Dimming constant current circuit

Abstract

The utility model relates to the technical field of dimming constant current, in particular to a dimming constant current circuit, which comprises a switch unit, a wireless intelligent unit and a plurality of constant current units, and each constant current unit comprises a constant current diode and a metal oxide semiconductor (MOS) tube which are connected in series. The first end of the constant-current diode and the MOS tube in each constant-current unit after being connected in series is electrically connected with the switch unit, and the second end of the constant-current diode and the MOS tube in each constant-current unit after being connected in series is connected with each other and is electrically connected with an external lamp unit. The signal control end of the wireless intelligent unit is electrically connected with the third end of the constant current diode and the MOS tube in each constant current unit after the constant current diode and the MOS tube are connected in series, and the wireless intelligent unit sends a switch control signal to control on and off of the constant current diode so as to achieve output current of different gears. The plurality of current regulative diodes respectively control the switch units to realize superposition of current, so as to realize constancy of the current.

Description

Technical Field

[0001] The utility model relates to the technical field of dimming constant current, in particular to a dimming constant current circuit. Background Art

[0002] At present, most of the smart dimming lamps on the market are still based on constant current integrated circuits, which are expensive, poor in scalability, and complex in circuits, which are not conducive to design and production. Therefore, the update of hardware circuits is bound to be the improvement of smart dimming constant current technology to meet market demand. The traditional constant current implementation methods include closed loop formation of integrated circuit algorithms, series resistance current limiting and PWM chopping. However, all three implementations have defects, as follows:

[0003] 1. Integrated circuit control is expensive:

[0004] The integrated circuits currently used are more expensive than constant current diodes due to their complex manufacturing process, such as cumbersome packaging and testing;

[0005] 2. The consistency of the series resistance constant current method is poor, uncontrollable and the constant current accuracy is rough:

[0006] Because the lamp bead and the resistor are in series, when the lamp bead is lit for a period of time, it will generate heat, causing the junction voltage of the lamp bead to decrease. At this time, the voltage divider ratio of the resistor and the lamp bead changes. Therefore, when the resistor divides more voltage, the current will naturally change. Moreover, the resistance value will fluctuate with the change of temperature, resulting in unstable current of the lamp bead. The current change cannot be stabilized in a constant state.

[0007] 3. The PWM chopper circuit has a stroboscopic visual effect, which is not good:

[0008] The PWM chopping circuit is a method of changing the output brightness based on high-speed switching. This method uses the residual error of the naked eye to perceive changes in brightness. However, high-speed switching always has the problem of high-frequency flickering, which is not suitable for some scenes such as office and reading, and is more likely to cause eye fatigue. Utility Model Content

[0009] The technical problem to be solved by the utility model is to provide a dimming constant current circuit to achieve constant current.

[0010] In order to solve the above technical problems, the technical solution adopted by the utility model is:

[0011] A dimming constant current circuit comprises a switch unit, a wireless intelligent unit and a plurality of constant current units, each of the constant current units comprises a constant current diode and a MOS tube connected in series with each other, a first end of the constant current diode and the MOS tube in each constant current unit connected in series is respectively electrically connected to the switch unit, a second end of the constant current diode and the MOS tube in each constant current unit connected in series is connected to each other and is respectively electrically connected to an external lamp unit, the switch unit is electrically connected to the external lamp unit, and a signal control end of the wireless intelligent unit is respectively electrically connected to a third end of the constant current diode and the MOS tube in each constant current unit connected in series.

[0012] Furthermore, the switching unit includes a first transistor, and the first of the constant current diodes and MOS tubes in each constant current unit are electrically connected in series to the base of the first transistor, the collector of the first transistor is electrically connected to the external lamp unit, and the collector of the first transistor is grounded.

[0013] Furthermore, the lamp unit includes a plurality of first light-emitting diodes connected in series, the number of the first light-emitting diodes is equal to the number of constant current units, one end of the plurality of first light-emitting diodes connected in series is electrically connected to the collector of the first transistor, and the other end of the plurality of first light-emitting diodes connected in series is electrically connected to the second end of the constant current diode and the MOS tube in each constant current unit respectively.

