CN211235997U - Output voltage detection circuit - Google Patents
Output voltage detection circuit Download PDFInfo
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- CN211235997U CN211235997U CN201922008187.0U CN201922008187U CN211235997U CN 211235997 U CN211235997 U CN 211235997U CN 201922008187 U CN201922008187 U CN 201922008187U CN 211235997 U CN211235997 U CN 211235997U
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Abstract
The utility model provides an output voltage detection circuit, which is applied to a LED constant current output circuit and comprises an analog detection circuit and a state judgment module; the analog detection circuit is used for acquiring a voltage signal of a preset position of the LED constant-current output circuit, converting the voltage signal into a detection signal and then sending the detection signal to the state judgment module; the state judgment module is used for determining that the LED constant current output circuit is in an output no-load state, an output short circuit state or a normal load state according to the detection signal. The utility model discloses an output voltage detection circuitry can acquire LED constant current output circuit's voltage signal through simulation detection circuitry and exchange for detected signal, supplies the state to judge that the module carries out load condition's judgement to improve the efficiency that load condition detected.
Description
Technical Field
The utility model relates to a circuit detection technical field particularly, relates to an output voltage detection circuit.
Background
When a load fails and needs to be detected, an existing LED constant-current output circuit generally uses a test instrument outside the circuit to detect, and a detection result can be obtained only after manual operation is carried out according to data detected by the test instrument, so that the detection efficiency is low.
SUMMERY OF THE UTILITY MODEL
In view of the above, the present invention provides an output voltage detection circuit to improve the efficiency of load state detection.
In order to achieve the above object, the utility model adopts the following technical scheme:
an output voltage detection circuit is applied to an LED constant current output circuit and comprises an analog detection circuit and a state judgment module;
the analog detection circuit is used for acquiring a voltage signal of a preset position of the LED constant-current output circuit, converting the voltage signal into a detection signal and then sending the detection signal to the state judgment module;
the state judgment module is used for determining that the LED constant current output circuit is in an output no-load state, an output short circuit state or a normal load state according to the detection signal.
Preferably, in the output voltage detection circuit, the LED constant current output circuit includes a DC-DC BUCK circuit, and the analog detection circuit is configured to be connected to a negative terminal output by the DC-DC BUCK circuit.
Preferably, in the output voltage detection circuit, the analog detection circuit includes a first resistor, a second resistor, and a first capacitor;
the first resistor is used for being connected to the negative pole end of the output LED of the DC-DC BUCK circuit and receiving a voltage signal of the negative pole end;
one end of the second resistor is connected with the first resistor, and the other end of the second resistor is grounded and used for dividing the received voltage signal;
the first capacitor is connected in parallel with the second resistor and used for stabilizing the voltage signal.
Preferably, in the output voltage detection circuit, the state determination module is connected between the first resistor and the second resistor, receives the detection signal output by the analog detection circuit, and determines the operating state of the DC-DC BUCK circuit according to the detection signal:
when the detection signal is determined to be lower than a first preset voltage value, determining that the DC-DC BUCK circuit is in a no-load state;
when the detection signal is determined to be a first voltage division value, determining that the DC-DC BUCK circuit is in a short-circuit state;
and when the detection signal is determined to be the second voltage division value, determining that the DC-DC BUCK circuit is in a normal loading state.
Preferably, in the output voltage detection circuit, the LED constant current output circuit includes a BUCK converter circuit, and the analog detection circuit obtains a voltage signal at a negative electrode end output by the BUCK converter circuit through an auxiliary winding group.
Preferably, in the output voltage detection circuit, the analog detection circuit includes a first auxiliary winding group, a first diode, a third resistor, a fourth resistor, and a second capacitor;
the first auxiliary winding group is used for being coupled with an auxiliary winding group on the negative electrode end of the BUCK converter circuit to obtain a voltage signal;
the anode of the first diode is connected with the first auxiliary winding group and used for rectifying the voltage signal into a positive voltage signal;
the third resistor is connected with the cathode of the first diode and used for receiving the positive voltage signal;
one end of the fourth resistor is connected with the third resistor, and the other end of the fourth resistor is grounded and used for dividing the received positive voltage signal;
the second capacitor is connected in parallel with the fourth resistor and used for stabilizing the positive voltage signal.
