Detection unit, driving circuit, semiconductor light source board, and luminaire for a luminaire

Abstract

This invention provides a detection unit for a lighting fixture, the lighting fixture comprising: a power input (10) for connecting to an external power supply (P), wherein the external power supply (P) has a second capacitor (Cg2) between it and a protective ground (PE); an external grounding interface (12) for connecting to the protective ground (PE) via an external grounding wire (W); an internal protective ground (14) connected to the external grounding interface (12); and an internal circuit forming a first capacitor (Cg1, Cy, Cp) with the internal protective ground; characterized in that the detection unit comprises: a detection circuit (50) for using the first capacitor (Cg1, Cy, Cp) to detect whether the internal protective ground (14) is connected to the protective ground (PE) via the external grounding interface (12) and the external grounding wire (W). This invention also provides a lighting fixture including the detection unit.

Description

Technical Field

[0001] This application belongs to the field of lighting technology, and particularly relates to luminaires with semiconductor light-emitting devices, specifically a detection unit, driving circuit, semiconductor light source board, and luminaire including the detection unit. Background Technology

[0002] For Class 1 luminaires, proper grounding is crucial. Insufficient grounding can pose a danger to installation and maintenance personnel, potentially requiring the installation of an additional residual current device (RCD). Lack of reliable grounding can also prevent lightning strikes from being conducted to the protective ground, leading to luminaire damage. Furthermore, external grounding lines can become unreliable over time or due to environmental changes, creating safety hazards. Utility Model Content

[0003] The purpose of this application is to detect whether the connection between the internal ground and the external ground is intact by using the parasitic capacitance inside the lamp. The underlying principle is to detect whether the capacitance between the external power supply and the protective ground is connected through the external ground and the internal ground capacitance of the lamp by using the grounding capacitance inside the lamp. If so, the external ground is good; if not, the external ground is faulty.

[0004] According to a first basic aspect of the present invention, a detection unit for a lamp is provided, the lamp having: A power input is provided for connection to an external power source, which has a second capacitor between the external power source and the protective ground. An external grounding interface is used to connect to the protective ground via an external grounding wire; The internal protective ground is connected to the external grounding interface; An internal circuit forms a first capacitor with the internal protective ground. The detection unit includes: A detection circuit is used to detect whether the internal protective ground is connected to the protective ground through the external grounding interface and the external grounding wire using the first capacitor.

[0005] This embodiment of the invention utilizes the existing first capacitor inside the lamp to detect whether the external grounding is good. It is low in cost, requires few components, and is simple and reliable to implement.

[0006] More specifically, the detection unit is used to use the first capacitor to detect whether the second capacitor between the external power supply and the protective ground is in the circuit, and to detect whether the internal protective ground is connected to the protective ground through the external grounding interface and the external grounding wire.

[0007] In one embodiment, the detection circuit includes Energy storage capacitor; A charging circuit is used to charge the energy storage capacitor to a certain voltage. A discharge circuit is used to discharge the energy storage capacitor through the internal protective ground and the external grounding interface; A voltage detection circuit is used to detect the voltage charged onto the first capacitor by the discharge circuit; The judgment circuit is used to determine whether the internal protective ground is connected to the protective ground through the external grounding interface and the external grounding wire based on whether the voltage charged on the first capacitor by the discharge circuit or the remaining voltage on the energy storage capacitor is less than a certain threshold.

[0008] Whether the second capacitor is connected to the first capacitor via an external grounding wire directly affects the total equivalent capacitance value of the system. Therefore, this embodiment uses the charging and discharging process and the voltage across the first capacitor or energy storage capacitor to determine the presence of the second capacitor, which can indirectly detect whether the external grounding is intact, and the detection accuracy is high.

[0009] In one embodiment, when the internal protective ground is connected to the protective ground through the external grounding interface and the external grounding wire, the second capacitor is also charged by the discharge circuit, such that the voltage at which the first capacitor is charged by the discharge circuit or the remaining voltage on the energy storage capacitor is less than the voltage at which the first capacitor is charged by the discharge circuit or the remaining voltage on the energy storage capacitor when the internal protective ground is not connected to the protective ground through the external grounding interface and the external grounding wire and therefore the second capacitor is not charged by the discharge circuit.

