WO2015090184A1

WO2015090184A1 - Method for detecting output conduction angle θ of triac dimmer

Info

Publication number: WO2015090184A1
Application number: PCT/CN2014/093947
Authority: WO
Inventors: 魏其萃; 翁大丰
Original assignee: 魏其萃
Priority date: 2013-12-17
Filing date: 2014-12-16
Publication date: 2015-06-25
Also published as: CN103687242B; CN103687242A

Abstract

Disclosed is a method for detecting an output conduction angle θ of a triac dimmer, comprising: connecting a nonlinear current source to an output end of a diode in a full-wave rectifier in parallel; and keeping an energy-storage voltage of a parasitic capacitor of the diode in the full-wave rectifier at zero before a triac dimmer has an output, and releasing the energy-storage voltage of the parasitic capacitor of the diode in the full-wave rectifier when an input at an alternating-current side of the full-wave rectifier approaches zero, thereby accurately detecting an output conduction angle θ of the triac dimmer with small power consumption.

Description

Method for detecting output conduction angle θ of thyristor dimmer

Technical field

The invention belongs to the field of electronic technology and relates to AC DC LED dimming and power control. More specifically, the present invention relates to a method for detecting a thyristor dimming signal for an LED illumination and a corresponding circuit (ie, a method of detecting an output conduction angle θ of the thyristor dimmer).

Background technique

In the AC-DC LED thyristor dimmable driving power supply, the input power and the corresponding dimming information, that is, the output conduction angle θ, can be transmitted through the on and off of the thyristor dimmer. Therefore, in general operation, the output power and current of the AC-DC LED thyristor dimmable driving power source are controlled by detecting the output conduction angle θ of the thyristor dimmer.

In the prior art, the simplest method for detecting the output conduction angle θ pulse is to first detect the pulse width corresponding to the output conduction angle θ, and then calculate the ratio of the pulse width corresponding to the conduction angle θ to the AC mains cycle; The specific implementation circuit of the detection method is completed by the AC-DC full-wave rectifier output voltage through the voltage comparator, that is, when the AC-DC full-wave rectifier outputs the conduction angle θ pulse voltage is greater than the voltage comparator At the valve level, the voltage comparator outputs a "1"level; when the conduction angle θ pulse voltage output by the AC-DC full-wave rectifier is less than the valve level of the voltage comparator, the voltage comparator outputs "0"Level; for more accurate voltage comparator output "1" and "0" level to reflect the conduction angle θ output of the AC-DC full-wave rectifier, the valve level of the voltage comparator should be selected lower However, there is a parasitic capacitance in the AC-DC full-wave rectifier circuit. Due to the energy storage of the parasitic capacitor, the instantaneous voltage value on the AC side of the AC-DC full-wave rectifier is reduced. When the diode in the AC-DC full-wave rectifier is reverse-biased by the stored voltage of the parasitic capacitor, the DC-side output of the AC-DC full-wave rectifier will not correspond to the input on the AC side. To make the DC-side output of the AC-DC full-wave rectifier correspond to the input on the AC side, remove the parasitic capacitance storage voltage of the diode in the AC-DC full-wave rectifier, that is, the parasitic capacitance storage voltage follows the input on the AC side. The most direct way is to connect a constant current source I _{DIS to} the output of the diode in the AC-DC full-wave rectifier. Generally, the constant current source I _{DIS is} greater than I _MIN (I _MIN is the size of this parasitic capacitor And the response time is determined; the parasitic capacitance storage voltage of the diode in the full-wave rectifier is released by the constant current source I _DIS , so that the parasitic capacitance storage voltage follows the input change of the AC side. The cost of this method is the power consumption P _DIS on the current source, ie P _DIS =V _IN ×I _DIS , and other problems such that the resulting output waveform does not reflect the conduction angle θ well.

Detecting the output conduction angle of an AC-DC full-wave rectifier in an AC-DC LED TRIAC dimmable driving power supply θ is the key point. The output conduction angle θ is concerned with when it is “1” and when it is “0”; it does not pay attention to how the output of this full-wave rectifier accurately follows the input change of the AC side, but only requires accurate time. It is "1" and when it is "0". The present invention seeks to accurately detect the output conduction angle θ of the thyristor dimmer with as little power as possible, when it is "1" and when it is "0".

