CN117750580A - Overvoltage protection circuit, dimming power supply and lamp - Google Patents

Abstract

The present disclosure relates to an overvoltage protection circuit, a dimming power supply and a lamp, the overvoltage protection circuit includes: a voltage follower configured to: the output end is respectively connected with the reverse input end and the electric signal regulating circuit and is used for providing a regulating signal for the electric signal regulating circuit; a clamp protection circuit configured to: the first end is connected with the positive input end of the voltage follower, and the second end is grounded and is used for limiting the amplitude of a voltage signal provided for the voltage follower to be smaller than or equal to a preset threshold value; a current limiting circuit configured to: the input end is used for receiving an external power supply signal, and the output end is connected with the first end of the clamping protection circuit and the positive input end of the voltage follower; an internal power supply circuit configured to: the input end is connected with an internal power supply, the output end is connected with the input end of the current limiting circuit, so that the voltage follower generates an adjusting signal with the amplitude being more than 0 and less than or equal to a preset threshold value, the dimming power supply is prevented from being damaged when the mains voltage is connected by mistake, and the protection cost of the dimming power supply is reduced.

Description

Overvoltage protection circuit, dimming power supply and lamp

Technical Field

The disclosure relates to the technical field of electronic circuits, and in particular relates to an overvoltage protection circuit, a dimming power supply and a lamp.

Background

The LED light source has different light emitting principle and power, and different current and voltage parameters, so that the LED light source has different internal wiring structure and circuit distribution, and the light source of different manufacturers has different dimming drive control requirements.

Common LED lighting dimming control schemes include silicon controlled dimming, pulse Width Modulation (PWM) dimming, 0-10V dimming, digital Addressable Lighting Interface (DALI) dimming, or wireless dimming (bluetooth, wiFi, radio frequency), among others. The 0-10V dimming system is also called a fluorescent dimming system or a five-wire dimming system, and when the 0-10V dimming power supply end is connected into the mains voltage by mistake, the power supply can be damaged, and the circuit is damaged.

Disclosure of Invention

Accordingly, it is necessary to provide an overvoltage protection circuit, a dimming power supply and a lamp for protecting a circuit when the dimming power supply is erroneously connected to an ac high voltage, so as to prevent the dimming power supply from being damaged when the dimming power supply is erroneously connected to a mains voltage, and reduce the protection cost of the dimming power supply.

To achieve the above and other objects, according to various embodiments of the present disclosure, a first aspect of the present disclosure provides an overvoltage protection circuit including a voltage follower, a clamp protection circuit, a current limiting circuit, and an internal power supply circuit, the voltage follower configured to: the output end is respectively connected with the reverse input end and the electric signal regulating circuit and is used for providing a regulating signal for the electric signal regulating circuit; the clamp protection circuit is configured to: the first end is connected with the positive input end of the voltage follower, and the second end is grounded and is used for limiting the amplitude of a voltage signal provided for the voltage follower to be smaller than or equal to a preset threshold value; the current limiting circuit is configured to: the input end is used for receiving an external power supply signal, and the output end is connected with the first end of the clamping protection circuit and the positive input end of the voltage follower; the internal power supply circuit is configured to: the input end is connected with an internal power supply, and the output end is connected with the input end of the current limiting circuit, so that the voltage follower generates an adjusting signal with the amplitude being more than 0 and less than or equal to a preset threshold value.

The overvoltage protection circuit in the embodiment comprises a voltage follower, a clamp protection circuit, a current limiting circuit and an internal power supply circuit, wherein an output end of the voltage follower is respectively connected with a reverse input end and an electric signal regulating circuit to provide a regulating signal for the electric signal regulating circuit; the first end of the clamping protection circuit is connected with the positive input end of the voltage follower, the second end of the clamping protection circuit is grounded, and the amplitude of a voltage signal provided for the voltage follower is limited to be smaller than or equal to a preset threshold value; receiving an external power supply signal through an input end of a current limiting circuit, and connecting an output end with a first end of a clamping protection circuit and a positive input end of a voltage follower; the input end of the internal power supply circuit is connected with an internal power supply, and the output end of the internal power supply circuit is connected with the input end of the current limiting circuit, so that the voltage follower generates an adjusting signal with the amplitude being more than 0 and less than or equal to a preset threshold value; when the power supply signal of the external power supply is out of the preset threshold range, the damage to the electric signal regulating circuit of the later stage is avoided. At present, when the 0-10V dimming power supply is connected to the mains voltage by mistake, the power supply is damaged, even the whole dimming circuit is damaged, or the dimming power supply is protected by adding other protection devices, but the occupation area of the protection devices in the circuit is large, and the input cost of the whole circuit is increased. According to the overvoltage protection circuit in the embodiment of the disclosure, through the arrangement of the voltage follower, the clamp protection circuit, the current limiting circuit and the internal power supply circuit, a sufficient and stable adjusting signal can be provided for a subsequent electric signal adjusting circuit, the circuit can be protected when a dimming power supply is in error connection with alternating-current high voltage, the dimming power supply is prevented from being damaged when the dimming power supply is in error connection with mains voltage, the whole circuit is small in size, and the protection cost of the dimming power supply is reduced.

