CN213521351U - Bus power supply circuit and system - Google Patents
Bus power supply circuit and system Download PDFInfo
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- CN213521351U CN213521351U CN202022485708.4U CN202022485708U CN213521351U CN 213521351 U CN213521351 U CN 213521351U CN 202022485708 U CN202022485708 U CN 202022485708U CN 213521351 U CN213521351 U CN 213521351U
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Abstract
The application provides a bus power supply circuit and system, and relates to the technical field of bus power supply. 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 respectively and electrically connected with the current limiting circuit, the reference voltage circuit, the voltage comparison circuit and the voltage conversion circuit and supplies power to the current limiting circuit, the reference voltage circuit and the voltage comparison circuit, the reference voltage circuit is respectively and electrically connected with the current limiting circuit and the voltage comparison circuit, and the voltage comparison circuit is respectively and electrically connected with the current limiting circuit and the voltage conversion circuit. The bus power supply circuit and the bus power supply system have the advantage that electronic devices in the current limiting circuit are protected when the slave device is in short circuit.
Description
Technical Field
The application relates to the technical field of bus power supply, in particular to a bus power supply circuit and system.
Background
The DALI (digital interface, a control signal) communication interface protocol is simple in coding and reliable in communication, and the high level and the low level are identified through the voltage difference of two lines, wherein the high level is greater than 9.5V, and the low level is less than 6.5V. The usual DALI device interface circuit allows a maximum of 64 slave devices to be connected.
In the existing DALI bus power supply circuit, slave equipment is supplied with power through a port of a current limiting circuit, however, because of more slave equipment, the situation of short circuit of the slave equipment may occur, so that the current in the current limiting circuit is increased, and electronic devices in the current limiting circuit are easily damaged.
In summary, the problem of the prior art is that when a short circuit condition occurs in the slave device, the electronic devices in the current limiting circuit are easily damaged.
SUMMERY OF THE UTILITY MODEL
The present application provides a bus power supply circuit and a bus power supply system, so as to solve the problem that an electronic device in a current limiting circuit is easily damaged when a slave device is in a short circuit condition in the prior art.
In order to achieve the above purpose, the embodiments of the present application employ the following technical solutions:
on one hand, the embodiment of the application provides a bus power supply circuit, which 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 respectively electrically connected with the current limiting circuit, the reference voltage circuit, the voltage comparison circuit and the voltage conversion circuit and supplies power to the current limiting circuit, the reference voltage circuit and the voltage comparison circuit, the reference voltage circuit is respectively electrically connected with the current limiting circuit and the voltage comparison circuit, and the voltage comparison circuit is respectively electrically connected with the current limiting circuit and the voltage conversion circuit; 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, and the bus interface is used for connecting a plurality of slave devices; the current limiting circuit is used for supplying power to the plurality of slave devices based on the first reference voltage; the voltage comparison circuit is used for acquiring a reference voltage from the current limiting circuit, determining whether the plurality of slave devices are short-circuited based on the reference voltage and the second reference voltage, and transmitting a conversion signal to the voltage conversion circuit when the slave devices are short-circuited; the voltage conversion circuit is used for reducing the output voltage of the voltage source after receiving the conversion signal so as to protect devices in the current limiting circuit.
Optionally, the current limiting circuit includes a first resistor, a first 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 sequentially electrically connected, the bus interface is connected in parallel with the first resistor, and the first driving module is respectively electrically connected with the voltage source and the first switch tube to drive the first switch tube to be turned on; the second driving module is electrically connected with one end of the second resistor and the second switching tube respectively so as to drive the second switching tube to be conducted; one end of the second resistor is also electrically connected with the voltage comparison circuit, and the other end of the second resistor is grounded.
Optionally, the first driving module includes a third resistor and a first voltage regulator tube, a second end of the first switch tube is electrically connected to the first resistor, a 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 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.
Optionally, the second driving module includes a first operational amplifier, a fourth resistor, a fifth resistor, and a negative feedback unit, a positive phase input terminal of the first operational amplifier is electrically connected to the reference voltage circuit to provide a first reference voltage to the positive phase input terminal through the reference voltage circuit, an 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 end of the first operational amplifier is electrically connected with 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 with the first end of the second switching tube; the negative feedback unit is used for adjusting the current value of the bus interface to be within a preset interval.
