Dimming circuit capable of adjusting minimum starting current

Abstract

The utility model relates to a dimming circuit capable of adjusting a minimum starting current. The dimming circuit comprises a master control circuit, a dimming signal input circuit, a minimum starting current adjusting circuit used for outputting a minimum starting current signal, and a switching circuit used for controlling a load. The master control circuit is connected with the dimming signal input circuit. The minimum starting current regulating circuit and the switching circuit are used for receiving a minimum starting current signal from the minimum starting current regulating circuit and then taking the minimum starting current signal as the minimum starting current of a load, so that dimming signals output to the main control circuit by the dimming signal input circuit can at least normally light the load; the loss of the light modulator of the light modulation signal circuit is reduced, the service life of the light modulator is prolonged, and the user experience is greatly improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a power supply field especially a dimming circuit of adjustable minimum starting current. BACKGROUND

[0002] Bulb and lamp holder are two basic components in lamps, which bear different functions respectively, but cooperate closely together to form lighting system.

[0003] Bulb is a component to produce light source, which makes filament inside bulb heat or excite fluorescent powder to emit light through the action of current, so as to illuminate the surrounding environment. There are various types of bulbs, and the common ones are incandescent lamp, halogen lamp, energy-saving lamp and LED lamp.

[0004] Lamp holder is a component to fix bulb and provide power supply for it. There are various types of lamp holders to meet the needs of different bulbs and installation environments. Common types of lamp holders are bayonet lamp holder and screw lamp holder.

[0005] Lamp holder generally does not have dimming function, and cannot adjust brightness according to actual use, which greatly affects the user experience. Later, lamp holders with dimming function appeared. The existing dimming principle is through dimmer, that is, using silicon controlled circuit to change sine wave by adjusting the conduction angle of each half wave of alternating current, so as to change the effective value of alternating current. However, the dimmer is generally controlled by a knob, and the knob needs to be rotated by a large angle to reach the minimum starting current of light, which is poor in user experience, and long-term use may cause damage to the knob and dimmer, affecting normal use.

[0006] Therefore, in the utility model patent application, the applicant carefully studies a dimming circuit of adjustable minimum starting current to solve the above problems. CONTENT OF THE UTILITY MODEL

[0007] The utility model mainly aims at providing a dimming circuit of adjustable minimum starting current, which is beneficial to reduce the loss of dimmer of dimming signal circuit, prolong the service life and greatly improve the user experience.

[0008] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0009] A dimming circuit of adjustable minimum starting current comprises a main control circuit, a dimming signal input circuit, a minimum starting current adjusting circuit for outputting minimum starting current signal and a switching circuit for controlling load.

[0010] The master control circuit is connected with the dimming signal input circuit, the minimum starting current adjusting circuit and the switch circuit respectively, and receives the minimum starting current signal from the minimum starting current adjusting circuit, and then the dimming signal output from the dimming signal input circuit to the master control circuit can normally light the load at least.

[0011] As a preferred solution, the dimming signal input circuit comprises a variable resistor VR1, the first fixed end of the variable resistor VR1 is used for connecting the VCC voltage end of the power supply circuit, the second fixed end of the variable resistor VR1 is grounded, and the movable end of the variable resistor VR1 is connected with the sensing resistor R5 and the master control circuit.

[0012] As a preferred solution, the switch circuit is a MOS tube switch circuit, which comprises a MOS tube Q2 and resistors R3 and R10 connected in series, the non-series node of the resistor R3 is connected with the gate of the MOS tube Q2, the drain of the MOS tube Q2 is grounded, the source of the MOS tube Q2 is used for connecting one end of the load, and the non-series node of the resistor R10 is connected with the master control circuit.

[0013] As a preferred solution, the minimum starting current adjusting circuit is a minimum starting current non-pole adjusting circuit or a minimum starting current pole adjusting circuit.

[0014] As a preferred solution, the minimum starting current non-pole adjusting circuit comprises a variable resistor VR2, the first fixed end of the variable resistor VR2 is used for connecting the VCC voltage end of the power supply circuit, the second fixed end of the variable resistor VR2 is grounded, and the movable end of the variable resistor VR2 is connected with the sensing resistor R6 and the master control circuit.

[0015] As a preferred solution, the minimum starting current pole adjusting circuit comprises a gear key SW1 and resistors R181 and R81 connected in series.

[0016] The non-series node of the resistor R181 is used for connecting the VCC voltage end of the power supply circuit, the non-series node of the resistor R81 is grounded, the series node of the resistor R181 and the resistor R81 is connected with the master control circuit, and the gear key SW1 is connected with the resistor R81 in parallel.

[0017] Compared with the prior art, the utility model has obvious advantages and beneficial effects, specifically speaking: mainly through the minimum starting current adjusting circuit, the minimum adjustment current value of the dimming signal input circuit can reach the minimum starting current of the load, which is beneficial to reduce the loss of the dimmer of the dimming signal circuit, prolong the service life, and greatly improve the user experience.