[0010] This implementation provides specific logic for determining whether a device is grounded based on voltage.

[0011] In an alternative implementation, the detection circuit includes: An RC charging circuit is used to charge the first capacitor using a given voltage or current; A timing circuit used for timing; A voltage detection circuit is used to measure the voltage across the first capacitor; The judgment circuit is used to determine whether the internal protective ground is connected to the protective ground through the external grounding interface and the external grounding wire, based on the charging time during which the first capacitor is charged to a certain voltage, or the voltage at which the first capacitor is charged after a certain charging time.

[0012] This alternative implementation uses the RC charging characteristics under timing conditions to analyze the charging characteristics of the system to the first capacitor, and indirectly obtains information on whether a second capacitor exists in the system, thereby determining whether the internal protective ground is connected to the protective ground through the external grounding interface and the external grounding wire.

[0013] In one specific implementation, when the internal protective ground is connected to the protective ground through the external grounding interface and the external grounding wire, the second capacitor is also charged by the RC charging circuit, causing... The charging time for the first capacitor to reach the specified voltage is greater than the time it takes for the first capacitor to reach the specified voltage when the internal protective ground is not connected to the protective ground through the external grounding interface and the external grounding wire, and therefore the second capacitor is not charged by the RC charging circuit. The voltage that the first capacitor reaches after the certain charging time is greater than the voltage that the first capacitor reaches after the certain charging time when the internal protective ground is not connected to the protective ground through the external grounding interface and the external grounding wire, and therefore the second capacitor is not charged by the RC charging circuit.

[0014] This specific implementation provides the logic for determining whether a device is grounded based on RC charging characteristics.

[0015] In one embodiment, the detection circuit further includes a pre-discharge circuit for short-circuiting the first capacitor before the discharge circuit operates.

[0016] This implementation method discharges the first capacitor before detection, which ensures the consistency and accuracy of the detection.

[0017] In one embodiment, the internal circuitry includes at least one of the following: A driving circuit, wherein a first parasitic capacitance is formed between the driving circuit and the internal protective ground as the first capacitor; A semiconductor light source board, wherein a second parasitic capacitance is formed between the semiconductor light source board and the internal protective ground as the first capacitance; A Y capacitor, connected to the internal protective ground, serves as the first capacitor, wherein the Y capacitor is formed by a discrete capacitor or by a copper plating on a circuit board. The detection circuit is used to detect whether the internal protective ground is connected to the protective ground through the external grounding interface and the external grounding wire using the first parasitic capacitor, the second parasitic capacitor and / or the Y capacitor.

[0018] This implementation provides three ways to realize the first capacitor. If an existing parasitic capacitor is used, no additional components are needed, making implementation relatively simple. If a Y capacitor is used, its capacitance value is relatively fixed, resulting in good detection accuracy.

[0019] In one specific embodiment, the detection unit is included in the driving circuit.

[0020] In another specific embodiment, the detection unit is included in the semiconductor light source plate.

[0021] Accordingly, a second aspect of this utility model provides a driving circuit, including the aforementioned detection unit.

[0022] Accordingly, a third aspect of this utility model provides a semiconductor light source board, including the aforementioned detection unit.

[0023] These two aspects provide ways to implement different locations where the detection unit can be placed.