Optionally, the negative feedback unit includes a sixth resistor, a second voltage regulator tube, and a first capacitor, one end of the sixth resistor is electrically connected to the positive 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 anode of the second voltage regulator tube, respectively, and the other end of the first capacitor and the cathode of the second voltage regulator tube are electrically connected to the output terminal of the first operational amplifier.
Optionally, the reference voltage circuit includes a seventh resistor, a voltage regulator, 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 regulator, the one end of the first voltage dividing unit, and the one end of the second voltage dividing unit, respectively, and the second end of the voltage regulator, the other end of the first voltage dividing unit, and the other end of the second voltage dividing unit are all grounded; the first voltage division unit is also electrically connected with the current limiting circuit and provides a first reference voltage for the current limiting circuit; the second voltage division unit is also electrically connected with the voltage comparison circuit and provides a second reference voltage for the voltage comparison circuit.
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 regulator, 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.
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 another end of a seventh resistor, another 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 comparing circuit, and another end of the fourth voltage dividing resistor and another end of the third capacitor are both grounded.
Optionally, the voltage comparison circuit includes a second operational amplifier, an eighth resistor, and a fourth capacitor, where one end of the eighth resistor is electrically connected to the current limiting circuit and is configured to obtain a reference voltage from the current limiting circuit, the other end of the eighth resistor is electrically connected to an inverting input terminal of the second operational amplifier and one end of the fourth capacitor, respectively, the other end of the fourth capacitor is grounded, a non-inverting input terminal 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, and an output terminal of the second operational amplifier is electrically connected to the voltage conversion circuit.
On the other hand, the embodiment of the present application further provides a bus power supply system, where the bus power supply system includes a plurality of slave devices and the bus power supply circuit, and the plurality of slave devices are all electrically connected to a bus interface of the bus power supply circuit.
Compared with the prior art, the method has the following beneficial effects:
the application provides a bus power supply circuit, which 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 respectively and electrically connected with the current limiting circuit, the reference voltage circuit, the voltage comparison circuit and the voltage conversion circuit and supplies power to the current limiting circuit, the reference voltage circuit and the voltage comparison circuit; 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, wherein the bus interface is used for connecting a plurality of slave devices; the current limiting circuit is used for supplying power to the plurality of slave devices based on the first reference voltage; the voltage comparison circuit is used for acquiring a reference voltage from the current limiting circuit, determining whether the plurality of slave devices are short-circuited or not based on the reference voltage and a second reference voltage, and transmitting a conversion signal to the voltage conversion circuit when the slave devices are short-circuited; the voltage conversion circuit is used for reducing the output voltage of the voltage source after receiving the conversion signal so as to protect devices in the current limiting circuit. The voltage conversion circuit provided by the application can reduce the output voltage of the voltage source when the slave equipment is in short circuit, so that the current value in the current limiting circuit cannot rise too high when the slave equipment is in short circuit, and the purpose of protecting electronic devices in the current limiting circuit is achieved.
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and it will be apparent to those skilled in the art that other related drawings can be obtained from the drawings without inventive effort.
Fig. 1 is a block diagram of a bus power supply circuit according to an embodiment of the present disclosure.
Fig. 2 is a circuit diagram of a current limiting circuit according to an embodiment of the present disclosure.
Fig. 3 is a circuit diagram of a reference voltage circuit according to an embodiment.
FIG. 4 is a schematic circuit diagram of a voltage comparison circuit according to an embodiment of the present application.
In the figure: 100-bus power supply circuit; 110-a voltage source; 120-a current limiting circuit; 130-reference voltage circuit; 140-a voltage comparison circuit; 150-a voltage conversion circuit; r1 — first resistance; r2 — second resistance; r3 — third resistance; r4-fourth resistor; r5-fifth resistor; r6-sixth resistance; r7 — seventh resistor; r8 — eighth resistance; 121-a first driving module; 122-a second drive module; q1-first switch tube; q2-second switch tube; z1-first stabilivolt; z2-second stabilivolt; IC 1-first op amp; IC 2-voltage regulator device; IC 3-second op amp; 131-a first voltage division unit; 132-a second voltage dividing unit; ra-a first divider resistance; rb-a second divider resistor; rc-third voltage dividing resistance; rd-fourth voltage dividing resistor.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Meanwhile, in the description of the present application, the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.
