A dimming circuit with peak-valley current control

Abstract

The present invention relates to the technical field of electronic circuits, and specifically to a dimming circuit controlled by peak-valley current, including a dimming circuit, a control circuit and a dimmer, wherein the dimming circuit includes a sampling resistor R, an inductor L, a capacitor C1, an electronic switch Q1 and an electronic switch Q2, wherein one end of the electronic switch Q1 is connected to a power source Vin, the other end of the electronic switch Q1 is connected to one end of the electronic switch Q2, the other end of the electronic switch Q2 is grounded, the capacitor C1 is connected in parallel with a load RL, one end of the capacitor C1 is connected to one end of the inductor L, the other end of the inductor L is connected to the electronic switch Q1 and the connecting end of the electronic switch Q2, the other end of the capacitor C1 is grounded through a sampling resistor R, and the connection point between the sampling resistor R and the capacitor C1 is used as a sampling point and connected to the control circuit. The substantial effect of the present invention is: a technical solution for DC linear dimming is provided, the requirements for the stability of the power supply are reduced, the power supply power is almost consumed by the LED lamp, and the energy consumption of the circuit is small.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a dimming circuit controlled by peak and valley currents. Background Art

[0002] Light-emitting diodes, or LEDs for short, are a commonly used light-emitting device that emits light by releasing energy through the recombination of electrons and holes. They are widely used in the field of lighting. LEDs can efficiently convert electrical energy into light energy and have a wide range of uses in modern society, such as lighting, flat panel displays, and medical devices. Load LED lamps require a driving circuit to drive them to work. At present, rectifying AC power into stable DC power to drive load LED lamps is an important dimming technology. Among them, the use of PWM dimming is currently the most important dimming method. However, the constant current control technology in the prior art either has the problem of high power consumption and high cost, or has the problem of poor dimming accuracy. PWM dimming requires a dedicated chip for control, and the quality of the chip directly affects the stability of the light, while the cost of a good quality chip is relatively high. For example, when the constant current value is increased, the current control error range will be proportionally expanded, and the control error range cannot be maintained at a constant value during the dimming process. Therefore, when the light is brightened, the flicker of the light will also increase, which is not conducive to eye health. Therefore, it is necessary to develop a dimming technology with a more stable control error during the dimming process.

[0003] For example, Chinese patent CN108235502A, published on June 29, 2018, is a constant current driving method and circuit for dimming a load LED lamp; based on a circuit consisting of a triode transistor and a load LED lamp, the triode transistor includes a field effect tube or a triode, and the load LED lamp is electrically connected to the source or drain of the field effect tube or the emitter or collector of the triode; the method includes the following steps: a voltage adjustment module is provided that is electrically connected to the gate of the field effect tube or the base of the triode, and the voltage adjustment module adjusts the voltage of the source of the field effect tube or the emitter of the triode by adjusting the voltage of the gate of the field effect tube or the base of the triode, thereby adjusting the current output to the load LED lamp to change to achieve the purpose of dimming. Its constant current driving method and circuit for dimming a load LED lamp can adjust the brightness of the load LED lamp to a very low level, and the load LED lamp will not flicker visible to the naked eye. However, in its technical solution, the flickering of the load LED lamp has high requirements on the stability of the power supply. When the input power supply is AC, it requires higher cost and power consumption for rectification. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the current dimming technology has the technical problems of high cost, large ripple and poor dimming stability. A dimming circuit with low power consumption and peak-valley current control with low requirements on power supply voltage stability is proposed.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a peak-valley current controlled dimming circuit, including a dimming circuit, a control circuit and a dimmer, the dimming circuit including a sampling resistor R, an inductor L, a capacitor C1, an electronic switch Q1 and an electronic switch Q2, one end of the electronic switch Q1 is connected to the power supply Vin, the other end of the electronic switch Q1 is connected to one end of the electronic switch Q2, the other end of the electronic switch Q2 is grounded, the capacitor C1 is connected in parallel with the load RL, one end of the capacitor C1 is connected to one end of the inductor L, the other end of the inductor L is connected to the connecting end of the electronic switch Q1 and the electronic switch Q2, the other end of the capacitor C1 is grounded through the sampling resistor R, the connecting point of the sampling resistor R and the capacitor C1 is used as a sampling point and connected to the control circuit, the dimmer, the control end of the electronic switch Q1 and the control end of the electronic switch Q2 are all connected to the control circuit. The inductor L is used to store electric energy, and the capacitor C1 plays the role of storing energy and filtering the AC component in the current flowing through the inductor L. By sampling the voltage across the resistor R, the current flowing through the inductor L can be obtained. When the current of the inductor L is lower than the set lower limit, the inductor L is charged through the circuit. When the current of the inductor L is higher than the set upper limit, the charging is stopped, so that the load LED lamp driving current with a sufficiently small current fluctuation amplitude is obtained through this technical solution. The power supply Vin can be a DC power supply or an AC power after half-wave shaping.