[0024] A fourth aspect of this utility model provides a lamp fixture having: A power input is provided for connection to an external power source, which has a second capacitor between the external power source and the protective ground. An external grounding interface is used to connect to the protective ground via an external grounding wire; Internal protective ground, connected to the external grounding interface; and An internal circuit forms a first capacitor with the internal protective ground. The lighting fixtures also include: Based on the detection unit of the first basic aspect mentioned above, or According to the driving circuit of the second aspect mentioned above, or The semiconductor light source board is based on the third aspect mentioned above. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 It is the equivalent circuit diagram of the existing luminaire and its connection to the protective ground; Figure 2 This is a schematic diagram showing the parasitic capacitance formed between the LED light board and the heat sink and housing of the lamp; Figure 3This is a schematic diagram showing the equivalent connection relationship between parasitic capacitances Cp and Cg1 and capacitance Cg2 between the power supply and protective ground under good grounding conditions. Figure 4 This is a schematic diagram showing the equivalent connection relationship of parasitic capacitances Cp and Cg1 when the capacitance Cg2 between the power supply and the protective ground is not in the circuit due to poor grounding. Figure 5A This is a schematic diagram of the further specific construction of the detection circuit 50 according to one embodiment of the present invention and the first stage of its operation. Figure 5B This is a schematic diagram of the second stage of the further specific construction and operation of the detection circuit 50 according to one embodiment of the present invention. Figure 6 This is a schematic diagram of a lamp that includes the detection circuit 50 according to the above embodiments of the present invention; Figure 7 This is a schematic diagram of a lamp that includes a detection circuit 50 according to another embodiment of the present invention; Figure 8 This is an implementation method that uses copper plating to form a Y capacitor; and Figure 9 This is a further specific construction of the detection circuit 50 according to another embodiment of the present invention. Detailed Implementation

[0027] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0028] Figure 1 An equivalent circuit diagram of an existing luminaire and its connection to protective ground is shown. The luminaire has: Power input 10 is used to connect to an external power supply P, which has a second capacitor Cg2 between the external power supply and the protective ground PE. External grounding interface 12 is used to connect to the protective ground PE via external grounding wire W; Internal protective ground 14 is connected to the external grounding interface 12; The internal circuitry forms a first capacitor Cg1, Cy, Cp with the internal protective ground.

[0029] The internal protective ground 14 is generally quite reliable. However, the external connection line W, the external grounding port 12, or the connection between the external connection line and the protective ground PE may be unreliable, causing the luminaire to fail to ground.

[0030] This utility model provides a detection unit for lighting fixtures, which includes: The detection circuit 50 is used to detect whether the internal protective ground 14 is connected to the protective ground PE through the external grounding interface 12 and the external grounding wire W using the first capacitance Cg1, Cy, Cp formed between the internal circuit of the lamp and the internal protective ground, that is, whether the grounding of the lamp is intact.

[0031] Generally, the internal protective layer of a luminaire can be considered as its metal casing.

[0032] There are many examples of internal circuits in lighting fixtures. In one example, the internal circuit of a lighting fixture is an LED board, where a parasitic capacitance Cp is typically generated between the copper foil traces on the LED board and the fixture's housing. The value of this parasitic capacitance is determined by the area of ​​the copper traces, the thickness of the insulation layer on the LED board (MCPCB, CEM-3, etc.), and the dielectric constant. Generally, parasitic capacitance ranges from hundreds of picofarads (pF) to tens of nanofarads (nF). Furthermore, if the LED board and housing are placed close together or have closely matched shapes, the parasitic capacitance Cp will become relatively large. Figure 2 A schematic diagram shows the parasitic capacitance Cp formed between the LED board and the heat sink and housing, which serve as internal protective ground.

[0033] The internal circuitry of a lamp can also be a driver circuit, for example... Figure 1 The rectifier bridge and boost circuit in the lamp. Parasitic capacitance Cg1 may also form between the driver circuit and the lamp housing. For example, the copper foil traces of the driver circuit, the metal heat sink of the switching element or inductor element, etc., may all form parasitic capacitance Cg1 between them and the lamp housing.

[0034] Sometimes the drive circuit is also connected to the casing through a specially formed capacitor, which is called a Y capacitor (CY), and will be described in detail later.

[0035] External power sources, especially their neutral output and protective ground, often have parasitic capacitance, as shown in Cg2 in the figure. Examples of external power sources include transformers and generators. The external power source and the lighting fixture are connected via the live wire (L) and the neutral wire (N).