In some embodiments, the overvoltage protection circuit further includes an input filter circuit configured to: the first end is connected with the positive input end of the voltage follower, and the second end is grounded, so that the electric signal input to the voltage follower can be limited.

In some embodiments, the overvoltage protection circuit further includes an output filter circuit configured to: the first end is connected with the output end of the voltage follower, the second end is connected with the input end of the electric signal regulating circuit, and the third end is grounded, so that electric signals input into the subsequent electric signal regulating circuit can be limited, and the subsequent circuit is protected.

In some embodiments, the output filter circuit includes a filter resistor and a filter capacitor, the filter resistor configured to: one end is connected with the output end of the voltage follower, and the other end is connected with the input end of the electric signal regulating circuit; the filter capacitance is configured to: one end is connected with the input end of the electric signal regulating circuit, and the other end is grounded.

In some embodiments, the clamp protection circuit includes a transient voltage suppression diode configured to: the positive input end of the voltage follower and the output end of the current limiting circuit are both connected with the cathode, the anode is grounded and used for limiting the amplitude of a voltage signal provided for the voltage follower to be smaller than or equal to a preset threshold value, and the transient voltage suppression diode can rapidly reduce the impedance at the two ends of the anode and the cathode when the voltage of the mains supply is accessed, and simultaneously absorb the voltage signal of the mains supply, fix the electric signals at the two ends of the anode and the cathode on a preset value and avoid the damage of subsequent circuit elements.

In some embodiments, the internal power supply circuit includes a diode and a current limiting branch, the diode configured to: the anode is connected with an internal power supply; the current limiting branch is configured to: the first end is connected with the cathode of the diode, the second end is connected with the input end of the current limiting circuit, and the electric signal input to the voltage follower can be limited through the current limiting branch circuit, so that the damage to circuit elements in a subsequent circuit is avoided.

A second aspect of the present disclosure provides a dimming power supply comprising a dimming circuit, a voltage follower, a clamp protection circuit, a current limiting circuit, and an internal power supply circuit; the dimming circuit is used for adjusting at least one electric signal of brightness, temperature, color, frequency and sound of the rear-stage lamp; the voltage follower is configured to: the output end is respectively connected with the reverse input end and the dimming circuit and is used for providing a dimming signal for the dimming circuit; the dimming signal is used for indicating the dimming circuit to adjust at least one electric signal of the rear-stage lamp; the clamp protection circuit is configured to: the first end is connected with the positive input end of the voltage follower, and the second end is grounded and is used for limiting the amplitude of a voltage signal provided for the voltage follower to be smaller than or equal to a preset threshold value; the current limiting circuit is configured to: the input end is used for receiving an external power supply signal, and the output end is connected with the first end of the clamping protection circuit and the positive input end of the voltage follower; the internal power supply circuit is configured to: the input end is connected with an internal power supply, and the output end is connected with the input end of the current limiting circuit, so that the voltage follower generates a dimming signal with the amplitude being more than 0 and less than or equal to a preset threshold value.