[0006] Preferably, the control circuit includes an integrated operational amplifier U1, an integrated operational amplifier U2, an integrated operational amplifier U3, an integrated operational amplifier U4, an integrated operational amplifier U5, a sampling resistor R1, a sampling resistor R2, a sampling resistor R3, a diode D1, a diode D2 and an RS trigger, the sampling point is connected to the in-phase end of the integrated operational amplifier U1 and the first end of the sampling resistor R3, the inverting input end of the integrated operational amplifier U1 is grounded through the sampling resistor R1, one end of the sampling resistor R2 is connected to the inverting input end of the integrated operational amplifier U1, the other end of the sampling resistor R2 is connected to the output end of the integrated operational amplifier U1, the output end of the integrated operational amplifier U1 is connected to the in-phase end of the integrated operational amplifier U3 and the inverting input end of the integrated operational amplifier U4, the inverting input end of the integrated operational amplifier U3 is connected to the reference signal Ihigh, the in-phase end of the integrated operational amplifier U4 is connected to the reference signal Ilow, and the integrated The output end of the integrated operational amplifier U3 is connected to the S end of the RS trigger, the output end of the integrated operational amplifier U4 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the R end of the RS trigger, the Q end of the RS trigger is connected to the control end of the electronic switch Q2, the Q non-end of the RS trigger is connected to the control end of the electronic switch Q1, one end of the sampling resistor R3 is connected to the sampling point, the other end of the sampling resistor R3 is connected to one end of the sampling resistor R4 and the inverting input end of the integrated operational amplifier U2, the non-inverting end of the integrated operational amplifier U2 is grounded, the output end of the integrated operational amplifier U2 is connected to the other end of the sampling resistor R4 and the non-inverting end of the integrated operational amplifier U5, the inverting input end of the integrated operational amplifier U5 is connected to the reference signal Ilow, the output end of the integrated operational amplifier U5 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the R end of the RS trigger, and the dimmer adjusts and outputs the reference signal Ihigh and the reference signal Ilow.

[0007] The working process of this circuit is as follows: when the current at the sampling point is between the reference signal Ihigh and the reference signal Ilow, the R input terminal and the S input terminal of the RS trigger are both low level, the RS trigger remains unchanged, and the inductor L and the capacitor C1 remain discharged or charged; if the inductor L and the capacitor C1 are in the discharge state, then after a period of time, the current flowing through the inductor L is lower than the set lower limit, the integrated operational amplifier U4 outputs a high level, the RS trigger flips, the electronic switch Q1 is turned on, the electronic switch Q2 is turned off, the capacitor C1 is charged through the inductor L, the electronic switch Q1 is turned on at the moment, the inductor L is also charged, the current flowing through the sampling resistor R is from right to left, the sampling point is a positive potential, the sampling current is recorded as a positive current, when the capacitor C1 is continuously When charging and its voltage is higher than the set upper limit, the current of the load LED lamp will be too large, and the current flowing through the inductor L and the sampling resistor R will be higher than the set upper limit. The integrated operational amplifier U3 will output a high level, causing the RS trigger to flip, the electronic switch Q1 to be turned off, the electronic switch Q2 to be turned on, the capacitor C1 to start discharging, and the inductor L to start discharging at the same time. When the voltage of the capacitor C1 is lower than the set lower limit, the current of the load LED lamp is too small, and the current flowing through the inductor L and the sampling resistor R is less than the set lower limit, and the RS trigger flips again; repeating this process ensures that the current flowing through the inductor L is maintained between the reference signal Ihigh and the reference signal Ilow, thereby achieving a stable driving effect on the load LED lamp.

