LED constant-current driving power supply and parallel constant-current lighting system

Abstract

The utility model discloses an LED constant current driving power supply comprising a PWM modulation circuit which is provided with a positive output end and a negative output end. The LED constant-current driving power supply is further provided with a counting feedback end used for receiving counting feedback signals representing the number of parallel branches of the LED light source module. The PWM modulation circuit is connected with the counting feedback end, and the PWM modulation circuit adjusts the output of the PWM modulation circuit according to the counting feedback signal, so that the output current of the LED constant-current driving power supply is a multiple of the number of the LED light source modules. The utility model also discloses a parallel constant current lighting system. According to the utility model, the advantages of constant current driving and parallel connection can be considered, the efficiency is high, the cost is low, the number of the LED light source modules connected in parallel can be calculated according to feedback, and the magnitude of the output current can be adjusted accordingly.

Description

Technical Field

[0001] The utility model relates to a lighting system, more specifically to an LED constant current driving power supply and a parallel constant current lighting system. Background Art

[0002] Existing LED lighting systems, such as LED light strip systems, usually use LED light source modules connected in series or in parallel to emit light. Since the current of each series unit in a series circuit is the same, and the voltage of each parallel unit in a parallel circuit is the same, in actual use, there are advantages and disadvantages to connecting LED light source modules in series or in parallel:

[0003] The series light strip system is usually driven by a constant current power supply with high efficiency, but the power supply voltage varies greatly with the load voltage, and the installation operation is not easy to achieve and the cost is high.

[0004] Parallel light strips are usually driven by a constant voltage power supply. The connection circuit is as follows: Fig.10 As shown, each parallel branch uses a resistor as a current limiting element, resulting in low system efficiency, high energy consumption, and excessive voltage drop in the system loop, causing obvious visible brightness differences between different parts of the light strip. However, it is convenient to use a standard constant voltage power supply, easy to install and operate, low cost, and good versatility. Therefore, it has a wide range of uses and a large demand.

[0005] Since the inherent characteristics of LED light sources are suitable for constant current light emission, the existing driving power supplies cannot adapt to LED light sources with different numbers of parallel branches, and their versatility and compatibility are poor. Utility Model Content

[0006] In order to solve the technical problems that the existing driving power supply cannot adapt to LED light sources with different numbers of parallel branches and has poor versatility and compatibility, the utility model provides an LED constant current driving power supply and a parallel constant current lighting system.

[0007] In order to solve the above technical problems, the technical solution adopted by the utility model is to design an LED constant current driving power supply, including a PWM modulation circuit, wherein the PWM modulation circuit has a positive output terminal and a negative output terminal;

[0008] The LED constant current driving power supply also has a counting feedback end for receiving a counting feedback signal representing the number of parallel branches of the LED light source module; the PWM modulation circuit is connected to the counting feedback end, and the PWM modulation circuit adjusts the output of the PWM modulation circuit according to the counting feedback signal so that the output current of the LED constant current driving power supply is a multiple of the number of the LED light source modules.

[0009] The PWM modulation circuit comprises:

[0010] A step-down constant current source chip, which has a power input terminal VIN, a current sampling terminal VS, a ground terminal GND, a drain terminal SW of a power switch, and a dimming terminal DIM; the power input terminal is connected to the positive electrode of a DC power supply;

[0011] A current sampling resistor connected between the power input terminal VIN and the current sampling terminal VS; the forward output terminal is connected to the current sampling terminal;

[0012] A rectifier diode connected between the power input terminal and the drain terminal of the power switch;

[0013] A voltage sampling resistor, one end of which is connected to the counting feedback end and the dimming end, and the other end of which is connected to the negative electrode of the DC power supply and the ground end;

[0014] A first filter capacitor, one end of which is connected to the positive electrode of the DC power supply, and the other end of which is connected to the negative electrode of the DC power supply;

[0015] A second filter capacitor connected between the positive output terminal and the negative output terminal;

[0016] An inductor, one end of which is connected to the drain end of the power switch, and the other end of which is connected to the negative output end.

[0017] The step-down constant current source chip is PT4115.

[0018] The PWM modulation circuit comprises:

[0019] A dimming and voltage-reducing constant current chip module, which has the positive output terminal and the negative output terminal;

[0020] The LED constant current driving power supply further includes a feedback signal conversion circuit connected between the dimming step-down constant current chip module and the counting feedback end, and the feedback signal conversion circuit includes:

[0021] A first voltage comparator, whose output end is connected to the dimming step-down constant current chip module, and whose in-phase input end is connected to the counting feedback end;

[0022] A twenty-sixth resistor, one end of which is connected to the forward output terminal, and the other end of which is connected to the non-inverting input terminal of the first voltage comparator;

[0023] A twenty-seventh resistor, one end of which is connected to the other end of the twenty-sixth resistor and the other end of which is grounded;

[0024] A twenty-fourth resistor, one end of which is connected to the forward output terminal, and the other end of which is connected to the output terminal of the first voltage comparator;

[0025] A twenty-fifth resistor, one end of which is connected to the output end of the first voltage comparator, and the other end of which is grounded;