The dimming circuit in the above embodiment includes a dimming circuit, a voltage follower, a clamp protection circuit, a current limiting circuit, and an internal power supply circuit; at least one electric signal of brightness, temperature, color, frequency and sound of the rear-stage lamp is regulated by the dimming circuit; the output end of the voltage follower is respectively connected with the reverse input end and the dimming circuit, so as to provide a dimming signal for the dimming circuit; the dimming signal is used for indicating the dimming circuit to adjust at least one electric signal of the rear-stage lamp; the first end of the clamping protection circuit is connected with the positive input end of the voltage follower, the second end of the clamping protection circuit is grounded, and the amplitude of a voltage signal provided for the voltage follower is limited to be smaller than or equal to a preset threshold value; the input end of the current limiting circuit receives an external power supply signal, and the output end of the current limiting circuit is connected with the first end of the clamping protection circuit and the positive input end of the voltage follower; the input end of the internal power supply circuit is connected with the internal power supply, and the output end of the internal power supply circuit is connected with the input end of the current limiting circuit, so that the voltage follower generates a dimming signal with the amplitude being more than 0 and less than or equal to a preset threshold value. At present, when the 0-10V dimming power supply is connected to the mains voltage by mistake, the power supply is damaged, even the whole dimming circuit is damaged, or the dimming power supply is protected by adding other protection devices, but the occupation area of the protection devices in the circuit is large, and the input cost of the dimming power supply is increased. According to the dimming power supply in the embodiment of the disclosure, through the setting of the dimming circuit, the voltage follower, the clamp protection circuit, the current limiting circuit and the internal power supply circuit, the dimming circuit can be provided with enough and stable adjusting signals, the circuit can be protected when the dimming power supply is in wrong connection with alternating-current high voltage, the dimming power supply is prevented from being damaged when the dimming power supply is in wrong connection with mains voltage, the whole circuit is small in size, and the protection cost of the dimming power supply is reduced.

In some embodiments, the clamp protection circuit includes a transient voltage suppression diode configured to: the positive input end of the cathode is connected with the positive input end of the voltage follower and the output end of the current limiting circuit, and the anode is grounded and used for limiting the amplitude of a voltage signal provided to the voltage follower to be smaller than or equal to a preset threshold value.

In some embodiments, the internal power supply circuit includes a diode and a current limiting branch, the diode configured to: the anode is connected with an internal power supply; the current limiting branch is configured to: the first end is connected with the cathode of the diode, and the second end is connected with the input end of the current limiting circuit.

A third aspect of the present disclosure provides a luminaire comprising a dimming power supply according to any one of the embodiments described above.

The lamp in the above embodiment includes the dimming power supply in any one of the above embodiments, and adjusts at least one electrical signal of brightness, temperature, color, frequency and sound of the subsequent lamp by the dimming circuit; the output end of the voltage follower is respectively connected with the reverse input end and the dimming circuit, so as to provide a dimming signal for the dimming circuit; the dimming signal is used for indicating the dimming circuit to adjust at least one electric signal of the rear-stage lamp; the first end of the clamping protection circuit is connected with the positive input end of the voltage follower, the second end of the clamping protection circuit is grounded, and the amplitude of a voltage signal provided for the voltage follower is limited to be smaller than or equal to a preset threshold value; the input end of the current limiting circuit receives an external power supply signal, and the output end of the current limiting circuit is connected with the first end of the clamping protection circuit and the positive input end of the voltage follower; the input end of the internal power supply circuit is connected with the internal power supply, and the output end of the internal power supply circuit is connected with the input end of the current limiting circuit, so that the voltage follower generates a dimming signal with the amplitude being more than 0 and less than or equal to a preset threshold value. The dimming circuit can provide enough and stable adjusting signals for the dimming circuit to control the brightness of the lamp, and the circuit can be protected when the dimming power supply is in error connection with alternating-current high voltage, so that the dimming power supply is prevented from being damaged when the dimming power supply is in error connection with mains supply voltage, the lamp is prevented from being damaged, the whole size of the circuit is small, and the protection cost of the dimming power supply is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the related art, the drawings that are required to be used in the embodiments or the related technical descriptions will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present disclosure, and other drawings may be obtained according to the drawings without inventive effort to those of ordinary skill in the art.

FIG. 1 is a schematic block diagram of an overvoltage protection circuit provided in an embodiment of the disclosure;

FIG. 2 is a schematic block diagram of an overvoltage protection circuit provided in another embodiment of the present disclosure;

FIG. 3 is a schematic block diagram of an overvoltage protection circuit provided in a further embodiment of the present disclosure;

FIG. 4 is a schematic circuit diagram of an overvoltage protection circuit according to an embodiment of the disclosure;

fig. 5 is a schematic block diagram of a dimming power supply according to an embodiment of the present disclosure;

fig. 6 is a schematic block diagram of a dimming power supply according to another embodiment of the present disclosure.

