Adjustable current limiting digital signal output circuit

Abstract

This utility model discloses an adjustable current-limiting digital signal output circuit, including an input power supply VCC, a voltage divider network, transistor switches, a filter capacitor, an MCU control module, and an output terminal OUT. The input power supply VCC provides energy to the entire circuit. The transistor switches include transistors Q1, Q2, and Q3. The filter capacitor suppresses noise and stabilizes the voltage. The MCU control module includes a microcontroller enable signal MCU_EN and a power ground GND. The voltage divider network includes a current-limiting resistor, a voltage-dividing resistor, and a pull-up resistor. The current-limiting resistor adjusts the current limit by changing its resistance value, the voltage-dividing resistor adjusts the transistor voltage, and the pull-up resistor ensures the transistor conducts when the microcontroller enable signal MCU_EN is valid. The output terminal OUT is located at the circuit's output port. Thus, short-circuit protection is achieved through a simple transistor and resistor-capacitor circuit. The circuit is simple, reliable, requires few components, is cost-effective, and is less prone to failure.

Description

Technical Field

[0001] This utility model relates to the technical field of circuit protection, and in particular to an adjustable current-limiting digital signal output circuit. Background Technology

[0002] Traditional power control circuits rely on a single transistor or MOSFET to achieve switching functions, which has the following drawbacks:

[0003] Low control precision: Single-stage transistor switches are easily affected by input voltage fluctuations, resulting in poor output stability;

[0004] High power consumption: The base current is uncontrollable when the circuit is on, resulting in static losses;

[0005] Insufficient scalability: Unable to implement multi-level current distribution or complex logic control. Utility Model Content

[0006] This utility model aims to at least partially solve one of the technical problems in the related art.

[0007] Therefore, the purpose of this utility model is to propose an adjustable current-limiting digital signal output circuit. By adjusting the resistor, the switching of the transistor is affected, thereby adjusting the maximum current of the logic voltage output. Short circuit protection is achieved through a simple transistor and resistor-capacitor circuit. The circuit is simple, reliable, has few components, is cost-effective, and is not prone to failure.

[0008] To achieve the above objectives, this utility model proposes an adjustable current-limiting digital signal output circuit, including an input power supply VCC, a voltage divider network, transistor switches, a filter capacitor, an MCU control module, and an output terminal OUT. The input power supply VCC provides energy to the entire circuit; the transistor switches include transistors Q1, Q2, and Q3; the filter capacitor suppresses noise and stabilizes voltage; the MCU control module includes a microcontroller enable signal MCU_EN and a power ground GND; the voltage divider network includes a current-limiting resistor, a voltage-dividing resistor, and a pull-up resistor. The current-limiting resistor adjusts the current limit by changing its resistance value; the voltage-dividing resistor adjusts the transistor voltage; the pull-up resistor ensures the transistor is turned on when the microcontroller enable signal MCU_EN is valid; and the output terminal OUT is located at the circuit's output port.

[0009] This utility model's adjustable current-limiting digital signal output circuit adjusts the maximum current of the logic voltage output by influencing the switching of the transistor through adjusting the resistor. Short-circuit protection is achieved through a simple transistor and resistor-capacitor circuit. The circuit is simple, reliable, has few components, is cost-effective, and is not prone to failure.

[0010] In addition, the adjustable current-limiting digital signal output circuit proposed in the application may also have the following additional technical features:

[0011] Specifically, the current-limiting resistor is resistor R1, which is electrically connected to the transistor to help control the base current.

[0012] Specifically, the voltage divider resistors include resistors R2, R3, and R5, wherein resistor R2 is used to control the base current of transistor Q2; resistor R3 is used to stabilize the voltage at the output terminal OUT; and resistor R5 is used to limit the emitter current of transistor Q3.

[0013] Specifically, the pull-up resistor R6 is electrically connected to the microcontroller enable signal MCU_EN and the transistor Q3.

[0014] Specifically, emitters Veb1, Veb2, and Veb3 are provided between transistors Q1, Q2, and Q3, and the emitters Veb1, Veb2, and Veb3 determine the conduction state of the transistors.