Preferably, in the output voltage detection circuit, the state determination module is connected between the third resistor and the fourth resistor, receives the detection signal output by the analog detection circuit, and determines the operating state of the BUCK converter circuit according to the positive voltage signal:
when the detection signal is determined to be lower than a second preset voltage value, determining that the BUCK converter circuit is in a no-load state;
when the detection signal is determined to be a pulse signal, determining that the BUCK converter circuit is in a short-circuit state;
and when the detection signal is determined to be in a high level, determining that the BUCK converter circuit is in a normal load state.
Preferably, in the output voltage detection circuit, the LED constant current output circuit includes a flyback converter circuit, and the analog detection circuit obtains a voltage signal at an output cathode end of the flyback converter circuit through an auxiliary winding group.
Preferably, in the output voltage detection circuit, the analog detection circuit includes a second auxiliary winding group, a second diode, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a third capacitor, a fourth capacitor, an optocoupler and a triode;
the second auxiliary winding group is used for being coupled with a voltage transformation output winding of the flyback converter circuit to obtain a voltage signal;
the anode of the second diode is connected with the second auxiliary winding group and is used for rectifying the voltage signal into a positive voltage signal;
one end of the fifth resistor is connected with the cathode of the anode of the second diode, and the other end of the fifth resistor is connected with the sixth resistor;
one end of the sixth resistor is connected with the fifth resistor, and the other end of the sixth resistor is grounded and used for dividing the received positive voltage signal;
the third capacitor is connected with the sixth resistor in parallel and used for stabilizing the positive voltage signal;
a first pin of the optocoupler is used for being connected between the fifth resistor and the sixth resistor, a second pin of the optocoupler is grounded, a third pin of the optocoupler is connected to a base electrode of the triode through the eighth resistor, and a fourth pin of the optocoupler receives a driving power supply with a preset voltage value and is connected to a collector electrode of the triode through the seventh resistor;
the emitting electrode of the triode is grounded and is connected with the base electrode through a ninth resistor;
the fourth capacitor is connected with the ninth resistor in parallel.
Preferably, in the output voltage detection circuit, the state determination module is configured to be connected to a collector of the triode, receive a detection signal output by the analog detection circuit, and determine the operating state of the flyback converter circuit according to the detection signal:
when the detection signal is determined to be at a high level, determining that the flyback converter circuit is in an idle state;
when the detection signal is determined to be a pulse signal, determining that the flyback converter circuit is in a short-circuit state;
and when the detection signal is determined to be at a low level, determining that the flyback converter circuit is in a normal load state.
The utility model provides an output voltage detection circuit, which is applied to a LED constant current output circuit and comprises an analog detection circuit and a state judgment module; the analog detection circuit is used for acquiring a voltage signal of a preset position of the LED constant-current output circuit, converting the voltage signal into a detection signal and then sending the detection signal to the state judgment module; the state judgment module is used for determining that the LED constant current output circuit is in an output no-load state, an output short circuit state or a normal load state according to the detection signal. The utility model discloses an output voltage detection circuitry can acquire LED constant current output circuit's voltage signal through simulation detection circuitry and exchange for detected signal, supplies the state to judge that the module carries out load condition's judgement to improve the efficiency that load condition detected.
In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.
Drawings
In order to illustrate the technical solution of the present invention more clearly, the drawings that are needed in the embodiments will be briefly described below, and it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope of the present invention. Like components are numbered similarly in the various figures.
Fig. 1 is a structural diagram of an output voltage detection circuit provided in embodiment 1 of the present invention;
fig. 2 is a structural diagram of an output voltage detection circuit provided in embodiment 2 of the present invention;
fig. 3 is a structural diagram of an output voltage detection circuit according to embodiment 3 of the present invention;
fig. 4 is a structural diagram of an output voltage detection circuit according to embodiment 4 of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments.
The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiment of the present invention, all other embodiments obtained by the person skilled in the art without creative work belong to the protection scope of the present invention.
Hereinafter, the terms "including", "having", and their derivatives, which may be used in various embodiments of the present invention, are only intended to indicate specific features, numbers, steps, operations, elements, components, or combinations of the foregoing, and should not be construed as first excluding the existence of, or adding to, one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.
Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the present invention belong. The terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning that is consistent with their contextual meaning in the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in various embodiments of the present invention.
Example 1
Fig. 1 is a structural diagram of an output voltage detection circuit according to embodiment 1 of the present invention.