[0014] Furthermore, the switch unit includes a plurality of second triodes, the number of the second triodes is equal to the number of the constant current units, the bases of the second triodes are electrically connected one-to-one with the first ends of the constant current diodes and MOS tubes in the constant current units after being connected in series, and the emitters of the plurality of second triodes are electrically connected to each other and are all grounded.

[0015] Furthermore, the lamp unit includes a plurality of second light-emitting diodes, the number of the second light-emitting diodes is equal to the number of the second triodes, the cathodes of the second light-emitting diodes are electrically connected to the collectors of the second triodes in a one-to-one correspondence, and the anodes of the plurality of second light-emitting diodes are electrically connected to each other and to the second end of the constant current diode and the MOS tube in each constant current unit that are connected in series.

[0016] The beneficial effects of the utility model are:

[0017] The present solution is provided with a switch unit, a wireless intelligent unit and a plurality of constant current units, each of which includes a constant current diode and a MOS tube connected in series with each other, the first end of the constant current diode and the MOS tube in each constant current unit after being connected in series with each other is electrically connected to the switch unit respectively, the second end of the constant current diode and the MOS tube in each constant current unit after being connected in series with each other is connected to each other and is electrically connected to an external lamp unit respectively, the switch unit is electrically connected to the external lamp unit, the signal control end of the wireless intelligent unit is electrically connected to the third end of the constant current diode and the MOS tube in each constant current unit after being connected in series with each other, the switch control signal is sent by the wireless intelligent unit to control the conduction and cut-off of the constant current diode respectively to achieve output currents of different gears, and the plurality of constant current diodes respectively control the switch unit to realize the superposition of currents, thereby realizing the constant current. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a circuit schematic diagram of Embodiment 1 of the dimming constant current circuit of the utility model;

[0019] Figure 2 This is a circuit schematic diagram of Embodiment 2 of the dimming constant current circuit of the utility model;

[0020] Figure 3 The circuit schematic diagram of the wireless intelligent unit of the dimming constant current circuit of the utility model;

[0021] Description of labels:

[0022] 1. Switch unit; 2. Constant current unit; 3. Lamp unit. DETAILED DESCRIPTION

[0023] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0024] Please refer to Figure 1 and Figure 2 , the technical solution adopted by the utility model is:

[0025] A dimming constant current circuit comprises a switch unit, a wireless intelligent unit and a plurality of constant current units, each of the constant current units comprises a constant current diode and a MOS tube connected in series with each other, a first end of the constant current diode and the MOS tube in each constant current unit connected in series is respectively electrically connected to the switch unit, a second end of the constant current diode and the MOS tube in each constant current unit connected in series is connected to each other and is respectively electrically connected to an external lamp unit, the switch unit is electrically connected to the external lamp unit, and a signal control end of the wireless intelligent unit is respectively electrically connected to a third end of the constant current diode and the MOS tube in each constant current unit connected in series.

[0026] From the above description, it can be seen that the beneficial effects of the utility model are:

[0027] The present solution is provided with a switch unit, a wireless intelligent unit and a plurality of constant current units, each of which includes a constant current diode and a MOS tube connected in series with each other, the first end of the constant current diode and the MOS tube in each constant current unit after being connected in series with each other is electrically connected to the switch unit respectively, the second end of the constant current diode and the MOS tube in each constant current unit after being connected in series with each other is connected to each other and is electrically connected to an external lamp unit respectively, the switch unit is electrically connected to the external lamp unit, the signal control end of the wireless intelligent unit is electrically connected to the third end of the constant current diode and the MOS tube in each constant current unit after being connected in series with each other, the switch control signal is sent by the wireless intelligent unit to control the conduction and cut-off of the constant current diode respectively to achieve output currents of different gears, and the plurality of constant current diodes respectively control the switch unit to realize the superposition of currents, thereby realizing the constant current.

[0028] Furthermore, further, the switching unit includes a first transistor, and the first of the constant current diodes and MOS tubes in each constant current unit are electrically connected in series to the base of the first transistor respectively, the collector of the first transistor is electrically connected to the external lamp unit, and the collector of the first transistor is grounded.

