Circuit for automatically regulating the indicator light according to the output voltage

Abstract

The application provides a circuit for automatically adjusting indicator light according to output voltage, which comprises a first comparison circuit, a second comparison circuit, a logic circuit, LED light D1, LED light D2, LED light D4, switch tube Q1, switch tube Q2, switch tube Q3, switch tube Q4, switch tube Q5, resistor R3 and resistor R6. When the output voltage Vbus is less than the first voltage threshold Vth1, LED light D1 is not lighted, LED light D2 is lighted, and LED light D4 is not lighted; when the output voltage Vbus is greater than or equal to the first voltage threshold Vth1 and less than or equal to the second voltage threshold Vth2, LED light D1 is not lighted, LED light D2 is not lighted, and LED light D4 is lighted; when the output voltage Vbus is greater than the second voltage threshold Vth2, LED light D1 is lighted, LED light D2 is not lighted, and LED light D4 is not lighted. Compared with the prior art, the application automatically realizes different LED indicator light lighting according to different output voltage values, so that the user can know the state of the current output power consumption through the indicator light.

Description

[0001] The present application relates to the technical field of circuit design, in particular to a circuit for automatically adjusting an indicator light according to an output voltage.

[0002] USB (Universal serial bus, i.e. Universal Serial Bus) connector PD (Power delivery, i.e. a fast charging technology in USB connector) fast charging product output voltage values have 5V, 9V, 12V, 15V, 20V several cases, which can be classified according to the output voltage value. 5V as a class, 9V, 12V, 15V as a class, 20V as a class (can be divided according to the actual needs of the voltage). According to the different PD fast charging output voltage values, the indicator light color can be automatically adjusted, thereby realizing three different LED (light-emitting diode, i.e. light-emitting diode) light emission. There is no prior art solution to achieve the above function.

[0003] Therefore, it is necessary to provide a circuit for automatically adjusting an indicator light according to an output voltage.

[0004] One of the purposes of the present application is to provide a circuit for automatically adjusting an indicator light according to an output voltage, which can automatically realize different LED indicator light emission according to different output voltage values, so that the user can know the current output power consumption state through the indicator light.

[0005] ​​​According to one aspect of the present application, the present application provides a circuit for automatically adjusting indicator light according to output voltage, comprising a first comparison circuit, a second comparison circuit, a logic circuit, LED light D1, LED light D2, LED light D4, switch tube Q1, switch tube Q2, switch tube Q3, switch tube Q4, switch tube Q5, resistor R3 and resistor R6, the input end of the first comparison circuit is connected with output voltage Vbus, and the output end thereof is connected with the first input end E of the logic circuit; the input end of the second comparison circuit is connected with the output voltage Vbus, and the output end thereof is connected with the second input end G of the logic circuit; the LED light D4 and the switch tube Q4 are connected in series between the output voltage Vbus and the ground end, the control end of the switch tube Q4 is connected with the output end F of the logic circuit; the first connection end of the switch tube Q5 is connected with connection node B, the control end thereof is connected with the output end of the second comparison circuit, and the second connection end thereof is grounded; the first connection end of the switch tube Q1 is connected with the output voltage Vbus, the control end thereof is connected with connection node A, and the second connection end thereof is connected with the first connection end of the switch tube Q2; the first connection end and the control end of the switch tube Q2 are both connected with the connection node B, the second connection end thereof is connected with the anode of the LED light D2, and the cathode of the LED light D2 is grounded; the resistor R3 is connected between the first connection end of the switch tube Q1 and the connection node A; one end of the resistor R6 is connected with the connection node A, and the other end thereof is connected with the output end F of the logic circuit; the LED light D1 and the switch tube Q3 are connected in series between the output voltage Vbus and the ground end, and the control end of the switch tube Q3 is connected with the connection node B.

[0006] Compared with the prior art, the present application automatically realizes different LED indicator light emission according to different output voltage values, so that the user can know the current output power consumption state through the indicator light. BRIEF DESCRIPTION OF DRAWINGS

[0007] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor. Among them:

[0008] Figure 1 The schematic diagram of the circuit for automatically adjusting indicator light according to output voltage in one embodiment of the present application. DETAILED DESCRIPTION

[0009] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the present application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0010] As used herein, the term "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the implementation can be included in at least one implementation of the application. The appearances of the phrase "in one embodiment" or "in an embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Terms such as coupled, connected, linked, attached, or the like, as used herein mean the joining of two members together to form a single piece, whether directly or indirectly, whether loose or fixed, whether permanent or only temporary, and whether mechanically, electrically, magnetically, logically, or chemically. In the present application, "greater than or equal to" means greater than or equal to, and "less than or equal to" means less than or equal to.

[0011] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "right", "left", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, are terms of reference for the purpose of illustrating and describing the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the application.