As described in the background art, in the existing DALI bus power supply circuit, the slave devices are powered through the ports of the current limiting circuit, however, since there are many slave devices, the slave devices may be short-circuited, which may cause the current in the current limiting circuit to increase, and may easily damage the electronic devices in the current limiting circuit.
In view of the above, in order to solve the above problem, embodiments of the present application provide a bus power supply circuit, which achieves the purpose of protecting electronic devices in a current limiting circuit by reducing an output voltage of a voltage source when a slave device is short-circuited.
The following is an exemplary description of the bus power supply circuit provided in the present application:
as an optional implementation manner, referring to fig. 1, the bus power supply circuit 100 includes a voltage source 110, a current limiting circuit 120, a reference voltage circuit 130, a voltage comparing circuit 140, and a voltage converting circuit 150, where the voltage source 110 is electrically connected to the current limiting circuit 120, the reference voltage circuit 130, the voltage comparing circuit 140, and the voltage converting circuit 150, respectively, and supplies power to the current limiting circuit 120, the reference voltage circuit 130, and the voltage comparing circuit 140, where the reference voltage circuit 130 is electrically connected to the current limiting circuit 120 and the voltage comparing circuit 140, and the voltage comparing circuit 140 is electrically connected to the current limiting circuit 120 and the voltage converting circuit 150, respectively.
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 comparing circuit 140; the current limiting circuit 120 includes a bus interface for connecting a plurality of slave devices; the current limiting circuit 120 is configured to supply power to a plurality of slave devices based on a first reference voltage; the voltage comparison circuit 140 is configured to obtain a reference voltage from the current limiting circuit 120, determine whether the plurality of slave devices are short-circuited based on the reference voltage and a second reference voltage, and transmit a switching signal to the voltage conversion circuit 150 when the plurality of slave devices are short-circuited; the voltage converting circuit 150 is used for reducing the output voltage of the voltage source 110 after receiving the converting signal, so as to protect the devices in the current limiting circuit 120. Optionally, the voltage source 110 is a constant voltage source.
Generally, the number of slave devices may reach 64 at most, and when there is a short circuit of a slave device, the current value in the current limiting circuit 120 may increase, possibly damaging the electronic devices in the current limiting circuit 120. In the bus power supply circuit 100 according to the embodiment of the present disclosure, the voltage comparison circuit 140 may be used to determine whether the slave device is short-circuited, and transmit the switching signal to the voltage conversion circuit 150 when the slave device is short-circuited, so that the voltage conversion circuit reduces the output voltage of the voltage source 110, and protects devices in the current limiting circuit 120 from being damaged.
Optionally, referring to fig. 2, the current limiting circuit 120 includes a first resistor R1, a first switch Q1, a second switch Q2, a second resistor R2, a first driving module 121, and a second driving module 122, wherein a voltage source 110, the first resistor R1, a first switch Q1, a second switch Q2, and a second resistor R2 are sequentially electrically connected, a bus interface is connected in parallel with the first resistor R1, and the first driving module 121 is electrically connected to the voltage source 110 and the first switch Q1 respectively to drive the first switch Q1 to be turned on; the second driving module 122 is electrically connected to one end of the second resistor R2 and the second switching tube Q2, respectively, to drive the second switching tube Q2 to be turned on; one end of the second resistor R2 is also electrically connected to the voltage comparator circuit 140, and the other end of the second resistor R2 is grounded.
With this arrangement, 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 transistor Q1, the second switch transistor Q2, and the second resistor R2.
Generally, in the bus power supply circuit 100, the voltage of the bus interface is higher than 9.5V and lower than 6.5V, and therefore, the output voltage of the voltage source 110 needs to be higher than 9.5V, and optionally, the voltage of the output of the voltage source 110 may be 12V to 22.5V, for example, the output voltage of the voltage source 110 is 15V.