[0029] From the above description, it can be seen that by utilizing the amplification current characteristics of the transistor and the current relationship I c +I b =I e , I c =β*I b , by controlling I b To control I e Current is used to achieve the purpose of constant current; multiple constant current diodes are connected in parallel to achieve the purpose of expanding the output current.

[0030] Furthermore, the lamp unit includes a plurality of first light-emitting diodes connected in series, the number of the first light-emitting diodes is equal to the number of constant current units, one end of the plurality of first light-emitting diodes connected in series is electrically connected to the collector of the first transistor, and the other end of the plurality of first light-emitting diodes connected in series is electrically connected to the second end of the constant current diode and the MOS tube in each constant current unit respectively.

[0031] Furthermore, the switch unit includes a plurality of second triodes, the number of the second triodes is equal to the number of the constant current units, the bases of the second triodes are electrically connected one-to-one with the first ends of the constant current diodes and MOS tubes in the constant current units after being connected in series, and the emitters of the plurality of second triodes are electrically connected to each other and are all grounded.

[0032] From the above description, it can be seen that by utilizing the amplification current characteristics of the transistor and the current relationship I c +I b =I e , I c =β*I b , by controlling I b To control I e The purpose of constant current is achieved by controlling multiple transistors in parallel at the same time to achieve multiple colors, which can achieve the purpose of switching.

[0033] Furthermore, the lamp unit includes a plurality of second light-emitting diodes, the number of the second light-emitting diodes is equal to the number of the second triodes, the cathodes of the second light-emitting diodes are electrically connected to the collectors of the second triodes in a one-to-one correspondence, and the anodes of the plurality of second light-emitting diodes are electrically connected to each other and to the second end of the constant current diode and the MOS tube in each constant current unit that are connected in series.

[0034] Please refer to Figure 1 and Figure 3 , Embodiment 1 of the present utility model is:

[0035] A dimming constant current circuit comprises a switch unit 1, a wireless intelligent unit and a plurality of constant current units 2, each of the constant current units 2 comprises a constant current diode and a MOS tube connected in series with each other, a first end of the constant current diode and the MOS tube in each of the constant current units 2 connected in series is respectively electrically connected to the switch unit 1, a second end of the constant current diode and the MOS tube in each of the constant current units 2 connected in series is connected to each other and is respectively electrically connected to an external lamp unit 3, the switch unit 1 is electrically connected to the external lamp unit 3, and a signal control end of the wireless intelligent unit is respectively electrically connected to a third end of the constant current diode and the MOS tube in each of the constant current units 2 connected in series.

[0036] The switch unit 1 includes a first transistor, and the first of the constant current diodes and MOS tubes in each constant current unit 2 are electrically connected in series to the base of the first transistor respectively, the collector of the first transistor is electrically connected to the external lamp unit 3, and the collector of the first transistor is grounded.

[0037] The lamp unit 3 includes a plurality of first light-emitting diodes connected in series, the number of the first light-emitting diodes is equal to the number of constant current units 2, one end of the plurality of first light-emitting diodes connected in series is electrically connected to the collector of the first transistor, and the other end of the plurality of first light-emitting diodes connected in series is electrically connected to the second end of the constant current diode and the MOS tube in each constant current unit 2 connected in series.

[0038] The wireless intelligent unit includes a chip MK1, a first pin of the chip MK1 is connected to a clock signal, a third pin of the chip MK1 is connected to a VDD voltage, and a fifth pin of the chip MK1 is grounded.

[0039] The wireless intelligent unit can be Bluetooth, wifi, 2.4G, infrared, etc., for receiving external signals, and then transmitting the signals to different constant current diodes to achieve the effect of controlling current and color temperature.

[0040] In this embodiment, the number of the constant current units 2 is three, and the constant current diodes and MOS tubes in the three constant current units 2 are respectively represented as a constant current diode D1 (model SM4A15S) and a MOS tube Q1 (model UT2311), a constant current diode D2 (model SM4A15S) and a MOS tube Q2 (model UT2311), and a constant current diode D3 (model SM4A15S) and a MOS tube Q3 (model UT2311).

[0041] In this embodiment, the first transistor is represented by transistor Q4 (model: NPN13005).

