CN113423155B - Input voltage secondary detection circuit and working method thereof - Google Patents
Input voltage secondary detection circuit and working method thereof Download PDFInfo
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- CN113423155B CN113423155B CN202110678874.2A CN202110678874A CN113423155B CN 113423155 B CN113423155 B CN 113423155B CN 202110678874 A CN202110678874 A CN 202110678874A CN 113423155 B CN113423155 B CN 113423155B
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- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
Abstract
The embodiment of the invention discloses an input voltage secondary detection circuit and a working method thereof, wherein the circuit comprises a transformer auxiliary winding T1C, a resistance voltage divider unit, a power supply unit, a switching element and an RC integrating unit, wherein the power supply unit is also connected with a digital control unit; the switch element is connected with the digital control unit; the transformer auxiliary winding T1C and the resistance voltage divider unit process the input alternating current voltage signal, and the voltage of the power supply unit is superposed to obtain real-time direct current signal pulse; the direct current signal pulse carries a characteristic input switching element of an alternating current input signal; when the switch element is switched on, the voltage of the RC integral unit follows the amplitude of the direct current signal pulse, when the switch element is switched off, the RC integral unit cannot be charged quickly, and the voltage of the RC integral unit bears and keeps the alternating current input signal according to a set rule and is supplied to the digital control unit for detection. The embodiment of the invention realizes the isolation detection of the alternating current input signal and does not occupy too much resources and cost.
Description
Technical Field
The invention relates to the technical field of voltage detection circuits, in particular to an input voltage secondary detection circuit and a working method thereof.
Background
With the popularization of LED lighting technology in road lighting, the reliability requirement for the driving Power supply is higher and higher, and under abnormal conditions, necessary protection must be provided to prevent the driving Power supply from being damaged, and if the input voltage, which is one of the abnormalities, is too low or too high, the Power supply may be overheated or the voltage stress may be too high, which may affect the service life of the Power supply and even cause damage, and it is important how to sense the change of the input voltage and provide a stable and reliable signal to the digital control unit, especially in the application of single-stage PFC (Power Factor Correction) isolation dimming intelligent lighting driving with a built-in single-chip microcomputer.
In single-stage PFC isolated dimming smart lighting drive applications, the voltage on the transformer winding that powers the digital control unit carries the input voltage signal. However, the signal is a series of high frequency pulses, and the direct detection of these pulses occupies a large amount of resources of the digital control unit to process the detection signal, and a chip with a higher clock is required to detect the valid signal, thereby increasing the overall cost.
Therefore, there is a need to design a new circuit to implement isolated detection of ac input signals, and provide stable and reliable signals to the digital control unit, while not occupying too much resources, so as to reduce the cost.
Disclosure of Invention
The invention provides an input voltage secondary detection circuit and a working method thereof.
In order to solve the technical problems, the invention aims to realize the following technical scheme: an input voltage secondary detection circuit comprising a transformer auxiliary winding T1C, a resistive voltage divider unit, a power supply unit, a switching element, and an RC integration unit, the transformer auxiliary winding T1C being connected to the resistive voltage divider unit, the resistive voltage divider unit being connected to the switching element, the RC integration unit being connected to the switching element; the power supply unit is connected with the resistance voltage divider unit; the power supply unit is connected with the RC integrating unit and is also connected with a digital control unit; the switch element is connected with the digital control unit; the transformer auxiliary winding T1C and the resistance voltage divider unit process the input alternating current voltage signal, and the voltage of the power supply unit is superposed to obtain real-time direct current signal pulse; the direct current signal pulse carries the characteristics of an alternating current input signal and is input into the switch element; when the switch element is switched on, the voltage of the RC integral unit follows the amplitude of the direct current signal pulse, when the switch element is switched off, the RC integral unit cannot be charged quickly, and the voltage of the RC integral unit bears and keeps the alternating current input signal according to a set rule and is supplied to the digital control unit for detection.
The further technical scheme is as follows: the switching element includes a transistor Q2, the base of the transistor Q2 being connected to the resistive divider unit.
The further technical scheme is as follows: the resistance voltage divider unit comprises a diode D1, a resistor R4, a resistor R5 and a resistor R6, and the power supply unit is connected with the diode D1, the resistor R4, the resistor R5 and the resistor R6 in sequence.
The further technical scheme is as follows: the cathode of the diode D1 is connected with the transformer auxiliary winding T1C, and the anode of the diode D1 is connected with one end of the resistor R4.
The further technical scheme is as follows: one end of the resistor R5 and one end of the resistor R6 are respectively connected with the base electrode of the triode Q2.