[0026] A second voltage comparator having an output terminal, a non-inverting input terminal and an inverting input terminal;

[0027] A twenty-eighth resistor, one end of which is connected to the forward output terminal, and the other end of which is connected to the output terminal of the second voltage comparator;

[0028] A twenty-ninth resistor, one end of which is connected to the output end of the second voltage comparator, and the other end of which is connected to the inverting input end of the first voltage comparator and the inverting input end of the second voltage comparator;

[0029] A twenty-fourth capacitor, one end of which is connected to the inverting input terminal of the second voltage comparator, and the other end of which is grounded;

[0030] a twentieth resistor, one end of which is connected to the output terminal of the second voltage comparator, and the other end of which is connected to the non-inverting input terminal of the second voltage comparator;

[0031] A twenty-first resistor, one end of which is connected to the forward output terminal, and the other end of which is connected to the non-inverting input terminal of the second voltage comparator;

[0032] A twenty-second resistor has one end connected to the non-inverting input terminal of the second voltage comparator and the other end grounded.

[0033] The LED constant current driving power supply also includes a PWM dimming signal, which is superimposed with the output of the feedback signal conversion circuit and then output to the dimming step-down constant current chip module.

[0034] The PWM modulation circuit comprises:

[0035] The PFC control chip has an inverting input terminal INV of an error amplifier, an output terminal COMP of the error amplifier, a main input terminal MULT of a multiplier, an input terminal CS of a PWM comparator, a demagnetization induction input terminal ZCD of a boost inductor, a ground terminal GND, a gate driver output terminal GD, and a power supply terminal VCC;

[0036] a thirty-first resistor, one end of which is connected to the positive electrode of the power supply and the negative output terminal, and the other end of which is connected to the main input terminal of the multiplier;

[0037] A thirty-second resistor, one end of which is connected to the other end of the thirty-first resistor, and the other end of which is connected to the negative electrode of the power supply and grounded;

[0038] A thirty-third capacitor, one end of which is connected to the negative output terminal, and the other end of which is grounded;

[0039] A thirty-fourth capacitor, one end of which is connected to the main input terminal of the multiplier and the other end of which is grounded;

[0040] A thirty-third resistor, one end of which is connected to the inverting input terminal of the error amplifier, and the other end of which is grounded;

[0041] a thirty-fourth resistor, one end of which is connected to the counting feedback terminal, and the other end of which is connected to the main input terminal of the multiplier;

[0042] a thirty-fifth resistor, one end of which is connected to the inverting input terminal of the error amplifier, and the other end of which is connected to the power supply terminal;

[0043] a thirty-fifth capacitor, one end of which is connected to the inverting input terminal of the error amplifier, and the other end of which is connected to the output terminal of the error amplifier;

[0044] A thirty-seventh resistor, one end of which is connected to the negative output terminal, and the other end of which is connected to the power supply terminal;

[0045] A thirty-sixth capacitor, one end of which is connected to the power supply terminal, and the other end of which is grounded;

[0046] A thirty-seventh capacitor, two ends of which are connected to the positive output terminal and the negative output terminal respectively;

[0047] A thirty-second diode, a cathode of which is connected to the forward output terminal;

[0048] a 30th field effect transistor, a drain of which is connected to the anode of the 32nd diode;

[0049] A thirty-sixth resistor, one end of which is connected to the gate of the thirtieth field effect transistor, and the other end is connected to the output end of the gate driver;

[0050] A thirty-ninth resistor, one end of which is connected to the source of the thirtieth field effect transistor, and the other end of which is grounded;

[0051] A third transformer, two ends of its primary winding are respectively connected to the negative output end and the drain of the thirtieth field effect transistor;

[0052] a thirty-eighth resistor, one end of which is connected to one end of the secondary winding of the third transformer, and the other end of which is connected to the demagnetization induction input end of the boost inductor; the other end of the secondary winding of the third transformer is connected to the ground end and is grounded;

[0053] The thirty-first diode has a cathode connected to the power supply end, and an anode connected to one end of the thirty-eighth resistor.

[0054] The PFC control chip is chip L6562A.

[0055] The utility model also provides a parallel constant current lighting system, the parallel constant current lighting system includes the above-mentioned LED constant current driving power supply, and the parallel constant current lighting system also includes a parallel constant current lighting unit connected to the LED constant current driving power supply and driven by the LED constant current driving power supply;

[0056] The parallel constant current lighting unit comprises:

[0057] A positive terminal connected to the positive output terminal of the LED constant current driving power supply;

[0058] A negative terminal connected to the negative output terminal of the LED constant current driving power supply;

[0059] LED light source modules, including at least two, and each LED light source module is connected in parallel between the positive terminal and the negative terminal;

[0060] A counting terminal connected to a counting feedback terminal of the LED constant current driving power supply;

[0061] A counting resistor module, one end of which is connected to the counting end, and the other end of which is connected to the positive terminal, the negative terminal or the control signal terminal; the counting resistor module includes at least two counting resistors, and the number of each counting resistor is arranged in proportion to the number of each LED light source module, and each counting resistor is arranged in series or in parallel.