[0042] In this embodiment, the number of the first light-emitting diodes is three, namely light-emitting diode LED1 (using a 9V / 1W lamp bead with parameter specifications), light-emitting diode LED2 (using a 9V / 1W lamp bead with parameter specifications) and light-emitting diode LED3 (using a 9V / 1W lamp bead with parameter specifications).

[0043] In this embodiment, the dimming constant current circuit further includes a resistor R1 (R1≤VIN / (I D1 +I D2 +I D3 ), where VIN is the input voltage, I D1 ,I D2 and I D3 Respectively represent the maximum current of constant current diode D1, constant current diode D2 and constant current diode D3) and resistor R2 (R2 ≥ (VIN-U LED ) / I Q4 , where U LED is the total voltage of LED1, LED2 and LED3, I Q4 is the saturation current of transistor Q4).

[0044] The specific connection relationship between the above components is:

[0045] The anode of the constant current diode D1 is electrically connected to the anode of the constant current diode D2, the anode of the constant current diode D3 and one end of the resistor R1 respectively, the cathode of the constant current diode D1 is electrically connected to the drain of the MOS tube Q1, the source of the MOS tube Q1 is electrically connected to the source of the MOS tube Q2, the source of the MOS tube Q3 and the base of the triode Q4 respectively, the gate of the MOS tube Q1 is electrically connected to the sixth pin of the chip MK1, the collector of the triode Q4 is electrically connected to the cathode of the light emitting diode LED1, the anode of the light emitting diode LED1 is electrically connected to the cathode of the light emitting diode LED2, the anode of the light emitting diode LED2 is electrically connected to the cathode of the light emitting diode LED3, the anode of the light emitting diode LED3 is electrically connected to one end of the resistor R2, and the other end of the resistor R2 is electrically connected to the other end of the resistor R1;

[0046] The cathode of the constant current diode D2 is electrically connected to the drain of the MOS tube Q2, and the gate of the MOS tube Q1 is electrically connected to the fourth pin of the chip MK1;

[0047] The cathode of the constant current diode D3 is electrically connected to the drain of the MOS tube Q3, and the gate of the MOS tube Q3 is electrically connected to the second pin of the chip MK1.

[0048] The working principle of the above dimming constant current circuit is:

[0049] This embodiment is a series dimming constant current circuit, which controls the conduction and shutdown of the MOS tube by sending three switch signals through the wireless intelligent unit to control the constant current diodes of different gears to control the output current;

[0050] In the multi-speed constant current of the series-connected LED, the chip MK1 sends out three switch control signals O / F_1, O / F_2 and O / F_3 to control the on and off of the MOS tubes Q3, MOS tubes Q2 and MOS tubes Q1 respectively to achieve the series connection of the constant current diode D3, the constant current diode D2 and the constant current diode D1 with the base of the transistor Q4; assuming that the switch control signal O / F_1 intervenes, the MOS tube Q3 is turned on at this time, and after the MOS tube Q3 is turned on, the constant current diode D3 is also turned on; according to the constant current characteristic of the constant current diode D3, when the input voltage VIN is limited by the resistor R1, it forms a loop with the constant current diode D3, the MOS tube Q3 and the base of the transistor Q4, and when the input voltage VIN reaches the constant current threshold of the constant current diode D3, the current of the constant current diode D3 is in a constant current state, and the current is I D3 According to the transistor characteristic, the magnification is constant, Ic = β * Ib, then the collector current of the transistor (i.e. the current of the light-emitting diode LED1, the light-emitting diode LED2 and the light-emitting diode LED3) I LED1 =βI D3, so the current of the light-emitting diode LED1 is in a constant state at this time; by analogy, when the MOS tube Q1 and the MOS tube Q2 are turned on successively, the current of the light-emitting diode changes with the change of the base current of the transistor, thereby achieving constant current of different gears.