Summary of the invention

The technical problem to be solved by the present invention is to provide a method for accurately detecting the output conduction angle θ of the thyristor dimmer with as little power consumption as possible.

In order to solve the above technical problem, the present invention provides a method for detecting an output conduction angle θ of a thyristor dimmer, including a full-wave rectifier bridge in a thyristor dimmer and a full thyristor dimmer A non-linear current source connected in parallel with the wave rectifier bridge; the parasitic capacitance storage voltage of the full-wave rectifier bridge remains zero until the output of the thyristor dimmer has an output, and the input on the AC side of the full-wave rectifier bridge is near zero When the parasitic capacitance storage voltage of the full-wave rectifier bridge is released, the output conduction angle θ of the thyristor dimmer is accurately detected.

As an improvement of the method for detecting the output conduction angle θ of the thyristor dimmer according to the present invention, the non-linear current source is a four-terminal voltage-controlled current source device, including a detection input terminal G for detecting the magnitude of the external voltage, and an output. The periodic square wave pulse corresponds to the output conduction angle θ of the thyristor dimmer and the output control signal terminal D, the current input terminal A and the current input terminal K of the corresponding frequency; the input voltage V at the detection input terminal G _{During the} increase of _G by 0, the input ground current I _{DIS of the} current input terminal A is decreased by the maximum current I _MAX as the input voltage V _G of the detection input terminal G increases; when the input voltage V _{G of the} input terminal G is detected When the voltage is higher than the turn-on voltage V _FIX , the steady-state input ground current I _{DIS of the} current input terminal A is zero, the output control signal terminal D outputs a “1” level; and the input voltage V _G at the detection input terminal _G is turned on. V _FIX process is reduced, reducing the input voltage V _G to the input current I _DIS current input terminal a with the zero detection input terminal G is increased; when the input voltage detection input terminal V _G is equal to G 0 steady state current is input into the input terminal a of the current I _DIS The maximum current I _MAX; output control signal output terminal D "0" level.

Further improvement of the method for detecting the output conduction angle θ of the thyristor dimmer according to the present invention: the non-linear current source comprises a high voltage N-channel MOSFET, a low voltage P-channel MOSFET, a resistor R1, and a module 1; The module 1 provides a gate-fixed bias voltage V _{BIAS of the} high voltage N-channel MOSFET, and shapes the input voltage V _G signal input to the detection input terminal G into an output control signal D ₁ of the square wave pulse output; when the detection input terminal G When the input voltage V _{G is} greater than the turn-on voltage V _FIX , the output control signal D ₁ is at the "1"level; when the input voltage V _G =0 of the sense input terminal G, the output control signal D ₁ is at the "0" level.

Further improvement of the method for detecting the output conduction angle θ of the thyristor dimmer according to the present invention: the nonlinear current source includes a high voltage N-channel MOSFET, a low voltage P-channel MOSFET, a resistor R1, a resistor R2, and a low voltage N-channel. MOSFET and module 2; the gate of the high voltage N-channel MOSFET is provided by module 2 or otherwise providing a fixed bias voltage V _BIAS ; the module 2 also shapes the signal input to the control terminal V _G into a square wave pulse output control signal output from D _1; the resistor R2, low voltage N-channel MOSFET and an output control signal D constitutes _a switch current I _D D ₁ outputs a control signal controlled by the high-voltage N-channel MOSFET; the control module further 2 The low-voltage N-channel MOSFET constitutes a switching current I _D controlled by the output control signal D ₁ ; when the input voltage V _{G of the} detection input terminal G is greater than the turn-on voltage V _FIX , the output control signal D ₁ is "1"level; When the input voltage V _G =0 of the input terminal G, the output control signal D ₁ is at the "0" level.

Further improvement of the method for detecting the output conduction angle θ of the thyristor dimmer according to the present invention: the nonlinear current source comprises a high voltage N-channel MOSFET, a low voltage N-channel MOSFET, a resistor R1 and a module 3; 3, the signal input to the input voltage V _G of the detection input terminal G is also shaped by the built-in turn-on voltage V _FIX into an output control signal D ₁ of the square wave pulse output; the gate of the high-voltage N-channel MOSFET is provided by the module 3 Or a fixed bias voltage V _BIAS provided by other means; the high voltage N-channel MOSFET, the resistor R1 and the low voltage N-channel MOSFET form a switching current I _D controlled by the output control signal D ₁ through a high voltage N-channel MOSFET; 3 also controls the low-voltage N-channel MOSFET, which constitutes the switching current I _D controlled by the output control signal D ₁ ; when the input voltage V _{G of the} detection input terminal G is greater than the turn-on voltage V _FIX , the output control signal D ₁ is "1" When the input voltage V _{G of the} detection input terminal G is smaller than the turn-on voltage V _FIX , the output control signal D ₁ is at the “0” level.