[0062] The resistance values ​​of the counting resistors are the same.

[0063] The rated voltages of the LED light source modules are the same.

[0064] The utility model sets a PWM modulation circuit, which has a positive output terminal and a negative output terminal; the LED constant current driving power supply also has a counting feedback terminal for receiving a counting feedback signal representing the number of parallel branches of the LED light source module; the PWM modulation circuit is connected to the counting feedback terminal, and the PWM modulation circuit adjusts the output of the PWM modulation circuit according to the counting feedback signal, so that the output current of the LED constant current driving power supply is a multiple of the number of the LED light source modules. Therefore, the number of LED light source modules can be calculated according to the counting feedback signal obtained by the counting feedback terminal, and constant current is used for driving, and the corresponding current is output to drive the LED light source module to work, which can take into account the advantages of constant current driving and parallel connection, with high efficiency and low cost, and the number of parallel LED light source modules can be calculated according to feedback, and the size of the output current can be adjusted accordingly, and the versatility and compatibility are good. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] The present invention is described in detail below with reference to the embodiments and drawings, wherein:

[0066] Figure 1 This is a circuit diagram of the first embodiment of the parallel constant current lighting unit of the utility model;

[0067] Figure 2 This is a circuit diagram of the second embodiment of the parallel constant current lighting unit of the utility model;

[0068] Figure 3 This is a circuit diagram of the third embodiment of the parallel constant current lighting unit of the utility model;

[0069] Figure 4 This is a circuit diagram of the fourth embodiment of the parallel constant current lighting unit of the utility model;

[0070] Figure 5 This is the principle diagram of the utility model parallel constant current lighting system;

[0071] Figure 6 This is a circuit diagram of the first embodiment of the parallel constant current lighting system of the utility model;

[0072] Figure 7 This is a circuit diagram of the second embodiment of the parallel constant current lighting system of the utility model;

[0073] Figure 8 This is a circuit diagram of the third embodiment of the parallel constant current lighting system of the utility model;

[0074] Fig. 9 This is a circuit diagram of a fourth embodiment of the parallel constant current lighting system of the utility model;

[0075] Fig.10 The present invention is a circuit diagram of a constant voltage power supply driving parallel light strips in the prior art. DETAILED DESCRIPTION

[0076] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings:

[0077] Please also see Figures 1 to 5 The utility model parallel constant current lighting unit 1 comprises a positive terminal DC+, a negative terminal DC-, an LED light source module, a counting terminal Rf, and a counting resistor module 12. Among them:

[0078] The positive terminal DC+ is used to connect to the positive output terminal of the LED constant current driving power supply, and the negative terminal DC- is used to connect to the negative output terminal of the LED constant current driving power supply, thereby providing driving power for the LED light source module.

[0079] The LED light source modules include at least two, and each LED light source module is connected in parallel between the positive terminal and the negative terminal. In this specific embodiment, the LED light source modules include n, namely LED light source module L1, LED light source module L2, ..., LED light source module Ln. n is an integer greater than or equal to 1.

[0080] Of course, the LED light source module may also include only one, in which case the LED light source module is connected between the positive terminal and the negative terminal.

[0081] The counting terminal Rf is used to be connected to the counting feedback terminal of the LED constant current driving power supply, and is mainly used to feed back to the LED constant current driving power supply the number of parallel LED light source modules.

[0082] One end of the counting resistor module 12 is connected to the counting end, and the other end is connected to the positive terminal, the negative terminal or the control signal end. The counting resistor module includes at least two counting resistors, and the number of each counting resistor is proportional to the number of each LED light source module, and each counting resistor is arranged in series or in parallel. The number of counting resistors can be the same as the number of LED light source modules and arranged one-to-one, or a plurality of LED light source modules correspond to one counting resistor. Considering the cuttability of the light strip, the number of counting resistors is the same as the number of LED light source modules to keep the number of counting resistors the same as the number of LED light source modules when cutting, thereby improving the accuracy of feedback. In this specific embodiment, the counting resistor module includes n counting resistors, namely, counting resistor Rf1, counting resistor Rf2, ..., counting resistor Rfn, and n is an integer greater than or equal to 1. The control signal end can be a power supply, a dimming circuit, etc.

[0083] When only one LED light source module is included, one end of the counting resistor module is connected to the counting end, and the other end is connected to the positive terminal, the negative terminal or the control signal end. The counting resistor module can be implemented using one counting resistor.

[0084] exist Figure 1 In the embodiment, each counting resistor is connected in parallel between the positive terminal and the counting terminal; Figure 2 In the embodiment, each counting resistor is connected in parallel between the negative terminal and the counting terminal; Figure 3 In the embodiment, each counting resistor is connected in series, and can be connected in series between the positive electrode terminal and the counting terminal, between the negative electrode terminal and the counting terminal, or between the counting terminal and the control signal terminal. Figure 1 , Figure 2 and Figure 3 In the embodiment, each of the LED light source modules forms an LED light strip. Figure 4In the embodiment, the LED light source module is an LED lamp, a plurality of LED lamp beads are arranged in the LED lamp, the circuit boards of the LED lamps are independent of each other, and the circuit boards are connected by wires. Of course, a combination of LED lamps and LED light strips can also be used, that is, at least one of the LED light source modules is an LED lamp, and a plurality of LED lamp beads are arranged in the LED lamp.