[0051] Please refer to Figures 1 to 3 , Embodiment 2 of the present utility model is:

[0052] The differences between the second embodiment and the first embodiment are as follows:

[0053] Please refer to Figure 2 , the switch unit 1 includes a plurality of second triodes, the number of the second triodes is equal to the number of the constant current units 2, the bases of the second triodes are electrically connected one by one with the first ends of the constant current diodes and the MOS tubes in the constant current units 2 connected in series, and the emitters of the plurality of the second triodes are electrically connected to each other and are all grounded;

[0054] The lamp unit 3 includes a plurality of second light-emitting diodes, the number of the second light-emitting diodes is equal to the number of the second triodes, the cathodes of the second light-emitting diodes are electrically connected to the collectors of the second triodes in a one-to-one correspondence, and the anodes of the plurality of second light-emitting diodes are electrically connected to each other and to the second end of the constant current diode and the MOS tube in each constant current unit 2 connected in series.

[0055] In this embodiment, the number of the constant current units 2 is three, and the constant current diodes and MOS tubes in the three constant current units 2 are respectively represented as constant current diode D4 (model SM4A45S) and MOS tube Q5 (model UT2311), constant current diode D5 (model SM4A45S) and MOS tube Q6 (model UT2311), and constant current diode D6 (model SM4A45S) and MOS tube Q7 (model UT2311).

[0056] The number of the second transistors is three, namely, transistor Q8 (model NPN13005), transistor Q9 (model NPN13005) and transistor Q10 (model NPN13005). The number of the second light-emitting diodes is three, namely, light-emitting diode LED4 (using a 9V / 1W lamp bead with parameter specifications), light-emitting diode LED5 (using a 9V / 1W lamp bead with parameter specifications) and light-emitting diode LED6 (using a 9V / 1W lamp bead with parameter specifications).

[0057] In this embodiment, the dimming constant current circuit further includes a resistor R3 (R3≤VIN / (I D4 +I D5 +I D6 ), where VIN is the input voltage, I D4 ,ID5 and I D6 Respectively represent the maximum current of constant current diode D4, constant current diode D5 and constant current diode D6) and resistor R4 (R4 ≥ (VIN-U LED ) / (I Q8 +I Q9 +I Q10 ), where U LED is the total voltage of the light emitting diodes LED8, LED9 and LED10, I Q8 ,I Q9 and I Q10 are the saturation currents of transistor Q8, transistor Q9 and transistor Q10 respectively).

[0058] Please refer to Figure 2 and Figure 3 , the specific connection relationship between the above components is:

[0059] The anode of the constant current diode D4 is electrically connected to the anode of the constant current diode D5, the anode of the constant current diode D6 and one end of the resistor R3 respectively, the cathode of the constant current diode D4 is electrically connected to the drain of the MOS tube Q5, the source of the MOS tube Q5 is electrically connected to the base of the transistor Q8, the gate of the MOS tube Q5 is electrically connected to the sixth pin of the chip MK1, the collector of the transistor Q8 is electrically connected to the cathode of the light emitting diode LED4, the anode of the light emitting diode LED4 is electrically connected to the anode of the light emitting diode LED5, the anode of the light emitting diode LED6 and one end of the resistor R4 respectively, and the other end of the resistor R4 is electrically connected to the other end of the resistor R3;

[0060] The cathode of the constant current diode D5 is electrically connected to the drain of the MOS tube Q6, the source of the MOS tube Q6 is electrically connected to the base of the transistor Q9, the collector of the transistor Q9 is electrically connected to the cathode of the light emitting diode LED5, and the gate of the MOS tube Q6 is electrically connected to the fourth pin of the chip MK1;

[0061] The cathode of the constant current diode D6 is electrically connected to the drain of the MOS tube Q7, the source of the MOS tube Q7 is electrically connected to the base of the transistor Q10, and the gate of the MOS tube Q7 is electrically connected to the second pin of the chip MK1.

[0062] The working principle of the above dimming constant current circuit is:

[0063] This embodiment is a parallel dimming constant current circuit, which controls the conduction and shutdown of the MOS tube by sending three switching signals through the wireless intelligent unit to control the conduction of different constant current diodes, so as to achieve the conduction of different transistors. When different constant current diodes are involved, the lamp beads with different color temperatures in different circuits (respectively referring to light-emitting diode LED4, light-emitting diode LED5 and light-emitting diode LED6) are alternately turned on to achieve color temperature conversion, thereby realizing the constant current and the switching of color temperature.