[0012] Please refer to Figure 1 As shown in the figure, it is a schematic diagram of the circuit for automatically adjusting the indicator lamp according to the output voltage in one embodiment of the present application. Figure 1 The circuit for automatically adjusting the indicator lamp according to the output voltage shown in the figure includes a first comparison circuit 110, a second comparison circuit 120, a logic circuit 130, an LED lamp D1, an LED lamp D2, an LED lamp D4, a switch tube Q1, a switch tube Q2, a switch tube Q3, a switch tube Q4, a switch tube Q5, a resistor R3, and a resistor R6.

[0013] The input end of the first comparison circuit 110 is connected with the output voltage Vbus, and the output end thereof is connected with the first input end E of the logic circuit 130. The input end of the second comparison circuit 120 is connected with the output voltage Vbus, and the output end thereof is connected with the second input end G of the logic circuit 130. The LED lamp D4 and the switch tube Q4 are connected in series between the output voltage Vbus and the ground end, and the control end of the switch tube Q4 is connected with the output end F of the logic circuit 130. The first connection end of the switch tube Q5 is connected with the connection node B, the control end thereof is connected with the output end of the second comparison circuit 120, and the second connection end thereof is grounded. The first connection end of the switch tube Q1 is connected with the output voltage Vbus, the control end thereof is connected with the connection node A, and the second connection end thereof is connected with the first connection end of the switch tube Q2. The first connection end and the control end of the switch tube Q2 are both connected with the connection node B, the second connection end thereof is connected with the anode of the LED lamp D2, and the cathode of the LED lamp D2 is grounded. The resistance R3 is connected between the first connection end of the switch tube Q1 and the connection node A. One end of the resistance R6 is connected with the connection node A, and the other end thereof is connected with the output end F of the logic circuit 130. The LED lamp D1 and the switch tube Q3 are connected in series between the output voltage Vbus and the ground end, and the control end of the switch tube Q3 is connected with the connection node B. Figure 1 In the specific embodiment shown, the anode of the LED lamp D4 is connected with the output voltage Vbus, the cathode thereof is connected with the first connection end of the switch tube Q4, and the second connection end of the switch tube Q4 is grounded. The anode of the LED lamp D1 is connected with the output voltage Vbus, the cathode thereof is connected with the first connection end of the switch tube Q3, and the second connection end of the switch tube Q3 is grounded.

[0014] The first comparison circuit 110 is used for comparing the size of the output voltage Vbus and the first voltage threshold Vth1, and outputs the first comparison result through the output end thereof. When the output voltage Vbus is less than the first voltage threshold Vth1, the output end of the first comparison circuit 110 outputs the first logic level (for example, low level). When the output voltage Vbus is greater than or equal to the first voltage threshold Vth1, the output end of the first comparison circuit 110 outputs the second logic level (for example, high level).

[0015] The second comparison circuit 120 is used for comparing the size of the output voltage Vbus and the second voltage threshold Vth2, and outputs the second comparison result through the output end thereof. When the output voltage Vbus is less than or equal to the second voltage threshold Vth2, the output end of the second comparison circuit 120 outputs the second logic level (for example, high level). When the output voltage Vbus is greater than the second voltage threshold Vth2, the output end of the second comparison circuit 120 outputs the first logic level (for example, low level).

[0016] Logic circuit 130 performs logical operations on the first comparison result output by the first comparison circuit 110 and the second comparison result output by the second comparison circuit 120, and outputs the logical operation result through its output terminal F. When the output terminal of the first comparison circuit 110 outputs a second logic level (e.g., high level) and the output terminal of the second comparison circuit 120 outputs a second logic level (e.g., high level), the output terminal F of logic circuit 130 outputs a second logic level (e.g., high level); otherwise, the output terminal F of logic circuit 130 outputs a first logic level (e.g., low level). The first voltage threshold Vth1 is less than the second voltage threshold Vth2.

[0017] When the output voltage Vbus is less than the first voltage threshold Vth1, the output of the first comparator circuit 110 outputs the first logic level, the output of the second comparator circuit 120 outputs the second logic level, and the output of the logic circuit 130 outputs the first logic level. At this time, the switching transistors Q1, Q2, Q3, and Q4 are turned off, and the switching transistor Q5 is turned on, so that LED D1 does not light up, LED D2 lights up, and LED D4 does not light up.

[0018] When the output voltage Vbus is greater than or equal to the first voltage threshold Vth1 and less than or equal to the second voltage threshold Vth2, the output terminal of the first comparator circuit 110 outputs the second logic level, the output terminal of the second comparator circuit 120 outputs the second logic level, and the output terminal F of the logic circuit 130 outputs the second logic level. At this time, the switching transistors Q1, Q2, Q3, Q4, and Q5 are turned on, so that LED D1 does not light up, LED D2 does not light up, and LED D4 lights up.