A further improvement of the method for detecting the output conduction angle θ of the thyristor dimmer according to the present invention: the module 1, the module 2 and the module 3 can each be composed of a comparator and a logic circuit.

As a further improvement of the method for detecting the output conduction angle θ of the thyristor dimmer according to the present invention, the module 1, the module 2 and the module 3 are each provided with a hysteresis voltage ΔV.

In the method for detecting the conduction angle θ of the thyristor dimmer of the present invention, the parasitic capacitance storage voltage of the full-wave rectifier bridge is maintained at zero before the output of the thyristor dimmer, and is full-wave rectified The input near the zero of the bridge AC side releases the parasitic capacitance storage voltage of the full-wave rectifier bridge, so that the output conduction angle θ of the thyristor dimmer can be accurately detected with as little power consumption as possible.

Externally, the non-linear current source required in the above process is a four-terminal voltage-controlled current source device (as shown in Figure 1, including the sense input terminal G, the output control signal terminal D, the current input terminal A, and the current into the ground). End K); detecting input terminal G detecting external voltage magnitude; output control signal terminal D outputting periodic square wave pulse corresponding to thyristor dimmer output conduction angle θ and corresponding frequency; the other ends of the nonlinear current source are Current input terminal A and current into ground terminal K. As the input voltage V _G of the sense input terminal G is increased by 0, the input ground current I _{DIS of the} current input terminal A is decreased by the maximum current I _MAX as the input voltage V _G of the detection input terminal G increases (due to the loop Positive feedback action, usually this process time is relatively short); when the input voltage V _{G of the} detection input terminal G is greater than the turn-on voltage V _FIX , the steady-state input ground current I _{DIS of the} current input terminal A is zero, and the control signal is output The output of terminal D is "1" level. As the input voltage V _G of the detection input terminal G is decreased by the turn-on voltage V _FIX , the input ground current I _{DIS of the} current input terminal A is increased by zero with the decrease of the input voltage V _G of the detection input terminal G (due to the ring The positive feedback action of the circuit, usually the process time is relatively short); when the input voltage V _{G of the} detection input terminal G is equal to 0, the steady-state input ground current I _DIS of the current input terminal A reaches the maximum current I _MAX ; The output of the signal terminal D is at the "0" level.

When the input voltage V _{G of the} detection input terminal G is greater than the turn-on voltage V _FIX , the output control signal terminal D is “1” level; the input current to the ground current I _{DIS of the} nonlinear current source is zero, corresponding to the work of the nonlinear current source. The consumption is P _DIS :

P _DIS =V _IN ·I _DIS (V _G >V _FIX )=V _IN ·0=0 (1)

Where V _IN is the full-wave rectifier output voltage; I _DIS is the current input to the ground current, which is zero.

When the input voltage V _{G of the} detection input terminal G is less than the turn-on voltage V _FIX , the input current of the non-linear current source is I _DIS (V _G ), and the corresponding instantaneous power consumption is a function of the full-wave rectifier output voltage V _IN P _DIS (V _IN ):

Where V _G is the input voltage corresponding to the detection input terminal G; I _DIS (V _G ) is the input current of the current source that varies with the input voltage V _{G of the} detection input terminal G; k is the full-wave rectifier output voltage V _IN pair The reciprocal of the voltage division ratio α of the input voltage V _G of the input terminal G is detected.

When the input voltage V _G =0 of the input terminal G is detected, the corresponding full-wave rectifier output voltage V _IN is also zero; the input current of the nonlinear current source is I _MAX , and the output control signal terminal D is “0” level. The power consumption corresponding to the non-linear current source is P _DIS :

P _DIS =V _IN ·I _MAX =0·I _MAX =0 (3)

Since the input voltage V _{G is} greater than the turn-on voltage V _FIX and equal to 0, the steady-state power consumption of the nonlinear current source is zero, and only the input voltage V _{G is} between 0 and V _FIX , and the nonlinear current source has a formula. (2) Instantaneous power consumption as shown. Due to the positive feedback of the loop, the process time of the transition process is usually short, so the average power consumption of the nonlinear current source is quite low.

