A bus power supply circuit and system

Abstract

The present application provides a bus power supply circuit and system, which relate to the field of bus power supply technology. The bus power supply circuit includes a voltage source, a current limiting circuit, a reference voltage circuit, a voltage comparison circuit and a voltage conversion circuit. The voltage source is electrically connected to the current limiting circuit, the reference voltage circuit, the voltage comparison circuit and the voltage conversion circuit respectively, and supplies power to the current limiting circuit, the reference voltage circuit and the voltage comparison circuit. The reference voltage circuit is electrically connected to the current limiting circuit and the voltage comparison circuit respectively, and the voltage comparison circuit is electrically connected to the current limiting circuit and the voltage conversion circuit respectively. The bus power supply circuit and system provided by the present application have the advantage of protecting the electronic devices in the current limiting circuit when the slave device is short-circuited.

Description

Technical Field

[0001] The present application relates to the technical field of bus power supply, and in particular to a bus power supply circuit and system. Background Art

[0002] DALI (Dali signal, a control signal) communication interface protocol has simple coding and reliable communication. It identifies high and low levels through the voltage difference between the two lines. A voltage greater than 9.5V is a high level, and a voltage less than 6.5V is a low level. The usual DALI device interface circuit allows a maximum of 64 slave devices to be connected.

[0003] In the existing DALI bus power supply circuit, the slave device is powered by the port of the current limiting circuit. However, due to the large number of slave devices, a short circuit may occur in the slave device, causing the current in the current limiting circuit to increase, which can easily damage the electronic devices in the current limiting circuit.

[0004] In summary, the prior art has the problem that when a short circuit occurs in a slave device, the electronic components in the current limiting circuit are easily damaged. Summary of the invention

[0005] The purpose of the present application is to provide a bus power supply circuit and system to solve the problem in the prior art that when a short circuit occurs in a slave device, the electronic components in the current limiting circuit are easily damaged.

[0006] In order to achieve the above purpose, the technical solution adopted in the embodiment of the present application is as follows:

[0007] On the one hand, an embodiment of the present application provides a bus power supply circuit, the bus power supply circuit comprising a voltage source, a current limiting circuit, a reference voltage circuit, a voltage comparison circuit and a voltage conversion circuit, the voltage source being electrically connected to the current limiting circuit, the reference voltage circuit, the voltage comparison circuit and the voltage conversion circuit, and supplying power to the current limiting circuit, the reference voltage circuit and the voltage comparison circuit, the reference voltage circuit being electrically connected to the current limiting circuit and the voltage comparison circuit, the voltage comparison circuit being electrically connected to the current limiting circuit and the voltage conversion circuit, respectively; the reference voltage circuit being electrically connected to the current limiting circuit and the voltage comparison circuit, respectively; the reference voltage circuit being electrically connected to the current limiting circuit and the voltage conversion circuit; The first reference voltage is provided for the voltage comparison circuit, and the second reference voltage is provided for the voltage comparison circuit; the current limiting circuit includes a bus interface, and the bus interface is used to connect multiple slave devices; and the current limiting circuit is used to power the multiple slave devices based on the first reference voltage; the voltage comparison circuit is used to obtain a reference voltage from the current limiting circuit, and determine whether the multiple slave devices are short-circuited based on the reference voltage and the second reference voltage, and transmit a conversion signal to the voltage conversion circuit when short-circuited; the voltage conversion circuit is used to reduce the output voltage of the voltage source after receiving the conversion signal to protect the devices in the current limiting circuit.

[0008] Optionally, the current limiting circuit includes a first resistor, a first switch tube, a second switch tube, a second resistor, a first driving module and a second driving module, the voltage source, the first resistor, the first switch tube, the second switch tube, and the second resistor are electrically connected in sequence, the bus interface is connected in parallel with the first resistor, the first driving module is electrically connected to the voltage source and the first switch tube, respectively, to drive the first switch tube to turn on; the second driving module is electrically connected to one end of the second resistor and the second switch tube, respectively, to drive the second switch tube to turn on; one end of the second resistor is also electrically connected to the voltage comparison circuit, and the other end of the second resistor is grounded.

[0009] Optionally, the first driving module includes a third resistor and a first voltage regulator tube, the second end of the first switch tube is electrically connected to the first resistor, the third end of the first switch tube is electrically connected to the second switch tube, one end of the third resistor is electrically connected to the voltage source, the other end of the third resistor is respectively electrically connected to the first end of the first switch tube and the negative electrode of the first voltage regulator tube, and the positive electrode of the voltage regulator tube is electrically connected to the second end of the first switch tube.