[0015] Specifically, the filter capacitor includes capacitor C1 and capacitor C2, wherein capacitor C1 is connected in parallel between the emitter Veb3 and the power ground GND; and capacitor C2 is connected in series between resistor R6 and the microcontroller enable signal MCU_EN.

[0016] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, in which:

[0018] Figure 1 This is the circuit schematic diagram of this utility model. Detailed Implementation

[0019] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. Rather, the embodiments of the present invention include all variations, modifications, and equivalents falling within the appended spirit and connotation.

[0020] like Figure 1As shown, the adjustable current-limiting digital signal output circuit of this utility model embodiment includes an input power supply VCC, a voltage divider network, a transistor switch, a filter capacitor, an MCU control module, and an output terminal OUT.

[0021] The input power supply VCC is used to provide energy for the entire circuit, and the transistor switch includes transistors Q1, Q2 and Q3.

[0022] It should be noted that the positive terminal of the input power supply VCC is electrically connected to resistor R1 and then connected to power ground GND.

[0023] Furthermore, the base of transistor Q2 (NPN type) is connected to VCC through a voltage divider network, the emitter is grounded, and the collector drives the base of Q1;

[0024] The base of transistor Q1 (NPN type) is controlled by transistor Q2, and the collector is connected to the output terminal OUT through resistor R3 to realize the main current output;

[0025] The base of transistor Q3 (NPN type) is pulled up by the microcontroller enable signal MCU_EN through resistor R6, and the collector is grounded through a filter network (resistors R7 and C1), which controls the on / off state of the entire circuit.

[0026] The filter capacitor is used to suppress noise and stabilize voltage. The MCU control module includes a microcontroller enable signal MCU_EN and a power ground GND.

[0027] The voltage divider network includes a current-limiting resistor, a voltage-dividing resistor, and a pull-up resistor.

[0028] The current-limiting resistor is used to adjust the current limit by changing its resistance value; the voltage divider resistor is used to adjust the transistor voltage; the pull-up resistor is used to ensure that the transistor is turned on when the microcontroller enable signal MCU_EN is valid; and the output terminal OUT is set at the output port of the circuit.

[0029] Preferably, the current-limiting resistor is a resistor R1, which is electrically connected to the transistor to help control the base current.

[0030] It should be noted that resistors R1 and R2 are connected in series. The resistance value of resistor R1 can be changed according to the requirements to achieve the function of adjustable current limiting. The formula for calculating the current limiting adjustment is Veb2 / i, where Veb2 is the turn-on voltage drop of Q2 and i is the desired current limiting turn-off current value (mA).

[0031] Furthermore, resistor R4 adjusts the base current of transistor Q1, limiting the maximum current at the output terminal OUT.

[0032] Preferably, the voltage divider resistors include resistors R2, R3, and R5.

[0033] Among them, resistor R2 is used to control the base current of transistor Q2, resistor R3 is used to stabilize the voltage at the output terminal OUT, and resistor R5 is used to limit the emitter current of transistor Q3.

[0034] It should be noted that the base of transistor Q2 is connected to VCC via R1 for voltage division and is current-limited by resistor R2, while the emitter is directly grounded and the collector outputs to the emitter Veb1 to control the base current of transistor Q1.

[0035] Preferably, the pull-up resistor R6 is electrically connected to the microcontroller enable signal MCU_EN and the transistor Q3.

[0036] It should be noted that the base of transistor Q3 is connected to the microcontroller enable signal MCU_EN through resistor R6 and filtered through capacitor C2, the emitter is grounded through resistor R5, and the collector is connected to the emitter Veb3 through resistor R7 and filtered through capacitor C1 and grounded.

[0037] Preferably, emitters Veb1, Veb2, and Veb3 are provided between transistors Q1, Q2, and Q3, and the emitters Veb1, Veb2, and Veb3 determine the conduction state of the transistors.