The output voltage detection circuit 100 is applied to an output voltage detection circuit 101, and includes an analog detection circuit 110 and a state determination module 120.
The analog detection circuit 110 is configured to obtain a voltage signal of a preset position of the output voltage detection circuit 101, convert the voltage signal into a detection signal, and send the detection signal to the state determination module 120;
the embodiment of the utility model provides an in, this simulation detection circuitry 110 can acquire voltage signal through lug connection to output voltage detection circuitry 101, also can be through setting up supplementary winding group, utilize the mode of signal coupling to acquire the voltage signal that output voltage detection circuitry 101 predetermines the position, and carry out the partial pressure to the voltage signal who acquires, filter, after handling such as stable and isolation, generate detection signal and send to state judgment module 120, so that state judgment module 120 judges the present operating condition of output voltage detection circuitry 101 according to detection signal. The working states of the output voltage detection circuit 101 include a no-load state, a short circuit state and a normal loaded state, the no-load state is also output by being connected to the LED lamp, the short circuit state is also the short circuit of the anode and the cathode of the LED lamp, and the normal loaded state is that the output voltage detection circuit 101 is normally connected to the LED lamp and drives the LED lamp.
The state determining module 120 is configured to be connected to the analog detecting circuit 110, receive the detection signal, and determine that the output voltage detecting circuit 101 is in an output no-load state, an output short-circuit state, or a normal on-load state according to the detection signal.
The embodiment of the utility model provides an in, this state judgment module 120 connects simulation detection circuitry 110, receives the detected signal of simulation detection circuitry 110 output, can confirm that output voltage detection circuitry 101 is in output no-load state, output short-circuit state or the load state of journey according to this detected signal to alright in time investigate output voltage detection circuitry 101's trouble, control output voltage detection circuitry 101's operation.
In the embodiment of the present invention, the state determining module 120 can be a single chip microcomputer.
Example 2
Fig. 2 is a structural diagram of an output voltage detection circuit according to embodiment 2 of the present invention.
The output voltage detection circuit 200 includes an analog detection circuit 210 and a state determination module 220;
the analog detection circuit 210 is configured to obtain a voltage signal of a preset position of the LED constant current output circuit, convert the voltage signal into a detection signal, and send the detection signal to the state judgment module 220;
the state judgment module 220 is configured to be connected to the analog detection circuit 210, receive the detection signal, and determine that the LED constant current output circuit is in an output no-load state, an output short circuit state, or a normal on-load state according to the detection signal.
In the embodiment of the present invention, the LED constant current output circuit includes a DC-DC BUCK circuit 201, the analog detection circuit 210 is connected to the negative terminal output by the DC-DC BUCK circuit 201.
The analog detection circuit 210 includes a first resistor 211, a second resistor 212, and a first capacitor 213;
the first resistor 211 is used for being connected to the negative terminal of the output LED of the DC-DC BUCK circuit 201 and receiving a voltage signal of the negative terminal;
one end of the second resistor 212 is connected to the first resistor 211, and the other end is grounded, so as to divide the received voltage signal;
the first capacitor 213 is connected in parallel with the second resistor 212 for stabilizing the voltage signal.
The state determining module 220 is configured to be connected between the first resistor 211 and the second resistor 212, receive the detection signal output by the analog detecting circuit 210, and determine the operating state of the DC-DC BUCK circuit 201 according to the detection signal:
when the detection signal is determined to be lower than a first preset voltage value, determining that the DC-DC BUCK circuit 201 is in an idle state;
when the detection signal is determined to be the first voltage division value, determining that the DC-DC BUCK circuit 201 is in a short-circuit state;
when the detection signal is determined to be the second voltage division value, the DC-DC BUCK circuit 201 is determined to be in a normal loading state.
The embodiment of the utility model provides an in, under the condition that does not destroy BUCK circuit steady operation itself, increase bypass circuit and acquire voltage signal, also set up the simulation detection circuitry 210 that above-mentioned components and parts are constituteed promptly, be connected to the LED output negative pole end of BUCK circuit through this simulation detection circuitry 210. The first resistor 211 is connected to the negative end and performs voltage signal division with the second resistor 212, for example, when the state determination module 220 is a single chip microcomputer, the maximum voltage value of a signal borne by the single chip microcomputer is 4.5V, at this time, the acquired voltage signal can be divided to be less than 4.5V by the first resistor 211 and the second resistor 212, and then the voltage signal is filtered and stabilized by the first capacitor 213, so that misjudgment of the single chip microcomputer is prevented.