[0010] Optionally, the second driving module includes a first operational amplifier, a fourth resistor, a fifth resistor and a negative feedback unit, the non-phase input terminal of the first operational amplifier is electrically connected to the reference voltage circuit to provide a first reference voltage for the non-phase input terminal through the reference voltage circuit, the inverting input terminal of the first operational amplifier is electrically connected to one end of the fourth resistor and one end of the negative feedback unit, respectively, and the other end of the fourth resistor is electrically connected to one end of the second resistor; the output terminal of the first operational amplifier is electrically connected to one end of the fifth resistor and the other end of the negative feedback unit, respectively, and the other end of the fifth resistor is electrically connected to the first end of the second switch tube; wherein the negative feedback unit is used to adjust the current value of the bus interface to be within a preset range.

[0011] Optionally, the negative feedback unit includes a sixth resistor, a second voltage regulator and a first capacitor, one end of the sixth resistor is electrically connected to the non-phase input terminal of the first op amp, the other end of the sixth resistor is respectively electrically connected to one end of the first capacitor and the positive electrode of the second voltage regulator, and the other end of the first capacitor and the negative electrode of the second voltage regulator are both electrically connected to the output terminal of the first op amp.

[0012] Optionally, the reference voltage circuit includes a seventh resistor, a voltage stabilizing device, a first voltage dividing unit and a second voltage dividing unit, one end of the seventh resistor is electrically connected to the voltage source, the other end of the seventh resistor is electrically connected to the first end of the voltage stabilizing device, one end of the first voltage dividing unit and one end of the second voltage dividing unit, the second end of the voltage stabilizing device, the other ends of the first voltage dividing unit and the second voltage dividing unit are all grounded; the first voltage dividing unit is also electrically connected to the current limiting circuit and provides a first reference voltage for the current limiting circuit; the second voltage dividing unit is also electrically connected to the voltage comparison circuit and provides a second reference voltage for the voltage comparison circuit.

[0013] Optionally, the first voltage-dividing unit includes a first voltage-dividing resistor, a second voltage-dividing resistor and a second capacitor, one end of the first voltage-dividing resistor is electrically connected to the other end of the seventh resistor and the third end of the voltage stabilizing device, respectively, the other end of the first voltage-dividing resistor is electrically connected to one end of the second voltage-dividing resistor, one end of the second capacitor and the current limiting circuit, and the other end of the second voltage-dividing resistor and the other end of the second capacitor are both grounded.

[0014] Optionally, the second voltage-dividing unit includes a third voltage-dividing resistor, a fourth voltage-dividing resistor and a third capacitor, one end of the third voltage-dividing resistor is electrically connected to the other end of the seventh resistor, the other end of the third voltage-dividing resistor is electrically connected to one end of the fourth voltage-dividing resistor, one end of the third capacitor and the voltage comparison circuit, and the other end of the fourth voltage-dividing resistor and the other end of the third capacitor are both grounded.

[0015] Optionally, the voltage comparison circuit includes a second op amp, an eighth resistor and a fourth capacitor, one end of the eighth resistor is electrically connected to the current limiting circuit and is used to obtain a reference voltage from the current limiting circuit, the other end of the eighth resistor is electrically connected to the inverting input of the second op amp and one end of the fourth capacitor respectively, the other end of the fourth capacitor is grounded, the non-inverting input of the second op amp is electrically connected to the voltage comparison circuit to provide a second reference voltage for the second op amp through the voltage comparison circuit, and the output of the second op amp is electrically connected to the voltage conversion circuit.

[0016] On the other hand, an embodiment of the present application further provides a bus power supply system, which includes a plurality of slave devices and the above-mentioned bus power supply circuit, and the plurality of slave devices are all electrically connected to the bus interface of the bus power supply circuit.

[0017] Compared with the prior art, this application has the following beneficial effects:

[0018] The present application provides a bus power supply circuit, which includes a voltage source, a current limiting circuit, a reference voltage circuit, a voltage comparison circuit and a voltage conversion circuit. The voltage source is electrically connected to the current limiting circuit, the reference voltage circuit, the voltage comparison circuit and the voltage conversion circuit, respectively, and supplies power to the current limiting circuit, the reference voltage circuit and the voltage comparison circuit. The reference voltage circuit is electrically connected to the current limiting circuit and the voltage comparison circuit, respectively, and the voltage comparison circuit is electrically connected to the current limiting circuit and the voltage conversion circuit, respectively; the reference voltage circuit provides a first reference voltage for the current limiting circuit and provides a second reference voltage for the voltage comparison circuit; the current limiting circuit includes a bus interface, which is used to connect multiple slave devices; and the current limiting circuit is used to supply power to the multiple slave devices based on the first reference voltage; the voltage comparison circuit is used to obtain a reference voltage from the current limiting circuit, and determine whether the multiple slave devices are short-circuited based on the reference voltage and the second reference voltage, and transmit a conversion signal to the voltage conversion circuit when short-circuited; the voltage conversion circuit is used to reduce the output voltage of the voltage source after receiving the conversion signal to protect the components in the current limiting circuit. Since the voltage conversion circuit provided in the present application can reduce the output voltage of the voltage source when the slave device is short-circuited, the current value in the current limiting circuit will not rise too high when the slave device is short-circuited, thereby achieving the purpose of protecting the electronic devices in the current limiting circuit.

[0019] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A module schematic diagram of a bus power supply circuit provided in an embodiment of the present application.

[0022] Figure 2 A circuit diagram of a current limiting circuit provided in an embodiment of the present application.

[0023] Figure 3 Please provide a circuit diagram of a reference voltage circuit provided in the embodiment.

[0024] Figure 4 A circuit diagram of a voltage comparison circuit provided in an embodiment of the application.

[0025] In the figure: 100-bus power supply circuit; 110-voltage source; 120-current limiting circuit; 130-reference voltage circuit; 140-voltage comparison circuit; 150-voltage conversion circuit; R1-first resistor; R2-second resistor; R3-third resistor; R4-fourth resistor; R5-fifth resistor; R6-sixth resistor; R7-seventh resistor; R8-eighth resistor; 121-first drive module; 122-second drive module; Q1-first switch tube; Q2-second switch tube; Z1-first voltage regulator tube; Z2-second voltage regulator tube; IC1-first op amp; IC2-voltage regulator device; IC3-second op amp; 131-first voltage divider unit; 132-second voltage divider unit; Ra-first voltage divider resistor; Rb-second voltage divider resistor; Rc-third voltage divider resistor; Rd-fourth voltage divider resistor. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0028] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0029] As described in the background technology, in the existing DALI bus power supply circuit, the slave device is powered by the port of the current limiting circuit. However, since there are many slave devices, a slave device short circuit may occur, causing the current in the current limiting circuit to increase, which can easily damage the electronic devices in the current limiting circuit.

[0030] In view of this, in order to solve the above problems, an embodiment of the present application provides a bus power supply circuit, which achieves the purpose of protecting electronic devices in the current limiting circuit by reducing the output voltage of the voltage source when the slave device is short-circuited.

[0031] The bus power supply circuit provided in this application is exemplarily described below:

[0032] As an alternative implementation, see Figure 1 The bus power supply circuit 100 includes a voltage source 110, a current limiting circuit 120, a reference voltage circuit 130, a voltage comparison circuit 140 and a voltage conversion circuit 150. The voltage source 110 is electrically connected to the current limiting circuit 120, the reference voltage circuit 130, the voltage comparison circuit 140 and the voltage conversion circuit 150, and supplies power to the current limiting circuit 120, the reference voltage circuit 130 and the voltage comparison circuit 140. The reference voltage circuit 130 is electrically connected to the current limiting circuit 120 and the voltage comparison circuit 140, and the voltage comparison circuit 140 is electrically connected to the current limiting circuit 120 and the voltage conversion circuit 150.

[0033] Among them, the reference voltage circuit 130 provides a first reference voltage for the current limiting circuit 120 and provides a second reference voltage for the voltage comparison circuit 140; the current limiting circuit 120 includes a bus interface, which is used to connect multiple slave devices; and the current limiting circuit 120 is used to power multiple slave devices based on the first reference voltage; the voltage comparison circuit 140 is used to obtain a reference voltage from the current limiting circuit 120, and determine whether multiple slave devices are short-circuited based on the reference voltage and the second reference voltage, and transmit a conversion signal to the voltage conversion circuit 150 when short-circuited; the voltage conversion circuit 150 is used to reduce the output voltage of the voltage source 110 after receiving the conversion signal to protect the devices in the current limiting circuit 120. Optionally, the voltage source 110 is a constant voltage source.

[0034] Generally, the number of slave devices can be up to 64. When a slave device is short-circuited, the current value in the current limiting circuit 120 will increase, which may damage the electronic components in the current limiting circuit 120. In the bus power supply circuit 100 provided in the embodiment of the present application, the voltage comparison circuit 140 can be used to determine whether the slave device is short-circuited, and when the slave device is short-circuited, a conversion signal is transmitted to the voltage conversion circuit 150, so that the voltage conversion circuit reduces the output voltage of the voltage source 110, thereby protecting the components in the current limiting circuit 120 from being damaged.