[0085] By setting the counting resistors so that the number of counting resistors is proportional to the number of LED light source modules, the number of LED light source modules in parallel can be calculated by measuring the voltage of the counting resistors, and the output current of the LED constant current drive power supply can be adjusted accordingly to ensure that when different numbers of light source modules are connected in parallel, the current of each light source module is the same and the overall system efficiency is high.

[0086] In this specific embodiment, for the convenience of calculation, the resistance values ​​of the counting resistors are the same.

[0087] In this specific embodiment, when the counting resistors are connected in parallel, the other end of the counting resistor module is connected to the positive terminal or the negative terminal, and when the counting resistors are connected in series, the other end of the counting resistor module is connected to the control signal terminal.

[0088] In this specific embodiment, the rated voltage of each LED light source module is the same. By ensuring that the resistance of each LED light source module branch is the same, the current of each LED light source module branch is the same, and there is no need to set resistors in the LED light source module branches to reduce voltage and limit current.

[0089] When the parallel constant current lighting unit is applied to a parallel constant current lighting system, the parallel constant current lighting system includes an LED constant current driving power supply 2 and a parallel constant current lighting unit 1 connected to the LED constant current driving power supply and driven by the LED constant current driving power supply; the LED constant current driving power supply has a positive output terminal, a negative output terminal and a counting feedback terminal.

[0090] The parallel constant current lighting unit includes a positive terminal, a negative terminal, an LED light source module, a counting terminal, and a counting resistor module.

[0091] The positive electrode terminal is connected to the positive output terminal of the LED constant current driving power supply.

[0092] The negative terminal is connected to the negative output terminal of the LED constant current driving power supply. The positive terminal is connected to the positive output terminal of the LED constant current driving power supply, and the negative terminal is connected to the negative output terminal of the LED constant current driving power supply, so that the LED constant current driving power supply provides driving power for the LED light source module.

[0093] The LED light source modules include at least two, and each LED light source module is connected in parallel between the positive electrode terminal and the negative electrode terminal.

[0094] The counting end is connected to the counting feedback end of the LED constant current driving power supply, and is mainly used to feed back to the LED constant current driving power supply the number of parallel LED light source modules.

[0095] One end of the counting resistor module 12 is connected to the counting end, and the other end is connected to the positive terminal, the negative terminal or the control signal end. The counting resistor module includes at least two counting resistors, and the number of each counting resistor is proportional to the number of each LED light source module, and each counting resistor is arranged in series or in parallel. The number of counting resistors can be the same as the number of LED light source modules and arranged one-to-one, or a plurality of LED light source modules correspond to one counting resistor. Considering the cuttability of the light strip, the number of counting resistors is the same as the number of LED light source modules to keep the number of counting resistors the same as the number of LED light source modules when cutting, thereby improving the accuracy of feedback. In this specific embodiment, the counting resistor module Rf includes n counting resistors, namely, counting resistor Rf1, counting resistor Rf2, ..., counting resistor Rfn, and n is an integer greater than or equal to 1. The control signal end can be a power supply, a dimming circuit, etc.

[0096] The LED constant current driving power supply generates a counting feedback signal according to the collection signal of the counting feedback end, and adjusts the output of the LED constant current driving power supply according to the counting feedback signal, so that the output current of the LED constant current driving power supply is a multiple of the number of the LED light source modules.

[0097] By setting counting resistors, the number of each counting resistor is set proportionally to the number of each LED light source module, so that the number of LED light source modules connected in parallel can be calculated by measuring the voltage of the counting resistor, and the output current of the LED constant current drive power supply can be adjusted accordingly to ensure that when different numbers of light source modules are connected in parallel, the current of each light source module is the same and the overall system efficiency is high.

[0098] For light strips, counting resistors are evenly spaced on the strips, and the number of counting resistors is proportional to the constant current accuracy. When cutting the light strips, the more counting resistors there are, the higher the feedback accuracy is, and the higher the constant current accuracy of the LED constant current driver output is.

[0099] The parallel constant current lighting system is described in detail below: The parallel constant current lighting system includes an LED constant current driving power supply and a parallel constant current lighting unit connected to and driven by the LED constant current driving power supply.

[0100] The LED constant current driving power supply includes a PWM modulation circuit, which has a positive output terminal and a negative output terminal. The LED constant current driving power supply also has a counting feedback terminal for receiving a counting feedback signal representing the number of parallel branches of the LED light source module; the PWM modulation circuit is connected to the counting feedback terminal, and the PWM modulation circuit adjusts the output of the PWM modulation circuit according to the counting feedback signal, so that the output current of the LED constant current driving power supply is a multiple of the number of the LED light source modules.