Reference numerals illustrate:

100. an overvoltage protection circuit; 110. a voltage follower; 111. the output end of the voltage follower; 112. a voltage follower inverting input; 113. a voltage follower positive input; 120. a clamp protection circuit; 121. a clamp protection circuit first end; 122. a second end of the clamping protection circuit; 130. a current limiting circuit; 131. the input end of the current limiting circuit; 132. the output end of the current limiting circuit; 140. an internal power supply circuit; 141. an internal power supply circuit input; 142. an internal power supply circuit output; 143. a current limiting branch; 1431. a first end of the current limiting branch; 1432. a current limiting branch second end; 150. an external power source; 160. an input filter circuit; 161. inputting a first end of the filter circuit; 162. inputting a second end of the filter circuit; 170. an output filter circuit; 171. an output filter circuit first end; 172. a second end of the output filter circuit; 173. outputting a third end of the filter circuit; 200. a dimming power supply; 210. a dimming circuit; t, transient voltage suppression diode; t1, transient voltage suppression diode anode; VCC, internal power supply; t2, transient voltage suppression diode cathode; D. a diode; d1, diode anode; d2, diode cathode; r1, a first current limiting resistor; r2, a second current limiting resistor; r3, a third current limiting resistor; r4, a filter resistor; r5, a fifth current limiting resistor; r6, a sixth current limiting resistor; r7, a seventh current limiting resistor; c1, a first capacitor; c2, a filter capacitor; and C3, a second capacitor.

Detailed Description

In order that the disclosure may be understood, a more complete description of the disclosure will be rendered by reference to the appended drawings. Embodiments of the present disclosure are illustrated in the accompanying drawings. This disclosure may, however, be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used in the description of the disclosure herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure.

It will be understood that the terms "first," "second," and the like, as used in this disclosure, may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element. For example, a first resistance may be referred to as a second resistance, and similarly, a second resistance may be referred to as a first resistance, without departing from the scope of the present disclosure. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

Where the terms "comprising," "having," and "including" are used herein, another component may also be added unless explicitly defined as such, e.g., "consisting of … …," etc. Unless mentioned to the contrary, singular terms may include plural and are not to be construed as being one in number.

It is to be understood that in the following embodiments, "connected" is understood to mean "electrically connected", "communicatively connected", etc., if the connected circuits, modules, units, etc., have electrical or data transfer between them.

It is understood that "at least one" means one or more and "a plurality" means two or more. "at least part of an element" means part or all of the element.

As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof. Also, the term "and/or" as used in this specification includes any and all combinations of the associated listed items.

The 0-10V dimming is also called 0-10V signal dimming, and is an analog dimming mode. The dimming power supply is different from a silicon controlled rectifier dimming power supply, namely, two interfaces of 0-10V are added on a 0-10V power supply (+10V and-10V), and the output current of the power supply is controlled by changing the voltage of 0-10V so as to achieve dimming. The lamp is brightest at 10V and is turned off at 0V. The light-adjusting device has the functions of a switch at 0-10V, and is simple in light-adjusting application, high in precision, good in compatibility and high in cost performance. However, when the 0-10V dimming power supply terminal is erroneously connected to the mains voltage, for example, the ac voltage is 90V-305V, the power supply may be damaged, resulting in circuit damage.

Based on this, referring to fig. 1, in an embodiment of the disclosure, an overvoltage protection circuit 100 is provided, the overvoltage protection circuit 100 includes a voltage follower 110, a clamp protection circuit 120, a current limiting circuit 130, and an internal power supply circuit 140, and the voltage follower 110 is configured to: the output end 111 is connected with the reverse input end 112 and an electric signal adjusting circuit (not shown) respectively and is used for providing an adjusting signal for the electric signal adjusting circuit; the clamp protection circuit 120 is configured to: the first end 121 is connected to the positive input end 113 of the voltage follower 110, and the second end 122 is grounded, so as to limit the amplitude of the voltage signal provided to the voltage follower 110 to be less than or equal to a preset threshold; the current limiting circuit 130 is configured to: the input end 131 is used for receiving a power supply signal of the external power supply 150, and the output end 132 is connected with the first end 121 of the clamp protection circuit 120 and the positive input end 113 of the voltage follower 110; the internal power supply circuit 140 is configured to: the input terminal 141 is connected to the internal power source VCC, and the output terminal 142 is connected to the input terminal 131 of the current limiting circuit 130, so that the voltage follower 110 generates an adjustment signal having an amplitude greater than 0 and less than or equal to a preset threshold value.