[0035] Optional, see Figure 2 The current limiting circuit 120 includes a first resistor R1, a first switch tube Q1, a second switch tube Q2, a second resistor R2, a first driving module 121 and a second driving module 122. The voltage source 110, the first resistor R1, the first switch tube Q1, the second switch tube Q2 and the second resistor R2 are electrically connected in sequence. The bus interface is connected in parallel with the first resistor R1. The first driving module 121 is electrically connected to the voltage source 110 and the first switch tube Q1 respectively to drive the first switch tube Q1 to turn on; the second driving module 122 is electrically connected to one end of the second resistor R2 and the second switch tube Q2 respectively to drive the second switch tube Q2 to turn on; one end of the second resistor R2 is also electrically connected to the voltage comparison circuit 140, and the other end of the second resistor R2 is grounded.

[0036] With this configuration, the voltage value of the bus interface is actually the voltage of the first resistor R1 , and the output voltage of the voltage source 110 is divided by the first resistor R1 , the first switch tube Q1 , the second switch tube Q2 and the second resistor R2 .

[0037] Generally, in the bus power supply circuit 100, the voltage of the bus interface is greater than 9.5V for a high level and less than 6.5V for a low level. Therefore, the output voltage of the voltage source 110 needs to be greater than 9.5V. Optionally, the output voltage of the voltage source 110 can be 12V~22.5V. For example, the output voltage of the voltage source 110 is 15V.

[0038] At the same time, the current value in the current limiting circuit 120 cannot be too large or too small. When the current value is too large, the first switch tube Q1 and the second switch tube Q2 will be damaged; but when the current value is too small, it cannot meet the requirements of the slave device. Therefore, by setting the first resistor R1, the first switch tube Q1, the second switch tube Q2 and the second resistor R2, the resistance values ​​of the first resistor R1 and the second resistor R2 can be set to ensure that the current in the current limiting circuit 120 meets the requirements.

[0039] Optionally, the first driving module 121 includes a third resistor R3 and a first voltage regulator tube Z1, the second end of the first switch tube Q1 is electrically connected to the first resistor R1, the third end of the first switch tube Q1 is electrically connected to the second switch tube Q2, one end of the third resistor R3 is electrically connected to the voltage source 110, the other end of the third resistor R3 is respectively electrically connected to the first end of the first switch tube Q1 and the negative electrode of the first voltage regulator tube Z1, and the positive electrode of the voltage regulator tube is electrically connected to the second end of the first switch tube Q1.

[0040] As an implementation, the first switch tube Q1 can be a MOS tube, such as a 4N60 MOS tube. On this basis, the other end of the third resistor R3 is electrically connected to the gate of the MOS tube, and the drain and source of the MOS tube are electrically connected to the first resistor R1 and the second switch tube Q2 respectively.

[0041] The first voltage regulator Z1 and the third resistor R3 form a driving circuit of the MOS tube. Optionally, the first voltage regulator Z1 can be a 15V voltage regulator to stabilize the gate driving voltage of the MOS tube within 15V.

[0042] Optionally, the second driving module 122 includes a first op amp IC1, a fourth resistor R4, a fifth resistor R5 and a negative feedback unit, the non-phase input terminal of the first op amp IC1 is electrically connected to the reference voltage circuit 130 to provide a first reference voltage for the non-phase input terminal through the reference voltage circuit 130, the inverting input terminal of the first op amp IC1 is electrically connected to one end of the fourth resistor R4 and one end of the negative feedback unit, respectively, and the other end of the fourth resistor R4 is electrically connected to one end of the second resistor R2; the output terminal of the first op amp IC1 is electrically connected to one end of the fifth resistor R5 and the other end of the negative feedback unit, respectively, and the other end of the fifth resistor R5 is electrically connected to the first end of the second switch tube Q2, wherein the negative feedback unit is used to adjust the current value of the bus interface to be within a preset range.

[0043] Optionally, the second switch tube Q2 can be a triode, for example, a triode of model 2SD1803. On this basis, the base of the triode is electrically connected to the output end of the first op amp IC1, the emitter of the triode is electrically connected to the second resistor R2, and the base of the triode is electrically connected to the positive electrode of the MOS tube and the first voltage regulator tube Z1 respectively.