[0101] The LED constant current driver calculates the number of LED light source modules by counting feedback signals, thereby changing the output of the PWM chip, and further matching the output current of the LED constant current driver with the number of LED light source modules, so that the output current can automatically adapt to the number of parallel branches, with good versatility and compatibility.

[0102] Embodiment 1

[0103] Please also see Figure 6 In this specific embodiment, the PWM modulation circuit includes a step-down constant current source chip U1, a current sampling resistor R01, a rectifier diode D01, a voltage sampling resistor R02, a first filter capacitor C01, a second filter capacitor C02 and an inductor L. Wherein:

[0104] The step-down constant current source chip U1 has a power input terminal VIN, a current sampling terminal VS, a ground terminal GND, a drain terminal SW of a power switch, and a dimming terminal DIM; the power input terminal is connected to the positive electrode of the DC power supply.

[0105] The current sampling resistor R01 is connected between the power input terminal VIN and the current sampling terminal VS; the positive output terminal is connected to the current sampling terminal. The current sampling resistor R01 is used to set the rated maximum output current of the constant current power supply.

[0106] The rectifier diode D01 is connected between the power input terminal and the drain terminal of the power switch.

[0107] One end of the voltage sampling resistor R02 is connected to the counting feedback end and the dimming end, and the other end is connected to the negative electrode of the DC power supply and the ground end. The counting feedback signal generated by the counting resistor module flows through the voltage sampling resistor R02. By detecting the voltage of the voltage sampling resistor, the resistance value of the technical resistor module can be obtained, thereby obtaining the number of LED light source modules.

[0108] One end of the first filter capacitor C01 is connected to the positive electrode of the DC power supply, and the other end is connected to the negative electrode of the DC power supply. The first filter capacitor is used to filter the power input.

[0109] The second filter capacitor C02 is connected between the positive output terminal and the negative output terminal.

[0110] One end of the inductor L is connected to the drain end of the power switch, and the other end is connected to the negative output end.

[0111] In this specific embodiment, the step-down constant current source chip is PT4115.

[0112] Embodiment 2

[0113] Please also see Figure 7 In this specific embodiment, the PWM modulation circuit includes a dimming step-down constant current chip module and a feedback signal conversion circuit.

[0114] The dimming buck constant current chip module has the positive output terminal and the negative output terminal. In this specific embodiment, the dimming buck constant current chip module is composed of the dimming buck constant current chip H5119SL and its peripheral circuit. The peripheral circuit includes capacitor C01, capacitor C02, capacitor C03, resistor R01, resistor R02, resistor R03, diode D01, switch MOS tube Q and inductor L.

[0115] Capacitor C01 is used to filter the power input, resistor R01 and capacitor C02 provide working power for the chip, and resistor R03 is used to set the rated maximum output current of the constant current power supply.

[0116] The feedback signal conversion circuit is connected between the dimming step-down constant current chip module and the counting feedback terminal, and the feedback signal conversion circuit includes a first voltage comparator LM393-A, a twenty-sixth resistor R26, a twenty-seventh resistor R27, a twenty-fourth resistor R24, a twenty-fifth resistor R25, a second voltage comparator LM393-B, a twenty-eighth resistor R28, a twenty-ninth resistor R29, a twenty-fourth capacitor C24, a twentieth resistor R20, a twenty-first resistor R21, and a twenty-second resistor R22. Wherein:

[0117] The output end of the first voltage comparator LM393-A is connected to the dimming step-down constant current chip module, and the in-phase input end thereof is connected to the counting feedback end.

[0118] One end of the twenty-sixth resistor R26 is connected to the positive output end, and the other end is connected to the non-inverting input end of the first voltage comparator.

[0119] One end of the twenty-seventh resistor R27 is connected to the other end of the twenty-sixth resistor, and the other end is grounded.

[0120] One end of the twenty-fourth resistor R24 ​​is connected to the forward output end, and the other end is connected to the output end of the first voltage comparator.

[0121] A twenty-fifth resistor R25 has one end connected to the output end of the first voltage comparator and the other end grounded.

[0122] The second voltage comparator LM393-B has an output terminal, a non-inverting input terminal and an inverting input terminal.

[0123] One end of the twenty-eighth resistor R28 is connected to the forward output end, and the other end is connected to the output end of the second voltage comparator.

[0124] One end of the twenty-ninth resistor R29 is connected to the output end of the second voltage comparator, and the other end is connected to the inverting input end of the first voltage comparator and the inverting input end of the second voltage comparator.

[0125] A twenty-fourth capacitor C24 has one end connected to the inverting input terminal of the second voltage comparator, and the other end grounded.

[0126] A twentieth resistor R20 has one end connected to the output end of the second voltage comparator, and the other end connected to the non-inverting input end of the second voltage comparator.

[0127] A twenty-first resistor R21 has one end connected to the forward output end, and the other end connected to the non-inverting input end of the second voltage comparator.

[0128] One end of the twenty-second resistor R22 is connected to the non-inverting input terminal of the second voltage comparator, and the other end thereof is grounded.