[0019] When the output voltage Vbus is greater than the second voltage threshold Vth2, the output terminal of the first comparator circuit 110 outputs the second logic level, the output terminal of the second comparator circuit 120 outputs the first logic level, and the output terminal F of the logic circuit 130 outputs the first logic level. At this time, the switching transistor Q1 is turned on, the switching transistor Q2 is turned off, the switching transistor Q3 is turned on, the switching transistor Q4 is turned off, and the switching transistor Q5 is turned off. LED D1 lights up, LED D2 does not light up, and LED D4 does not light up.

[0020] In summary, this invention automatically illuminates different LED indicator lights (e.g., LED D1, LED D2, and LED D4) according to different output voltage values ​​Vbus, so that users can know the current output power consumption status through the indicator lights.

[0021] exist Figure 1In the specific embodiment shown, the output voltage value Vbus is the output voltage of the USB connector PD fast charging product; LED D1 is LED_green, LED D2 is LED_red, and LED D4 is LED_blue, that is, LED D1, LED D2, and LED D4 are LEDs with different colors.

[0022] exist Figure 1 In the specific embodiment shown, switch Q1 is a PNP transistor, and the first connection terminal, the second connection terminal, and the control terminal of switch Q1 are the emitter, collector, and base of the PNP transistor, respectively; switch Q2 is a PNP transistor, and the first connection terminal, the second connection terminal, and the control terminal of switch Q2 are the emitter, collector, and base of the PNP transistor, respectively; switch Q3 is an NPN transistor, and the first connection terminal, the second connection terminal, and the control terminal of switch Q3 are the collector, emitter, and base of the NPN transistor, respectively; switch Q4 is an NPN transistor, and the first connection terminal, the second connection terminal, and the control terminal of switch Q4 are the collector, emitter, and base of the NPN transistor, respectively; switch Q5 is an NPN transistor, and the first connection terminal, the second connection terminal, and the control terminal of switch Q5 are the collector, emitter, and base of the NPN transistor, respectively.

[0023] exist Figure 1 In the specific embodiment shown, the first comparator circuit 110 includes resistors R11 and R14, a Zener diode D6, and a voltage comparator U1. One end of resistor R11 is connected to the output voltage Vbus, and the other end is connected to connection node C. Resistor R14 is connected between connection node C and ground. The negative terminal of Zener diode D6 is connected to connection node D, and its positive terminal is grounded. Connection node D is connected to the output voltage Vbus. The first input terminal of voltage comparator U1 is connected to connection node C, and its second input terminal is connected to connection node D. Its output terminal serves as the output terminal of the first comparator circuit 110, and its power supply terminal is connected to the power supply voltage VDD1. The operating voltage of Zener diode D6 is less than the first voltage threshold Vth1. The second comparator circuit 120 includes resistors R7 and R16, a Zener diode D7, and a voltage comparator U2. One end of resistor R7 is connected to the output voltage Vbus, and the other end is connected to connection node H. Resistor R16 is connected between connection node H and ground. The negative terminal of Zener diode D7 is connected to connection node I, and its positive terminal is grounded. Connection node I is connected to the output voltage Vbus. The first input terminal of voltage comparator U2 is connected to connection node I, and its second input terminal is connected to connection node H. Its output terminal serves as the output terminal of the second comparator circuit 120, and its power supply terminal is connected to the power supply voltage VDD1. The operating voltage of Zener diode D7 is less than the second voltage threshold Vth2.

[0024] exist Figure 1In the specific embodiment shown, the first comparator circuit 110 further includes a resistor R13 and a capacitor C1. Resistor R13 is connected between the output voltage Vbus and connection node D; capacitor C1 is connected between connection node C and ground. The second comparator circuit 120 further includes a resistor R5 and a capacitor C2. Resistor R5 is connected between the output voltage Vbus and connection node I; capacitor C2 is connected between connection node H and ground. Resistors R13 and R5 are current-limiting resistors, preventing excessive circuit current from burning out voltage comparators U1 and U2; capacitors C1 and C2 are filter capacitors, providing filtering functionality.

[0025] exist Figure 1 In the specific embodiment shown, the first input terminal and the second input terminal of voltage comparator U1 are its inverting input terminal and its non-inverting input terminal, respectively; the first input terminal and the second input terminal of voltage comparator U2 are its inverting input terminal and its non-inverting input terminal, respectively.