The further technical scheme is as follows: the RC integrating unit comprises a resistor R7 and a capacitor C2, the resistor R7 is connected to the power supply unit and the emitter of the transistor Q2, one end of the capacitor C2 is connected to the emitter of the transistor Q2, the other end of the capacitor C2 is connected to the collector of the transistor Q2 and connected to signal ground, and one end of the capacitor C2 connected to the emitter of the transistor Q2 is connected to the digital control unit.
The further technical scheme is as follows: the power supply unit is connected with the base of the triode Q2 through the resistor R6.
The further technical scheme is as follows: the transformer auxiliary winding T1C is connected with the base of the triode Q2 through the diode D1, the resistor R4 and the resistor R5 in sequence.
The further technical scheme is as follows: the power supply unit comprises the transformer auxiliary winding T1C, a rectifying and filtering subunit and a linear LDO circuit which are connected in sequence.
The invention also provides a working method of the input voltage secondary detection circuit, which comprises the following steps:
the transformer auxiliary winding T1C and the resistance voltage divider unit process the input alternating current voltage signal, and the voltage of the power supply unit is superposed to obtain real-time direct current signal pulse; the direct current signal pulse carries an alternating current input signal characteristic input switch element; when the switch element is switched on, the voltage of the RC integral unit follows the amplitude of the direct current signal pulse, when the switch element is switched off, the time constant of the RC integral unit is large, the voltage cannot be charged quickly, and the voltage of the RC integral unit bears and keeps the alternating current input signal according to a set rule and is supplied to the digital control unit for detection.
Compared with the prior art, the invention has the beneficial effects that: according to the invention, the transformer auxiliary winding T1C, the resistance voltage divider unit, the power supply unit, the switch element and the RC integral unit are arranged, the resistance voltage divider unit and the power supply unit together integrate pulse signals on the transformer auxiliary winding T1C into identifiable input signals, the switch element and the RC integral unit are utilized to collect and maintain the input signals into stable direct current signals, the alternating current input signals are borne according to a given rule and are supplied to the digital control unit, the isolation detection of the alternating current input signals is realized, and simultaneously, too much resources and cost are not occupied.
The invention is further described below with reference to the accompanying drawings and specific embodiments.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic block diagram of an input voltage secondary detection circuit according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a specific circuit of the input voltage secondary detection circuit according to an embodiment of the present invention.
The labels in the figures illustrate:
10. a resistive voltage divider unit; 20. a switching element; 30. an RC integration unit; 40. a power supply unit; (ii) a 50. A digital control unit.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.
Referring to fig. 1, fig. 1 is a schematic block diagram of an input voltage secondary detection circuit according to an embodiment of the present invention, which can be applied to a digital power driving circuit with a digital control unit 50, i.e., a control chip, to implement isolation detection on an input ac signal, and provide a stable and reliable signal to the digital control unit 50, while not occupying too many resources and reducing the cost.
Referring to fig. 1, the input voltage secondary detection circuit includes a transformer auxiliary winding T1C, a resistor divider unit 10, a power supply unit 40, a switching element 20, and an RC integration unit 30, wherein the transformer auxiliary winding T1C is connected to the resistor divider unit 10, the resistor divider unit 10 is connected to the switching element 20, and the RC integration unit 30 is connected to the switching element 20; the power supply unit 40 is connected to the resistive divider unit 10; the power supply unit 40 is connected with the RC integrating unit 30, and the power supply unit 40 is also connected with a digital control unit 50; the switching element 20 is connected with the digital control unit 50; the transformer auxiliary winding T1C and the resistance voltage divider unit 10 process the input alternating current voltage signal, and the voltage of the power supply unit 40 is superposed to obtain real-time direct current signal pulse; a characteristic input switching element 20 in which the dc signal pulses carry ac input signals; when the switch element is turned on, the voltage of the RC integration unit 30 follows the amplitude of the dc signal pulse, and when the switch element 20 is turned off, the RC integration unit 30 is not charged quickly, and the voltage of the RC integration unit 30 bears and maintains the ac input signal according to a set rule, and is provided to the digital control unit 50 for detection.
In the present embodiment, the RC integrating unit 30 is connected with a digital control unit 50.
The pulse signals of the transformer auxiliary winding T1C and the resistance voltage divider unit 10 are superposed with the power supply signal of the power supply unit 40 to form a stable alternating current input frequency multiplication following signal, and a stable and reliable signal is provided for the digital control unit 50 to detect, so that a control instruction is sent according to the signal, the high-frequency pulse signal is not required to be directly detected, too many resources are not occupied, and the cost can be reduced.
Referring to fig. 2, fig. 2 is a schematic diagram of an embodiment of an input voltage secondary detection circuit according to the present invention; the switching element 20 described above includes a transistor Q2, the base of the transistor Q2 being connected to the resistive divider block 10. The following and holding process of the ac signal by the RC integration unit 30 is realized by turning on and off the transistor Q2.