In the embodiment of the present invention, under the condition that the positive terminal and the negative terminal of the LED output of the above-mentioned DC-DC BUCK circuit 201 are not loaded, the voltage value obtained by the analog detection circuit 210 is very low and is approximately zero due to no loop of the whole DC-DC BUCK circuit 201, so that the corresponding logic can be set in the state judgment module 220 to perform the no-load judgment, for example, whether the voltage of the detection signal obtained by the circuit judgment is lower than 0.3V or not can be judged, and it is described that the DC-DC BUCK circuit 201 is no-load when the voltage is lower than 0.3V.
The embodiment of the utility model provides an in, when the positive terminal and the negative pole end short circuit of DC-DC BUCK circuit 201's LED output, the voltage lug connection of positive terminal is on first resistance 211, carry out the partial pressure through second resistance 212, the voltage value of the detected signal that analog detection circuit 210 generated carries out the first partial pressure value after the partial pressure for the maximum voltage value of DC-DC BUCK circuit 201 output this moment, when the voltage value of the detected signal that state judgement circuit judgement acquireed equals first partial pressure value, then explain DC-DCBUCK circuit 201 short circuit.
In the embodiment of the present invention, when the positive terminal and the negative terminal of the LED output of the DC-DC BUCK circuit 201 are loaded, the voltage value of the voltage signal obtained by the first resistor 211 is the voltage value of the maximum voltage output by the DC-DC BUCK circuit 201 minus the voltage value of the load, and similarly, a second voltage division value can be obtained after voltage division. When the voltage value of the detection signal acquired by the state judgment circuit is equal to the second voltage division value, it indicates that the DC-DC BUCK circuit 201 is short-circuited and normally loaded.
Example 3
Fig. 3 is a structural diagram of an output voltage detection circuit according to embodiment 3 of the present invention.
The output voltage detection circuit 300 includes an analog detection circuit 310 and a state determination module 320;
the analog detection circuit 310 is configured to obtain a voltage signal of a preset position of the LED constant current output circuit, convert the voltage signal into a detection signal, and send the detection signal to the state judgment module 320;
the state judgment module 320 is configured to be connected to the analog detection circuit 310, receive the detection signal, and determine that the LED constant current output circuit is in an output no-load state, an output short circuit state, or a normal on-load state according to the detection signal.
In the embodiment of the present invention, the LED constant current output circuit includes the BUCK converter circuit 301, the analog detection circuit 310 acquires the voltage signal of the negative pole terminal output by the BUCK converter circuit 301 through the auxiliary winding group.
The analog detection circuit 310 includes a first auxiliary winding 311, a first diode 312, a third resistor 313, a fourth resistor 314, and a second capacitor 315;
the first auxiliary winding set 311 is configured to be coupled to an auxiliary winding set on the negative terminal of the BUCK converter circuit 301, so as to obtain a voltage signal;
the anode of the first diode 312 is connected to the first auxiliary winding 311 for rectifying the voltage signal into a positive voltage signal;
the third resistor 313 is connected to the cathode of the first diode 312 for receiving the positive voltage signal;
one end of the fourth resistor 314 is connected to the third resistor 313, and the other end is grounded, so as to divide the received positive voltage signal;
the second capacitor 315 is connected in parallel with the fourth resistor 314 for stabilizing the positive voltage signal.
The state determining module 320 is configured to be connected between the third resistor 313 and the fourth resistor 314, receive the detection signal output by the analog detecting circuit 310, and determine the operating state of the BUCK converter circuit 301 according to the detection signal:
when the detection signal is determined to be lower than a second preset voltage value, determining that the BUCK converter circuit 301 is in a no-load state;
determining that the BUCK converter circuit 301 is in a short-circuit state when the detection signal is determined to be a pulse signal;
when it is determined that the detection signal is at a high level, it is determined that the BUCK converter circuit 301 is in a normal on-load state.