[0026] When the output voltage Vbus is less than the first voltage threshold Vth1, the Zener diode D6 may or may not operate. The values ​​of resistors R11 and R14 are required to ensure that when the output voltage Vbus is less than the first voltage threshold Vth1, the voltage at node D is higher than the voltage at node C, and the voltage comparator U1 outputs a low level. When the output voltage Vbus is greater than or equal to the first voltage threshold Vth1, the Zener diode D6 operates, the voltage at node D is lower than the voltage at node C, and the voltage comparator U1 outputs a high level. When the output voltage Vbus is less than or equal to the second voltage threshold Vth2, the Zener diode D7 may or may not operate. The values ​​of resistors R7 and R16 are required to ensure that when the output voltage Vbus is less than the second voltage threshold Vth2, the voltage at node I is higher than the voltage at node H, and the output of voltage comparator U2 is high. When the output voltage Vbus is greater than the second voltage threshold Vth2, the Zener diode D7 operates, the voltage at node I is lower than the voltage at node H, and the output of voltage comparator U2 is low. Here, the first voltage threshold Vth1 is less than the second voltage threshold Vth2.

[0027] exist Figure 1 In the specific embodiment shown, the logic circuit 130 is an AND gate circuit, which includes diodes D3 and D5. The cathode of diode D5 serves as the first input terminal E of the logic circuit 130, and its anode is connected to the output terminal F of the logic circuit 130. The cathode of diode D3 serves as the second input terminal G of the logic circuit 130, and its anode is connected to the output terminal F of the logic circuit 130. The output terminal F of the logic circuit 130 is connected to the power supply voltage VDD2. The power supply voltage VDD2 is greater than the power supply voltage VDD1, and the power supply voltage VDD1 is greater than the second voltage threshold Vth2.

[0028] exist Figure 1 In the specific embodiment shown, the circuit for automatically adjusting the indicator light according to the output voltage further includes resistors R1, R2, R4, R8, R9, R10, R12, and R15. Specifically, resistor R1 is connected in series with LED D1 and switch Q3 between the output voltage Vbus and ground; resistor R2 and LED D2 are connected in series between the second connection terminal of switch Q2 and ground; resistor R4 is connected between the first connection terminal of switch Q2 and connection node B; resistor R8 is connected between the output terminal of the second comparator circuit 120 and the control terminal of switch Q5; resistor R9 is connected between the power supply voltage VDD2 and the output terminal F of logic circuit 130; resistor R10 is connected in series with LED D4 and switch Q4 between the output voltage Vbus and ground; resistor R12 is connected between the output terminal F of logic circuit 130 and the control terminal of switch Q4; and resistor R15 is connected between connection node B and the control terminal of switch Q3. Figure 1 In the specific embodiment shown, resistor R1 is connected between the output voltage Vbus and the positive terminal of LED D1; resistor R2 is connected between the second terminal of switching transistor Q2 and the positive terminal of LED D2; and resistor R10 is connected between the output voltage Vbus and the positive terminal of LED D4. Resistors R1, R2, and R10 control the current in the three branches of LEDs D1, D2, and D4, providing brightness control and protection for the LED indicator lights. Resistors R4, R8, R9, R12, and R15 are current-limiting resistors, preventing excessive current from burning out the transistors.

[0029] The following is a detailed introduction Figure 1 The circuit shown illustrates the working principle of the indicator light that automatically adjusts based on the output voltage.

[0030] When the PD fast charging output voltage Vbus is less than the first voltage threshold Vth1, the red light illuminates while the green and blue lights remain off. When the PD fast charging output voltage Vbus is less than the first voltage threshold Vth1, since the Zener diode D7 may or may not operate, the values ​​of resistors R7 and R16 need to be adjusted to ensure that when the output voltage Vbus is less than the second voltage threshold Vth2, the voltage at node I is higher than the voltage at node H. Therefore, the output of voltage comparator U2 is high (or, the output of the second comparator circuit 120 is the second logic level), causing transistor Q5 to conduct. This results in a low voltage at node B, causing transistor Q3 to cut off, and LED D1 to remain off, meaning the green light branch is cut off, thus preventing the green light from illuminating. When the PD fast charging output voltage Vbus is less than the first voltage threshold Vth1, the voltage of the connection node D is higher than the voltage of the connection node C when the output voltage Vbus is less than the first voltage threshold Vth1. Therefore, the output of the voltage comparator U1 is low (or the output of the first comparator circuit 110 is the first logic level). This causes the output of the logic circuit 130 to be low (or the output of the logic circuit 130 is the first logic level), which turns off the transistor Q4 and the LED D4 does not light up. That is, the blue light branch is cut off, thus making the blue light not light up. Since the output terminal F of logic circuit 130 is at a low level, the voltage at connection node A is obtained by voltage division by resistors R3 and R6. Therefore, the voltage at connection node A is less than the PD fast charging output voltage Vbus, causing transistor Q1 to conduct. The collector voltage of transistor Q1 is at a high level, which means the emitter voltage of transistor Q2 is at a high level. Since the voltage at connection node B is at a low level at this time, the emitter voltage of transistor Q2 is higher than the base voltage, causing transistor Q2 to conduct. The collector of transistor Q2 is at a high level, and LED D2 lights up, that is, the red light branch is turned on, thus realizing the red light. In other words, when the PD fast charging output voltage Vbus is less than the first voltage threshold Vth1, the Zener diode D7 can work or not work, the output of the voltage comparator U2 is high, the Zener diode D6 can work or not work, the output of the voltage comparator U1 is low, the output of the logic circuit 130 is low, and the voltage at the connection node A is less than the PD fast charging output voltage Vbus. At this time, the switching transistors Q1, Q2, Q3, and Q4 are turned off, and the switching transistor Q5 is turned on, so that LED D1 does not light up, LED D2 lights up, and LED D4 does not light up.

