the sampling resistor (R1) rises accordingly, and after comparing it with the output voltage of the digital-to-analog converter (DAC), the comparator (U1) detects the difference and triggers the current limit protection mechanism.

[0048] In this embodiment, the fifth resistor (R5) functions as a voltage divider, preventing the voltage fluctuations at the voltage output terminal (V_out) from being directly transmitted to the reference voltage input terminal (IN_REF), thereby protecting the reference voltage source from voltage fluctuations and ensuring the stability of the reference voltage. Through the voltage dividing effect of the fifth resistor (R5), the reference voltage input terminal (IN_REF) can obtain a stable voltage reference, thereby improving the precision of current limiting control.

[0049] Please refer to Figure 1 In an alternative embodiment, the digital-to-analog converter (DAC) is connected to the base of the first transistor (Q2) through the sixth resistor (R6), as described in Embodiment 1.

[0050] The digital-to-analog converter (DAC) is connected to the base of the first transistor (Q2) through the sixth resistor (R6), allowing the analog voltage signal output by the digital-to-analog converter (DAC) to directly act on the base of the first transistor (Q2), thereby controlling the conduction degree of the first transistor (Q2). The sixth resistor (R6) functions as a current limiter, preventing the output current of the digital-to-analog converter (DAC) from being too large and damaging the base of the first transistor (Q2). When the analog voltage signal output by the digital-to-analog converter (DAC) changes, it acts on the base of the first transistor (Q2) through the sixth resistor (R6), changing the conduction degree of the first transistor (Q2). Changes in the conduction degree of the first transistor (Q2) affect the collector current, which in turn affects the working state of the subsequent circuit, achieving the limitation and adjustment of the output current. Assuming that the digital-to-analog converter (DAC) is set to output a specific analog voltage signal as a reference for current limiting control. This voltage signal acts on the base of the first transistor (Q2) through the sixth resistor (R6), causing the first transistor (Q2) to be in a certain conduction state. When the current at the voltage output terminal (V_out) increases, the voltage drop across the sampling resistor (R1) increases and is fed back to the input terminal of the comparator (U1). The comparator (U1) compares the voltage across the sampling resistor (R1) with the reference voltage output by the digital-to-analog converter (DAC), and when the voltage across the sampling resistor (R1) exceeds the reference voltage, the comparator (U1) outputs a control signal that adjusts the conduction degree of the output control transistor (Q1) through the subsequent circuit, thereby limiting the output current.

[0051] In this embodiment, the analog voltage signal output by the digital-to-analog converter (DAC) serves as a reference for current limiting, and the sixth resistor (R6) controls the base voltage of the first transistor (Q2), achieving dynamic adjustment of the output current. The current limiting and voltage dividing effects of the sixth resistor (R6) effectively isolate the direct coupling between the output of the digital-to-analog converter (DAC) and the base of the first transistor (Q2), reducing the impact of fluctuations in the output of the digital-to-analog converter (DAC) on the working state of the first transistor (Q2).

[0052] Please refer to Figure 1 , in an alternative embodiment, the second input of the comparator (U1) and the connection point of the sampling resistor (R1) is the first sampling point (V1), which is used to collect the load voltage of the sampling resistor (R1).

[0053] The first input of the comparator (U1) and the connection point of the third resistor (R3) is the second sampling point (V2), which is used to collect the load voltage of the third resistor (R3).

[0054] The comparator (U1) is used to compare the size of two input voltage signals and output a high or low level signal according to the comparison result. In the current limiting regulation circuit, the comparator (U1) monitors the change of the load current and triggers the current limiting protection mechanism when the current exceeds the preset value. The first sampling point (V1) is the connection point of the sampling resistor (R1) and the second input of the comparator (U1). The sampling resistor (R1) is usually used as a sampling resistor, connected in series in the load loop, to convert the load current into a voltage signal. The first sampling point (V1) collects the voltage drop across the sampling resistor (R1), which is the voltage generated by the load current on R1. This voltage signal directly reflects the size of the load current of the sampling resistor (R1), and when the load current increases, the voltage of V1 will also rise accordingly. The second sampling point (V2) is the connection point of the third resistor (R3) and the first input of the comparator (U1). The third resistor (R3) is used to divide the reference voltage output by the digital-to-analog converter (DAC) and input it to the first input of the comparator (U1). V2 collects the voltage drop across the third resistor (R3), which is also used as the reference voltage of the comparator (U1) for comparison with the voltage signal of the first sampling point (V1). The comparator (U1) continuously monitors the voltage signals of the first sampling point (V1) and the second sampling point (V2). When the voltage of V1 exceeds the voltage of V2, the comparator (U1) will output a high level signal to trigger the current limiting protection mechanism. After triggering the current limiting protection, the circuit will adjust the conduction degree of the output control transistor (Q1) to limit the load current, preventing the current from continuing to increase and damaging the load element.