As an example, please continue to refer to fig. 1, the overvoltage protection circuit 100 includes a voltage follower 110, a clamp protection circuit 120, a current limiting circuit 130, and an internal power supply circuit 140, and provides an adjustment signal to the electrical signal adjustment circuit by connecting an output terminal 111 of the voltage follower 110 with an inverting input terminal 112 and the electrical signal adjustment circuit, respectively; by connecting the first terminal 121 of the clamp protection circuit 120 to the positive input terminal 113 of the voltage follower 110, the second terminal 122 is grounded, limiting the magnitude of the voltage signal provided to the voltage follower 110 to be less than or equal to a preset threshold; receiving a power supply signal from an external power supply 150 through an input end 131 of the current limiting circuit 130, and connecting an output end 132 with a first end 121 of the clamp protection circuit 120 and a positive input end 113 of the voltage follower 110; by connecting the input terminal 141 of the internal power supply circuit 140 to the internal power supply VCC, the output terminal 142 is connected to the input terminal 131 of the current limiting circuit 130, so that the voltage follower 110 generates an adjustment signal having an amplitude greater than 0 and less than or equal to a preset threshold value; when the power supply signal of the external power supply 150 is out of the preset threshold range, the damage to the electric signal regulating circuit at the later stage is avoided. At present, when the 0-10V dimming power supply is connected to the mains voltage by mistake, the power supply is damaged, even the whole dimming circuit is damaged, or the dimming power supply is protected by adding other protection devices, but the occupation area of the protection devices in the circuit is large, and the input cost of the whole circuit is increased. According to the overvoltage protection circuit 100 in the disclosed embodiment, through the arrangement of the voltage follower 110, the clamp protection circuit 120, the current limiting circuit 130 and the internal power supply circuit 140, not only can enough and stable adjusting signals be provided for a subsequent electric signal adjusting circuit, but also the circuit can be protected when the dimming power supply is in error connection with alternating-current high voltage, so that the dimming power supply is prevented from being damaged when the dimming power supply is in error connection with mains voltage, and the whole circuit is small in size, and the protection cost of the dimming power supply is reduced.

Specifically, a voltage follower (also referred to as a buffer amplifier, a unit gain amplifier, or an isolation amplifier) is an operational amplifier circuit whose output voltage is equal to the input voltage. Therefore, the voltage follower operational amplifier does not amplify the input signal and the voltage gain is 1, the voltage follower acts as a buffer, does not amplify or attenuate the signal, consumes very little current, does not interfere with the original circuit, and provides the same voltage signal as the output. The preset threshold range in embodiments of the present disclosure may be 0-10V, such as 1V, 2V, 3V, 4V, 5V, 6V, 7V, 8V, 9V, or 10V, etc. When the external power supply provides 0-10V of electric signal input, the voltage follower can convert the 0-10V signal into a low-output impedance signal, so that the later-stage dimming circuit can normally control the 0-10V power supply output.

In some embodiments, referring to fig. 2, the overvoltage protection circuit 100 further includes an input filter circuit 160, the input filter circuit 160 being configured to: the first terminal 161 is connected to the positive input terminal 113 of the voltage follower 110, and the second terminal 162 is grounded, so that the electrical signal input to the voltage follower 110 can be limited.

In some embodiments, referring to fig. 3, the overvoltage protection circuit 100 further includes an output filter circuit 170, the output filter circuit 170 being configured to: the first end 171 is connected to the output end 111 of the voltage follower 110, the second end 172 is connected to an input end (not shown) of the electric signal conditioning circuit, and the third end 173 is grounded, so that the electric signal input to the subsequent electric signal conditioning circuit can be limited, and the subsequent circuit can be protected.

In some embodiments, referring to fig. 4, the input filter circuit 160 further includes a first capacitor C1, and the first capacitor C1 is configured to: one end is connected to the positive input of the voltage follower 110 and the other end is grounded. The first capacitor C1 controls the electric signal flowing into the voltage follower 110, prevents the electric signal outside the preset threshold range from flowing in, and prevents the subsequent circuit from being damaged.

In some embodiments, please continue to refer to fig. 4, the current limiting circuit further includes a first current limiting resistor R1, a second current limiting resistor R2, and a third current limiting resistor R3, where the first current limiting resistor R1, the second current limiting resistor R2, and the third current limiting resistor R3 may provide high impedance to limit the electrical signal flowing into the clamp protection circuit 120 when the electrical signal flowing beyond the preset threshold range, and the first current limiting resistor R1, the second current limiting resistor R2, and the third current limiting resistor R3 may be the same or different.