[0018] In order to more clearly set forth the structural features and functions of the utility model, the following will be combined with the specific embodiments to make a detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is the circuit schematic of an embodiment of the utility model;

[0020] Figure 2 is the circuit schematic of another embodiment of the utility model.

[0021] Explanation of reference numerals:

[0022] 11, main control circuit 12, dimming signal input circuit

[0023] 13, switch circuit 141, minimum starting current stepless adjustment circuit

[0024] 142, minimum starting current step adjustment circuit

[0025] 15, rectifier circuit 16, zero point detection circuit

[0026] 17, power supply circuit DETAILED DESCRIPTION

[0027] The utility model will be further described below in combination with the drawings and specific embodiments.

[0028] As Figure 1 and Figure 2 Indicated, a minimum starting current adjustable dimming circuit, comprising main control circuit 11, dimming signal input circuit 12, minimum starting current adjustment circuit for outputting minimum starting current signal and switch circuit 13 for controlling load,

[0029] Main control circuit 11 is connected dimming signal input circuit 12, minimum starting current adjustment circuit and switch circuit 13 respectively to receive minimum starting current signal from minimum starting current adjustment circuit after being minimum starting current signal to load and then make dimming signal output to main control circuit 11 of dimming signal input circuit 12 all can at least normally light load.

[0030] In the embodiment, main control circuit 11 includes the main control chip U1 of type PC0123F.Connect dimming signal input circuit 12 with pin 7 of main control chip U1 to receive dimming signal, connect minimum starting current adjustment circuit with pin 4 of main control chip U1 to receive minimum starting current signal, connect switch circuit 13 with pin 3 of main control chip U1 to output control signal to switch circuit 13.

[0031] In the embodiment, the dimming signal input circuit 12 comprises a variable resistor VR1, the first fixed end of the variable resistor VR1 is used for connecting the VCC voltage end of the power supply circuit 17, the second fixed end of the variable resistor VR1 is grounded, and the active end of the variable resistor VR1 is connected with the sensing resistor R5 and the pin 7 of the master control chip U1 of the master control circuit 11. By adjusting the active end of the variable resistor VR1, the voltage between the pin 7 of the master control chip U1 of the master control circuit 11, the partial circuit of the variable resistor VR1 and the resistor 5 can be adjusted, so that the input of the stepless change dimming signal is realized.

[0032] In the embodiment, the switch circuit 13 is a MOS tube switch circuit, which comprises a MOS tube Q2 and resistors R3 and R10 connected in series, the non-series node of the resistor R3 is connected with the gate of the MOS tube Q2, the drain of the MOS tube Q2 is grounded, the source of the MOS tube Q2 is used for connecting one end of the load, and the non-series node of the resistor R10 is connected with the master control circuit 11.

[0033] In the embodiment, the minimum starting current of the LED lamp L1 is taken as 10A for example. Before the minimum starting current adjusting circuit is not used, if the adjusting variable resistor VR1 of the dimming signal input circuit 12 is directly used, it is necessary to adjust the active end of the variable resistor VR1 to the middle part so as to make the LED lamp L1 reach the minimum starting current, assuming that the range of the variable resistor VR1 is 0-20A.

[0034] If the minimum starting current adjusting circuit is used, the active end of the variable resistor VR1 only needs to be slightly adjusted, so as to make the LED lamp L1 reach the minimum starting current, without the need of adjusting the active end of the variable resistor VR1 to the middle part, which greatly reduces the loss of the variable resistor VR1 and prolongs the service life thereof.

[0035] The minimum starting current adjusting circuit is a minimum starting current stepless adjusting circuit 141 or a minimum starting current step adjusting circuit 142.

[0036] In the embodiment, the minimum starting current stepless adjusting circuit 141 comprises a variable resistor VR2, the first fixed end of the variable resistor VR2 is used for connecting the VCC voltage end of the power supply circuit 17, the second fixed end of the variable resistor VR2 is grounded, and the active end of the variable resistor VR2 is connected with the sensing resistor R6 and the pin 4 of the master control chip U1 of the master control circuit 11.

[0037] In another embodiment, the minimum starting current step adjusting circuit 142 comprises a gear button SW1 and resistors R181 and R81 connected in series.

[0038] The non-series node of the resistor R181 is used to connect the VCC voltage end of the power supply circuit 17, the non-series node of the resistor R81 is grounded, and the series node of the resistor R181 and the resistor R81 is connected to the pin 4 of the master control chip U1 of the master control circuit 11. The gear button SW1 is connected in parallel with the resistor R81. When the gear button SW1 is pressed, the resistor R81 is short-circuited, the current signal received by the pin 4 of the master control chip U1 of the master control circuit 11 becomes larger, and then the minimum starting current value is increased in the form of gear.

[0039] The rectifier circuit 15, the zero point detection circuit 16 and the power supply circuit 17 for power supply are further included. The two alternating current input ends of the rectifier circuit 15 are connected to the mains. In the embodiment, the load is an LED lamp L1. The two ends of the LED lamp L1 are connected in parallel with the capacitor C2.