[0055] In this embodiment: the first sampling point (V1) directly collects the voltage drop on the sampling resistor (R1), which is proportional to the load current, thereby realizing the monitoring of the load current. The second sampling point (V2) collects the reference voltage of the digital-to-analog converter (DAC) after being divided by the third resistor (R3), providing a stable comparison reference for the comparator (U1). By comparing the voltage signals of V1 and V2, the comparator (U1) can accurately determine whether the load current exceeds the preset value and trigger the current limiting protection mechanism. When the voltage output end (V_out) exceeds the preset current limiting value, the comparator (U1) outputs a control signal to trigger the current limiting protection, preventing the circuit components from being damaged due to overcurrent, and ensuring that the output current always remains within a safe range through the comparator (U1).

[0056] In combination Figure 1 Embodiment, please refer to Figure 2 , the second aspect of the present application provides a control method embodiment of a programmable current limiting regulation output circuit, which comprises:

[0057] S101, set a preset current value I through a digital-to-analog converter (DAC);

[0058] The digital-to-analog converter (DAC) converts the digital control signal into an analog voltage signal. The analog voltage signal output by the digital-to-analog converter (DAC) is divided by the third resistor R3 and then serves as the reference voltage of the first input end of the comparator (U1). The reference voltage corresponds to the preset current value I, and by adjusting the digital input value of the digital-to-analog converter (DAC), the output voltage can be changed, thereby setting different current limiting thresholds. The relationship between the preset current value I and the output voltage of the digital-to-analog converter (DAC) is determined by the resistance value of the sampling resistor (R1).

[0059] S102, collect the load voltage of the second sampling point (V2) through the first input end of the comparator (U1), and collect the voltage of the first sampling point (V1) through the second input end of the comparator (U1);

[0060] The first input end of the comparator (U1) collects the reference voltage signal of the digital-to-analog converter (DAC) after being divided by the third resistor (R3), i.e. the voltage of the second sampling point (V2). This voltage serves as the reference for current limiting control and reflects the voltage threshold corresponding to the preset current value I. The second input end of the comparator (U1) collects the voltage drop on the sampling resistor (R1) caused by the load current, i.e. the voltage of the first sampling point (V1).

[0061] S103, compare the voltages of the first input end and the second input end through the comparator (U1);

[0062] The comparator (U1) continuously compares the voltage signals at its two input terminals and outputs a high or low level signal according to the comparison result. When V1 is less than V2, the comparator (U1) outputs a low level signal, indicating that the load current has not exceeded the preset value I, and the circuit is working normally. When V1 is greater than V2, the comparator (U1) outputs a high level signal, indicating that the load current has exceeded the preset value I, triggering the current limiting protection mechanism.

[0063] Optionally, before the comparator (U1) compares the voltages at the first and second input terminals, it includes:

[0064] The voltages at the first and second input terminals are digitally filtered to filter out high frequency noise interference.

[0065] First, the voltage signals at the first and second input terminals of the comparator (U1) are sampled and quantized by the analog-to-digital converter (ADC), converting the analog signals to digital signals. The average of a plurality of consecutive sample values is taken to smooth the signal fluctuations. A digital low-pass filter is designed to filter out high frequency noise. The sample values are sorted, and the middle value is taken as the output, effectively suppressing impulse noise. The filtered digital signal is converted back to an analog signal by the digital-to-analog converter (DAC) and input to the input terminal of the comparator (U1). The filtered analog signal is smoother and has reduced high frequency noise. After digital filtering, the voltage signals at the second and first input terminals are more stable, and the comparator (U1) can make judgments based on the true load current information. Digital filtering can effectively filter out high frequency noise, avoiding the misjudgment of voltage fluctuations caused by noise as an overcurrent signal, thereby ensuring that the comparator (U1) makes judgments based on the true load current information. By eliminating noise interference, the comparator (U1) triggers current limiting protection only when the load current truly exceeds the preset value, improving the accuracy of current limiting control.

[0066] S104, if the voltage at the second input terminal is greater than the voltage at the first input terminal;

[0067] The comparator (U1) detects that V1>V2, indicating that the load current exceeds the preset value I, and the comparator (U1) outputs a high level signal, which is used as a control signal to drive the subsequent circuit.

[0068] S105, then the output terminal of the comparator (U1) controls the second triode (Q3) to conduct, and disconnects the output control transistor (Q1) through the reference voltage input terminal (IN_REF).

[0069] The comparator (U1) outputs a high-level signal to the base of the second transistor (Q3), making it conductive. After the second transistor (Q3) is turned on, the current path in the circuit changes. The reference voltage input terminal (IN_REF) is connected to the base of the output control transistor (Q1), and the voltage change directly affects the conduction state of the output control transistor (Q1). When the second transistor (Q3) is turned on, the voltage at the reference voltage input terminal (IN_REF) is pulled low, causing the base voltage of the output control transistor (Q1) to be insufficient, and the output control transistor (Q1) is turned off. After the output control transistor (Q1) is turned off, the load current is cut off, thereby realizing current limiting protection.