The embodiment of the utility model provides an in, can utilize the principle of transformer coupling, at BUCK converter circuit 301 around supplementary winding group in addition, through the signal on the vary voltage output winding of supplementary winding group coupling BUCK converter circuit 301 to carry out power isolation with BUCK converter circuit 301, under not influencing BUCK converter circuit 301 operating condition, detect the voltage signal of BUCK converter circuit 301 output negative pole end with the mode that increases bypass circuit and judge operating condition. The first auxiliary winding 311 couples signals on the transforming output winding of the BUCK converter circuit 301, and has an isolation effect. The voltage signal coupled to the first diode 312 is rectified to obtain a positive voltage signal, and the positive voltage signal is divided by the third resistor 313 and the fourth resistor 314 to be reduced to a value below the voltage applied to the state determination module 320, so that the detection signal can be obtained after the filtering by the second capacitor 315 is stable.
The embodiment of the present invention provides an embodiment, under the empty circumstances of positive terminal and negative pole end that BUCK converter circuit 301 outputs, the voltage signal that the coupling of first supplementary winding group 311 obtained is very weak, and the voltage value is very low, consequently can set up a circuit logic in state judgment module 320, when the detected signal who acquires is less than the second default, then explains that BUCK converter circuit 301 is empty.
The embodiment of the present invention provides an embodiment, under the condition that the positive terminal and the negative terminal of BUCK converter circuit 301 output are short-circuited, the voltage signal that the coupling of first supplementary winding group 311 obtains follows BUCK converter circuit 301 and gets into the hiccup state, and the coupling also obtains pulsed voltage signal, therefore sets up a circuit logic in state judgment module 320, when the detected signal who acquires is pulse signal, then explains BUCK converter circuit 301 short circuit.
The embodiment of the utility model provides an in, under the positive terminal and the negative pole end on-load condition of BUCK converter circuit 301 output, the voltage value of the voltage signal that first supplementary winding group 311 coupling obtained can be calculated through BUCK converter circuit 301 output voltage value and turn ratio, and this turn ratio is the turn ratio of first supplementary winding group 311 and vary voltage output winding. After the voltage signal obtained by coupling is rectified, divided and filtered, the obtained voltage type should be high level, so a circuit logic is set in the state judgment module 320, and when the obtained detection signal is high level, it indicates that the BUCK converter circuit 301 is normally loaded.
Example 4
Fig. 4 is a structural diagram of an output voltage detection circuit according to embodiment 4 of the present invention.
The output voltage detection circuit 400 includes an analog detection circuit 410 and a state determination module 420;
the analog detection circuit 410 is configured to obtain a voltage signal of a preset position of the LED constant current output circuit, convert the voltage signal into a detection signal, and send the detection signal to the state judgment module 420;
the state judgment module 420 is configured to be connected to the analog detection circuit 410, receive the detection signal, and determine that the LED constant current output circuit is in an output no-load state, an output short circuit state, or a normal on-load state according to the detection signal.
In the embodiment of the utility model, LED constant current output circuit includes flyback converter circuit 401, analog detection circuit 410 acquires through supplementary wire winding group flyback converter circuit 401's the voltage signal of the output negative pole end.
The analog detection circuit 410 includes a second auxiliary winding group 411, a second diode 412, a fifth resistor 413, a sixth resistor 414, a seventh resistor 415, an eighth resistor 416, a ninth resistor 417, a third capacitor 418, a fourth capacitor 419, an optical coupler 4110, and a transistor 4111;
the second auxiliary winding group 411 is configured to couple with a voltage transformation output winding of the flyback converter circuit 401 to obtain a voltage signal;
the anode of the second diode 412 is connected to the second auxiliary winding group 411 for rectifying the voltage signal into a positive voltage signal;
one end of the fifth resistor 413 is connected to the cathode of the anode of the second diode 412, and the other end of the fifth resistor 413 is connected to the sixth resistor 414;
one end of the sixth resistor 414 is connected to the fifth resistor 413, and the other end is grounded, so as to divide the received positive voltage signal;
the third capacitor 418 is connected in parallel with the sixth resistor 414 for stabilizing the positive voltage signal;
a first pin of the optical coupler 4110 is configured to be connected between the fifth resistor 413 and the sixth resistor 414, a second pin of the optical coupler 4110 is grounded, a third pin of the optical coupler is connected to a base of the transistor 4111 through the eighth resistor 416, and a fourth pin of the optical coupler receives a driving power of a preset voltage value and is connected to a collector of the transistor 4111 through the seventh resistor 415;
the emitter of the triode 4111 is grounded and is connected with the base through a ninth resistor 417;
the fourth capacitor 419 is connected in parallel with the ninth resistor 417.