[0008] When the brightness of the load LED lamp is adjusted to a higher level, the sampling current will be lower than the set lower limit before the discharge of the inductor L is completed, and the sampling point is always at a positive potential. When the brightness of the load LED lamp is adjusted to a lower level, if the discharge of the inductor L is completed and the sampling current is still higher than the set lower limit, the capacitor C1 will discharge through the inductor L and the sampling resistor R. The current flowing through the sampling resistor R is from left to right. The sampling point collects a negative potential, that is, a negative current. When the sampling point collects a negative potential, the integrated operational amplifier U3 outputs a low level. After the negative potential is reversely amplified by the integrated operational amplifier U2, if it is greater than the reference signal Ilow, the integrated operational amplifier U5 outputs a high level, causing the RS trigger to flip, and the inductor L and the capacitor C1 to recharge. The upper limit and the lower limit determine the brightness of the load LED.

[0009] Preferably, the electronic switch Q1 and the electronic switch Q2 are both N-MOS tubes.

[0010] Preferably, the capacitor C1 is an electrolytic capacitor, the positive electrode of the electrolytic capacitor is connected to the inductor, and the negative electrode of the electrolytic capacitor is connected to the sampling resistor R.

[0011] Preferably, the dimmer includes a single-chip microcomputer U7 and a 0-10V dimming signal generator. The 0-10V dimming signal generator is connected to the port of the single-chip microcomputer U7 through a voltage-dividing resistor. The single-chip microcomputer U7 converts the 0-10V dimming signal into two PWM signals. The two PWM signals are used as reference signals Ihigh and Ilow after RC filtering, and the difference between Ihigh and Ilow is a constant.

[0012] As an alternative, the dimmer includes a conductor seat, an insulating frame, a plurality of left resistance wires, a plurality of right resistance wires, a left contact block, a right contact block, an insulating sliding handle, a sampling resistor R13 and a sampling resistor R14, a plurality of left resistance wires are arranged and fixed on the left side of the conductor seat, a plurality of right resistance wires are arranged and fixed on the right side of the conductor seat, the left resistance wire and the right resistance wire are aligned, the lower ends of the left resistance wire and the right resistance wire are connected to the conductor seat, the upper ends of the left resistance wire and the right resistance wire are fixedly connected to the insulating frame, the insulating sliding handle is slidably connected to the insulating frame, and the left contact wire is fixed to the insulating frame. The contact block and the right contact block are both fixed on the insulating sliding handle. The lengths of the left contact block and the right contact block are equivalent to the arrangement lengths of the left resistance wire and the right resistance wire. The left contact block abuts against the left resistance wire, and the right contact block abuts against the right resistance wire. The diameter of the left resistance wire is smaller than that of the right resistance wire. The left contact block is connected to the DC power supply Vcc, and the right contact block is connected to the sampling resistor R14 and the resistor group R13 in sequence and then grounded. The voltage at the conductor seat is used as the reference signal Ihigh, and the output voltage at the connection end of the sampling resistor R14 and the sampling resistor R13 is used as the reference signal Ilow. The left contact block contacts N left resistance wires, and the total resistance is 1 / N of a single resistance wire. The left resistance wire and the right resistance wire are different in thickness. Therefore, when the insulating sliding handle slides in the same way, R11 and R12 can maintain a fixed ratio relationship, thereby ensuring that △U remains unchanged, that is, the value of the current difference △I remains unchanged.

[0013] Alternatively, the dimmer includes an upper contact block, a lower contact block, an upper resistance wire, a lower resistance wire, a dimming knob, a sampling resistor R13 and a sampling resistor R14. The dimming knob is fixedly mounted with a rotary arm. The upper contact block and the lower contact block are both mounted on the rotary arm. The lower contact block is closer to the dimming knob than the upper contact block. The upper contact block abuts against the upper resistance wire, and the lower contact block abuts against the lower resistance wire. The upper resistance wire and the lower resistance wire have the same thickness and conductivity. The left end of the upper resistance wire is connected to the left end of the lower resistance wire, the lower contact block is connected to a DC power supply Vcc, the upper contact block is connected to the sampling resistor R14 and the resistor group R13 in sequence and then grounded, the voltage at the connection between the upper resistance wire and the lower resistance wire is used as a reference signal Ihigh, and the output voltage at the connection end of the sampling resistor R14 and the sampling resistor R13 is used as a reference signal Ilow. When the dimming knob rotates, the rotating arm is driven to rotate. Since the upper contact block is farther away from the dimming knob, when the dimming knob rotates by the same angle, the resistance values ​​of the upper resistor wire and the lower resistor wire connected to the circuit can maintain a fixed ratio, thereby ensuring that △U remains unchanged, that is, the value of the current difference △I remains unchanged.