[0031] When the PD fast charging output voltage Vbus is greater than or equal to the first voltage threshold Vth1 and less than or equal to the second voltage threshold Vth2, the blue light will illuminate while the green and red lights will not. When the PD fast charging output voltage Vbus is greater than or equal to the first voltage threshold Vth1 and less than or equal to the second voltage threshold Vth2, since the Zener diode D7 may or may not operate, the values ​​of resistors R7 and R16 need to be matched to ensure that when the output voltage Vbus is less than the second voltage threshold Vth2, the voltage at connection node I is higher than the voltage at connection node H. Therefore, the output of voltage comparator U2 is high (or, the output of the second comparator circuit 120 outputs the second logic level). Simultaneously, when the PD fast charging output voltage Vbus is greater than or equal to the first voltage threshold Vth1 and less than or equal to the second voltage threshold Vth2, due to the operation of the Zener diode D6, the voltage at connection node D is lower than the voltage at connection node C. Therefore, the output of voltage comparator U1 is high (or, in other words, the output of the first comparator circuit 110 outputs the second logic level), thereby making the output of logic circuit 130 high (or, in other words, the output of logic circuit 130 outputs the second logic level). Transistor Q4 conducts, LED D4 illuminates, i.e., the blue light branch is activated, thus enabling the blue light to illuminate. When the PD fast charging output voltage Vbus is greater than or equal to the first voltage threshold Vth1 and less than or equal to the second voltage threshold Vth2, the voltage at connection node D6 is lower than the voltage at connection node C. Therefore, the output of voltage comparator U1 is high (or, in other words, the output of the first comparator circuit 110 outputs the second logic level), thus enabling the output of logic circuit 130 to be high (or, in other words, the output of logic circuit 130 outputs the second logic level). Transistor Q4 conducts, LED D4 illuminates, i.e., the blue light branch is activated, thus enabling the blue light to illuminate. When the voltage threshold Vth2 is reached, since the power supply voltage VDD2 is greater than the power supply voltage VDD1, and the power supply voltage VDD1 is greater than the second voltage threshold Vth2, the voltage at node A is greater than the PD fast charging output voltage Vbus. This causes transistor Q1 to be cut off, resulting in a low collector voltage for transistor Q1, which in turn causes a low emitter voltage for transistor Q2. Transistor Q2 is cut off, and LED D2 does not light up, meaning the red light branch is cut off, thus the red light is off. Since the output of voltage comparator U2 is high, transistor Q5 is turned on, resulting in a low voltage at node B. Transistor Q3 is cut off, and LED D1 is off, meaning the green light branch is cut off, thus the green light is off. In other words, when the PD fast charging output voltage Vbus is greater than or equal to the first voltage threshold Vth1 and less than or equal to the second voltage threshold Vth2, the Zener diode D7 can work or not work, the output of the voltage comparator U2 outputs a high level, the Zener diode D6 works, the output of the voltage comparator U1 outputs a high level, the output of the logic circuit 130 is high, and the voltage at the connection node A is greater than the PD fast charging output voltage Vbus. At this time, the switching transistors Q1, Q2, and Q3 are cut off, Q4 and Q5 are turned on, so that LED D1 does not light up, LED D2 does not light up, and LED D4 lights up.