DRAWINGS

The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings.

1 is an external characteristic diagram of a nonlinear current source of the present invention;

2 is a typical application schematic diagram of a non-linear current source and an alternating current dimmer (Dimmer);

Figure 3 is a specific circuit diagram 1 of a non-linear current source;

4 is a specific circuit diagram 2 of a non-linear current source;

Figure 5 is a specific circuit diagram 3 of the non-linear current source;

Figure 6 is a typical circuit diagram 1 of a typical application of a non-linear current source and an AC dimmer (Dimmer);

Figure 7 is a typical circuit diagram 2 of a typical application of a non-linear current source and an AC dimmer (Dimmer);

Figure 8 is a typical application circuit diagram of a non-linear current source and an AC dimmer (Dimmer);

Figure 9 is a typical application circuit diagram of a non-linear current source and an AC dimmer (Dimmer);

Figure 10 is a typical circuit diagram of a typical application of a non-linear current source and an AC dimmer (Dimmer);

Figure 11 is a typical circuit diagram of a typical application of a non-linear current source and an AC dimmer (Dimmer).

detailed description

Figure 1 to Figure 2 show the method of detecting the output conduction angle θ of the thyristor dimmer; including a non-linear current source connected to the output of the full-wave rectifier bridge to store the parasitic capacitance of the full-wave rectifier bridge The voltage remains zero until the thyristor dimmer has an output, and the parasitic capacitance storage voltage of the full-wave rectifier bridge is released near the input of the AC side of the full-wave rectifier bridge, so that the work can be as small as possible. It is used to accurately detect the output conduction angle θ of the thyristor dimmer.

The nonlinear current source described above has the following characteristics:

Externally, the non-linear current source described above is a four-terminal voltage-controlled current source device (as shown in Figure 1, including the sense input terminal G, the output control signal terminal D, the current input terminal A, and the current input terminal K). The detection input terminal G detects the external voltage level; the output control signal terminal D outputs the periodic square wave pulse corresponding to the output conduction angle θ of the thyristor dimmer and the corresponding frequency; the other ends of the nonlinear current source are the current input Terminal A and current enter ground terminal K.

As the input voltage V _G of the sense input terminal G is increased by 0, the input ground current I _{DIS of the} current input terminal A is decreased by the maximum current I _MAX as the input voltage V _G of the detection input terminal G increases (due to the loop Positive feedback action, usually this process time is relatively short); when the input voltage V _{G of the} detection input terminal G is greater than the turn-on voltage V _FIX , the steady-state input ground current I _{DIS of the} current input terminal A is zero, and the control signal is output The output of terminal D is "1" level.

As the input voltage V _G of the detection input terminal G is decreased by the turn-on voltage V _FIX , the input ground current I _{DIS of the} current input terminal A is increased by zero with the decrease of the input voltage V _G of the detection input terminal G (due to the ring The positive feedback action of the circuit, usually the process time is relatively short); when the input voltage V _{G of the} detection input terminal G is equal to 0, the steady-state input ground current I _DIS of the current input terminal A reaches the maximum current I _MAX ; The output of the signal terminal D is at the "0" level.

According to the characteristics of the nonlinear current source described above, it can be known that:

P _DIS =V _IN ·I _DIS (V _G >V _FIX )=V _IN ·0=0 (1)

P _DIS =V _IN ·I _MAX =0·I _MAX =0 (3)

The application principle circuit of the specific nonlinear current source is shown in Figure 2.

Due to the action of the nonlinear current source I _DIS , the square wave pulse width outputted by the output control signal terminal D can accurately reflect the output conduction angle θ of the corresponding thyristor dimmer, that is, when is "1", The time is "0". The output control signal terminal D is used for control of the output power of the subsequent power converter.