[0044] By setting the second switch tube Q2 and the second driving circuit, the current limiting function can be achieved. The first reference voltage of the non-inverting input terminal of the first operational amplifier IC1 is provided by the reference voltage circuit 130. Optionally, the first reference voltage can be 0.53V, and the resistance value of the second resistor R2 can be 2.2Ω. Then, the current limit of the current limiting circuit 120 can be calculated to be 0.53V / 2.2Ω=240mA.

[0045] Meanwhile, the fourth resistor R4 is a current limiting resistor to prevent the current entering the inverting input terminal of the first operational amplifier IC1 from being too large. The fifth resistor R5 is a base driving current limiting resistor of the second switch tube Q2.

[0046] Optionally, the negative feedback unit includes a sixth resistor R6, a second voltage regulator tube Z2 and a first capacitor, one end of the sixth resistor R6 is electrically connected to the non-phase input terminal of the first operational amplifier IC1, the other end of the sixth resistor R6 is respectively electrically connected to one end of the first capacitor and the positive electrode of the second voltage regulator tube Z2, and the other end of the first capacitor and the negative electrode of the second voltage regulator tube Z2 are both electrically connected to the output terminal of the first operational amplifier IC1.

[0047] By setting a negative feedback unit, the current of the bus interface can be adjusted between 0-240mA and can work stably.

[0048] In other words, in order to meet the power supply requirements of the slave device, the current of the bus interface cannot be too low. Generally, the required current of each slave device is 2mA, and it can carry up to 64 slaves, so the current of the bus interface cannot be lower than 130mA. On this basis, by means of the voltage division of the first resistor R1, the second resistor R2, the first switch tube Q1 and the second switch tube Q2, it can be ensured that the current flowing through the bus interface is not less than 130mA. At the same time, by setting the second drive module 122 and the negative feedback unit, the current of the bus interface can be stabilized at less than 240mA.

[0049] At the same time, when the slave device is short-circuited, the first resistor R1 is short-circuited, and the output voltage of the voltage source 110 is completely loaded on the first switch tube Q1, the second switch tube Q2 and the second resistor R2. Since the second resistor R2 is relatively low, the current in the current will increase, which may cause damage to the first switch tube Q1 and the second switch tube Q2. In this embodiment, once the slave device is short-circuited, the voltage at the inverting input terminal of the first op amp IC1 will be greater than 0.53V. At this time, the first op amp IC1 outputs a low level, and the second switch tube Q2 is in a cut-off state. When the second switch tube Q2 is in a cut-off state, the inverting input terminal cannot collect voltage, that is, the voltage at the inverting input terminal is less than 0.53V, and the second switch tube Q2 is turned on again, and the cycle continues. In addition, when the voltage conversion circuit controls the output voltage of the voltage source 110 to decrease during a short circuit, so the current flowing through the triode decreases linearly.

[0050] As an alternative implementation, see Figure 3The reference voltage circuit 130 includes a seventh resistor R7, a voltage stabilizing device IC2, a first voltage dividing unit 131 and a second voltage dividing unit 132. One end of the seventh resistor R7 is electrically connected to the voltage source 110, and the other end of the seventh resistor R7 is electrically connected to the first end of the voltage stabilizing device IC2, one end of the first voltage dividing unit 131 and one end of the second voltage dividing unit 132 respectively. The second end of the voltage stabilizing device IC2, the other ends of the first voltage dividing unit 131 and the second voltage dividing unit 132 are all grounded; the first voltage dividing unit 131 is also electrically connected to the current limiting circuit 120 and provides a first reference voltage for the current limiting circuit 120; the second voltage dividing unit 132 is also electrically connected to the voltage comparison circuit 140 and provides a second reference voltage for the voltage comparison circuit 140.

[0051] Among them, the first voltage-dividing unit 131 includes a first voltage-dividing resistor Ra, a second voltage-dividing resistor Rb and a second capacitor, one end of the first voltage-dividing resistor Ra is electrically connected to the other end of the seventh resistor R7 and the third end of the voltage stabilizing device IC2, the other end of the first voltage-dividing resistor Ra is electrically connected to one end of the second voltage-dividing resistor Rb, one end of the second capacitor and the current limiting circuit 120, and the other end of the second voltage-dividing resistor Rb and the other end of the second capacitor are both grounded.

[0052] The second voltage-dividing unit 132 includes a third voltage-dividing resistor Rc, a fourth voltage-dividing resistor Rd and a third capacitor. One end of the third voltage-dividing resistor Rc is electrically connected to the other end of the seventh resistor R7, and the other end of the third voltage-dividing resistor Rc is electrically connected to one end of the fourth voltage-dividing resistor Rd, one end of the third capacitor and the voltage comparison circuit 140. The other end of the fourth voltage-dividing resistor Rd and the other end of the third capacitor are both grounded.