The state determining module 420 is configured to be connected to a collector of the triode 4111, receive the detection signal output by the analog detecting circuit 410, and determine the operating state of the flyback converter circuit 401 according to the detection signal:
when the detection signal is determined to be at a high level, determining that the flyback converter circuit 401 is in an idle state;
when the detection signal is determined to be a pulse signal, determining that the flyback converter circuit 401 is in a short-circuit state;
when the detection signal is determined to be at a low level, the flyback converter circuit 401 is determined to be in a normal load state.
The embodiment of the utility model provides an in, can utilize the principle of transformer coupling, around supplementary winding group in addition outside flyback converter circuit 401, through supplementary winding group coupling flyback converter circuit 401's the signal on the vary voltage output winding to carry out power isolation with flyback converter circuit 401, under the mode that does not influence flyback converter circuit 401 operating condition, the mode that detects flyback converter circuit 401 output negative pole end with increasing bypass circuit judges operating condition. Meanwhile, an optical coupler 4110 is further arranged in the analog detection circuit 410 to perform signal isolation transmission, so that the influence on the flyback converter circuit 401 is further reduced. The second auxiliary winding group 411 couples signals on the voltage transformation output winding of the flyback converter circuit 401, and has an isolation effect. The voltage signal coupled to the second diode 412 in a rectifying mode is used for obtaining a positive voltage signal, the voltage signal is divided by the sixth resistor 414 and the seventh resistor 415, the positive voltage signal is reduced to a value below the voltage borne by the state judgment module 420, the voltage signal is filtered stably by the second capacitor, and finally the detection signal can be obtained by the optical coupler 4110 and the triode 4111 for isolation transmission.
The embodiment of the utility model provides an in, under the empty loaded condition of positive terminal and negative pole end of flyback converter circuit 401 output, the voltage signal who obtains through the coupling is more weak, consequently can not drive opto-coupler 4110 and triode 4111 and carry out normal work, consequently triode 4111's collecting electrode operating voltage is higher, for the high level, consequently sets up a circuit logic in state judgment module 420, when the detected signal who acquires is the high level, then explains flyback converter circuit 401 empty load.
The embodiment of the utility model provides an in, under the positive terminal of flyback converter circuit 401 output and the condition of negative pole end short circuit, the signal that the coupling of second auxiliary winding obtained follows flyback converter circuit 401 and gets into hiccup state, and also the coupling obtains the pulsed signal, consequently sets up a circuit logic in state judgment module 420, when the detected signal who acquires is pulse signal, then explains flyback converter circuit 401 short circuit.
The embodiment of the utility model provides an in, under the circumstances that the positive terminal and the negative pole end area of flyback converter circuit 401 output carried, voltage signal that obtains through the coupling is stronger, and drive opto-coupler 4110 and triode 4111 carry out normal work to make triode 4111's collecting electrode operating voltage lower, for the low level, consequently set up a circuit logic in state judgment module 420, when the detected signal who acquires was the low level, then explain flyback converter circuit 401 area and carry.
Claims (10)
1. An output voltage detection circuit is characterized by being applied to an LED constant current output circuit and comprising an analog detection circuit and a state judgment module;
the analog detection circuit is used for acquiring a voltage signal of a preset position of the LED constant-current output circuit, converting the voltage signal into a detection signal and then sending the detection signal to the state judgment module;
the state judgment module is used for determining that the LED constant current output circuit is in an output no-load state, an output short circuit state or a normal load state according to the detection signal.
2. The output voltage detection circuit of claim 1, wherein the LED constant current output circuit comprises a DC-DC BUCK circuit, and the analog detection circuit is configured to be connected to a negative terminal of an output of the DC-DC BUCK circuit.
3. The output voltage detection circuit of claim 2, wherein the analog detection circuit comprises a first resistor, a second resistor, and a first capacitor;
the first resistor is used for being connected to the negative pole end of the output LED of the DC-DC BUCK circuit and receiving a voltage signal of the negative pole end;
one end of the second resistor is connected with the first resistor, and the other end of the second resistor is grounded and used for dividing the received voltage signal;
the first capacitor is connected in parallel with the second resistor and used for stabilizing the voltage signal.