Embodiment 1, as shown in FIG. 3, is a specific circuit diagram of a non-linear current source (non-linear current source I): the main body of the non-linear current source includes a high-voltage N-channel MOSFET Q1, a low-voltage P-channel MOSFET Q2, and a resistor. R1 and means 1; gate high voltage N-channel MOSFET Q1 is fixed bias voltage V _bIAS supplied by the module 1, or otherwise; module in addition to providing a bias voltage V _bIAS, but also the control input terminal of squaring up the signal V _G The output of the wave pulse output controls the signal D ₁ .

When the input voltage V _{G of the} detection input terminal G is greater than the turn-on voltage V _FIX , the output control signal D ₁ is “1” level; when the input voltage V _G =0 of the detection input terminal G, the output control signal D ₁ is “0”. "Level, as follows:

As can be seen from Figure 3, the turn-on voltage V _FIX of the non-linear current source I is:

V _FIX =V _BIAS -V _{N_th} +V _{F_th} (4)

Where V _{N_th} is the N-channel MOSFET turn-on voltage; V _{P_th} is the P-channel MOSFET turn-on voltage. The voltage control current I _DIS expression of the nonlinear current source I is:

When V _{G is} greater than V _FIX , I _DIS (V _G )=0 (6)

The output control signal D ₁ is "1" level.

When V _G =0,

The output control signal D ₁ is at a "0" level.

The module 1 described above is composed of a comparator and a logic circuit, and has a built-in hysteresis voltage ΔV.

Embodiment 2, as shown in FIG. 4, is a specific circuit diagram of a non-linear current source (non-linear current source II): the non-linear current source II is a non-linear current source driven by V _G feedback control, including a high-voltage N-channel. MOSFET Q1, low voltage P-channel MOSFET Q2, resistor R1, resistor R2, low voltage N-channel MOSFET Q3, and module 2; the gate of the high voltage N-channel MOSFET is a fixed bias voltage V _BIAS provided by module 2 or otherwise; Module 2 also shapes the input control terminal V _G into an output control signal D ₁ of the square wave pulse output; the resistor R2, the low voltage N-channel MOSFET Q3 and the output control signal D ₁ form an output through the high voltage N-channel MOSFET Q1. The switching current I _D controlled by the control signal D ₁ ; the module 2 also controls the low voltage N-channel MOSFET Q3 to constitute the switching current I _D controlled by the output control signal D ₁ .

When the input voltage V _{G of the} detection input terminal G is greater than the turn-on voltage V _FIX , the output control signal D ₁ is “1” level; when the input voltage V _G =0 of the detection input terminal G is output, the output control signal D ₁ is “ 0"level; the details are as follows:

As can be seen from Figure 4, the turn-on voltage V _FIX of the non-linear current source II is:

V _FIX =V _BIAS -V _{N_th} +V _{F_th} (8)

The voltage control current I _DIS expression of this non-linear current source II is:

When V _{G is} greater than V _FIX , I _DIS (V _G )=0 (10)

The output control signal D ₁ is "1" level.

When V _G =0,

The output control signal D ₁ is at a "0" level.

The output of the switch current I _D controlled by the output control signal D is:

When D is "1" level, I _D =0 (12)

When D is "0" level,

So, when V _G =0,

The module 2 described above is composed of a comparator and a logic circuit, and has a built-in hysteresis voltage ΔV.

Embodiment 3, as shown in FIG. 5, is a specific circuit diagram of a non-linear current source (non-linear current source III): the non-linear current source III includes a high-voltage N-channel MOSFET Q1, a low-voltage N-channel MOSFET Q2, and a resistor R1. And the module 3; the module 3 also inputs the signal input to the input voltage V _G of the detection input terminal G through the built-in turn-on voltage V _FIX to the output control signal D ₁ of the square wave pulse output, and the gate of the high-voltage N-channel MOSFET is Module 3 provides or otherwise provides a fixed bias voltage V _BIAS ; high voltage N-channel MOSFET Q1, resistor R1 and low voltage N-channel MOSFET Q2 form a switching current I _D controlled by output control signal D ₁ through high voltage N-channel MOSFET Q1 Module 3 also controls low voltage N-channel MOSFET Q2, which constitutes the switching current I _D controlled by output control signal D ₁ .

When the input voltage V _{G of the} detection input terminal G is greater than the turn-on voltage V _FIX , the output control signal D ₁ is “1” level; when the input voltage V _{G of the} detection input terminal G is less than the turn-on voltage V _FIX , the control signal D is output. ₁ is "0"level; the details are as follows:

When V _{G is} greater than V _FIX , I _D =0 (15)

The output control signal D is "1" level.