[0014] The substantial effect of the present invention is: the inductor L is used to store electric energy, the capacitor C1 plays the role of storing energy and filtering the AC component in the current flowing through the inductor L, and the current flowing through the inductor L can be obtained by sampling the voltage across the resistor R. When the current of the inductor L is lower than the set lower limit, the inductor L is charged through the circuit, and when the current of the inductor L is higher than the set upper limit, the charging is stopped, so that the load LED lamp driving current with a sufficiently small current fluctuation amplitude is obtained through the technical solution; a technical solution for DC linear dimming is provided, the circuit is simple, the power supply power is almost consumed by the load LED lamp, and the energy consumption of the circuit is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of a dimming circuit according to Embodiment 1.

[0016] Figure 2 This is a control circuit schematic diagram of Example 1.

[0017] Figure 3 This is a schematic diagram of the dimmer of Example 3.

[0018] Figure 4 , Figure 5 This is a structural diagram of a dimmer according to Embodiment 3.

[0019] Figure 6 This is a structural diagram of a dimmer according to Embodiment 4.

[0020] Figure 7 This is the voltage timing diagram at various points during the dimming process of the control circuit.

[0021] Figure 8 This is the voltage timing diagram at various points during the dimming process of the control circuit when the dimming voltage is small.

[0022] Among them: 1. left contact block, 2. left resistance wire, 3. conductor seat, 4. insulation frame, 5. insulation sliding handle, 6. right contact block, 7. right resistance wire, 8. upper contact block, 9. lower contact block, 10. upper resistance wire, 11. lower resistance wire, 12. swing arm, 13. dimming knob. DETAILED DESCRIPTION

[0023] The specific implementation of the present invention will be further described below through specific examples in conjunction with the accompanying drawings.

[0024] Embodiment 1:

[0025] A peak-valley current controlled dimming circuit, such as Figure 1As shown, this embodiment includes a dimming circuit, a control circuit and a dimmer. The dimming circuit includes a sampling resistor R, an inductor L, a capacitor C1, an electronic switch Q1 and an electronic switch Q2. One end of the electronic switch Q1 is connected to the power supply Vin, the other end of the electronic switch Q1 is connected to one end of the electronic switch Q2, and the other end of the electronic switch Q2 is grounded. The capacitor C1 is connected in parallel with the load LED lamp. One end of the capacitor C1 is connected to one end of the inductor L, and the other end of the inductor L is connected to the connecting end of the electronic switch Q1 and the electronic switch Q2. The other end of the capacitor C1 is grounded through the sampling resistor R. The connecting point of the sampling resistor R and the capacitor C1 is used as a sampling point and connected to the control circuit. The sampling point collects the current flowing through the inductor L. The dimmer, the control end of the electronic switch Q1 and the control end of the electronic switch Q2 are all connected to the control circuit. The control circuit periodically controls the on and off of the electronic switch Q1 and the electronic switch Q2 to control the current flowing through the load LED lamp. The inductor L is used to store electric energy, and the capacitor C1 plays the role of storing energy and filtering the AC component in the current flowing through the inductor L. By sampling the voltage across the resistor R, the current flowing through the inductor L can be obtained. When the current of the inductor L is lower than the set lower limit, the inductor L is charged through the circuit. When the current of the inductor L is higher than the set upper limit, the charging is stopped, so that the load LED lamp driving current with a sufficiently small current fluctuation amplitude is obtained through this technical solution. The power supply Vin can be a DC power supply or an AC power after half-wave shaping.