[0129] The second voltage comparator LM393-B, the 28th resistor R28, the 29th resistor R29, the 20th resistor R20, the 21st resistor R21, the 22nd resistor R22 and the 24th capacitor C24 form a triangular wave generator, and the first voltage comparator LM393-A, the 24th resistor R24, the 25th resistor R25, the 26th resistor R26 and the 27th resistor R27 form a voltage comparator. The positive terminal voltage of the first voltage comparator is formed by the preset DC voltage division of the 26th resistor R26 in series with the 27th resistor R27, and the voltage division of the counting resistor module in series to form a counting feedback signal voltage, which is compared with the triangular wave generator, and outputs a PWM high and low level signal divided by the 24th resistor R24 ​​and the 25th resistor R25.

[0130] Of course, the counting feedback signal voltage may also be isolated from the feedback end of the chip. The isolation method can avoid mutual interference between the parallel constant current lighting unit and the chip.

[0131] Embodiment 3

[0132] Please also see Figure 8 This embodiment is similar to Figure 7The difference of the second embodiment is that: a PWM dimming signal is added, and the added PWM dimming signal is superimposed on the counting feedback signal to control the LED constant current drive power supply to output the corresponding current, so as to realize the parallel constant current and the dimming control function at the same time. That is, the LED constant current drive power supply also includes a PWM dimming signal, which is superimposed on the output of the feedback signal conversion circuit and then output to the dimming buck constant current chip module.

[0133] Embodiment 4

[0134] Please also see Fig. 9 In this specific embodiment, the PWM modulation circuit includes a PFC control chip U31, a thirty-first resistor R31, a thirty-second resistor R32, a thirty-third capacitor C33, a thirty-fourth capacitor C34, a thirty-third resistor R33, a thirty-fourth resistor R34, a thirty-fifth resistor R35, a thirty-fifth capacitor C35, a thirty-seventh resistor R37, a thirty-sixth capacitor C36, a thirty-seventh capacitor C37, a thirty-second diode D32, a thirtieth field effect transistor Q30, a thirty-sixth resistor R36, a thirty-ninth resistor R39, a third transformer T, a thirty-eighth resistor R38, and a thirty-first diode D31 D. Wherein:

[0135] The PFC control chip U31 has an inverting input terminal INV of the error amplifier, an output terminal COMP of the error amplifier, a main input terminal MULT of the multiplier, an input terminal CS of the PWM comparator, a demagnetization induction input terminal ZCD of the boost inductor, a ground terminal GND, a gate driver output terminal GD, and a power supply terminal VCC.

[0136] One end of the thirty-first resistor R31 is connected to the positive electrode of the power supply and the negative output end, and the other end is connected to the main input end MULT of the multiplier.

[0137] One end of the thirty-second resistor R32 is connected to the other end of the thirty-first resistor, and the other end is connected to the negative electrode of the power supply and grounded.

[0138] One end of the thirty-third capacitor C33 is connected to the negative output end, and the other end is grounded.

[0139] One end of the thirty-fourth capacitor C34 is connected to the main input end of the multiplier, and the other end is grounded.

[0140] One end of the thirty-third resistor R33 is connected to the inverting input terminal INV of the error amplifier, and the other end is grounded.

[0141] One end of the thirty-fourth resistor R34 is connected to the counting feedback end, and the other end is connected to the main input end MULT of the multiplier.

[0142] One end of the thirty-fifth resistor R35 is connected to the inverting input terminal INV of the error amplifier, and the other end is connected to the power supply terminal VCC.

[0143] One end of the thirty-fifth capacitor C35 is connected to the inverting input terminal INV of the error amplifier, and the other end is connected to the output terminal COMP of the error amplifier.

[0144] One end of the thirty-seventh resistor R37 is connected to the negative output end, and the other end is connected to the power supply end VCC.

[0145] One end of the thirty-sixth capacitor C36 is connected to the power supply terminal VCC, and the other end is grounded.

[0146] Two ends of the thirty-seventh capacitor C37 are connected to the positive output end and the negative output end respectively.

[0147] The cathode of the thirty-second diode D32 is connected to the forward output terminal;

[0148] The drain of the 30th field effect transistor Q30 is connected to the anode of the 32nd diode D32;

[0149] One end of the thirty-sixth resistor R36 is connected to the gate of the thirtieth field effect transistor, and the other end is connected to the gate driver output terminal GD.

[0150] One end of the thirty-ninth resistor R39 is connected to the source of the thirtieth field effect transistor Q30, and the other end is grounded.

[0151] Two ends of the primary winding of the third transformer T3 are connected to the negative output end and the drain of the thirtieth field effect transistor respectively.

[0152] One end of the thirty-eighth resistor R38 is connected to one end of the secondary winding of the third transformer T3, and the other end is connected to the demagnetization induction input terminal ZCD of the boost inductor; the other end of the secondary winding of the third transformer T3 is connected to the ground terminal GND and grounded.

[0153] The cathode of the thirty-first diode D31 is connected to the power supply terminal VCC, and the anode is connected to one end of the thirty-eighth resistor R38.