4. The output voltage detection circuit of claim 3, wherein the state determination module is connected between the first resistor and the second resistor, receives the detection signal output by the analog detection circuit, and determines the operating state of the DC-DC BUCK circuit according to the detection signal:
when the detection signal is determined to be lower than a first preset voltage value, determining that the DC-DC BUCK circuit is in a no-load state;
when the detection signal is determined to be a first voltage division value, determining that the DC-DC BUCK circuit is in a short-circuit state;
and when the detection signal is determined to be the second voltage division value, determining that the DC-DC BUCK circuit is in a normal loading state.
5. The output voltage detection circuit according to claim 1, wherein the LED constant current output circuit includes a BUCK converter circuit, and the analog detection circuit obtains a voltage signal of a negative terminal output by the BUCK converter circuit through an auxiliary winding group.
6. The output voltage detection circuit of claim 5, wherein the analog detection circuit comprises a first auxiliary winding, a first diode, a third resistor, a fourth resistor, and a second capacitor;
the first auxiliary winding group is used for being coupled with an auxiliary winding group on the negative electrode end of the BUCK converter circuit to obtain a voltage signal;
the anode of the first diode is connected with the first auxiliary winding group and used for rectifying the voltage signal into a positive voltage signal;
the third resistor is connected with the cathode of the first diode and used for receiving the positive voltage signal;
one end of the fourth resistor is connected with the third resistor, and the other end of the fourth resistor is grounded and used for dividing the received positive voltage signal;
the second capacitor is connected in parallel with the fourth resistor and used for stabilizing the positive voltage signal.
7. The output voltage detection circuit of claim 6, wherein the state determination module is connected between the third resistor and the fourth resistor, receives the detection signal output by the analog detection circuit, and determines the operating state of the BUCK converter circuit according to the positive voltage signal:
when the detection signal is determined to be lower than a second preset voltage value, determining that the BUCK converter circuit is in a no-load state;
when the detection signal is determined to be a pulse signal, determining that the BUCK converter circuit is in a short-circuit state;
and when the detection signal is determined to be in a high level, determining that the BUCK converter circuit is in a normal load state.
8. The output voltage detection circuit according to claim 1, wherein the LED constant current output circuit includes a flyback converter circuit, and the analog detection circuit obtains a voltage signal at an output cathode terminal of the flyback converter circuit through an auxiliary winding group.
9. The output voltage detection circuit according to claim 8, wherein the analog detection circuit comprises a second auxiliary winding group, a second diode, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a third capacitor, a fourth capacitor, an optocoupler, and a triode;
the second auxiliary winding group is used for being coupled with a voltage transformation output winding of the flyback converter circuit to obtain a voltage signal;
the anode of the second diode is connected with the second auxiliary winding group and is used for rectifying the voltage signal into a positive voltage signal;
one end of the fifth resistor is connected with the cathode of the anode of the second diode, and the other end of the fifth resistor is connected with the sixth resistor;
one end of the sixth resistor is connected with the fifth resistor, and the other end of the sixth resistor is grounded and used for dividing the received positive voltage signal;
the third capacitor is connected with the sixth resistor in parallel and used for stabilizing the positive voltage signal;
a first pin of the optocoupler is used for being connected between the fifth resistor and the sixth resistor, a second pin of the optocoupler is grounded, a third pin of the optocoupler is connected to a base electrode of the triode through the eighth resistor, and a fourth pin of the optocoupler receives a driving power supply with a preset voltage value and is connected to a collector electrode of the triode through the seventh resistor;
the emitting electrode of the triode is grounded and is connected with the base electrode through a ninth resistor;
the fourth capacitor is connected with the ninth resistor in parallel.
10. The output voltage detection circuit of claim 9, wherein the state determination module is configured to be connected to a collector of the transistor, receive a detection signal output by the analog detection circuit, and determine the operating state of the flyback converter circuit according to the detection signal:
when the detection signal is determined to be at a high level, determining that the flyback converter circuit is in an idle state;
when the detection signal is determined to be a pulse signal, determining that the flyback converter circuit is in a short-circuit state;
and when the detection signal is determined to be at a low level, determining that the flyback converter circuit is in a normal load state.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922008187.0U CN211235997U (en) | 2019-11-19 | 2019-11-19 | Output voltage detection circuit |
Applications Claiming Priority (1)
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