[0026] like Figure 2As shown, the control circuit includes an integrated operational amplifier U1, an integrated operational amplifier U2, an integrated operational amplifier U3, an integrated operational amplifier U4, an integrated operational amplifier U5, a sampling resistor R1, a sampling resistor R2, a sampling resistor R3, a diode D1, a diode D2 and an RS trigger, the sampling point is connected to the in-phase end of the integrated operational amplifier U1 and the first end of the sampling resistor R3, the inverting input end of the integrated operational amplifier U1 is grounded through the sampling resistor R1, one end of the sampling resistor R2 is connected to the inverting input end of the integrated operational amplifier U1, the other end of the sampling resistor R2 is connected to the output end of the integrated operational amplifier U1, the output end of the integrated operational amplifier U1 is connected to the in-phase end of the integrated operational amplifier U3 and the inverting input end of the integrated operational amplifier U4, the inverting input end of the integrated operational amplifier U3 is connected to the reference signal Ihigh, the in-phase end of the integrated operational amplifier U4 is connected to the reference signal Ilow, and the integrated operational amplifier U4 is connected to the inverting input end of the integrated operational amplifier U1. The output end of the operational amplifier U3 is connected to the S end of the RS trigger, the output end of the integrated operational amplifier U4 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the R end of the RS trigger, the Q end of the RS trigger is connected to the control end of the electronic switch Q2, the Q non-end of the RS trigger is connected to the control end of the electronic switch Q1, one end of the sampling resistor R3 is connected to the sampling point, the other end of the sampling resistor R3 is connected to one end of the sampling resistor R4 and the inverting input end of the integrated operational amplifier U2, the non-inverting end of the integrated operational amplifier U2 is grounded, the output end of the integrated operational amplifier U2 is connected to the other end of the sampling resistor R4 and the non-inverting end of the integrated operational amplifier U5, the inverting input end of the integrated operational amplifier U5 is connected to the reference signal Ilow, the output end of the integrated operational amplifier U5 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the R end of the RS trigger, and the dimmer adjusts and outputs the reference signal Ihigh and the reference signal Ilow.

[0027] The working process of this circuit is as follows: Figure 7As shown, when the sampling point current is between the reference signal Ihigh and the reference signal Ilow, the R input terminal and the S input terminal of the RS trigger are both low level, the RS trigger remains unchanged, and the inductor L and the capacitor C1 remain discharged or charged; if the inductor L and the capacitor C1 are in the discharge state, then after a period of time, the current flowing through the inductor L is lower than the set lower limit, the integrated operational amplifier U4 outputs a high level, the RS trigger flips, the electronic switch Q1 is turned on, the electronic switch Q2 is turned off, the capacitor C1 is charged through the inductor L, the electronic switch Q1 is turned on, the inductor L is also charged, the current flowing through the sampling resistor R is from right to left, the sampling point is a positive potential, the sampling current is recorded as a positive current, when the capacitor C1 is continuously charged and its When the voltage is higher than the set upper limit, the current of the load LED lamp will be too large, and the current flowing through the inductor L and the sampling resistor R will be higher than the set upper limit. The integrated operational amplifier U3 will output a high level, causing the RS trigger to flip, the electronic switch Q1 to be turned off, the electronic switch Q2 to be turned on, the capacitor C1 to start discharging, and the inductor L to start discharging. When the voltage of the capacitor C1 is lower than the set lower limit, the current of the load LED lamp is too small, and the current flowing through the inductor L and the sampling resistor R is less than the set lower limit, and the RS trigger flips again; repeating this process ensures that the current flowing through the inductor L is maintained between the reference signal Ihigh and the reference signal Ilow, thereby achieving a stable driving effect of the load LED lamp.

[0028] When the brightness of the load LED lamp is adjusted to a higher level, the sampling current will be lower than the set lower limit before the discharge of the inductor L is completed, and the sampling point is always at a positive potential. Figure 8 As shown, when the brightness of the load LED lamp is adjusted to a lower level, if the inductor L is discharged and the sampling current is still higher than the set lower limit, the capacitor C1 will discharge through the inductor L and the sampling resistor R. The current flowing through the sampling resistor R is from left to right. The sampling point collects a negative potential, that is, a negative current. When the sampling point collects a negative potential, the integrated operational amplifier U3 outputs a low level. After the negative potential is reversely amplified by the integrated operational amplifier U2, if it is greater than the reference signal Ilow, the integrated operational amplifier U5 outputs a high level, causing the RS trigger to flip, and the inductor L and the capacitor C1 are recharged. The upper limit and the lower limit determine the brightness of the load LED.

[0029] Embodiment 2:

[0030] Based on the first embodiment, this embodiment provides an alternative technical solution for the dimmer, the dimmer includes a single-chip microcomputer U7 and a 0-10V dimming signal generator, the 0-10V dimming signal generator is connected to the port of the single-chip microcomputer U7 through a voltage-dividing resistor, the single-chip microcomputer U7 converts the 0-10V dimming signal into a PWM signal, and the PWM signal is used as the reference signal Ihigh and Ilow after RC filtering. The rest of the structure is the same as the first embodiment, and the generation of the PWM signal by the single-chip microcomputer is a mature and commonly used prior art, so this embodiment does not involve software improvement and any method improvement.

