A shunt circuit for controlling the current of LED lamp through PWM signal

Abstract

The present invention discloses a shunt circuit for controlling the current of an LED lamp through a PWM signal, comprising: a first diode, a signal filtering circuit, a triode, a first field effect transistor, a first resistor, a second resistor, a second field effect transistor, a third resistor, a second diode and a fourth resistor. The present invention can make the current flowing through the LED lamp less than or equal to 1mA, thereby reducing the brightness of the LED lamp, achieving the desired lighting effect, and further expanding the use range of the LED lamp.

Description

Technical Field

[0001] The present invention relates to the field of LED lamps, and in particular to a shunt circuit for controlling the current of an LED lamp through a PWM signal. Background Art

[0002] The shunt circuit of the PWM signal controlling the current of the LED lamp is usually applied to stage lamps or landscape lamps, so that the lighting effect of the LED lamp can achieve the desired purpose and let the audience or tourists experience the corresponding scene atmosphere.

[0003] In the prior art, when the PWM signal is output to control the LED drive, the minimum output current is 30-100mA, that is, the minimum current flowing through the LED lamp is 30-100mA, which causes the brightness of the LED lamp to be very bright and cannot achieve the desired lighting effect, thus limiting the scope of use of the LED lamp. Summary of the invention

[0004] The purpose of the present invention is to provide a shunt circuit for controlling the current of an LED lamp through a PWM signal, so as to solve the problem in the prior art that when the LED drive is controlled by a PWM signal, the minimum output current is 30-100mA, which causes the brightness of the LED lamp to be very bright and cannot achieve the desired lighting effect, thereby limiting the use range of the LED lamp.

[0005] In order to solve the above problems, the present invention provides a shunt circuit for controlling the current of an LED lamp through a PWM signal, comprising: a first diode, a signal filtering circuit, a transistor, a first field effect transistor, a first resistor, a second resistor, a second field effect transistor, a third resistor, a second diode and a fourth resistor;

[0006] The positive electrode of the first diode is used to access the PWM signal, and the two ends of the signal filtering circuit are electrically connected to the negative electrode of the first diode and the base of the transistor respectively;

[0007] The emitter of the transistor is grounded, and the collector of the transistor is electrically connected to the gate of the first field effect transistor and the cathode of the second diode respectively;

[0008] The source of the first field effect transistor is grounded, and the drain of the first field effect transistor is electrically connected to the first end of the first resistor;

[0009] The second end of the first resistor is electrically connected to the gate of the second field effect transistor and the first end of the second resistor respectively, and the second end of the second resistor is used to be electrically connected to the positive electrode of the LED lamp;

[0010] The source electrode of the second field effect tube is electrically connected to the first end of the third resistor, and the second end of the third resistor is used to be electrically connected to the negative electrode of the LED lamp;

[0011] The anode of the second diode is electrically connected to the fourth resistor, and the second end of the fourth resistor is used to be electrically connected to the anode of the LED lamp.

[0012] Preferably, the signal filtering circuit includes a fifth resistor and a capacitor, and the fifth resistor is arranged in parallel with the capacitor.

[0013] Preferably, a third diode is further included, wherein the cathode of the third diode is electrically connected to the anode of the second diode, and the cathode of the third diode is grounded.

[0014] Preferably, the third diode is a Zener diode.

[0015] Preferably, the first diode and the second diode are both rectifier diodes with a model number of IN4148.

[0016] Preferably, the transistor is an NPN transistor of model 8050SG-G.

[0017] Preferably, the first field effect transistor is an N-channel field effect transistor of model VMOS3262.

[0018] Preferably, the second field effect transistor is a P-channel field effect transistor of model TDM31035.

[0019] Compared with the prior art, the shunt circuit for controlling the current of the LED lamp through a PWM signal in the present invention is electrically connected through a first diode, a signal filtering circuit, a transistor, a first field effect transistor, a first resistor, a second resistor, a second field effect transistor, a third resistor, a second diode and a fourth resistor, so that the current flowing through the LED lamp is less than or equal to 1mA, thereby reducing the brightness of the LED lamp, achieving the desired lighting effect, and further expanding the scope of use of the LED lamp. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A device connection diagram of a shunt circuit for controlling the current of an LED lamp through a PWM signal is provided for an embodiment of the present invention.

[0022] Among them, 10. Signal filtering circuit. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The embodiment of the present invention provides a shunt circuit for controlling the current of an LED lamp through a PWM signal. Figure 1 As shown, it includes a first diode D6, a signal filtering circuit 10, a transistor Q9, a first field effect transistor Q8, a first resistor R45, a second resistor R40, a second field effect transistor Q7, a third resistor R6, a second diode D5 and a fourth resistor R30.

[0025] Among them, PWM is pulse width modulation.

[0026] Specifically, the anode of the first diode D6 is used to access the PWM signal, and the two ends of the signal filtering circuit 10 are electrically connected to the cathode of the first diode D6 and the base of the transistor Q9 respectively.

[0027] The emitter of the transistor Q9 is grounded, and the collector of the transistor Q9 is electrically connected to the gate of the first field effect transistor Q8 and the cathode of the second diode D5 respectively.

[0028] The source of the first field effect transistor Q8 is grounded, and the drain of the first field effect transistor Q8 is electrically connected to the first end of the first resistor R45.

[0029] The second end of the first resistor R45 is electrically connected to the gate of the second field effect transistor Q7 and the first end of the second resistor R40 respectively. The second end of the second resistor R40 is used to be electrically connected to the positive electrode of the LED lamp.

