CN210775797U

CN210775797U - Lamp dead pixel detection circuit based on current mirror

Info

Publication number: CN210775797U
Application number: CN201921493214.1U
Authority: CN
Inventors: 薛冬英; 薛乐平
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-09-10
Filing date: 2019-09-10
Publication date: 2020-06-16
Anticipated expiration: 2029-09-10

Abstract

For solving the trouble spot detection problem in the middle of the DMX512 circuit, the utility model provides a lamps and lanterns dead pixel detection circuitry based on current mirror, its characterized in that: including detection controller, current mirror module and a plurality of DMX512 module of treating to detect, the detection controller is connected in order with each DMX512 module, the current mirror module includes current source Itest, current source Iout, resistance R1, resistance R2 and controllable switch S, current source Itest and resistance R1 series connection are between VCC end and GND end, current source Iout, resistance R2 and controllable switch S series connection are between VCC end and GND end, the detection controller has voltage detection end and switch control end, current source Itest and resistance R1 ' S tie point is as the ground point of each DMX512 module, current source Iout and resistance R2 ' S tie point with the voltage detection end links to each other in order to feed back this point voltage, controllable switch S ' S control end with the switch control end links to each other in order to realize the on-off control of controllable switch S.

Description

Lamp dead pixel detection circuit based on current mirror

Technical Field

The utility model is used for DMX512 control circuit, concretely relates to lamps and lanterns dead pixel detection circuitry based on current mirror.

Background

At present, in an LED lamplight driving system circuit based on a DMX512 protocol, under most conditions, the number of LED lamps is large and dense, and if one or some lamps are burnt out or have problems, the LED lamps are not easy to find; because the current is relatively weak originally when the LED lamp is normally used, the LED lamp can not be detected or is detected wrongly, and if the specific position of the problem lamp is to be determined, the time and the labor are wasted due to the need of detecting one by one.

SUMMERY OF THE UTILITY MODEL

For solving the trouble spot detection problem in the middle of the DMX512 circuit, the utility model provides a lamps and lanterns dead pixel detection circuitry based on current mirror, its concrete technical content is as follows:

a lamp dead pixel detection circuit based on a current mirror comprises a detection controller, a current mirror module and a plurality of DMX512 modules to be detected, the detection controller is connected with each DMX512 module in sequence, the current mirror module comprises a current source Itest, a current source Iout, a resistor R1, a resistor R2 and a controllable switch S, the current source Itest and the resistor R1 are connected in series between the VCC terminal and the GND terminal, the current source Iout, the resistor R2 and the controllable switch S are connected in series between the VCC terminal and the GND terminal, the detection controller is provided with a voltage detection end and a switch control end, the connection point of the current source Itest and the resistor R1 is used as the grounding point of each DMX512 module, the connection point of the current source Iout and the resistor R2 is connected with the voltage detection terminal to feed back the point voltage, and the control end of the controllable switch S is connected with the switch control end to realize on-off control of the controllable switch S.

In one or more embodiments of the present invention, the resistance of the resistor R2 is much larger than the resistance of the resistor R1.

In one or more embodiments of the present invention, the DMX512 modules are connected to the light source respectively, and the detection controller drives each DMX512 module to light the light source in order to obtain the corresponding voltage.

The utility model has the advantages that: when the DMX512 modules are detected one by one, the light source current of each module flows to a branch where a current source Itest is located from a grounding end, and the current is amplified on the side of a current source Iout according to the current mirror principle, so that weak light source current is collected by a detection controller and is judged whether to be in a normal working state, and damage detection on each DMX512 module and a light source is convenient, quick and accurate.

Drawings

Fig. 1 is a schematic circuit diagram of the present invention.