[0053] Optionally, the resistance values ​​of the first voltage-dividing resistor Ra, the second voltage-dividing resistor Rb, the third voltage-dividing resistor Rc, and the fourth voltage-dividing resistor Rd are not the same. In addition, the voltage-stabilizing device IC2 provided in the present application can adopt a 2.5V voltage-stabilizing device IC2, so the voltage at the other end of the seventh resistor R7 can be stabilized to 2.5V. On this basis, the 2.5V voltage is divided by the first voltage-dividing resistor Ra and the second voltage-dividing resistor Rb, and filtered by the second capacitor, and a first basic voltage of 0.53V can be obtained, and the first reference voltage can be transmitted to the non-inverting input terminal of the first op amp IC1 in the current limiting circuit 120. Similarly, the 2.5V voltage is divided by the third voltage-dividing resistor Rc and the fourth voltage-dividing resistor Rd, and filtered by the third capacitor, and a second basic voltage of 0.5V can be obtained, and the second reference voltage is transmitted to the voltage comparison circuit 140.

[0054] As an implementation, see Figure 4The voltage comparison circuit 140 includes a second operational amplifier IC3, an eighth resistor R8 and a fourth capacitor. One end of the eighth resistor R8 is electrically connected to the current limiting circuit 120 and is used to obtain a reference voltage from the current limiting circuit 120. The other end of the eighth resistor R8 is electrically connected to the inverting input terminal of the second operational amplifier IC3 and one end of the fourth capacitor respectively. The other end of the fourth capacitor is grounded. The non-inverting input terminal of the second operational amplifier IC3 is electrically connected to the voltage comparison circuit 140 to provide a second reference voltage for the second operational amplifier IC3 through the voltage comparison circuit 140. The output terminal of the second operational amplifier IC3 is electrically connected to the voltage conversion circuit 150.

[0055] The eighth resistor R8 and the fourth capacitor form an RC filter circuit, and the RC filter circuit samples the voltage of the second resistor R2 in the current limiting circuit 120 .

[0056] When the short circuit time of the two ends of the bus interface is greater than a certain time, for example, greater than 10ms, the voltage sampled by the RC filter circuit reaches 0.53V. At this time, the voltage of the inverting input terminal of the second operational amplifier IC3 is 0.53V, which exceeds the 0.5V of the non-inverting input terminal. The output terminal of the second operational amplifier IC3 outputs a low level. The voltage conversion circuit 150 receives the conversion signal, and then reduces the output voltage of the voltage source 110, for example, reduces the output voltage of the voltage source 110 to 5V. At this time, the current during the short circuit still does not exceed 240mA.

[0057] It should be noted that the numerical values ​​provided in this application are for illustration only. In other embodiments, other parameters may also be used. For example, the current value may not exceed 220 mA.

[0058] At the same time, this embodiment does not impose any limitation on the circuit structure of the voltage conversion circuit 150. For example, it may include a circuit structure of a diode and a resistor. When the second op amp IC3 outputs a low level, part of the output voltage of the voltage source 110 is consumed by the resistor, so the voltage output to the current limiting circuit 120 is reduced.

[0059] It can be understood that through this implementation, when there is no slave device pulling down, that is, when a high level needs to be transmitted to the slave device, the bus voltage difference between the positive terminal DALI+ and the negative terminal DALI- of the bus interface is greater than 12V, and the voltage source 110 obtains a driving voltage of the MOS tube>10V through the third resistor R3 and the first voltage regulator Z1, and the MOS tube is turned on, and the three electrodes are in the amplification area. There is a voltage difference between the voltage difference of the bus interface and the identification high level 9.5V, ensuring that there is sufficient voltage drop for high-level long-distance transmission.

[0060] When the slave device pulls down the bus, that is, when a low level needs to be transmitted to the slave device, the bus voltage difference between the positive terminal DALI+ and the negative terminal DALI- of the bus interface decreases, and the voltage of the voltage source 110 is instantly loaded on the first switch tube Q1 and the second switch tube Q2. The second switch tube Q2 works in the amplification area, and the current between the collector and the emitter rises rapidly, so that the maximum current limit of 240mA passes through the bus interface. Ensure that when the slave device pulls down the bus power supply circuit 100, the bus power supply current is greater than 130mA, meeting the requirement of connecting 64 slave devices.

[0061] When the device that is pulling down gives up pulling down, the bus voltage difference of the bus interface rises rapidly. When the bus voltage difference is >6.5V, it returns to the state of transmitting a high level to the slave device.