[0040] The direct current positive output end of the rectifier circuit 15 is respectively connected to the input end of the power supply circuit 17 and the input end of the zero point detection circuit 16, and the output end of the power supply circuit 17 outputs the VCC voltage end. The direct current negative output end of the rectifier circuit 15 is grounded. The rectifier circuit 15 includes a bridge rectifier ZD3.

[0041] The rectifier circuit 15 converts the mains with positive half cycle and negative half cycle into a direct current pulse voltage signal with only positive half cycle; the master control chip U1 of the master control circuit 11 outputs a PWM signal with a corresponding duty ratio to the MOS tube switching circuit according to the dimming signal input by the dimming signal input circuit 12, and then controls the current size of the LED lamp, so as to realize dimming. Moreover, the master control chip U1 of the master control circuit 11 detects the zero point (zero voltage point) of the direct current pulse voltage signal through the zero point detection circuit 16, and controls the starting point of the high level of each period of the PWM signal to be the same as the zero point of the direct current pulse voltage signal, so that the current of the LED lamp is the same in each period of the PWM signal.

[0042] The output end of the zero point detection circuit 16 is connected to the pin 2 of the master control chip U1 of the master control circuit 11. The master control circuit 11 detects the direct current pulse through the zero point detection circuit 16.

[0043] In the embodiment, the zero point detection circuit 16 includes a resistor R20, a resistor R26 and a triode Q4; the resistor R20 and the resistor R26 are connected in series, and the non-series node of the resistor R20 is connected to the direct current positive output end of the rectifier circuit 15. The series node of the resistor R20 and the resistor R26 is connected to the base of the triode Q4, the emitter of the triode Q4 and the non-series node of the resistor R26 are both grounded, and the collector of the triode Q4 is connected to the pin 2 of the master control chip U1.

[0044] When the direct current pulse voltage signal is at zero point, the triode Q4 is turned off so that the zero point detection circuit 16 does not output signal to the main control circuit 11.

[0045] The utility model discloses design key points are at, it mainly is through minimum starting current adjusting circuit, can make the minimum adjustment current value of dimming signal input circuit can reach the minimum starting current of load, is favorable to reduce the loss of dimmer of dimming signal circuit, prolongs its service life, greatly promotes user experience.

[0046] The above is only the preferred embodiment of the utility model, and does not limit the technical range of the utility model in any way, so any slight modification, equivalent change and modification made according to the technical essence of the utility model to the above embodiment still belong to the range of the technical scheme of the utility model.

Claims

1. A dimming circuit with adjustable minimum start-up current, characterized by: The application relates to a minimum starting current regulating circuit for a light-emitting diode (LED) lamp, which comprises a main control circuit, a dimming signal input circuit, a minimum starting current regulating circuit for outputting a minimum starting current signal and a switch circuit for controlling a load. The main control circuit is connected with the dimming signal input circuit, the minimum starting current regulating circuit and the switch circuit respectively, receives the minimum starting current signal from the minimum starting current regulating circuit, takes the minimum starting current signal as the minimum starting current of the load, and then makes the dimming signal output by the dimming signal input circuit to the main control circuit at least normally light up the load.

2. The adjustable minimum start-up current dimmer circuit of claim 1, wherein: The dimming signal input circuit comprises a variable resistor VR1, the first fixed end of the variable resistor VR1 is used for connecting a VCC voltage end of a power supply circuit, the second fixed end of the variable resistor VR1 is grounded, and the movable end of the variable resistor VR1 is connected with a sensing resistor R5 and the main control circuit.

3. The adjustable minimum start-up current dimmer circuit of claim 1, wherein The switch circuit is a MOS tube switch circuit, which comprises a MOS tube Q2 and series-connected resistors R3 and R10, the non-series connection node of the resistor R3 is connected with the gate of the MOS tube Q2, the drain of the MOS tube Q2 is grounded, the source of the MOS tube Q2 is used for connecting one end of the load, and the non-series connection node of the resistor R10 is connected with the main control circuit.

4. The adjustable minimum start-up current dimmer circuit of claim 1, wherein The minimum starting current regulating circuit is a minimum starting current non-pole regulating circuit or a minimum starting current pole regulating circuit.

5. The adjustable minimum start-up current dimmer circuit of claim 4, wherein The minimum starting current non-pole regulating circuit comprises a variable resistor VR2, the first fixed end of the variable resistor VR2 is used for connecting the VCC voltage end of the power supply circuit, the second fixed end of the variable resistor VR2 is grounded, and the movable end of the variable resistor VR2 is connected with a sensing resistor R6 and the main control circuit.

6. The adjustable minimum start-up current dimming circuit of claim 4, wherein: The minimum starting current pole regulating circuit comprises a gear key SW1 and series-connected resistors R181 and R81. The non-series connection node of the resistor R181 is used for connecting the VCC voltage end of the power supply circuit, the non-series connection node of the resistor R81 is grounded, the series connection node of the resistor R181 and the resistor R81 is connected with the main control circuit, and the gear key SW1 is connected with the resistor R81 in parallel.

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