Detailed Description

The scheme of the present application is further described below with reference to fig. 1:

a lamp dead-spot detection circuit based on a current mirror comprises a detection controller, a current mirror module and a plurality of DMX512 modules to be detected, wherein the detection controller is sequentially connected with the DMX512 modules, the current mirror module comprises a current source Itest, a current source Iout, a resistor R1, a resistor R2 and a controllable switch S, the current source Itest and the resistor R1 are connected between a VCC end and a GND end in series, the current source Iout, the resistor R2 and the controllable switch S are connected between the VCC end and the GND end in series, the detection controller is provided with a voltage detection end and a switch control end, a connection point of the current source Itest and the resistor R1 is used as a grounding point of each DMX512 module, a connection point of the current source Iout and the resistor R2 is connected with the voltage detection end to feed back the voltage of the point, the control end of the controllable switch S is connected with the switch control end to realize on-off control of the controllable switch S, the resistance of the resistor R2 is far larger than that of the resistor R1. The DMX512 modules are respectively connected with a light source, and the detection controller drives each DMX512 module to sequentially light the light sources to obtain corresponding voltage.

The utility model discloses a theory of operation:

when the voltage detection circuit works normally, the controllable switch S is in a disconnected state, the branch where the resistor R2 is located is not conducted, and no voltage is output at a voltage detection point, namely V _ out is zero;

when the LED light source in the circuit needs to be detected whether to be damaged or not and the damaged position, the detection controller closes the controllable switch S to enable the branch where the resistor R2 is located to be conducted, and therefore the voltage detection point generates voltage output; the detection controller sends a signal to the DMX512 module to enable the DMX512 module to sequentially operate (i.e., light the light source connected to the DMX512 module), at this time, the current of the light source flows through the branch where the resistor R1 is located through the ground terminal of the DMX512 module to form a test current I _ test, and since the current mirror module mirrors the test current I _ test to the other side in a ratio of 1:1, the output voltage V _ out = I _ test R2. Generally, the normal operating current of the LED light source is relatively small, and if the LED light source is detected directly and is difficult to detect or has a large error, the small current can be converted into a large voltage to represent the large voltage through the amplification effect of the resistor R2, for example, if the LED light source with the normal operating current of 30mA is selected, and the resistor R2 is set to 100 Ω and is much larger than the resistor R1, then V _ out = I _ test × 100 Ω =30mA × 100 Ω =3V, so that the voltage with the amplitude is relatively easy to detect and is not easy to generate an error.

At this time, if the LED light source has an open-circuit fault, I _ test is 0mA, and V _ out = I _ test × 100 Ω = 0V; if the LED light source is short-circuited, the current flowing through the LED light source will be very large, such as 100mA or more, when V _ out = I _ test × 100 Ω =100mA × 100 Ω =10V or more.

The detection controller records the output voltage V _ out of each DMX512 module and then reports the recorded output voltage V _ out to the upper computer, or directly reports the recorded output voltage V _ out to the upper computer, the upper computer can determine whether the light source corresponding to the DMX512 module is damaged or not through recording, and the position of the damaged lamp can be accurately judged according to the ID of the DMX512 module so as to facilitate timely repair.

The above preferred embodiments should be considered as examples of the embodiments of the present application, and technical deductions, substitutions, improvements and the like similar to, similar to or based on the embodiments of the present application should be considered as the protection scope of the present patent.

Claims

1. The utility model provides a lamps and lanterns dead pixel detection circuitry based on current mirror which characterized in that: including detection controller, current mirror module and a plurality of DMX512 module of treating to detect, the detection controller is connected in order with each DMX512 module, the current mirror module includes current source Itest, current source Iout, resistance R1, resistance R2 and controllable switch S, current source Itest and resistance R1 series connection are between VCC end and GND end, current source Iout, resistance R2 and controllable switch S series connection are between VCC end and GND end, the detection controller has voltage detection end and switch control end, current source Itest and resistance R1 ' S tie point is as the ground point of each DMX512 module, current source Iout and resistance R2 ' S tie point with the voltage detection end links to each other in order to feed back this point voltage, controllable switch S ' S control end with the switch control end links to each other in order to realize the on-off control of controllable switch S.

2. The current mirror-based lamp dead-center detection circuit of claim 1, wherein: the resistance of the resistor R2 is far larger than that of the resistor R1.

3. The current mirror-based lamp dead-center detection circuit of claim 1, wherein: the DMX512 modules are respectively connected with a light source, and the detection controller drives each DMX512 module to sequentially light the light sources to obtain corresponding voltage.