[0032] When the PD fast charging output voltage Vbus is greater than the second voltage threshold Vth2, the green light illuminates while the red and blue lights remain off. When the PD fast charging output voltage Vbus is greater than the second voltage threshold Vth2, due to the operation of Zener diode D7, the voltage at connection node I is lower than the voltage at connection node H. Therefore, the output of voltage comparator U2 is low (or, in other words, the output of the second comparator circuit 120 outputs the first logic level). Simultaneously, when the PD fast charging output voltage Vbus is greater than the second voltage threshold Vth2, due to the operation of Zener diode D6, the voltage at connection node D is lower than the voltage at connection node C. Therefore, the output of voltage comparator U1 is high (or, in other words, the output of the first comparator circuit 110 outputs the second logic level), resulting in a low output (or, in other words, a low output (or, a low output (first logic level)) at the output of logic circuit 130. Because the output of logic circuit 130 is low, transistor Q4 is cut off, LED D4 does not illuminate, meaning the blue light branch is cut off, thus preventing the blue light from illuminating. Since the output F of logic circuit 130 is low, the voltage at node A is obtained by voltage division by resistors R3 and R6. Therefore, the voltage at node A is less than the output voltage Vbus, causing transistor Q1 to conduct. The collector voltage of transistor Q1 is high, meaning the emitter voltage of transistor Q2 is also high. Because the output of voltage comparator U2 is low, transistor Q5 is cut off. Since the emitter voltage of transistor Q2 is high, the voltage at node B is high and approximately equal to the emitter voltage of transistor Q2. This causes transistor Q2 to cut off, and LED D2 does not light up, meaning the red light branch is cut off, thus the red light is off. Because the voltage at node B is high, transistor Q3 conducts, and LED D1 lights up, meaning the green light branch is on, thus the green light is on. In other words, when the PD fast charging output voltage Vbus is greater than the second voltage threshold Vth2, the Zener diode D7 operates, the output of the voltage comparator U2 is low, the Zener diode D6 operates, the output of the voltage comparator U1 is high, the output of the logic circuit 130 is low, and the voltage at node A is less than the PD fast charging output voltage Vbus. At this time, the switching transistors Q1, Q2, Q3, Q4, and Q5 are turned on, LED D1 lights up, LED D2 does not light up, and LED D4 does not light up.

[0033] In summary, the present invention can automatically illuminate (e.g., display colors) different LED indicator lights (e.g., LED D1, LED D2, and LED D4) according to different PD fast charging output voltage values, so that users can know the current status of PD fast charging output power consumption through the indicator light color.

[0034] It should be noted that any modifications made by those skilled in the art to the specific embodiments of the present invention do not depart from the scope of the claims. Accordingly, the scope of the claims is not limited to the foregoing specific embodiments.

Claims

1. A circuit for automatically adjusting an indicator light based on output voltage, characterized in that, It includes a first comparator circuit, a second comparator circuit, a logic circuit, LEDs D1, D2, and D4, switching transistors Q1, Q2, Q3, Q4, and Q5, and resistors R3 and R6. The input terminal of the first comparator circuit is connected to the output voltage Vbus, and its output terminal is connected to the first input terminal E of the logic circuit. The input terminal of the second comparator circuit is connected to the output voltage Vbus, and its output terminal is connected to the second input terminal G of the logic circuit. The LED D4 and the switching transistor Q4 are connected in series between the output voltage Vbus and the ground terminal. The control terminal of the switching transistor Q4 is connected to the output terminal F of the logic circuit. The first connection terminal of the switching transistor Q5 is connected to the connection node B, its control terminal is connected to the output terminal of the second comparator circuit, and its second connection terminal is grounded. The first connection terminal of the switching transistor Q1 is connected to the output voltage Vbus, its control terminal is connected to the connection node A, and its second connection terminal is connected to the first connection terminal of the switching transistor Q2. The first connection terminal and the control terminal of the switching transistor Q2 are both connected to the connection node B, and its second connection terminal is connected to the positive terminal of the LED D2. The negative terminal of the LED D2 is grounded. The resistor R3 is connected between the first connection terminal of the switching transistor Q1 and the connection node A. One end of the resistor R6 is connected to the connection node A, and the other end is connected to the output terminal F of the logic circuit. The LED D1 and the switching transistor Q3 are connected in series between the output voltage Vbus and the ground terminal. The control terminal of the switching transistor Q3 is connected to the connection node B. When the output voltage Vbus is less than the first voltage threshold Vth1, the output terminal of the first comparator circuit outputs a first logic level, the output terminal of the second comparator circuit outputs a second logic level, and the output terminal F of the logic circuit outputs the first logic level. At this time, the switching transistors Q1, Q2, Q3, and Q4 are turned off, and the switching transistor Q5 is turned on, so that the LED D1 does not light up, the LED D2 lights up, and the LED D4 does not light up. When the output voltage Vbus is greater than or equal to the first voltage threshold Vth1 and less than or equal to the second voltage threshold Vth2, the output terminal of the first comparator circuit outputs a second logic level, the output terminal of the second comparator circuit outputs a second logic level, and the output terminal F of the logic circuit outputs a second logic level. At this time, the switching transistors Q1, Q2, and Q3 are cut off, Q4 and Q5 are turned on, so that LED D1 does not light up, LED D2 does not light up, and LED D4 lights up. When the output voltage Vbus is greater than the second voltage threshold Vth2, the output terminal of the first comparator circuit outputs a second logic level, the output terminal of the second comparator circuit outputs a first logic level, and the output terminal F of the logic circuit outputs the first logic level. At this time, the switching transistor Q1 is turned on, the switching transistor Q2 is turned off, the switching transistor Q3 is turned on, the switching transistor Q4 is turned off, and the switching transistor Q5 is turned off, causing LED D1 to light up, LED D2 to not light up, and LED D4 to not light up. Wherein, the first voltage threshold Vth1 is less than the second voltage threshold Vth2. The output voltage Vbus is the output voltage of USB connector PD fast charging products. The output voltage of the USB connector PD fast charging product is 5V, 9V, 12V, 15V or 20V. The output voltage Vbus is divided into three categories according to the value of the output voltage Vbus. The first voltage threshold Vth1 and the second voltage threshold Vth2 can distinguish these three types of output voltage.