Meanwhile, the current value in the current limiting circuit 120 cannot be too large or too small, and when the current value is too large, the first switching tube Q1 and the second switching tube Q2 may be damaged; however, when the current value is too small, the requirement of the slave device cannot be satisfied. Therefore, by providing the first resistor R1, the first switch tube Q1, the second switch tube Q2 and the second resistor R2, the current in the current limiting circuit 120 can be ensured to meet the requirement by setting the resistances of the first resistor R1 and the second resistor R2.
Optionally, the first driving module 121 includes a third resistor R3 and a first voltage regulator tube Z1, a second end of the first switch tube Q1 is electrically connected to the first resistor R1, a 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 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.
As an implementation, the first switch Q1 may be a MOS transistor, for example, a MOS transistor with a model number of 4N 60. In addition, the other end of the third resistor R3 is electrically connected to the gate of the MOS transistor, and the drain and the source of the MOS transistor are electrically connected to the first resistor R1 and the second switch transistor Q2, respectively.
The first regulator tube Z1 and the third resistor R3 form a driving circuit of the MOS tube, and optionally, the first regulator tube Z1 may be a 15V regulator tube, so as to stabilize the gate driving voltage of the MOS tube within 15V.
Optionally, the second driving module 122 includes a first operational amplifier IC1, a fourth resistor R4, a fifth resistor R5, and a negative feedback unit, a positive phase input terminal of the first operational amplifier IC1 is electrically connected to the reference voltage circuit 130 to provide a first reference voltage to the positive phase input terminal through the reference voltage circuit 130, an inverting input terminal of the first operational amplifier 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; an output end of the first operational amplifier 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 Q2, wherein the negative feedback unit is configured to adjust a current value of the bus interface to be within a preset interval.
Alternatively, the second switching tube Q2 may be a triode, for example, type 2SD 1803. On the basis, the base electrode of the triode is electrically connected with the output end of the first operational amplifier IC1, the emitter electrode of the triode is electrically connected with the second resistor R2, and the base electrode of the triode is electrically connected with the MOS tube and the anode of the first voltage regulator tube Z1 respectively.
The second switching tube Q2 and the second driving circuit are provided to limit the current. The first reference voltage at the non-inverting input of the first operational amplifier IC1 is provided by the reference voltage circuit 130, and optionally, the first reference voltage may be 0.53V, and the resistance of the second resistor R2 may be 2.2 Ω, so that the current limit of the current limiting circuit 120 may be calculated as 0.53V/2.2 Ω -240 mA.
Meanwhile, the fourth resistor R4 is a current limiting resistor, which prevents excessive current from entering the inverting input terminal of the first operational amplifier IC 1. The fifth resistor R5 is a base-driven current-limiting resistor of the second switch Q2.
Optionally, the negative feedback unit includes a sixth resistor R6, a second regulator tube Z2, and a first capacitor, one end of the sixth resistor R6 is electrically connected to the positive-phase input terminal of the first operational amplifier IC1, the other end of the sixth resistor R6 is electrically connected to one end of the first capacitor and the positive electrode of the second regulator tube Z2, and the other end of the first capacitor and the negative electrode of the second regulator tube Z2 are electrically connected to the output terminal of the first operational amplifier IC 1.
By arranging the negative feedback unit, the current of the bus interface can be adjusted to be between 0 and 240mA and the stable operation can be realized.
In other words, the current of the bus interface cannot be too low in order to meet the power supply requirements of the slave device. Typically, the required current of each slave device is 2mA, and at most 64 slaves can be carried, so the current of the bus interface cannot be lower than 130 mA. On the basis, the current flowing through the bus interface can be ensured to be not lower than 130mA in a voltage division mode through the first resistor R1, the second resistor R2, the first switch tube Q1 and the second switch tube Q2. Meanwhile, by arranging the second driving module 122 and the negative feedback unit, the current of the bus interface can be stabilized to be less than 240 mA.