[0038] It should be noted that the base of transistor Q1 is driven by the emitter Veb1, which is directly grounded, while the collector is output to the output terminal OUT through resistor R3, and drives the base of transistor Q3 through resistor R4 to control the switching state of transistor Q3.

[0039] Preferably, the filter capacitor includes capacitor C1 and capacitor C2.

[0040] The capacitor C1 is connected in parallel between the emitter Veb3 and the power ground GND, and the capacitor C2 is connected in series between the resistor R6 and the microcontroller enable signal MCU_EN.

[0041] Specifically, the current limiting adjustment steps of the output circuit are as follows: when the microcontroller enable signal MCU_EN is entered, the voltage drop of the emitter Veb3 is greater than 0.7V, then the transistor Q3 is turned on. At this time, the voltage drop of the emitter Veb1 is greater than 0.7V, then the transistor Q1 is turned on, and VCC is normally output to the output terminal OUT.

[0042] A current-limiting protection circuit is formed by resistors R1 and R2 and transistor Q2. When the current flowing through resistor R1 is greater than 61mA or a short circuit occurs, the voltage drop across the emitter Veb2 of transistor Q2 is greater than 0.7V, causing transistor Q2 to conduct. This will cause the voltage drop across the emitter Veb1 of transistor Q1 to be less than 0.7V, causing transistor Q1 to turn off. This forms a circuit for current limiting and short-circuit protection. The resistance value of resistor R1 can be changed as needed to achieve adjustable current limiting. The formula for current limiting adjustment is Veb2 / i, where Veb2 is the turn-on voltage drop of Q2 and i is the desired current limiting turn-off current value (mA).

[0043] In summary, the adjustable current-limiting digital signal output circuit of this utility model adjusts the maximum current of the logic voltage output by adjusting the resistor to affect the switching of the transistor. It achieves short-circuit protection through a simple transistor and resistor-capacitor circuit. The circuit is simple, reliable, has few components, is cost-effective, and is not prone to failure.

[0044] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An adjustable current-limiting digital signal output circuit, characterized in that, It includes the input power supply VCC, voltage divider network, transistor switch, filter capacitor, MCU control module, and output terminal OUT. The input power supply VCC is used to provide energy for the entire circuit. The transistor switch includes transistors Q1, Q2, and Q3; The filter capacitor is used to suppress noise and stabilize voltage; The MCU control module includes a microcontroller enable signal MCU_EN and a power ground GND; The voltage divider network includes a current-limiting resistor, a voltage-dividing resistor, and a pull-up resistor, wherein, The current-limiting resistor is used to adjust the current limit by changing its resistance value; The voltage divider resistor is used to adjust the transistor voltage; The pull-up resistor is used to ensure that the transistor is turned on when the microcontroller enable signal MCU_EN is valid; The output terminal OUT is set at the output port of the circuit.

2. The adjustable current-limiting digital signal output circuit according to claim 1, characterized in that, The current-limiting resistor is resistor R1, which is electrically connected to the transistor and is used to control the base current.

3. The adjustable current-limiting digital signal output circuit according to claim 1, characterized in that, The voltage divider resistors include resistors R2, R3, and R5, wherein... The resistor R2 is used to control the base current of transistor Q2; The resistor R3 is used to stabilize the voltage at the output terminal OUT; The resistor R5 is used to limit the emitter current of transistor Q3.

4. The adjustable current-limiting digital signal output circuit according to claim 1, characterized in that, The pull-up resistor R6 is electrically connected to the microcontroller enable signal MCU_EN and the base of the transistor Q3.

5. The adjustable current-limiting digital signal output circuit according to claim 1, characterized in that, The transistors Q1, Q2, and Q3 are provided with emitters Veb1, Veb2, and Veb3, which determine the conduction state of the transistors.

6. The adjustable current-limiting digital signal output circuit according to claim 5, characterized in that, The filter capacitor includes capacitor C1 and capacitor C2, wherein, The capacitor C1 is connected in parallel between the emitter Veb3 and the power ground GND; The capacitor C2 is connected in series with the resistor R6 and the microcontroller enable signal MCU_EN.

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