2. The circuit for automatically adjusting the indicator light based on the output voltage according to claim 1, characterized in that, The first comparison circuit is used to compare the output voltage Vbus with the first voltage threshold Vth1, and outputs the first comparison result through its output terminal; The second comparison circuit is used to compare the output voltage Vbus and the second voltage threshold Vth2, and outputs the second comparison result through its output terminal; The logic circuit is used to perform logical operations on the first comparison result output by the first comparison circuit and the second comparison result output by the second comparison circuit, and outputs the logical operation result through its output terminal F.

3. The circuit for automatically adjusting the indicator light according to the output voltage as described in claim 2, characterized in that, The positive terminal of the LED lamp D4 is connected to the output voltage Vbus, and its negative terminal is connected to the first connection terminal of the switching transistor Q4. The second connection terminal of the switching transistor Q4 is grounded. The positive terminal of the LED lamp D1 is connected to the output voltage Vbus, and its negative terminal is connected to the first connection terminal of the switching transistor Q3. The second connection terminal of the switching transistor Q3 is grounded.

4. The circuit for automatically adjusting the indicator light according to the output voltage as described in claim 2, characterized in that, The first comparison circuit includes resistors R11 and R14, a Zener diode D6, and a voltage comparator U1. One end of resistor R11 is connected to the output voltage Vbus, and the other end is connected to connection node C. Resistor R14 is connected between connection node C and ground. The negative terminal of the Zener diode D6 is connected to connection node D, and its positive terminal is grounded. Connection node D is connected to the output voltage Vbus. The first input terminal of the voltage comparator U1 is connected to connection node C, its second input terminal is connected to connection node D, its output terminal serves as the output terminal of the first comparison circuit, and its power supply terminal is connected to the power supply voltage VDD1. The operating voltage of the Zener diode D6 is less than the first voltage threshold Vth1. The second comparator circuit includes resistors R7 and R16, a Zener diode D7, and a voltage comparator U2. One end of resistor R7 is connected to the output voltage Vbus, and the other end is connected to connection node H. Resistor R16 is connected between connection node H and ground. The negative terminal of Zener diode D7 is connected to connection node I, and its positive terminal is grounded. Connection node I is connected to the output voltage Vbus. The first input terminal of voltage comparator U2 is connected to connection node I, its second input terminal is connected to connection node H, its output terminal serves as the output terminal of the second comparator circuit, and its power supply terminal is connected to the power supply voltage VDD1. The operating voltage of Zener diode D7 is less than the second voltage threshold Vth2.

5. The circuit for automatically adjusting the indicator light according to the output voltage as described in claim 4, characterized in that, The first comparator circuit further includes a resistor R13 and a capacitor C1, wherein the resistor R13 is connected between the output voltage Vbus and the connection node D; and the capacitor C1 is connected between the connection node C and the ground terminal. The second comparison circuit further includes a resistor R5 and a capacitor C2. The resistor R5 is connected between the output voltage Vbus and the connection node I; the capacitor C2 is connected between the connection node H and the ground terminal.

6. The circuit for automatically adjusting the indicator light according to the output voltage as described in claim 4, characterized in that, The switching transistor Q1 is a PNP transistor, and the first connection terminal, the second connection terminal, and the control terminal of the switching transistor Q1 are the emitter, collector, and base of the PNP transistor, respectively. The switching transistor Q2 is a PNP transistor, and the first connection terminal, the second connection terminal, and the control terminal of the switching transistor Q2 are the emitter, collector, and base of the PNP transistor, respectively. The switching transistor Q3 is an NPN transistor, and the first connection terminal, the second connection terminal, and the control terminal of the switching transistor Q3 are the collector, emitter, and base of the NPN transistor, respectively. The switching transistor Q4 is an NPN transistor, and the first connection terminal, the second connection terminal, and the control terminal of the switching transistor Q4 are the collector, emitter, and base of the NPN transistor, respectively. The switching transistor Q5 is an NPN transistor, and the first connection terminal, the second connection terminal, and the control terminal of the switching transistor Q5 are the collector, emitter, and base of the NPN transistor, respectively.