[0036] When the external grounding is intact, from the perspective of the positive terminal and ground inside the lamp, Cg1 and Cg2 can be considered to be connected in parallel, and then connected in series with Cp. Figure 3 The equivalent circuit diagram for this situation is shown. However, if the external ground is disconnected, from the perspective of the positive terminal inside the lamp, it can be equivalently considered that only Cg1 and Cp are connected in series. Figure 4The equivalent circuit diagram for this situation is shown. The equivalent capacitance values ​​are different in these two cases. Therefore, this embodiment of the present invention proposes measuring this capacitance value to detect whether Cg2 is connected to the lamp, and thereby determine whether the external grounding is intact or disconnected.

[0037] There are many ways to measure capacitance. This utility model will describe one method in detail below.

[0038] Detection circuit 50 includes Energy storage capacitor Cr; The charging circuit VDD, S3 is used to charge the energy storage capacitor Cr to a certain voltage. The discharge circuit S1 is used to discharge the energy storage capacitor Cr through the internal protective ground and the external grounding interface. If the external grounding wire is good, it will discharge to Cg2. A voltage detection circuit is used to detect the voltage across the first capacitor that has been charged by the discharge circuit, and The judgment circuit is used to determine whether the internal protective ground 14 is connected to the protective ground through the external grounding interface 12 and the external grounding line W based on whether the voltage charged on the first capacitor by the discharge circuit or the remaining voltage on the energy storage capacitor Cr is less than a certain threshold.

[0039] Preferably, to ensure accuracy and consistency in each test, the detection circuit 50 further includes a pre-discharge circuit S2, used to short-circuit the first capacitor to discharge it before the discharge circuit S1 operates. If the external grounding wire is good, capacitor Cg2 will also be discharged.

[0040] Figure 5A The following diagram illustrates the further detailed construction of the detection circuit 50 and the first stage of its operation. The charging circuit includes a power supply VDD and a switch S3 connected in series with the energy storage capacitor Cr. The pre-discharge circuit includes a switch S2 connected in parallel across the series-connected capacitors Cp and Cg1. The discharging circuit includes a switch S1 connected to the energy storage capacitor Cr and the series-connected capacitors Cp and Cg1. The switches can be implemented using MOSFETs or bipolar junction transistors (BJTs), and their switching can be controlled by the MCU. The detection circuit can be constructed using the ADC within the MCU, and the judgment circuit can be implemented using the internal logic of the MCU.

[0041] In the first stage of operation, switches S2 and S3 are turned on, and S1 is turned off. The energy storage capacitor Cr is charged to a certain voltage by Vdd. Parasitic capacitances Cp, Cg1, and Cg2, which may be connected to the circuit through an external ground wire, are discharged. After stabilization, the voltage of the energy storage capacitor Cr is the same as the voltage of Vdd, and its charge Qcr = Vcr * Cr.

[0042] Figure 5BThe second stage of the detection circuit 50's operation is shown in further detail. Switches S2 and S3 are open, and switch S1 is closed. The charge on the energy storage capacitor Cr is discharged to the parasitic capacitor Cp, capacitor Cg1, and possibly capacitor Cg2 in the circuit. After reaching a steady state, the ADC can measure the voltage charged on the first capacitor by the discharge circuit or the remaining voltage on the energy storage capacitor Cr.

[0043] With proper grounding, if Cg2 is present in the circuit, the total equivalent capacitance is the sum of the capacitance obtained by connecting Cg2 and Cg1 in parallel and then in series with the parasitic capacitance Cp, plus the capacitance of Cr. Therefore, the voltage measured by the ADC should be... V1=Qcr / (Cr+(Cp*Cg1 / / Cg2 / (Cp+Cg1 / / Cg2))).

[0044] In the event of a fault in any of the external grounding terminals, external grounding wires, or external connection lines to the protective ground, grounding fails, and Cg2 is not present in the circuit. Therefore, the total equivalent capacitance of the capacitor is the capacitance obtained by connecting Cg1 and the parasitic capacitance Cp in series, plus the capacitance of Cr. The voltage measured by the ADC should then be... V2= Qcr / (Cr+(Cp*Cg1 / (Cp+Cg1))).