[0062] When the bus interface is short-circuited, the reference voltage is 0.53V after filtering through the eighth resistor R8 and the fourth capacitor. When the voltage at the non-inverting input terminal of the second op amp IC3 is 0.53V, the second op amp IC3 outputs a low level, and the voltage source 110 is pulled down to 5V through the voltage conversion circuit 150. At this time, the 5V voltage passes through the bus interface, the first switch tube Q1, the second switch tube Q2 and the second resistor R2 to the ground. When the voltage source 110 is short-circuited for a long time, the voltage is reduced to 5V, which plays a good role in protecting the first switch tube Q1 and the second switch tube Q2 of the semiconductor device.

[0063] Based on the above embodiments, the present application further provides a bus power supply system, which includes multiple slave devices and the above bus power supply circuit 100 , and the multiple slave devices are all electrically connected to the bus interface of the bus power supply circuit 100 .

[0064] In summary, the present application provides a bus power supply circuit, which includes a voltage source, a current limiting circuit, a reference voltage circuit, a voltage comparison circuit and a voltage conversion circuit. The voltage source is electrically connected to the current limiting circuit, the reference voltage circuit, the voltage comparison circuit and the voltage conversion circuit, respectively, and supplies power to the current limiting circuit, the reference voltage circuit and the voltage comparison circuit. The reference voltage circuit is electrically connected to the current limiting circuit and the voltage comparison circuit, respectively, and the voltage comparison circuit is electrically connected to the current limiting circuit and the voltage conversion circuit, respectively; the reference voltage circuit provides a first reference voltage for the current limiting circuit and provides a second reference voltage for the voltage comparison circuit; the current limiting circuit includes a bus interface, which is used to connect multiple slave devices; and the current limiting circuit is used to supply power to the multiple slave devices based on the first reference voltage; the voltage comparison circuit is used to obtain a reference voltage from the current limiting circuit, and determine whether the multiple slave devices are short-circuited based on the reference voltage and the second reference voltage, and transmit a conversion signal to the voltage conversion circuit when short-circuited; the voltage conversion circuit is used to reduce the output voltage of the voltage source after receiving the conversion signal to protect the devices in the current limiting circuit. Since the voltage conversion circuit provided in the present application can reduce the output voltage of the voltage source when the slave device is short-circuited, the current value in the current limiting circuit will not rise too high when the slave device is short-circuited, thereby achieving the purpose of protecting the electronic devices in the current limiting circuit.

[0065] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0066] It will be apparent to those skilled in the art that the present application is not limited to the details of the exemplary embodiments described above, and that the present application can be implemented in other specific forms without departing from the spirit or essential features of the present application. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present application. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A bus power supply circuit, characterized in that: The bus power supply circuit comprises a voltage source, a current limiting circuit, a reference voltage circuit, a voltage comparison circuit and a voltage conversion circuit, wherein the voltage source is electrically connected to the current limiting circuit, the reference voltage circuit, the voltage comparison circuit and the voltage conversion circuit respectively, and supplies power to the current limiting circuit, the reference voltage circuit and the voltage comparison circuit, wherein the reference voltage circuit is electrically connected to the current limiting circuit and the voltage comparison circuit respectively, and the voltage comparison circuit is electrically connected to the current limiting circuit and the voltage conversion circuit respectively; The reference voltage circuit provides a first reference voltage for the current limiting circuit and provides a second reference voltage for the voltage comparison circuit; The current limiting circuit comprises a bus interface, the bus interface is used to connect a plurality of slave devices; and the current limiting circuit is used to supply power to the plurality of slave devices based on the first reference voltage; The voltage comparison circuit is used to obtain a reference voltage from the current limiting circuit, and determine whether the plurality of slave devices are short-circuited based on the reference voltage and the second reference voltage, and transmit a conversion signal to the voltage conversion circuit when a short circuit occurs; The voltage conversion circuit is used to reduce the output voltage of the voltage source after receiving the conversion signal, so as to protect the components in the current limiting circuit; The current limiting circuit includes a first resistor, a first switch tube, a second switch tube, a second resistor, a first driving module and a second driving module. The voltage source, the first resistor, the first switch tube, the second switch tube and the second resistor are electrically connected in sequence. The bus interface is connected in parallel with the first resistor. The first driving module is electrically connected to the voltage source and the first switch tube respectively to drive the first switch tube to turn on. The second driving module is electrically connected to one end of the second resistor and the second switch tube respectively to drive the second switch tube to turn on. One end of the second resistor is also electrically connected to the voltage comparison circuit, and the other end of the second resistor is grounded. The reference voltage circuit comprises a seventh resistor, a voltage stabilizing device, a first voltage dividing unit and a second voltage dividing unit, one end of the seventh resistor is electrically connected to the voltage source, the other end of the seventh resistor is electrically connected to the first end of the voltage stabilizing device, one end of the first voltage dividing unit and one end of the second voltage dividing unit respectively, and the second end of the voltage stabilizing device, the other ends of the first voltage dividing unit and the second voltage dividing unit are all grounded; The first voltage dividing unit is also electrically connected to the current limiting circuit and provides a first reference voltage for the current limiting circuit; the second voltage dividing unit is also electrically connected to the voltage comparison circuit and provides a second reference voltage for the voltage comparison circuit; The voltage comparison circuit includes a second operational amplifier, an eighth resistor and a fourth capacitor. One end of the eighth resistor is electrically connected to the current limiting circuit and is used to obtain a reference voltage from the current limiting circuit. The other end of the eighth resistor is electrically connected to the inverting input of the second operational amplifier and one end of the fourth capacitor respectively. The other end of the fourth capacitor is grounded. The non-inverting input of the second operational amplifier is electrically connected to the voltage comparison circuit to provide a second reference voltage for the second operational amplifier through the voltage comparison circuit. The output of the second operational amplifier is electrically connected to the voltage conversion circuit.