7. The circuit for automatically adjusting the indicator light according to the output voltage as described in claim 6, characterized in that, The first and second input terminals of the voltage comparator U1 are its inverting input terminal and its non-inverting input terminal, respectively. The first and second input terminals of the voltage comparator U2 are its inverting input terminal and its non-inverting input terminal, respectively. The logic circuit is an AND gate circuit.

8. The circuit for automatically adjusting the indicator light according to the output voltage as described in claim 7, characterized in that, When the output voltage Vbus is less than the first voltage threshold Vth1, the Zener diode D6 is either active or inactive, the voltage at connection node D is higher than the voltage at connection node C, and the output of the voltage comparator U1 is low. When the output voltage Vbus is greater than or equal to the first voltage threshold Vth1, the Zener diode D6 is active, the voltage at connection node D is lower than the voltage at connection node C, and the output of the voltage comparator U1 is high. When the output voltage Vbus is less than or equal to the second voltage threshold Vth2, the Zener diode D7 is either active or inactive, the voltage at connection node I is higher than the voltage at connection node H, and the output of the voltage comparator U2 is high. When the output voltage Vbus is greater than the second voltage threshold Vth2, the Zener diode D7 is active, the voltage at connection node I is lower than the voltage at connection node H, and the output of the voltage comparator U2 is low.

9. The circuit for automatically adjusting the indicator light according to the output voltage as described in claim 7, characterized in that, The logic circuit includes diodes D3 and D5. The cathode of diode D5 serves as the first input terminal E of the logic circuit, and its anode is connected to the output terminal F of the logic circuit. The cathode of diode D3 serves as the second input terminal G of the logic circuit, and its anode is connected to the output terminal F of the logic circuit. The output terminal F of the logic circuit is connected to the power supply voltage VDD2. Wherein, the power supply voltage VDD2 is greater than the power supply voltage VDD1, and the power supply voltage VDD1 is greater than the second voltage threshold Vth2.

10. The circuit for automatically adjusting the indicator light according to the output voltage as described in claim 7 or 9, characterized in that, When the output voltage Vbus is less than the first voltage threshold Vth1, the Zener diode D7 is either active or inactive, the output of the voltage comparator U2 is high, the Zener diode D6 is either active or inactive, the output of the voltage comparator U1 is low, the output of the logic circuit F is low, and the voltage of the connection node A is less than the output voltage Vbus. At this time, the switching transistors Q1, Q2, Q3, and Q4 are turned off, and Q5 is turned on, so that LED D1 does not light up, LED D2 lights up, and LED D4 does not light up. When the output voltage Vbus is greater than or equal to the first voltage threshold Vth1 and less than or equal to the second voltage threshold Vth2, the Zener diode D7 is either active or inactive, the output of the voltage comparator U2 is high, the Zener diode D6 is active, the output of the voltage comparator U1 is high, the output of the logic circuit F is high, and the voltage at node A is greater than the output voltage Vbus. At this time, the switching transistors Q1, Q2, and Q3 are off, Q4 and Q5 are on, causing LED D1 to not light up, LED D2 to not light up, and LED D4 to light up. When the output voltage Vbus is greater than the second voltage threshold Vth2, the Zener diode D7 operates, the output of the voltage comparator U2 is low, the Zener diode D6 operates, the output of the voltage comparator U1 is high, the output of the logic circuit F is low, and the voltage of the connection node A is less than the output voltage Vbus. At this time, the switch Q1 is turned on, the switch Q2 is turned off, the switch Q3 is turned on, the switch Q4 is turned off, the switch Q5 is turned off, the LED D1 illuminates, the LED D2 does not illuminate, and the LED D4 does not illuminate.

11. The circuit for automatically adjusting the indicator light according to the output voltage as described in claim 9, characterized in that, It also includes resistors R1, R2, R4, R8, R9, R10, R12, and R15. In this configuration, resistor R1 is connected in series with LED D1 and switch Q3 between the output voltage Vbus and ground; resistor R2 is connected in series with LED D2 between the second connection terminal of switch Q2 and ground; resistor R4 is connected between the first connection terminal of switch Q2 and connection node B; resistor R8 is connected between the output terminal of the second comparator circuit and the control terminal of switch Q5; resistor R9 is connected between the power supply voltage VDD2 and the output terminal F of the logic circuit; resistor R10 is connected in series with LED D4 and switch Q4 between the output voltage Vbus and ground; resistor R12 is connected between the output terminal F of the logic circuit and the control terminal of switch Q4; and resistor R15 is connected between connection node B and the control terminal of switch Q3.

12. The circuit for automatically adjusting the indicator light according to the output voltage as described in claim 1, characterized in that, LEDs D1, D2, and D4 are LEDs with different color rendering.

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