[0154] The 31st resistor R31 and the 32nd resistor R32 divide the voltage and sample the rectified DC voltage waveform to improve the overall power factor of the power supply; the 37th capacitor C07 is the output filter capacitor. The 33rd resistor R33, the 35th resistor R35, and the 35th capacitor C35 are the output overvoltage protection ratio sampling network. The 30th field effect transistor Q30, the 32nd diode D32, the 37th capacitor C37 and the third transformer T3 are the constant current output switch circuit; the 36th resistor R36 is the field effect transistor gate drive resistor, the 37th resistor R37 is the chip startup resistor, and the 38th resistor R38 is the zero voltage detection resistor. The total resistance of the counting resistor module and the 32nd resistor R32 are connected in series to form a counting voltage signal, which is compared with the MOS current signal of the 39th resistor R39 at the input end CS of the chip's PWM comparator to form an L6562A internal PWM signal to regulate the output current of the constant current power supply. The 39th resistor R39 is used to set the peak value of the field effect transistor and the maximum rated output current of the constant current power supply.

[0155] In this specific embodiment, for the convenience of calculation, the resistance values ​​of the counting resistors are the same.

[0156] In this specific embodiment, the LED light source module is composed of a plurality of LED lamp beads connected in series, that is, in each LED light source module, the LED lamp beads are connected in series, and the LED light source modules are connected in parallel.

[0157] In this specific embodiment, the rated voltages of the LED light source modules are the same. By ensuring that the resistances of the branches of the LED light source modules are the same, the currents of the branches of the LED light source modules are the same, and there is no need to set resistors in the branches of the LED light source modules for voltage division.

[0158] The utility model sets a positive terminal, a negative terminal, a counting terminal, an LED light source module and a counting resistor module, and connects the LED light source module in parallel between the positive terminal and the negative terminal; a counting resistor module, one end of which is connected to the counting terminal, and the other end is connected to the positive terminal, the negative terminal or the control signal terminal; the counting resistor module includes at least two counting resistors, and the number of each counting resistor is proportional to the number of each LED light source module, and each counting resistor is set in series or in parallel. Therefore, the number of LED light source modules can be calculated according to the number of counting resistors, so that constant current can be used for driving, and the corresponding current can be output to drive the LED light source module to work, which can take into account the advantages of constant current driving and parallel connection, with high efficiency and low cost, and the number of parallel LED light source modules can be calculated according to the feedback of the counting resistor module, and the output current can be adjusted accordingly, with good versatility and compatibility.

[0159] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A LED constant current driving power supply, comprising a PWM modulation circuit, wherein the PWM modulation circuit has a positive output terminal and a negative output terminal, and is characterized in that: The LED constant current driving power supply also has a counting feedback end for receiving a counting feedback signal representing the number of parallel branches of the LED light source module; the PWM modulation circuit is connected to the counting feedback end, and the PWM modulation circuit adjusts the output of the PWM modulation circuit according to the counting feedback signal so that the output current of the LED constant current driving power supply is a multiple of the number of the LED light source modules.

2. The LED constant current driving power supply according to claim 1, characterized in that: The PWM modulation circuit comprises: A step-down constant current source chip, which has a power input terminal VIN, a current sampling terminal VS, a ground terminal GND, a drain terminal SW of a power switch, and a dimming terminal DIM; the power input terminal is connected to the positive electrode of a DC power supply; A current sampling resistor connected between the power input terminal VIN and the current sampling terminal VS; the forward output terminal is connected to the current sampling terminal; A rectifier diode connected between the power input terminal and the drain terminal of the power switch; A voltage sampling resistor, one end of which is connected to the counting feedback end and the dimming end, and the other end of which is connected to the negative electrode of the DC power supply and the ground end; A first filter capacitor, one end of which is connected to the positive electrode of the DC power supply, and the other end of which is connected to the negative electrode of the DC power supply; A second filter capacitor connected between the positive output terminal and the negative output terminal; An inductor, one end of which is connected to the drain end of the power switch, and the other end of which is connected to the negative output end.

3. The LED constant current driving power supply according to claim 2, characterized in that: The step-down constant current source chip is PT4115.

4. The LED constant current driving power supply according to claim 1, characterized in that: The PWM modulation circuit comprises: A dimming and voltage-reducing constant current chip module, which has the positive output terminal and the negative output terminal; The LED constant current driving power supply further includes a feedback signal conversion circuit connected between the dimming step-down constant current chip module and the counting feedback end, and the feedback signal conversion circuit includes: A first voltage comparator, whose output end is connected to the dimming step-down constant current chip module, and whose in-phase input end is connected to the counting feedback end; A twenty-sixth resistor, one end of which is connected to the forward output terminal, and the other end of which is connected to the non-inverting input terminal of the first voltage comparator; A twenty-seventh resistor, one end of which is connected to the other end of the twenty-sixth resistor and the other end of which is grounded; A twenty-fourth resistor, one end of which is connected to the forward output terminal, and the other end of which is connected to the output terminal of the first voltage comparator; A twenty-fifth resistor, one end of which is connected to the output end of the first voltage comparator, and the other end of which is grounded; A second voltage comparator having an output terminal, a non-inverting input terminal and an inverting input terminal; A twenty-eighth resistor, one end of which is connected to the forward output terminal, and the other end of which is connected to the output terminal of the second voltage comparator; A twenty-ninth resistor, one end of which is connected to the output end of the second voltage comparator, and the other end of which is connected to the inverting input end of the first voltage comparator and the inverting input end of the second voltage comparator; A twenty-fourth capacitor, one end of which is connected to the inverting input terminal of the second voltage comparator, and the other end of which is grounded; a twentieth resistor, one end of which is connected to the output terminal of the second voltage comparator, and the other end of which is connected to the non-inverting input terminal of the second voltage comparator; A twenty-first resistor, one end of which is connected to the forward output terminal, and the other end of which is connected to the non-inverting input terminal of the second voltage comparator; A twenty-second resistor has one end connected to the non-inverting input terminal of the second voltage comparator and the other end grounded.