[0031] Embodiment three:

[0032] This embodiment provides an alternative technical solution for the dimmer based on the first embodiment, such as Figure 4 , Figure 5 As shown, in this embodiment, the dimmer includes a conductor base 3, an insulating frame 4, a plurality of left resistance wires 2, a plurality of right resistance wires 7, a left contact block 1, a right contact block 6, an insulating sliding handle 5, a sampling resistor R13 and a sampling resistor R14, a plurality of left resistance wires 2 are arranged and fixed on the left side of the conductor base 3, a plurality of right resistance wires 7 are arranged and fixed on the right side of the conductor base 3, the left resistance wire 2 and the right resistance wire 7 are aligned, the lower ends of the left resistance wire 2 and the right resistance wire 7 are connected to the conductor base 3, the upper ends of the left resistance wire 2 and the right resistance wire 7 are fixedly connected to the insulating frame 4, the insulating sliding handle 5 is slidably connected to the insulating frame 4, and the left connection The contact block 1 and the right contact block 6 are both fixed on the insulating sliding handle 5. The lengths of the left contact block 1 and the right contact block 6 are equivalent to the arrangement lengths of the left resistance wire 2 and the right resistance wire 7. The left contact block 1 abuts against the left resistance wire 2, and the right contact block 6 abuts against the right resistance wire 7. The diameter of the left resistance wire 2 is smaller than that of the right resistance wire 7. The left contact block 1 is connected to the DC power supply Vcc, and the right contact block 6 is connected to the sampling resistor R14 and the resistor group R13 in sequence and then grounded. The voltage at the conductor seat 3 is used as the reference signal Ihigh, and the output voltage at the connection end of the sampling resistor R14 and the sampling resistor R13 is used as the reference signal Ilow. The remaining structures are the same as those in the first embodiment.

[0033] like Figure 3As shown, the circuit in the figure explains the principle of maintaining the current difference △I of the load LED lamp unchanged. Maintaining the current difference △I of the load LED lamp unchanged, the equivalent sampling resistance Rdet of the load LED lamp is considered to be a constant value, and the voltage U across the load LED lamp satisfies, when the adjustable resistor R11 is adjusted: U / (R11+R12+R13)*R12=△I*Rdet=△U, after deformation, it can be obtained that R12=U / (U-△U)*R11+U / (U-△U)*R13, that is, as long as R14=U / (U-△U)*R13 is guaranteed, the changes of the adjustable resistors R12 and R11 are proportional to each other, and △U can be maintained unchanged, that is, the value of the current difference △I is maintained unchanged. The output voltage between the adjustable resistors R12 and R11, because the integrated operational amplifier has an input resistance that can be regarded as a constant value, there is a part of the current flowing into the integrated operational amplifier from between the adjustable resistors R12 and R11, so the voltage signal can be regarded as a current signal. Similarly, since the integrated operational amplifier has an input resistance that can be regarded as a constant, after the sampling current is input into the integrated operational amplifier, a certain voltage will be generated to act on the input end of the integrated operational amplifier, and the integrated operational amplifier is regarded as receiving the current signal.

[0034] In this embodiment, the left contact block contacts N left resistance wires, and the total resistance is 1 / N of a single resistance wire. The left resistance wire and the right resistance wire have different thicknesses. Therefore, when the insulating sliding handle slides in the same way, R11 and R12 can maintain a fixed ratio relationship, thereby ensuring that △U remains unchanged, that is, maintaining the value of the current difference △I unchanged.