[0030] The source of the second field effect transistor Q7 is electrically connected to the first end of the third resistor R6, and the second end of the third resistor R6 is used to be electrically connected to the cathode of the LED lamp.

[0031] The anode of the second diode D5 is electrically connected to the fourth resistor R30 , and the second end of the fourth resistor R30 is used to be electrically connected to the anode of the LED lamp.

[0032] The first diode D6 and the second diode D5 are both rectifier diodes of model IN4148. Of course, according to actual needs, the first diode D6 and the second diode D5 can also use other models.

[0033] The transistor Q9 is an NPN transistor of model 8050SG-G. Of course, according to actual needs, the transistor Q9 can also use other models.

[0034] The first field effect transistor Q8 is an N-channel field effect transistor of model VMOS3262. Of course, according to actual needs, the first field effect transistor Q8 can also use other models.

[0035] The second field effect transistor Q7 is a P-channel field effect transistor of model TDM31035. Of course, according to actual needs, the second field effect transistor Q7 can also use other models.

[0036] Specifically, the signal filtering circuit 10 includes a fifth resistor R39 and a capacitor C5. The fifth resistor R39 and the capacitor C5 are connected in parallel, that is, two ends of the fifth resistor R39 and the capacitor C5 are electrically connected to the cathode of the first diode D6 and the base of the transistor Q9 respectively.

[0037] Furthermore, a third diode ZN1 is included, a cathode of the third diode ZN1 is electrically connected to the anode of the second diode D5, and a cathode of the third diode ZN1 is grounded.

[0038] The third diode ZN1 is a Zener diode.

[0039] The working principle of the shunt circuit for controlling the current of the LED lamp by the PWM signal in this embodiment is as follows: when the PWM inputs the minimum square wave signal, the transistor Q9 is turned on at the minimum, the voltage drop at point A is very small and basically does not change, the first field effect tube Q8 is turned on, the voltage at point B is basically reduced to 0V, the voltage at point C is divided by the second resistor R40 and the first resistor R45, so that the third field effect tube is turned on, and most of the LED output current flows through the third resistor R6, so that the current flowing through the LED lamp is less than or equal to 1mA. If the square wave signal input by the PWM is larger, the transistor Q9 is turned on more, the voltage drop at point A is also larger, the first field effect tube Q8 is turned on less, the voltage at point B is higher, the voltage at point C is also higher, the second field effect tube Q7 is turned on less, and the current flowing through the LED lamp is larger.

[0040] Compared with the prior art, the shunt circuit of the present embodiment controls the current of the LED lamp through a PWM signal, which is electrically connected through the first diode D6, the signal filtering circuit 10, the transistor Q9, the first field effect transistor Q8, the first resistor R45, the second resistor R40, the second field effect transistor Q7, the third resistor R6, the second diode D5 and the fourth resistor R30, so that the current flowing through the LED lamp can be less than or equal to 1mA, thereby reducing the brightness of the LED lamp, so that it can achieve the desired lighting effect, and further expanding the scope of use of the LED lamp.

[0041] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A shunt circuit for controlling the current of an LED lamp by a PWM signal, characterized in that: include: A first diode, a signal filtering circuit, a triode, a first field effect transistor, a first resistor, a second resistor, a second field effect transistor, a third resistor, a second diode and a fourth resistor; The positive electrode of the first diode is used to access the PWM signal, and the two ends of the signal filtering circuit are electrically connected to the negative electrode of the first diode and the base of the transistor respectively; The emitter of the transistor is grounded, and the collector of the transistor is electrically connected to the gate of the first field effect transistor and the cathode of the second diode respectively; The source of the first field effect transistor is grounded, and the drain of the first field effect transistor is electrically connected to the first end of the first resistor; The second end of the first resistor is electrically connected to the gate of the second field effect transistor and the first end of the second resistor respectively, and the second end of the second resistor is used to be electrically connected to the positive electrode of the LED lamp; The source electrode of the second field effect tube is electrically connected to the first end of the third resistor, and the second end of the third resistor is used to be electrically connected to the negative electrode of the LED lamp; The anode of the second diode is electrically connected to the fourth resistor, and the second end of the fourth resistor is used to be electrically connected to the anode of the LED lamp; The signal filtering circuit includes a fifth resistor and a capacitor, and the fifth resistor is arranged in parallel with the capacitor.

2. The shunt circuit for controlling the current of an LED lamp by a PWM signal according to claim 1, characterized in that: A third diode is also included, wherein a cathode of the third diode is electrically connected to an anode of the second diode, and a cathode of the third diode is grounded.

3. The shunt circuit for controlling the current of an LED lamp by a PWM signal according to claim 2, characterized in that: The third diode is a Zener diode.

4. The shunt circuit for controlling the current of an LED lamp by a PWM signal according to claim 1, characterized in that: The first diode and the second diode are both rectifier diodes with a model number of IN4148.

5. The shunt circuit for controlling the current of an LED lamp by a PWM signal according to claim 1, characterized in that: The transistor is an NPN transistor of model 8050SG-G.

6. The shunt circuit for controlling the current of an LED lamp by a PWM signal according to claim 1, characterized in that: The first field effect transistor is an N-channel field effect transistor of model VMOS3262.

7. The shunt circuit for controlling the current of an LED lamp by a PWM signal according to claim 1, characterized in that: The second field effect transistor is a P-channel field effect transistor of model TDM31035.

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