[0070] In this embodiment: the preset current value I is flexibly set by the digital-to-analog converter (DAC), which can accurately match the current demand of different loads and avoid damage or performance degradation caused by excessive or insufficient current. The load current is converted into a voltage signal by the sampling resistor (R1), and combined with the high-precision comparison function of the comparator (U1) to realize real-time and accurate monitoring of the load current. The fast comparison capability of the comparator (U1) enables the circuit to trigger current limiting protection in an instant when the load current exceeds the preset value, with a response time usually in the order of milliseconds, effectively preventing damage to the device due to overcurrent. Through the synergistic effect of the second transistor (Q3) and the output control transistor (Q1), the load current is quickly cut off or limited in the case of overcurrent, ensuring the safety of the load and circuit components.

[0071] It should be noted that the above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the scope of the present application. Therefore, the present application is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A programmable current limited regulated output circuit, characterized by, The application relates to a voltage output control circuit, which comprises the following components: a power supply end (VCC), a reference voltage input end (IN_REF), a digital-to-analog converter (DAC), a sampling resistor (R1), a comparator (U1), a first transistor (Q2), a second transistor (Q3), an output control transistor (Q1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6) and a voltage output end (V_out). The base of the first transistor (Q2) is connected to the output end of the digital-to-analog converter (DAC), the emitter is connected to the power supply end, and the collector is connected to the first input end of the comparator (U1); the digital-to-analog converter (DAC) is connected to the base of the first transistor (Q2) through the sixth resistor (R6); the second input end of the comparator (U1) is connected to the voltage output end (V_out) through the sampling resistor (R1); the digital-to-analog converter (DAC) is connected to the power supply end (VCC) through the second resistor (R2); the digital-to-analog converter (DAC) is connected to the voltage output end (V_out) through the third resistor (R3); the output end of the comparator (U1) is connected to the base of the second transistor (Q3), the collector of the second transistor (Q3) is connected to the reference voltage input end (IN_REF), and the emitter is connected to the voltage output end; the reference voltage input end (IN_REF) is connected to the voltage output end (V_out) through the fourth resistor (R4); the reference voltage input end (IN_REF) is connected to the voltage output end (V_out) through the fifth resistor (R5); the gate of the output control transistor (Q1) is connected to the reference voltage input end (IN_REF), the drain is connected to the power supply end (VCC), and the source is connected to the voltage output end (V_out); when the voltage at the first input end of the comparator (U1) is lower than the voltage at the second input end, the second transistor (Q3) is turned on, so that the voltage at the reference voltage input end (IN_REF) is pulled down to control the gate of the output control transistor (Q1), to limit the conduction degree of the output control transistor (Q1), and the voltage is output to the voltage output end (V_out) through the second transistor (Q3). The fourth resistor (R4) plays a role of voltage division and current limiting, ensures that the voltage change of the voltage output end (V_out) cannot be directly transmitted to the reference voltage input end (IN_REF), but is divided by a proper resistor value; in the current limiting control process, when the load current changes and causes the voltage fluctuation of the voltage output end (V_out), the voltage is transmitted to the reference voltage input end (IN_REF) through the fourth resistor (R4). ​ 2. The programmable current limited regulated output circuit of claim 1, wherein, The second input terminal of the comparator (U1) and the connecting point of the sampling resistor (R1) are a first sampling point (V1), and the first sampling point (V1) is used for collecting the load voltage of the sampling resistor (R1).

3. The programmable current limited regulated output circuit of claim 2, wherein, The first input terminal of the comparator (U1) and the connecting point of the third resistor (R3) are a second sampling point (V2), and the second sampling point (V2) is used for collecting the load voltage of the third resistor (R3).

4. A control method of a programmable current limit regulating output circuit, characterized by, The control method is applied to the programmable current limiting regulation output circuit in the claim 3, and the control method comprises: Setting a preset current value I through the digital-to-analog converter (DAC); Collecting the load voltage of the second sampling point (V2) through the first input terminal of the comparator (U1) and collecting the voltage of the first sampling point (V1) through the second input terminal of the comparator (U1); Comparing the voltage of the first input terminal and the voltage of the second input terminal through the comparator (U1); If the voltage of the second input terminal is greater than the voltage of the first input terminal; Then the output terminal of the comparator (U1) controls the second triode (Q3) to be turned on, and the output control transistor (Q1) is disconnected through the reference voltage input terminal (IN_REF).

5. The control method of a programmable current-limiting regulated output circuit according to claim 4, characterized by, Before the comparator (U1) compares the voltage of the first input terminal and the voltage of the second input terminal, the method comprises: Carrying out digital filtering processing on the voltage of the first input terminal and the voltage of the second input terminal, and filtering out high-frequency noise interference.

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