Meanwhile, when the slave device is shorted, the first resistor R1 is shorted, the output voltage of the voltage source 110 is fully loaded on the first switch tube Q1, the second switch tube Q2 and the second resistor R2, and the second resistor R2 is low, so that the current in the current is increased, which may cause damage to the first switch tube Q1 and the second switch tube Q2. In the present embodiment, once the slave device is short-circuited, the voltage at the inverting input terminal of the first operational amplifier IC1 will be greater than 0.53V, and at this time, the first operational amplifier IC1 outputs a low level, and the second switch Q2 is in an off state. When the second switch tube Q2 is in the off state, the voltage is not collected at the inverting input terminal, 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 is continued. In addition, since the output voltage of the short-circuit voltage conversion circuit control voltage source 110 decreases, the current flowing through the transistor decreases linearly.
As an alternative implementation manner, please refer to fig. 3, the reference voltage circuit 130 includes a seventh resistor R7, a voltage regulator IC2, a first voltage dividing unit 131, and a second voltage dividing unit 132, wherein one end of the seventh resistor R7 is electrically connected to the voltage source 110, the other end of the seventh resistor R7 is electrically connected to the first end of the voltage regulator IC2, one end of the first voltage dividing unit 131, and one end of the second voltage dividing unit 132, respectively, and the second end of the voltage regulator IC2, the other end of the first voltage dividing unit 131, and the other end of the second voltage dividing unit 132 are all grounded; the first voltage dividing unit 131 is further electrically connected to the current limiting circuit 120, and provides a first reference voltage for the current limiting circuit 120; the second voltage division unit 132 is also electrically connected to the voltage comparison circuit 140, and provides the voltage comparison circuit 140 with a second reference voltage.
The first voltage dividing unit 131 includes a first voltage dividing resistor Ra, a second voltage dividing resistor Rb and a second capacitor, wherein 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 regulator 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.
The second voltage dividing unit 132 includes a third voltage dividing resistor Rc, a fourth voltage dividing resistor Rd and a third capacitor, wherein one end of the third voltage dividing resistor Rc is electrically connected to the other end of the seventh resistor R7, 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 comparing circuit 140, and the other end of the fourth voltage dividing resistor Rd and the other end of the third capacitor are both grounded.
Optionally, the resistances 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 different. Moreover, the voltage regulator device IC2 provided by the present application may adopt a 2.5V voltage regulator device IC2, so that the voltage at the other end of the seventh resistor R7 may be regulated to 2.5V, and on this basis, the voltage of 2.5V may be divided by the first voltage dividing resistor Ra and the second voltage dividing resistor Rb, and at the same time, the first base voltage of 0.53V may be obtained through filtering by the second capacitor, and the first base voltage may be transmitted to the non-inverting input terminal of the first operational amplifier IC1 in the current limiting circuit 120. Similarly, the voltage of 2.5V is divided by the third voltage dividing resistor Rc and the fourth voltage dividing resistor Rd, and filtered by the third capacitor, so as to obtain a second base voltage of 0.5V, and transmit the second base voltage to the voltage comparing circuit 140.
As an implementation manner, referring to fig. 4, the 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 configured to obtain a reference voltage from the current limiting circuit 120, the other end of the eighth resistor R8 is electrically connected to an 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, a non-inverting input terminal of the second operational amplifier IC3 is electrically connected to the voltage comparison circuit 140, so as to provide a second reference voltage to the second operational amplifier IC3 through the voltage comparison circuit 140, and an output terminal of the second operational amplifier IC3 is electrically connected to the voltage conversion circuit 150.
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.
When the time of the short circuit between the two ends of the bus interface is longer than a certain time, for example, longer than 10ms, the voltage sampled by the RC filter circuit reaches 0.53V, and at this time, the voltage at the inverting input terminal of the second operational amplifier IC3 is 0.53V and exceeds 0.5V at 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 further reduces the output voltage of the voltage source 110, for example, reduces the output voltage of the voltage source 110 to 5V, and then the current at the time of the short circuit still does not exceed 240 mA.
It should be noted that the numerical values provided in the present application are all examples, and in other embodiments, other parameters may be adopted, for example, the current value may be not more than 220 mA.