[0035] Embodiment 4:

[0036] This embodiment provides an alternative technical solution for the dimmer based on the first embodiment, such as Figure 6As shown, in this embodiment, the dimmer includes an upper contact block 8, a lower contact block 9, an upper resistance wire 10, a lower resistance wire 11, a dimming knob 13, a sampling resistor R13 and a sampling resistor R14. The dimming knob 13 is fixedly mounted with a rotary arm 12. The upper contact block 8 and the lower contact block 9 are both mounted on the rotary arm 12. The lower contact block 9 is closer to the dimming knob 13 than the upper contact block 8. The upper contact block 8 abuts against the upper resistance wire 10, and the lower contact block 9 abuts against the lower resistance wire 11. The upper resistance wire 10 and the lower resistance wire 11 have the same thickness and conductivity. The left end of the upper resistance wire 10 is connected to the left end of the lower resistance wire 11, the lower contact block 9 is connected to the DC power supply Vcc, the upper contact block 8 is connected to the sampling resistor R14 and the resistor group R13 in sequence and then grounded, the voltage at the connection between the upper resistance wire 10 and the lower resistance wire 11 is used as the reference signal Ihigh, and the voltage output at the connection end of the sampling resistor R14 and the sampling resistor R13 is used as the reference signal Ilow. The remaining structures are the same as those in the first embodiment. When the dimming knob 13 rotates, the swing arm 12 is driven to rotate. Since the upper contact block 8 is farther away from the dimming knob 13, when the dimming knob 13 rotates by the same angle, the resistance values ​​of the upper resistance wire 10 and the lower resistance wire 11 connected to the circuit can maintain a fixed ratio relationship, thereby ensuring that △U remains unchanged, that is, the value of the current difference △I is maintained unchanged.

[0037] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A peak-valley current controlled dimming circuit, characterized in that: The invention comprises a dimming circuit, a control circuit and a dimmer, wherein the dimming circuit comprises a sampling resistor R, an inductor L, a capacitor C1, an electronic switch Q1 and an electronic switch Q2, wherein one end of the electronic switch Q1 is connected to a power source Vin, the other end of the electronic switch Q1 is connected to one end of the electronic switch Q2, the other end of the electronic switch Q2 is grounded, the capacitor C1 is connected in parallel with a load LED lamp, one end of the capacitor C1 is connected to one end of the inductor L, the other end of the inductor L is connected to the connecting end of the electronic switch Q1 and the electronic switch Q2, the other end of the capacitor C1 is grounded through the sampling resistor R, the connecting point between the sampling resistor R and the capacitor C1 is used as a sampling point and is connected to the control circuit, the sampling point collects the current flowing through the inductor L, the dimmer, the control end of the electronic switch Q1 and the control end of the electronic switch Q2 are connected to the control end of the electronic switch Q1 and the control end of the electronic switch Q2. The control terminals are connected to the control circuit, and the control circuit periodically controls the on-off of the electronic switch Q1 and the electronic switch Q2 to control the current flowing through the load LED lamp. When the brightness of the load LED lamp is increased, the sampling current is lower than the lower limit before the discharge of the inductor is completed, and the sampling point is a positive potential. When the brightness of the load LED lamp is reduced, if the discharge is completed, the current is higher than the lower limit, and the capacitor is discharged through the inductor and the sampling resistor. The current flowing through the sampling resistor is from left to right. The sampling point collects a negative potential, that is, a negative current is collected. When the sampling point collects a negative potential, the integrated operational amplifier U3 outputs a low level. After the negative potential is reversely amplified by the integrated operational amplifier U2, if it is greater than the reference signal Ilow, the operational amplifier outputs a high level to flip the trigger, and the inductor and capacitor are recharged. The upper and lower limits are set to determine the brightness of the load LED.

2. A peak-valley current controlled dimming circuit according to claim 1, characterized in that: The control circuit includes an integrated operational amplifier U1, an integrated operational amplifier U2, an integrated operational amplifier U3, an integrated operational amplifier U4, an integrated operational amplifier U5, a sampling resistor R1, a sampling resistor R2, a sampling resistor R3, a diode D1, a diode D2 and an RS trigger, a sampling point is connected to the in-phase end of the integrated operational amplifier U1 and the first end of the sampling resistor R3, an inverting input end of the integrated operational amplifier U1 is grounded through the sampling resistor R1, one end of the sampling resistor R2 is connected to the inverting input end of the integrated operational amplifier U1, the other end of the sampling resistor R2 is connected to the output end of the integrated operational amplifier U1, the output end of the integrated operational amplifier U1 is connected to the in-phase end of the integrated operational amplifier U3 and the inverting input end of the integrated operational amplifier U4, the inverting input end of the integrated operational amplifier U3 is connected to a reference signal Ihigh, the in-phase end of the integrated operational amplifier U4 is connected to a reference signal Ilow, The output end of the amplifier U3 is connected to the S end of the RS trigger, the output end of the integrated operational amplifier U4 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the R end of the RS trigger, the Q end of the RS trigger is connected to the control end of the electronic switch Q2, the Q non-end of the RS trigger is connected to the control end of the electronic switch Q1, one end of the sampling resistor R3 is connected to the sampling point, the other end of the sampling resistor R3 is connected to one end of the sampling resistor R4 and the inverting input end of the integrated operational amplifier U2, the non-inverting end of the integrated operational amplifier U2 is grounded, the output end of the integrated operational amplifier U2 is connected to the other end of the sampling resistor R4 and the non-inverting end of the integrated operational amplifier U5, the inverting input end of the integrated operational amplifier U5 is connected to the reference signal Ilow, the output end of the integrated operational amplifier U5 is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the R end of the RS trigger, and the dimmer adjusts and outputs the reference signal Ihigh and the reference signal Ilow.