[0045] The MCU can measure and record the V1 voltage upon the system's initial power-on (provided the grounding is intact). Subsequent periodic measurements are then performed. If the difference between the measured voltage and the V1 voltage exceeds a preset threshold, or approaches V2, the MCU will determine a grounding fault. The MCU should then disable the LED driver and issue an alarm.

[0046] Figure 6 This is a schematic diagram of a lamp that includes the detection circuit 50 according to the above embodiments of the present invention. The detection circuit 50 can be attached to the LED board or integrated into the driver circuit.

[0047] The above implementation method uses the parasitic capacitance Cg1 between the drive circuit and the internal protective ground, and the parasitic capacitance Cp between the lamp board and the internal protective ground for detection. The following will describe an implementation method using discrete components or Y capacitors formed by copper plating for detection.

[0048] A capacitor CY can be directly connected to the driver to the lamp housing or ground wire, wirelessly utilizing the parasitic capacitance on the LED board. For example... Figure 9 As shown, the driver's detection circuit is connected to the ground wire (lamp housing) via a CY capacitor. Figure 9 The MCU in the system can control the LED driver's on / off state and the alarm indicator. If an abnormality is detected, it can be indicated by the alarm indicator or by turning off the LED.

[0049] The CY capacitor can be a physical capacitor (such as a Y2 or Y1 capacitor) or a parasitic capacitance formed by copper pours on a PCB. A feasible method for addressing the parasitic capacitance generated by copper pours on a PCB is as follows: Figure 8 As shown, the copper plating on the front side connects to the detection circuit, while the copper plating on the back side connects to the casing via a conductor (wire is sufficient). The capacitance value can be adjusted by the size of the copper plating.

[0050] Using this method, the detection circuit is... Figure 5A and Figure 5B Similar to Cg2, except that Cp capacitor is added, which is the parasitic capacitance between the lamp board and the ground wire. The original Cp is replaced by CY, such as... Figure 9 As shown. Its working principle is as follows: In the first stage, switches S2 and S3 are on, and switch S1 is off. Switch S2 discharges capacitors CY, Cg1, and Cg2, while switch S3 charges capacitor Cr. At this time: Vdd=Vcr, Qcr=Vcr*Cr. Where Vcr is the voltage across capacitor Cr, Qcr is the charge on capacitor Cr, and Cr is the capacitance of capacitor Cr.

[0051] In the second stage, switch S1 is turned on, while switches S2 and S3 are turned off. With a good external ground, the charge on capacitor Cr transfers to CY, Cg1, and Cg2. The voltage Vcr will decrease due to this charge transfer. At this time: V1=Vcr=Qcr / (CY+(CY*Cg1 / / Cg2 / (CY+Cg1 / / Cg2))); In the event of an external grounding fault, only Cg1 and CY will be connected in series in the circuit. In this case, the voltage Vcr will be higher than when Cg2 is present. At this time: V2=Vcr= Qcr / (Cr+(Cp*Cg1 / (Cp+Cg1))); The controller compares the detected voltage of capacitor Cr with the previously detected voltage of capacitor Cr (V2-V1). If the voltage difference exceeds the threshold, it indicates that the external grounding wire has failed. At this time, the controller can issue an abnormal warning by switching on / off lights, flashing lights, or alarm indicator lights.

[0052] Besides detecting capacitance through charging and discharging voltage, it can also be detected using RC charging. For example, given a charging voltage (charging the capacitor logarithmically) or a charging current (charging the capacitor linearly), the charging time required for the capacitor in the system to reach a certain voltage is measured, indirectly obtaining information about the capacitance value. Alternatively, given a charging voltage or charging current and a fixed charging time, the capacitance value is indirectly obtained by measuring the voltage reached after that charging time.

[0053] Specifically, the detection capacitor includes An RC charging circuit is used to charge the first capacitors Cg1, Cy, and Cp using a given voltage or current. A timing circuit used for timing; A voltage detection circuit is used to measure the voltage across the first capacitors Cg1, Cy, and Cp. The judgment circuit is used to determine whether the internal protective ground 14 is connected to the protective ground PE through the external grounding interface 12 and the external grounding line W based on the charging time when the first capacitors Cg1, Cy, and Cp are charged to a certain voltage, or the voltage when the first capacitors Cg1, Cy, and Cp are charged to a certain voltage after a certain charging time.