When V _{G is} less than V _FIX ,

The output control signal D is at a "0" level.

The module 3 described above is composed of a comparator and a logic circuit, and has a built-in hysteresis voltage ΔV. In the actual circuit implementation, since the input voltage V _{G of the} detection input terminal G is accompanied by interference noise, the module 3 eliminates the interference noise by the hysteresis voltage ΔV.

The maximum current I _MAX is such that the output voltage of the full-wave rectifier remains at zero voltage before the TRIAC dimmer is turned on.

If the instantaneous output voltage V _{IN of the} full-wave rectifier is greater than V _FIX ×k (k is the voltage division ratio of the full-wave rectifier output voltage V _IN to the input terminal G voltage V _G ), the input voltage of the input voltage terminal G corresponding to the non-linear current source V _G does not turn on the voltage controlled current I _{DIS of the} non-linear current source. When the instantaneous output voltage V _{IN of the} full-wave rectifier is less than V _FIX × k, the input voltage V _G of the input voltage terminal G of the corresponding non-linear current source turns on the voltage control current I _{DIS of the} non-linear current source.

Since the input voltage V _G of the non-linear current source input voltage terminal G detects the loop positive feedback regulation of the non-linear current source I _{DIS to} the instantaneous output voltage V _IN of the full-wave rectifier, the input current to the ground current I of the non-linear current source _{The DIS} increases as the instantaneous output voltage of the full-wave rectifier decreases, until the input voltage V _{G of} its sense input _G is zero, thus reaching the maximum current I _MAX ; the same non-linear current source input into the ground current follows the full-wave rectifier The instantaneous output voltage increases and decreases until its input voltage V _{G at} the sense input _{G is} greater than V _FIX and decreases to zero.

Due to the action of the non-linear current source, the instantaneous output voltage of the full-wave rectifier will be somewhat different from the corresponding input voltage on the instantaneous AC side, but their corresponding pulse widths are guaranteed to be the same. This is the goal sought by the present invention.

Since the input voltage V _{G of the} detection input terminal G is greater than V _FIX and equal to 0, the steady-state power consumption of the non-linear current source is zero, and only the input voltage V _{G of the} input terminal G is detected to transition between 0 and V _FIX . In the case that I _{MAX is} only greater than I _MIN (I _MIN is determined by the size of the parasitic capacitance and response time), the nonlinear current source has a finite instantaneous power consumption P _DIS ; due to the positive feedback of the loop, usually this transition The process time Δt of the process is relatively short (us level). In terms of the mains frequency, the half cycle time T/2 (ms level) is much larger than Δt, and the average power consumption of the nonlinear current source is P _{DIS_AVG} is quite low. .

The output control signal D ₁ of the nonlinear current source is a periodic square wave. Due to the function of the full-wave rectifier, its frequency is the frequency multiplication of the input mains; its pulse width is the output conduction angle corresponding to the thyristor dimmer. θ; the square wave signal will be used for the control of the output current of the downstream power converter.

The specific circuit of the specific circuit of the non-linear current source one, two, three, and the typical application of the AC dimmer (Dimmer), the first, second, third, fourth, fifth, and sixth are shown in Figures 6, 7, and 8, respectively. , 9, 10 and 11 are shown. In Figures 9, 10, 11 the high current diode D _in can be replaced by two low current rectifier diodes.

Finally, it should also be noted that the above list is only one specific embodiment of the invention. It is apparent that the present invention is not limited to the above embodiment, and many variations are possible. All modifications that can be directly derived or conceived by those of ordinary skill in the art from the disclosure of the present invention are considered to be the scope of the present invention.