5. The LED constant current driving power supply according to claim 4, characterized in that: The LED constant current driving power supply also includes a PWM dimming signal, which is superimposed with the output of the feedback signal conversion circuit and then output to the dimming step-down constant current chip module.

6. The LED constant current driving power supply according to claim 1, characterized in that: The PWM modulation circuit comprises: A PFC control chip having an inverting input terminal of an error amplifier, an output terminal of an error amplifier, a main input terminal of a multiplier, an input terminal of a PWM comparator, a demagnetization sensing input terminal of a boost inductor, a ground terminal, an output terminal of a gate driver, and a power supply terminal; a thirty-first resistor, one end of which is connected to the positive electrode of the power supply and the negative output terminal, and the other end of which is connected to the main input terminal of the multiplier; A thirty-second resistor, one end of which is connected to the other end of the thirty-first resistor, and the other end of which is connected to the negative electrode of the power supply and grounded; A thirty-third capacitor, one end of which is connected to the negative output terminal, and the other end of which is grounded; A thirty-fourth capacitor, one end of which is connected to the main input terminal of the multiplier and the other end of which is grounded; A thirty-third resistor, one end of which is connected to the inverting input terminal of the error amplifier, and the other end of which is grounded; a thirty-fourth resistor, one end of which is connected to the counting feedback terminal, and the other end of which is connected to the main input terminal of the multiplier; a thirty-fifth resistor, one end of which is connected to the inverting input terminal of the error amplifier, and the other end of which is connected to the power supply terminal; a thirty-fifth capacitor, one end of which is connected to the inverting input terminal of the error amplifier, and the other end of which is connected to the output terminal of the error amplifier; A thirty-seventh resistor, one end of which is connected to the negative output terminal, and the other end of which is connected to the power supply terminal; A thirty-sixth capacitor, one end of which is connected to the power supply terminal, and the other end of which is grounded; A thirty-seventh capacitor, two ends of which are connected to the positive output terminal and the negative output terminal respectively; A thirty-second diode, a cathode of which is connected to the forward output terminal; a 30th field effect transistor, a drain of which is connected to the anode of the 32nd diode; A thirty-sixth resistor, one end of which is connected to the gate of the thirtieth field effect transistor, and the other end is connected to the output end of the gate driver; A thirty-ninth resistor, one end of which is connected to the source of the thirtieth field effect transistor, and the other end of which is grounded; A third transformer, two ends of its primary winding are respectively connected to the negative output end and the drain of the thirtieth field effect transistor; a thirty-eighth resistor, one end of which is connected to one end of the secondary winding of the third transformer, and the other end of which is connected to the demagnetization induction input end of the boost inductor; the other end of the secondary winding of the third transformer is connected to the ground end and is grounded; The thirty-first diode has a cathode connected to the power supply terminal and an anode connected to one end of the thirty-eighth resistor.

7. The LED constant current driving power supply according to claim 6, characterized in that: The PFC control chip is chip L6562A.

8. A parallel constant current lighting system, characterized in that: The parallel constant current lighting system comprises the LED constant current driving power supply according to any one of claims 1 to 7, and the parallel constant current lighting system further comprises a parallel constant current lighting unit connected to the LED constant current driving power supply and driven by the LED constant current driving power supply; The parallel constant current lighting unit comprises: A positive terminal connected to the positive output terminal of the LED constant current driving power supply; A negative terminal connected to the negative output terminal of the LED constant current driving power supply; LED light source modules, including at least two, and each LED light source module is connected in parallel between the positive terminal and the negative terminal; A counting terminal connected to a counting feedback terminal of the LED constant current driving power supply; A counting resistor module, one end of which is connected to the counting end, and the other end of which is connected to the positive terminal, the negative terminal or the control signal terminal; the counting resistor module includes at least two counting resistors, and the number of each counting resistor is arranged in proportion to the number of each LED light source module, and each counting resistor is arranged in series or in parallel.

9. The parallel constant current lighting system according to claim 8, characterized in that: The resistance values ​​of the counting resistors are the same.

10. The parallel constant current lighting system according to claim 9, characterized in that: The rated voltages of the LED light source modules are the same.

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