2. The bus power supply circuit according to claim 1, characterized in that: The first driving module includes a third resistor and a first voltage regulator tube, the second end of the first switch tube is electrically connected to the first resistor, the third end of the first switch tube is electrically connected to the second switch tube, one end of the third resistor is electrically connected to the voltage source, the other end of the third resistor is respectively electrically connected to the first end of the first switch tube and the negative electrode of the first voltage regulator tube, and the positive electrode of the voltage regulator tube is electrically connected to the second end of the first switch tube.

3. The bus power supply circuit according to claim 1, characterized in that: The second driving module includes a first operational amplifier, a fourth resistor, a fifth resistor and a negative feedback unit, the non-phase input terminal of the first operational amplifier is electrically connected to the reference voltage circuit to provide a first reference voltage for the non-phase input terminal through the reference voltage circuit, the inverting input terminal of the first operational amplifier is electrically connected to one end of the fourth resistor and one end of the negative feedback unit respectively, and the other end of the fourth resistor is electrically connected to one end of the second resistor; the output terminal of the first operational amplifier is electrically connected to one end of the fifth resistor and the other end of the negative feedback unit respectively, and the other end of the fifth resistor is electrically connected to the first end of the second switch tube; Wherein, the negative feedback unit is used to adjust the current value of the bus interface to be within a preset range.

4. The bus power supply circuit according to claim 3, characterized in that: The negative feedback unit includes a sixth resistor, a second voltage regulator and a first capacitor, one end of the sixth resistor is electrically connected to the non-phase input terminal of the first operational amplifier, the other end of the sixth resistor is electrically connected to one end of the first capacitor and the positive electrode of the second voltage regulator, respectively, and the other end of the first capacitor and the negative electrode of the second voltage regulator are both electrically connected to the output terminal of the first operational amplifier.

5. The bus power supply circuit according to claim 1, characterized in that: The first voltage-dividing unit includes a first voltage-dividing resistor, a second voltage-dividing resistor and a second capacitor, one end of the first voltage-dividing resistor is electrically connected to the other end of the seventh resistor and the third end of the voltage stabilizing device, respectively, the other end of the first voltage-dividing resistor is electrically connected to one end of the second voltage-dividing resistor, one end of the second capacitor and the current limiting circuit, and the other end of the second voltage-dividing resistor and the other end of the second capacitor are both grounded.

6. The bus power supply circuit according to claim 1, characterized in that: The second voltage-dividing unit includes a third voltage-dividing resistor, a fourth voltage-dividing resistor and a third capacitor, one end of the third voltage-dividing resistor is electrically connected to the other end of the seventh resistor, the other end of the third voltage-dividing resistor is electrically connected to one end of the fourth voltage-dividing resistor, one end of the third capacitor and the voltage comparison circuit, and the other end of the fourth voltage-dividing resistor and the other end of the third capacitor are both grounded.

7. A bus power supply system, characterized in that: The bus power supply system comprises a plurality of slave devices and a bus power supply circuit as claimed in any one of claims 1 to 6, wherein the plurality of slave devices are electrically connected to a bus interface of the bus power supply circuit.

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