In some embodiments, referring to fig. 4, the output filter circuit 170 includes a filter resistor R4 and a filter capacitor C2, where the filter resistor R4 is configured to: one end is connected with the output end of the voltage follower 110, and the other end is connected with the input end of the electric signal regulating circuit; the filter capacitor C2 is configured to: one end is connected with the input end of the electric signal regulating circuit, and the other end is grounded.

In some embodiments, referring still to fig. 4, the clamp protection circuit 120 includes a transient voltage suppression diode T configured to: the cathode is connected with the positive input end of the voltage follower 110 and the output end of the current limiting circuit 130, and the anode is grounded, so that the amplitude of a voltage signal provided to the voltage follower 110 is limited to be smaller than or equal to a preset threshold value, and the transient voltage suppression diode T can clamp and protect the voltage of a later-stage circuit to prevent the damage of the later-stage circuit caused by overlarge voltage.

In particular, in the application of electronic systems, the transient interference of voltage and current can often cause damage to electronic equipment, and the remarkable characteristic of the transient interference is that the action time is extremely short, but the voltage amplitude is high, the transient energy is large, so the destructiveness is very high. To avoid such damage, transient voltage suppression diodes are widely used. The transient voltage suppression diode can rapidly reduce the impedance at the two ends of the anode and the cathode when the voltage of the commercial power is accessed, and simultaneously absorbs the voltage signal of the commercial power, and fixes the electric signals at the two ends of the anode and the cathode at a preset value, so that the subsequent circuit elements are prevented from being damaged.

In some embodiments, referring to fig. 4, the internal power supply circuit 140 includes a diode D and a current limiting branch 143, the diode D configured to: the anode is connected with an internal power supply VCC; the current limiting branch 143 is configured to: the first end is connected with the cathode of the diode D, the second end is connected with the input end of the current limiting circuit 130, and the current limiting branch 143 can limit the electric signal input to the voltage follower 110, so as to avoid damage to circuit elements in subsequent circuits.

In some embodiments, please continue to refer to fig. 4, the current-limiting branch 144 includes a fifth current-limiting resistor R5, a sixth current-limiting resistor R6 and a seventh current-limiting resistor R7, and after the internal power VCC provides the electrical signal, the fifth current-limiting resistor R5, the sixth current-limiting resistor R6 and the seventh current-limiting resistor R7 can limit the electrical signal flowing into the current-limiting circuit 130 to protect the subsequent circuit, wherein the fifth current-limiting resistor R5, the sixth current-limiting resistor R6 and the seventh current-limiting resistor R7 can be the same or different.

It should be noted that, when the input end of the input filter circuit is suspended, i.e. is not connected with the external power supply, the direct current voltage provided by the internal power supply can be 12V, and the direct current voltage of 12V is sequentially input to the current limiting circuit through the diode, the fifth current limiting resistor, the sixth current limiting resistor and the seventh current limiting resistor, and the voltage is provided for the positive input end of the voltage follower through the current limiting circuit, so that the electric signal regulating circuit at the later stage can control the full load output of the power supply.

In some embodiments, please continue with fig. 4, the overvoltage protection circuit 100 further includes a second capacitor C3, the second capacitor C3 being configured to: one end is connected with an internal power VCC, and the other end is grounded; the internal power supply VCC is also grounded through a wire.

In some embodiments, referring to fig. 5, a dimming power supply 200 is provided, including a dimming circuit 210, a voltage follower 110, a clamp protection circuit 120, a current limiting circuit 130, and an internal power supply circuit 140; the dimming circuit 210 is used for adjusting at least one electrical signal of brightness, temperature, color, frequency and sound of the rear-stage lamp; the voltage follower 110 is configured to: the output terminal 111 is connected to the inverting input terminal 112 and the dimming circuit 210, respectively, and is configured to provide a dimming signal to the dimming circuit 210; the dimming signal is used for indicating the dimming circuit to adjust at least one electric signal of the rear-stage lamp; the clamp protection circuit 120 is configured to: the first end 121 is connected to the positive input end 113 of the voltage follower 110, and the second end 122 is grounded, so as to limit the amplitude of the voltage signal provided to the voltage follower 110 to be less than or equal to a preset threshold; the current limiting circuit 130 is configured to: the input end 131 is used for receiving a power supply signal of the external power supply 150, and the output end 132 is connected with the first end 121 of the clamp protection circuit 120 and the positive input end 113 of the voltage follower 110; the internal power supply circuit 140 is configured to: the input terminal 141 is connected to the internal power VCC, and the output terminal 142 is connected to the input terminal 131 of the current limiting circuit 130, so that the voltage follower 110 generates a dimming signal having an amplitude greater than 0 and less than or equal to a preset threshold.