In an embodiment, referring to fig. 2, the RC integration unit 30 includes a resistor R7 and a capacitor C2, the resistor R7 is connected to the power supply unit 40 and the emitter of the transistor Q2, the power supply unit 40 provides +5V, one end of the capacitor C2 is connected to the emitter of the transistor Q2, the other end of the capacitor C2 is connected to the collector of the transistor Q2 and connected to signal ground, and one end of the capacitor C2 connected to the emitter of the transistor Q2 is connected to the digital control unit 50, and after the ac input signal is superimposed on the +5V signal provided by the power supply unit 40, a signal is provided to the base of the transistor Q2, and the source of the transistor Q2 changes with the base. The time constants of the resistor R7 and the capacitor C2 are reasonably set, so that the voltage of the capacitor C2 closely follows the base signal of the triode Q2 when the triode Q2 is switched on, and the voltage of the capacitor C2 cannot be quickly charged when the base of the triode Q2 is switched off, so that the voltage of the capacitor C2 bears an alternating current input signal according to a given rule and is supplied to the digital control unit 50 for detection. The isolated detection of the ac input signal provides a reliable and stable signal to the digital control unit 50 without occupying too much resources and costs.
In one embodiment, referring to fig. 2, the power supply unit 40 provides +5V voltage, and is connected to the base of the transistor Q2 through the resistor R6, so as to superimpose the ac input signal and convert the ac input signal into the dc pulse signal.
In an embodiment, referring to fig. 2, the resistor divider unit 10 includes a diode D1, a resistor R4, a resistor R5 and a resistor R6, and the auxiliary transformer winding T1C of the power supply unit 40 is connected to the diode D1, the resistor R4, the resistor R5 and the resistor R6 in sequence.
The cathode of the diode D1 is connected to the transformer auxiliary winding T1C, and the anode of the diode D1 is connected to one end of the resistor R4.
One end of the resistor R5 and one end of the resistor R6 are respectively connected with the base electrode of the triode Q2.
The ac input signal is rectified by the diode D1, the resistor R4, and the resistor R5.
In one embodiment, referring to fig. 2, the power supply unit 40 includes a transistor Q1, a collector of the transistor Q1 is connected to the transformer auxiliary winding TIC, and a collector of the transistor Q1 is connected to the diode D1.
Specifically, the power supply unit 40 includes the transformer auxiliary winding T1C, a rectifying and filtering subunit, and a linear LDO circuit, which are connected in sequence, so as to rectify the input power supply signal and perform other processes to form a +5V voltage to be supplied to the digital control unit 50.
The power supply unit 40 is connected to the base of the transistor Q2 through the resistor R6.
The transformer auxiliary winding T1C is connected with the base of the triode Q2 through the diode D1, the resistor R4 and the resistor R5 in sequence.
By arranging the transformer auxiliary winding T1C, the resistor divider unit 10, the power supply unit 40, the switching element 20 and the RC integrating unit 30, the resistor divider unit 10 and the power supply unit 40 integrate pulse signals on the transformer auxiliary winding T1C into identifiable input signals, the input signals are collected and maintained into stable direct current signals by the switching element 20 and the RC integrating unit 30, the alternating current input signals are borne according to a given rule and are supplied to the digital control unit 50, and therefore isolation detection of the alternating current input signals is achieved, and meanwhile, too much resources and cost are not occupied.
In one embodiment, there is provided a method of operating an input voltage secondary detection circuit, including:
the transformer auxiliary winding T1C and the resistance voltage divider unit 10 process the input alternating current voltage signal, and the voltage of the power supply unit 40 is superposed to obtain real-time direct current signal pulse; the direct current signal pulse carries an alternating current input signal characteristic input switching element 20; when the switch element is turned on, the voltage of the RC integration unit 30 follows the amplitude of the dc signal pulse, when the switch element 20 is turned off, the time constant of the RC integration unit 30 is large, the voltage cannot be charged quickly, and the voltage of the RC integration unit 30 bears and maintains the ac input signal according to a set rule, and is provided to the digital control unit 50 for detection.
It should be noted that, as can be clearly understood by those skilled in the art, the specific implementation process of the operating method of the input voltage secondary detection circuit may refer to the corresponding description in the foregoing embodiment of the input voltage secondary detection circuit, and for convenience and brevity of description, no further description is provided herein.