3. A peak-valley current controlled dimming circuit according to claim 1 or 2, characterized in that: The electronic switch Q1 and the electronic switch Q2 are both N-MOS tubes.

4. A peak-valley current controlled dimming circuit according to claim 1 or 2, characterized in that: The capacitor C1 is an electrolytic capacitor, the positive electrode of the electrolytic capacitor is connected to the inductor, and the negative electrode of the electrolytic capacitor is connected to the sampling resistor R.

5. A peak-valley current controlled dimming circuit according to claim 1 or 2, characterized in that: The dimmer includes a single-chip microcomputer U7 and a 0-10V dimming signal generator. The 0-10V dimming signal generator is connected to the port of the single-chip microcomputer U7 through a voltage-dividing resistor. The single-chip microcomputer U7 converts the 0-10V dimming signal into two PWM signals. The two PWM signals are used as reference signals Ihigh and Ilow after RC filtering. The difference between Ihigh and Ilow is a constant value.

6. A peak-valley current controlled dimming circuit according to claim 1 or 2, characterized in that: The dimmer includes a conductor seat, an insulating frame, a plurality of left resistance wires, a plurality of right resistance wires, a left contact block, a right contact block, an insulating sliding handle, a sampling resistor R13 and a sampling resistor R14. The plurality of left resistance wires are arranged and fixed on the left side of the conductor seat, and the plurality of right resistance wires are arranged and fixed on the right side of the conductor seat. The left resistance wire and the right resistance wire are aligned and arranged. The lower ends of the left resistance wire and the right resistance wire are connected to the conductor seat. The upper ends of the left resistance wire and the right resistance wire are fixedly connected to the insulating frame. The insulating sliding handle is slidably connected to the insulating frame. The left contact block is The left and right contact blocks are fixed on the insulating sliding handle, the lengths of the left contact block and the right contact block are equivalent to the arrangement lengths of the left resistance wire and the right resistance wire, the left contact block abuts against the left resistance wire, and the right contact block abuts against the right resistance wire, the diameter of the left resistance wire is smaller than the right resistance wire, the left contact block is connected to the DC power supply Vcc, and the right contact block is connected to the sampling resistor R14 and the resistor group R13 in sequence and then grounded, the voltage at the conductor seat is used as the reference signal Ihigh, and the output voltage at the connection end of the sampling resistor R14 and the sampling resistor R13 is used as the reference signal Ilow.

7. A peak-valley current controlled dimming circuit according to claim 1 or 2, characterized in that: The dimmer includes an upper contact block, a lower contact block, an upper resistance wire, a lower resistance wire, a dimming knob, a sampling resistor R13 and a sampling resistor R14. The dimming knob is fixedly installed with a rotary arm. The upper contact block and the lower contact block are both installed on the rotary arm. The lower contact block is closer to the dimming knob than the upper contact block. The upper contact block abuts against the upper resistance wire, and the lower contact block abuts against the lower resistance wire. The upper resistance wire and the lower resistance wire have the same thickness and conductivity. The left end of the upper resistance wire is connected to the left end of the lower resistance wire, the lower contact block is connected to a DC power supply Vcc, the upper contact block is connected to the sampling resistor R14 and the resistor group R13 in sequence and then grounded, the voltage at the connection between the upper resistance wire and the lower resistance wire is used as a reference signal Ihigh, and the output voltage of the connection end of the sampling resistor R14 and the sampling resistor R13 is used as a reference signal Ilow.

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