In some embodiments, please continue with reference to fig. 5, the dimming circuit 200 includes a dimming circuit 210, a voltage follower 110, a clamp protection circuit 120, a current limiting circuit 130, and an internal power supply circuit 140; at least one electrical signal of brightness, temperature, color, frequency and sound of the rear-stage lamp is regulated by the dimming circuit 210; by connecting the output 111 of the voltage follower 110 with the inverting input 112 and the dimming circuit 210, respectively, a dimming signal is provided to the dimming circuit 210; the dimming signal is used for instructing the dimming circuit 210 to adjust at least one electrical signal of the subsequent luminaire; by connecting the first terminal 121 of the clamp protection circuit 120 to the positive input terminal 113 of the voltage follower 110, the second terminal 122 is grounded, limiting the magnitude of the voltage signal provided to the voltage follower 110 to be less than or equal to a preset threshold; receiving a power supply signal from an external power supply 150 through an input end 131 of the current limiting circuit 130, and connecting an output end 132 thereof with a first end 121 of the clamp protection circuit 120 and a positive input end 113 of the voltage follower 110; by connecting the input terminal 141 of the internal power supply circuit 140 to the internal power supply VCC, the output terminal 142 is connected to the input terminal 131 of the current limiting circuit 130, so that the voltage follower 110 generates a dimming signal having an amplitude greater than 0 and less than or equal to a preset threshold. At present, when the 0-10V dimming power supply is connected to the mains voltage by mistake, the power supply is damaged, even the whole dimming circuit is damaged, or the dimming power supply is protected by adding other protection devices, the occupied area of the protection devices in the circuit is large, and the input cost of the dimming power supply is increased. In the dimming power supply 200 of the disclosed embodiment, the overvoltage protection circuit 100 is formed by setting the voltage follower, the clamp protection circuit, the current limiting circuit and the internal power supply circuit, and is connected with the dimming circuit 210, so that not only can the dimming circuit 210 provide enough and stable adjusting signals, but also the circuit can be protected when the dimming power supply 200 is in error connection with alternating current high voltage, the dimming power supply 200 is prevented from being damaged when the mains voltage is in error connection, the whole circuit volume is small, and the protection cost of the dimming power supply 200 is reduced.

In some embodiments, referring to fig. 6, the clamp protection circuit 120 includes a transient voltage suppression diode T configured to: the cathode T2 is connected to both the positive input terminal 113 of the voltage follower 110 and the output terminal 132 of the current limiting circuit 130, and the anode T1 is grounded for limiting the amplitude of the voltage signal provided to the voltage follower 110 to be less than or equal to a predetermined threshold.

In some embodiments, referring to fig. 6, the internal power supply circuit 140 includes a diode D and a current limiting branch 143, the diode D configured to: the anode D1 is connected with an internal power supply VCC; the current limiting branch 143 is configured to: the first terminal 1431 is connected to the cathode D2 of the diode D, and the second terminal 1432 is connected to the input 131 of the current limiting circuit 130.

In some embodiments, a luminaire is provided that includes the dimming power supply of any of the embodiments described above. At least one electric signal of brightness, temperature, color, frequency and sound of the rear-stage lamp is regulated by the dimming circuit; the output end of the voltage follower is respectively connected with the reverse input end and the dimming circuit, so as to provide a dimming signal for the dimming circuit; the dimming signal is used for indicating the dimming circuit to adjust at least one electric signal of the rear-stage lamp; the first end of the clamping protection circuit is connected with the positive input end of the voltage follower, the second end of the clamping protection circuit is grounded, and the amplitude of a voltage signal provided for the voltage follower is limited to be smaller than or equal to a preset threshold value; the input end of the current limiting circuit receives an external power supply signal, and the output end of the current limiting circuit is connected with the first end of the clamping protection circuit and the positive input end of the voltage follower; the input end of the internal power supply circuit is connected with the internal power supply, and the output end of the internal power supply circuit is connected with the input end of the current limiting circuit, so that the voltage follower generates a dimming signal with the amplitude being more than 0 and less than or equal to a preset threshold value. The dimming circuit can provide enough and stable adjusting signals for the dimming circuit to control the brightness of the lamp, and the circuit can be protected when the dimming power supply is in error connection with alternating-current high voltage, so that the dimming power supply is prevented from being damaged when the dimming power supply is in error connection with mains supply voltage, the lamp is prevented from being damaged, the whole size of the circuit is small, and the protection cost of the dimming power supply is reduced.