Meanwhile, the circuit structure of the voltage converting circuit 150 is not limited in this embodiment, for example, it may include a circuit structure of a diode and a resistor, when the second amplifier IC3 outputs a low level, part of the output voltage of the voltage source 110 is consumed by the resistor, so that the voltage output to the current limiting circuit 120 is reduced.
It can be understood that, by this implementation, when no slave device pulls 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, the voltage source 110 obtains the driving voltage >10V of the MOS transistor through the third resistor R3 and the first voltage regulator tube Z1, the MOS transistor is turned on, and three electrodes are in the amplification region. The differential pressure of the bus interface and the differential pressure of the high level identification 9.5V ensure that enough voltage drop exists in the high level long-distance transmission.
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 is reduced, the voltage of the voltage source 110 is instantaneously loaded on the first switch tube Q1 and the second switch tube Q2, the second switch tube Q2 works in the amplification region, and the current between the collector and the emitter rapidly rises, so that the maximum limiting current 240mA passes through the bus interface. When the slave equipment pulls down the bus power supply circuit 100, the bus power supply current is larger than 130mA, and the requirement of connecting 64 slave equipment is met.
When the pull-down device gives up pulling down, the bus differential pressure of the bus interface rises rapidly, and when the bus differential pressure is greater than 6.5V, the state of transmitting high level to the slave device is returned again.
When the bus interface is short-circuited, the filtered voltage of the reference voltage passing through the eighth resistor R8 and the fourth capacitor is 0.53V, and when the voltage at the non-inverting input terminal of the second operational amplifier IC3 is high, the second operational amplifier 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 voltage of 5V is connected to the ground through the bus interface, the first switch tube Q1, the second switch tube Q2 and the second resistor R2. The voltage of the voltage source 110 is reduced to 5V in the long-term short circuit, and the purpose of protecting the first switch tube Q1 and the second switch tube Q2 of the semiconductor device is well achieved.
Based on the foregoing embodiments, the present application further provides a bus power supply system, where the bus power supply system includes a plurality of slave devices and the bus power supply circuit 100, and the plurality of slave devices are all electrically connected to the bus interface of the bus power supply circuit 100.
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, 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, 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, wherein the bus interface is used for connecting a plurality of slave devices; the current limiting circuit is used for supplying power to the plurality of slave devices based on the first reference voltage; the voltage comparison circuit is used for acquiring a reference voltage from the current limiting circuit, determining whether the plurality of slave devices are short-circuited or not based on the reference voltage and a second reference voltage, and transmitting a conversion signal to the voltage conversion circuit when the slave devices are short-circuited; the voltage conversion circuit is used for reducing the output voltage of the voltage source after receiving the conversion signal so as to protect devices in the current limiting circuit. The voltage conversion circuit provided by the application can reduce the output voltage of the voltage source when the slave equipment is in short circuit, so that the current value in the current limiting circuit cannot rise too high when the slave equipment is in short circuit, and the purpose of protecting electronic devices in the current limiting circuit is achieved.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.
It will be evident to those skilled in the art that the present application is not limited to the details of the foregoing illustrative embodiments, and that the present application may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Claims (10)
1. A bus power supply circuit is characterized by comprising 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 respectively electrically connected with the current limiting circuit, the reference voltage circuit, the voltage comparison circuit and the voltage conversion circuit and supplies power to the current limiting circuit, the reference voltage circuit and the voltage comparison circuit;
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, and the bus interface is used for connecting a plurality of slave devices; the current limiting circuit is used for supplying power to the plurality of slave devices based on the first reference voltage;
the voltage comparison circuit is used for acquiring a reference voltage from the current limiting circuit, determining whether the plurality of slave devices are short-circuited based on the reference voltage and the second reference voltage, and transmitting a conversion signal to the voltage conversion circuit when the slave devices are short-circuited;
the voltage conversion circuit is used for reducing the output voltage of the voltage source after receiving the conversion signal so as to protect devices in the current limiting circuit.