[0054] A specific judgment logic is: when the internal protective ground 14 is connected to the protective ground PE through the external ground interface 12 and the external ground wire W, the second capacitor Cg2 is also charged by the RC charging circuit, making... The charging time for the first capacitors Cg1, Cy, and Cp to reach the specified voltage is greater than the time it takes for the first capacitors Cg1, Cy, and Cp to reach the specified voltage when the internal protective ground 14 is not connected to the protective ground PE through the external ground interface 12 and the external ground wire W, and therefore the second capacitor Cg2 is not charged by the RC charging circuit. The voltage that the first capacitors Cg1, Cy, and Cp reach after the certain charging time is greater than the voltage that the first capacitors Cg1, Cy, and Cp reach after the certain charging time when the internal protective ground 14 is not connected to the protective ground PE through the external ground interface 12 and the external ground line W, and therefore the second capacitor Cg2 is not charged by the RC charging circuit.

[0055] It is understood that other detection methods may also exist to detect the presence of the second capacitor Cg2 through the first capacitor Cg1, thereby detecting whether the internal protective ground 14 is connected to the protective ground PE through the external grounding interface 12 and the external grounding wire W. Therefore, this utility model is not limited to the above two specific embodiments.

[0056] It should be noted that when a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to that other component.

[0057] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0058] Finally, it should be noted that the terms “comprising,” “including,” or any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device, without excluding the presence of other identical elements in the process, method, article, or terminal device that includes said elements.

[0059] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A detection unit for a lamp fixture, the lamp fixture having: A power input (10) is provided for connection to an external power source (P), which has a second capacitor (Cg2) between itself and protective ground (PE). An external grounding interface (12) is provided for connection to the protective earth (PE) via an external grounding wire (W); Internal protective ground (14) is connected to the external grounding interface (12); The internal circuitry forms a first capacitor (Cg1, Cy, Cp) with the internal protective ground. Its features are, The detection unit includes: A detection circuit (50) is used to detect whether the internal protective ground (14) is connected to the protective ground (PE) through the external grounding interface (12) and the external grounding wire (W) using the first capacitor (Cg1, Cy, Cp).

2. The detection unit for lamps according to claim 1, characterized in that, The detection circuit (50) is used to use the first capacitor (Cg1, Cy, Cp) to detect whether the second capacitor (Cg2) between the external power supply (P) and the protective ground (PE) is in the circuit, and to detect whether the internal protective ground (14) is connected to the protective ground (PE) through the external grounding interface (12) and the external grounding wire (W).

3. The detection unit for lamps according to claim 2, characterized in that, The detection circuit (50) includes: Energy storage capacitor (Cr); The charging circuit (VDD, S3) is used to charge the energy storage capacitor (Cr) to a certain voltage; The discharge circuit (S1) is used to discharge the energy storage capacitor (Cr) through the internal protective ground and external grounding interface (12); A voltage detection circuit is used to detect the voltage charged on the first capacitor (Cg1, Cy, Cp) by the discharge circuit (S1); The judgment circuit is used to determine whether the internal protective ground (14) is connected to the protective ground (PE) through the external grounding interface (12) and the external grounding wire (W) based on whether the voltage charged on the first capacitor (Cg1, Cy, Cp) by the discharge circuit (S1) or the remaining voltage on the energy storage capacitor (Cr) is less than a certain threshold.

4. The detection unit for lamps according to claim 3, characterized in that, When the internal protective ground (14) is connected to the protective ground (PE) through the external grounding interface (12) and the external grounding line (W), the second capacitor (Cg2) is also charged by the discharge circuit (S1), and the voltage of the first capacitor (Cg1, Cy, Cp) charged by the discharge circuit (S1) or the residual voltage on the energy storage capacitor (Cr) is less than the voltage of the first capacitor (Cg1, Cy, Cp) charged by the discharge circuit (S1) or the residual voltage on the energy storage capacitor (Cr) when the internal protective ground (14) is not connected to the protective ground (PE) through the external grounding interface (12) and the external grounding line (W) and therefore the second capacitor (Cg2) is not charged by the discharge circuit (S1).