While the invention has been described with reference to specific embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (9)
1. The input voltage secondary detection circuit is characterized by comprising a transformer auxiliary winding T1C, a resistor voltage divider unit, a power supply unit, a switching element and an RC integral unit, wherein the transformer auxiliary winding T1C is connected with the resistor voltage divider unit, the resistor voltage divider unit is connected with the switching element, and the RC integral unit is connected with the switching element; the power supply unit is connected with the resistance voltage divider unit; the power supply unit is connected with the RC integrating unit and is also connected with a digital control unit; the switch element is connected with the digital control unit; the transformer auxiliary winding T1C and the resistance voltage divider unit process the input alternating current voltage signal, and the voltage of the power supply unit is superposed to obtain real-time direct current signal pulse; the direct current signal pulse carries the characteristics of an alternating current input signal and is input into the switch element; when the switch element is switched on, the voltage of the RC integral unit follows the amplitude of the direct current signal pulse, when the switch element is switched off, the RC integral unit cannot be charged quickly, and the voltage of the RC integral unit bears and keeps the alternating current input signal according to a set rule and is supplied to the digital control unit for detection.
2. The input voltage secondary detection circuit of claim 1, wherein the switching element comprises a transistor Q2, a base of the transistor Q2 being connected to the resistive divider unit.
3. The input voltage secondary detection circuit according to claim 2, wherein the resistor divider unit comprises a diode D1, a resistor R4, a resistor R5 and a resistor R6, and the power supply unit is connected to the diode D1, the resistor R4, the resistor R5 and the resistor R6 in sequence.
4. The input voltage secondary detection circuit according to claim 3, wherein the cathode of the diode D1 is connected to the transformer auxiliary winding T1C, and the anode of the diode D1 is connected to one end of the resistor R4.
5. The input voltage secondary detection circuit according to claim 4, wherein one end of the resistor R5 and one end of the resistor R6 are respectively connected to the base of the transistor Q2.
6. The input voltage secondary detection circuit according to claim 5, wherein the RC integration unit comprises a resistor R7 and a capacitor C2, the resistor R7 is connected to the power supply unit and the emitter of the transistor Q2 respectively, one end of the capacitor C2 is connected to the emitter of the transistor Q2, the other end of the capacitor C2 is connected to the collector of the transistor Q2 and to signal ground, and one end of the capacitor C2 connected to the emitter of the transistor Q2 is connected to the digital control unit.
7. The input voltage secondary detection circuit of claim 6, wherein the power supply unit is connected to the base of the transistor Q2 through the resistor R6.
8. The input voltage secondary detection circuit according to claim 7, wherein the transformer auxiliary winding T1C is connected to the base of the transistor Q2 through the diode D1, the resistor R4 and the resistor R5 in sequence.
9. The working method of the input voltage secondary detection circuit is characterized by comprising the following steps:
the transformer auxiliary winding T1C and the resistance voltage divider unit process the input alternating current voltage signal, and the voltage of the power supply unit is superposed to obtain real-time direct current signal pulse; the direct current signal pulse carries an alternating current input signal characteristic input switch element; when the switch element is switched on, the voltage of the RC integral unit follows the amplitude of the direct current signal pulse, when the switch element is switched off, the time constant of the RC integral unit is large, the voltage cannot be charged quickly, and the voltage of the RC integral unit bears and keeps the alternating current input signal according to a set rule and is supplied to the digital control unit for detection.
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| CN202110678874.2A CN113423155B (en) | 2021-06-18 | 2021-06-18 | Input voltage secondary detection circuit and working method thereof |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202110678874.2A CN113423155B (en) | 2021-06-18 | 2021-06-18 | Input voltage secondary detection circuit and working method thereof |
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| CN113423155A CN113423155A (en) | 2021-09-21 |
| CN113423155B true CN113423155B (en) | 2022-05-31 |
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Citations (4)
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| GB1339224A (en) * | 1971-03-04 | 1973-11-28 | Licentia Gmbh | Delay element for a ac voltage logic system |
| CN101888730A (en) * | 2010-06-30 | 2010-11-17 | 海洋王照明科技股份有限公司 | Alternating current constant current source LED driving circuit |
| CN101895211A (en) * | 2009-05-22 | 2010-11-24 | 群康科技(深圳)有限公司 | Extensible switching power supply circuit |
| CN102946199A (en) * | 2012-11-09 | 2013-02-27 | 联合汽车电子有限公司 | Direct current insulation buck converter and matrix voltage detection circuit thereof |
-
2021
- 2021-06-18 CN CN202110678874.2A patent/CN113423155B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1339224A (en) * | 1971-03-04 | 1973-11-28 | Licentia Gmbh | Delay element for a ac voltage logic system |
| CN101895211A (en) * | 2009-05-22 | 2010-11-24 | 群康科技(深圳)有限公司 | Extensible switching power supply circuit |
| CN101888730A (en) * | 2010-06-30 | 2010-11-17 | 海洋王照明科技股份有限公司 | Alternating current constant current source LED driving circuit |
| CN102946199A (en) * | 2012-11-09 | 2013-02-27 | 联合汽车电子有限公司 | Direct current insulation buck converter and matrix voltage detection circuit thereof |
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| CN113423155A (en) | 2021-09-21 |
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