2. The bus power supply circuit according to claim 1, wherein the current limiting circuit includes a first resistor, a first 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, and the first driving module is electrically connected to the voltage source and the first switch tube, respectively, to drive the first switch tube to conduct; the second driving module is electrically connected with one end of the second resistor and the second switching tube respectively so as to drive the second switching tube to be conducted; one end of the second resistor is also electrically connected with the voltage comparison circuit, and the other end of the second resistor is grounded.
3. The bus power supply circuit according to claim 2, wherein the first driving module comprises a third resistor and a first voltage regulator tube, a second end of the first switch tube is electrically connected with the first resistor, a third end of the first switch tube is electrically connected with the second switch tube, one end of the third resistor is electrically connected with the voltage source, the other end of the third resistor is respectively electrically connected with a first end of the first switch tube and a negative electrode of the first voltage regulator tube, and a positive electrode of the voltage regulator tube is electrically connected with a second end of the first switch tube.
4. The bus power supply circuit according to claim 2, wherein the second driving module comprises a first operational amplifier, a fourth resistor, a fifth resistor and a negative feedback unit, wherein a positive phase input terminal of the first operational amplifier is electrically connected to the reference voltage circuit to provide a first reference voltage to the positive phase input terminal through the reference voltage circuit, an 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 end of the first operational amplifier is electrically connected with 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 with the first end of the second switching tube;
the negative feedback unit is used for adjusting the current value of the bus interface to be within a preset interval.
5. The bus power supply circuit according to claim 4, wherein the negative feedback unit comprises a sixth resistor, a second regulator tube and a first capacitor, one end of the sixth resistor is electrically connected to a positive 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 an anode of the second regulator tube, respectively, and the other end of the first capacitor and a cathode of the second regulator tube are electrically connected to an output terminal of the first operational amplifier.
6. The bus power supply circuit according to claim 1, wherein the reference voltage circuit includes a seventh resistor, a voltage regulator 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 regulator 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 regulator device, the first voltage dividing unit, and the other end of the second voltage dividing unit are all grounded;
the first voltage division unit is also electrically connected with the current limiting circuit and provides a first reference voltage for the current limiting circuit; the second voltage division unit is also electrically connected with the voltage comparison circuit and provides a second reference voltage for the voltage comparison circuit.
7. The bus power supply circuit of claim 6, wherein the first voltage dividing unit comprises 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 regulator, 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.
8. The bus power supply circuit of claim 6, wherein the second voltage divider comprises a third voltage divider resistor, a fourth voltage divider resistor and a third capacitor, wherein one end of the third voltage divider resistor is electrically connected to another end of a seventh resistor, the other end of the third voltage divider resistor is electrically connected to one end of the fourth voltage divider resistor, one end of the third capacitor and the voltage comparator, and the other end of the fourth voltage divider resistor and the other end of the third capacitor are both grounded.
9. The bus power supply circuit according to claim 1, wherein 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 configured to obtain a reference voltage from the current limiting circuit, the other end of the eighth resistor is electrically connected to an inverting input terminal of the second op amp and one end of the fourth capacitor, respectively, the other end of the fourth capacitor is grounded, a non-inverting input terminal of the second op amp is electrically connected to the voltage comparison circuit so as to provide a second reference voltage for the second op amp through the voltage comparison circuit, and an output terminal of the second op amp is electrically connected to the voltage conversion circuit.
10. A bus powering system, characterized in that it comprises a plurality of slave devices and a bus powering circuit according to any one of claims 1 to 9, said plurality of slave devices being electrically connected to a bus interface of said bus powering circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022485708.4U CN213521351U (en) | 2020-10-31 | 2020-10-31 | Bus power supply circuit and system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022485708.4U CN213521351U (en) | 2020-10-31 | 2020-10-31 | Bus power supply circuit and system |
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| Publication Number | Publication Date |
|---|---|
| CN213521351U true CN213521351U (en) | 2021-06-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022485708.4U Active CN213521351U (en) | 2020-10-31 | 2020-10-31 | Bus power supply circuit and system |
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| CN (1) | CN213521351U (en) |
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2020
- 2020-10-31 CN CN202022485708.4U patent/CN213521351U/en active Active
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