5. The detection unit for lamps according to claim 2, characterized in that, The detection circuit (50) includes: An RC charging circuit is used to charge the first capacitor (Cg1, Cy, Cp) using a given voltage or current. A timing circuit used for timing; A voltage detection circuit is used to measure the voltage across the first capacitor (Cg1, Cy, Cp); The judgment circuit is used to determine whether the internal protective ground (14) is connected to the protective ground (PE) through the external ground interface (12) and the external ground wire (W) based on the charging time when the first capacitor (Cg1, Cy, Cp) is charged to a certain voltage, or the voltage when the first capacitor (Cg1, Cy, Cp) is charged to a certain voltage after a certain charging time.

6. The detection unit for lamps according to claim 5, characterized in that, When the internal protective ground (14) is connected to the protective ground (PE) through the external ground interface (12) and the external ground wire (W), the second capacitor (Cg2) is also charged by the RC charging circuit, so that... The charging time for the first capacitor (Cg1, Cy, Cp) to be charged to the given voltage is greater than the time it takes for the first capacitor (Cg1, Cy, Cp) to be charged to the given voltage when the internal protective ground (14) is not connected to the protective ground (PE) through the external grounding interface (12) and the external grounding wire (W), and therefore the second capacitor (Cg2) is not charged by the RC charging circuit. The voltage at which the first capacitor (Cg1, Cy, Cp) is charged after the certain charging time is greater than the voltage at which the first capacitor (Cg1, Cy, Cp) is charged after the certain charging time when the internal protective ground (14) is not connected to the protective ground (PE) through the external ground interface (12) and the external ground line (W), and therefore the second capacitor (Cg2) is not charged by the RC charging circuit.

7. The detection unit for a lamp according to any one of claims 1 to 6, characterized in that, The detection circuit (50) further includes: The pre-discharge circuit (S2) is used to short-circuit the first capacitor (Cg1, Cy, Cp) before the discharge circuit (S1) is activated.

8. The detection unit for a lamp according to any one of claims 1 to 6, characterized in that, The internal circuitry includes at least one of the following: A driving circuit, wherein a first parasitic capacitance (Cg1) is formed between the driving circuit and the internal protective ground as the first capacitor; A semiconductor light source board, wherein a second parasitic capacitance (Cp) is formed between the semiconductor light source board and the internal protective ground as the first capacitance; A Y capacitor (Cy) is connected to the internal protective ground as the first capacitor, wherein the Y capacitor is formed by a discrete capacitor or by a copper plating on a circuit board. The detection circuit (50) is used to detect whether the internal protective ground (14) is connected to the protective ground (PE) through the external grounding interface (12) and the external grounding wire (W) using the first parasitic capacitor (Cg1), the second parasitic capacitor (Cp) and / or the Y capacitor (Cy).

9. The detection unit for lamps according to claim 8, characterized in that, The detection unit is included in the driving circuit.

10. The detection unit for a lamp according to claim 8, characterized in that, The detection unit is included in the semiconductor light source board.

11. A driving circuit, characterized in that, Includes the detection unit for lamps as described in claim 9.

12. A semiconductor light source board, characterized in that, Includes the detection unit for lamps as described in claim 10.

13. A lamp fixture, comprising: A power input (10) is provided for connection to an external power source (P), which has a second capacitor (Cg2) between itself and protective ground (PE). An external grounding interface (12) is provided for connection to the protective earth (PE) via an external grounding wire (W); Internal protective ground (14) is connected to the external grounding interface (12); as well as The internal circuitry forms a first capacitor (Cg1, Cy, Cp) with the internal protective ground. Its characteristic is that it further includes: The detection unit for a luminaire according to any one of claims 1 to 10, or The driving circuit according to claim 11, or The semiconductor light source board according to claim 12.

Images