In the description of the present specification, reference to the term "some embodiments," "other embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples merely represent a few embodiments of the present disclosure, which are described in more detail and are not to be construed as limiting the scope of the present disclosure. It should be noted that variations and modifications can be made by those skilled in the art without departing from the spirit of the disclosure, which are within the scope of the disclosure. Accordingly, the scope of the present disclosure should be determined from the following claims.

Claims (10)

1. An overvoltage protection circuit, comprising:

a voltage follower configured to: the output end is respectively connected with the reverse input end and the electric signal regulating circuit and is used for providing regulating signals for the electric signal regulating circuit;

a clamp protection circuit configured to: the first end is connected with the positive input end of the voltage follower, and the second end is grounded and is used for limiting the amplitude of a voltage signal provided for the voltage follower to be smaller than or equal to a preset threshold value;

a current limiting circuit configured to: the input end is used for receiving an external power supply signal, and the output end is connected with the first end of the clamping protection circuit and the positive input end of the voltage follower;

an internal power supply circuit configured to: the input end is connected with an internal power supply, and the output end is connected with the input end of the current limiting circuit, so that the voltage follower generates an adjusting signal with the amplitude being more than 0 and less than or equal to the preset threshold value.

2. The overvoltage protection circuit of claim 1, further comprising:

an input filter circuit configured to: the first end is connected with the positive input end of the voltage follower, and the second end is grounded.

3. The overvoltage protection circuit of claim 1, further comprising:

an output filter circuit configured to: the first end is connected with the output end of the voltage follower, the second end is connected with the input end of the electric signal regulating circuit, and the third end is grounded.

4. The overvoltage protection circuit of claim 3, wherein the output filter circuit comprises:

a filter resistor configured to: one end of the voltage follower is connected with the output end of the voltage follower, and the other end of the voltage follower is connected with the input end of the electric signal regulating circuit;

a filter capacitor configured to: one end is connected with the input end of the electric signal regulating circuit, and the other end is grounded.

5. The overvoltage protection circuit of any one of claims 1-4, wherein the clamp protection circuit comprises:

a transient voltage suppression diode configured to: the cathode is connected with the positive input end of the voltage follower and the output end of the current limiting circuit, and the anode is grounded and used for limiting the amplitude of a voltage signal provided for the voltage follower to be smaller than or equal to a preset threshold value.

6. The overvoltage protection circuit according to any one of claims 1-4, wherein the internal power supply circuit comprises:

a diode configured to: the anode is connected with the internal power supply;

a current limiting branch configured to: the first end is connected with the cathode of the diode, and the second end is connected with the input end of the current limiting circuit.

7. A dimming power supply, comprising:

the dimming circuit is used for adjusting at least one electric signal of brightness, temperature, color, frequency and sound of the rear-stage lamp;

a voltage follower configured to: the output end is respectively connected with the reverse input end and the dimming circuit and is used for providing a dimming signal for the dimming circuit; the dimming signal is used for indicating the dimming circuit to adjust at least one electric signal of the rear-stage lamp;

a clamp protection circuit configured to: the first end is connected with the positive input end of the voltage follower, and the second end is grounded and is used for limiting the amplitude of a voltage signal provided for the voltage follower to be smaller than or equal to a preset threshold value;

a current limiting circuit configured to: the input end is used for receiving an external power supply signal, and the output end is connected with the first end of the clamping protection circuit and the positive input end of the voltage follower;

an internal power supply circuit configured to: the input end is connected with an internal power supply, and the output end is connected with the input end of the current limiting circuit, so that the voltage follower generates a dimming signal with the amplitude being more than 0 and less than or equal to the preset threshold value.

8. The dimming power supply of claim 7, wherein the clamp protection circuit comprises:

a transient voltage suppression diode configured to: the cathode is connected with the positive input end of the voltage follower and the output end of the current limiting circuit, and the anode is grounded and used for limiting the amplitude of a voltage signal provided for the voltage follower to be smaller than or equal to a preset threshold value.

9. The dimmed power supply according to claim 7, wherein the internal power supply circuit comprises:

a diode configured to: the anode is connected with the internal power supply;

a current limiting branch configured to: the first end is connected with the cathode of the diode, and the second end is connected with the input end of the current limiting circuit.

10. A light fixture, comprising:

the dimming power supply of any of claims 7-9.