Claims

A method for detecting a conduction angle θ of a thyristor dimmer, comprising a full-wave rectifier bridge in a thyristor dimmer and a nonlinear current connected in parallel with a full-wave rectifier bridge in the thyristor dimmer The source is characterized in that the parasitic capacitance storage voltage of the full-wave rectifier bridge is kept at zero until the output of the thyristor dimmer has an output, and the full wave is obtained when the input of the AC side of the full-wave rectifier bridge approaches zero. The parasitic capacitance storage voltage of the rectifier bridge is released, thereby accurately detecting the output conduction angle θ of the thyristor dimmer.
The method for detecting a conduction angle θ of a thyristor dimmer according to claim 1, wherein the non-linear current source is a four-terminal voltage-controlled current source device, and includes a detection input for detecting an external voltage. G, the output period square wave pulse corresponds to the output conduction angle θ of the thyristor dimmer and the corresponding frequency of the output control signal terminal D, the current input terminal A and the current into the ground terminal K;

In the process in which the input voltage V G of the detection input terminal G is increased by 0, the input ground current I DIS of the current input terminal A is decreased by the maximum current I MAX as the input voltage V G of the detection input terminal G increases. When the input voltage V G of the detection input terminal G is greater than the turn-on voltage V FIX , the steady-state input ground current I DIS of the current input terminal A is zero, and the output control signal terminal D outputs “1” level;

During the process in which the input voltage V G of the detection input terminal G is decreased by the turn-on voltage V FIX , the input ground current I DIS of the current input terminal A is reduced by zero with the decrease of the input voltage V G of the detection input terminal G. When the input voltage V G of the detection input terminal G is equal to 0, the steady-state input ground current I DIS of the current input terminal A reaches the maximum current I MAX ; and the output control signal terminal D outputs the "0" level.
The method of detecting a thyristor dimmer output conduction angle θ according to claim 2, wherein said non-linear current source comprises a high voltage N-channel MOSFET, a low voltage P-channel MOSFET, a resistor R1, and a module 1 ;

The module 1 provides a gate-fixed bias voltage V BIAS of the high voltage N-channel MOSFET, and shapes the input voltage V G signal input to the detection input terminal G into an output control signal D 1 of the square wave pulse output;

When the input voltage V G of the detection input terminal G is greater than the turn-on voltage V FIX , the output control signal D 1 is “1” level;

When the input voltage V G =0 of the input terminal G is detected, the output control signal D 1 is at the "0" level.
The method for detecting a conduction angle θ of a thyristor dimmer according to claim 3, wherein the nonlinear current source comprises a high voltage N-channel MOSFET, a low voltage P-channel MOSFET, a resistor R1, a resistor R2, and a low voltage. N-channel MOSFET and module 2;

The gate of the high voltage N-channel MOSFET is provided by module 2 or otherwise provided with a fixed bias voltage V BIAS ;

The module 2 also shapes the signal input to the control terminal V G into an output control signal D 1 of the square wave pulse output;

The resistor R2, low voltage N-channel MOSFET and the output control signals D 1 channel MOSFET switch current I D D 1 outputs a control signal controlled by the high pressure N;

The module 2 also controls a low voltage N-channel MOSFET to constitute a switching current I D controlled by the output control signal D 1 ;

When the input voltage V G of the detection input terminal G is greater than the turn-on voltage V FIX , the output control signal D 1 is “1” level;

When the input voltage V G =0 of the input terminal G is detected, the output control signal D 1 is at the "0" level.
The method for detecting a conduction angle θ of a thyristor dimmer according to claim 4, wherein the non-linear current source comprises a high voltage N-channel MOSFET, a low voltage N-channel MOSFET, a resistor R1, and a module 3;

The module 3 also shapes the signal input to the input voltage V G of the detection input terminal G through the built-in turn-on voltage V FIX into an output control signal D 1 of the square wave pulse output;

The gate of the high voltage N-channel MOSFET is a fixed bias voltage V BIAS provided by module 3 or otherwise provided;

The high voltage N-channel MOSFET, the resistor R1 and the low voltage N-channel MOSFET form a switching current I D controlled by the output control signal D 1 through a high voltage N-channel MOSFET;

The module 3 also controls a low voltage N-channel MOSFET to constitute a switching current I D controlled by the output control signal D 1 ;

When the input voltage V G of the detection input terminal G is greater than the turn-on voltage V FIX , the output control signal D 1 is “1” level;

When the input voltage V G of the detection input terminal G is smaller than the turn-on voltage V FIX , the output control signal D 1 is at the "0" level.
The method for detecting a conduction angle θ of a thyristor dimmer according to claim 5, wherein:

The module 1, the module 2 and the module 3 are each composed of a comparator and a logic circuit.
The method for detecting the output conduction angle θ of the thyristor dimmer according to claim 6, wherein the module 1, the module 2 and the module 3 are each provided with a hysteresis voltage ΔV.