[0064] Reference Figure 1 As shown, the working principle of the series dimming constant current circuit is: when the input voltage VIN is input, MOS tubes Q1, MOS tubes Q2 and MOS tubes Q3 receive the signal from the wireless intelligent unit and start to conduct. When the O / F_1 signal is triggered, MOS tube Q3 is turned on, and the constant current diode D3 is turned on. The maximum current I D3 At this time, it is the base current of the transistor Q4. According to Ic=β*Ib, at this time, each light-emitting diode (referring to the light-emitting diode LED1, the light-emitting diode LED2 and the light-emitting diode LED3) is turned on and enters the constant current state. As the O / F_2 and O / F_3 signals are turned on according to the settings, the base current of the transistor Q4 is superimposed according to the gears, so that each light-emitting diode enters a constant current of different gears, thereby realizing the switching of different gears of brightness; the working principle of the parallel dimming constant current circuit is basically the same as the working principle of the series dimming constant current circuit. The difference is that the lamp beads (i.e., light-emitting diodes) are changed from series to parallel, which can realize the alternating conduction of lamp beads with different color temperatures, thereby realizing the switching of color temperature.

[0065] In summary, the utility model provides a dimming constant current circuit, which is provided by setting a switch unit, a wireless intelligent unit and a plurality of constant current units, each constant current unit includes a constant current diode and a MOS tube connected in series with each other, the first end of the constant current diode and the MOS tube in each constant current unit after being connected in series is respectively electrically connected to the switch unit, the second end of the constant current diode and the MOS tube in each constant current unit after being connected in series is connected to each other and is respectively electrically connected to an external lamp unit, the switch unit is electrically connected to the external lamp unit, the signal control end of the wireless intelligent unit is respectively electrically connected to the third end of the constant current diode and the MOS tube in each constant current unit after being connected in series, the switch control signal is sent by the wireless intelligent unit to respectively control the conduction and cutoff of the constant current diode to achieve output currents of different gears, and multiple constant current diodes respectively control the switch unit to realize the superposition of currents, thereby realizing the constant current.

[0066] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A dimming constant current circuit, characterized in that: It includes a switch unit, a wireless intelligent unit and a plurality of constant current units, each of the constant current units includes a constant current diode and a MOS tube connected in series with each other, the first end of the constant current diode and the MOS tube in each constant current unit after being connected in series is electrically connected to the switch unit respectively, the second end of the constant current diode and the MOS tube in each constant current unit after being connected in series is connected to each other and is electrically connected to an external lamp unit respectively, the switch unit is electrically connected to the external lamp unit, and the signal control end of the wireless intelligent unit is electrically connected to the third end of the constant current diode and the MOS tube in each constant current unit after being connected in series.

2. The dimming constant current circuit according to claim 1, characterized in that: The switch unit includes a first transistor, and the first of the constant current diodes and MOS tubes in each constant current unit are electrically connected in series to the base of the first transistor respectively, the collector of the first transistor is electrically connected to the external lamp unit, and the collector of the first transistor is grounded.

3. The dimming constant current circuit according to claim 2, characterized in that: The lamp unit includes a plurality of first light-emitting diodes connected in series, the number of the first light-emitting diodes is equal to the number of constant current units, one end of the plurality of first light-emitting diodes connected in series is electrically connected to the collector of the first transistor, and the other end of the plurality of first light-emitting diodes connected in series is electrically connected to the second end of the constant current diode and the MOS tube in each constant current unit connected in series.

4. The dimming constant current circuit according to claim 1, characterized in that: The switch unit includes a plurality of second triodes, the number of the second triodes is equal to the number of the constant current units, the bases of the second triodes are electrically connected one-to-one with the first ends of the constant current diodes and MOS tubes in the constant current units connected in series, and the emitters of the plurality of second triodes are electrically connected to each other and are all grounded.

5. The dimming constant current circuit according to claim 4, characterized in that: The lamp unit includes a plurality of second light-emitting diodes, the number of the second light-emitting diodes is equal to the number of the second triodes, the cathodes of the second light-emitting diodes are electrically connected to the collectors of the second triodes in a one-to-one correspondence, and the anodes of the plurality of second light-emitting diodes are electrically connected to each other and to the second end of the constant current diode and the MOS tube in each constant current unit connected in series.

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