CN108650737A - A kind of adaptive twin voltage LED lamp driving circuit - Google Patents

Abstract

This application discloses a kind of adaptive twin voltage LED lamp driving circuits, including：Rectification filtering module, for alternating current to be carried out rectification and filtering；DC converting module, the alternating current for exporting rectification filtering module are converted to direct current；Voltage sample module, for alternating current to be carried out sampling and filter shape；Constant-current driven module, for when the voltage that voltage sample module exports is less than predetermined voltage threshold, the first drive signal to be provided to the control terminal of the first control module, conversely, the second drive signal to be provided to the control terminal of the second control module；First control module, the parallel connection for controlling the first LED light string and the second LED light string；Second control module, the series connection for controlling the first LED light string and the second LED light string.The application by detecting judgement input voltage automatically, to adjust automatically circuit, carries out connection in series-parallel switching to LED, is not influenced inductively or capacitively, accommodation is wide, and stability is good, and accuracy rate is high.

Description

An adaptive dual-voltage LED lamp driving circuit

technical field

The invention relates to the field of drive circuits, in particular to an adaptive dual-voltage LED lamp drive circuit.

Background technique

At present, with the continuous promotion of LED products, customers have more stringent requirements on product prices. Many manufacturers use linear or RC buck mode to drive LED lamps to reduce costs. The biggest drawback of this solution is that it is not suitable for wide Voltage requirements, so the application of linear regulated drive or RC step-down drive in wide-voltage countries and regions is very limited.

The circuit of the existing linear dual-voltage scheme generally adopts the triode switching method to change the linear output voltage; however, due to the instability of the inherent parameters of the triode itself, the circuit output is very dependent on the accuracy of the components, so the circuit output is unstable; The step-down solution is a capacitive circuit, and its large capacitance will interfere with the normal operation of the triode circuit, so the mainstream triode solution is not suitable for the resistance-capacitance step-down circuit.

Contents of the invention

In view of this, the purpose of the present invention is to provide an adaptive dual-voltage LED lamp driving circuit, which can automatically detect and judge the input voltage, and switch between series and parallel LEDs without being affected by capacitance or inductance. The specific plan is as follows:

An adaptive dual-voltage LED lamp driving circuit, used to drive a first LED light string and a second LED light string, comprising: a rectification and filtering module, a DC conversion module, a voltage sampling module, a constant current driving module, a first control module and The second control module; wherein,

The rectification and filtering module is used to rectify and filter the alternating current;

The input terminal of the DC conversion module is connected to the rectifying and filtering module, the positive output terminal is respectively connected to the anode of the first LED light string and the first terminal of the constant current drive module, and the negative output terminal is connected to the first terminal of the constant current drive module. The cathodes of the two LED light strings are connected and grounded; the DC conversion module is used to convert the AC power output by the rectification and filtering module into DC power;

The input end of the voltage sampling module is connected to the rectification and filtering module, and the output end is connected to the second end of the constant current drive module; the voltage sampling module is used for sampling and summing the alternating current output by the rectification and filtering module filter shaping;

The third terminal and the fourth terminal of the constant current drive module are respectively connected to the control terminal of the first control module, the fifth terminal is connected to the control terminal of the second control module, and the sixth terminal is grounded; The current drive module is used to provide a first drive signal to the control terminal of the first control module when the voltage output by the voltage sampling module is lower than a preset voltage threshold, and when the voltage output by the voltage sampling module is greater than a preset voltage threshold When the voltage threshold is reached, a second drive signal is provided to the control terminal of the second control module;

The input terminal of the first control module is respectively connected to the positive output terminal of the DC conversion module and the cathode of the first LED light string, and the output terminal is respectively connected to the negative output terminal of the DC conversion module and the second The anode connection of the LED light string; the first control module is used to control the parallel connection of the first LED light string and the second LED light string;

The input end of the second control module is connected to the cathode of the first LED light string, and the output end is connected to the anode of the second LED light string; the second control module is used to control the first LED light string string and the second LED light string in series.

Preferably, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, the rectification and filtering module includes a rectification bridge and a first capacitor;

The positive input end of the rectifier bridge is connected to the positive input end of the alternating current, the negative input end is connected to the negative input end of the alternating current, and the positive output end is respectively connected to the input end of the voltage sampling circuit and the positive input end of the DC conversion module connected, the negative output terminal is connected to the negative input terminal of the DC conversion module;

The first capacitor is connected between the positive output terminal and the negative output terminal of the rectifier bridge.

Preferably, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, the voltage sampling module includes a first resistor, a second resistor and a second capacitor;

The first end of the first resistor is the input end of the voltage sampling module, and the second end is respectively connected to the first end of the second resistor and the second end of the constant current drive module;

The second end of the second resistor is grounded;

The second capacitor is connected to both ends of the second resistor.

Preferably, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, the constant current driving module includes a step-down unit, a single-chip microcomputer, and a current limiting unit; wherein,

The input end of the step-down unit is the first end of the constant current drive module, the first output end is connected to the power supply end of the single-chip microcomputer, and the second output end is grounded; the step-down unit is used to convert the DC conversion module Stepping down the output direct current, and supplying power to the single-chip microcomputer;

The voltage detection terminal of the single-chip microcomputer is the second terminal of the constant current driving module, the first driving terminal is connected with the first input terminal of the current limiting unit, and the second driving terminal is connected with the second input terminal of the current limiting unit. The third drive terminal is connected to the third input terminal of the current limiting unit, and the ground terminal is connected to the ground; the single-chip microcomputer is used to compare the voltage output by the voltage sampling module with the preset voltage threshold, and according to the comparison result , transmitting the first drive signal to the first input terminal and the second input terminal of the current limiting unit, and transmitting the second drive signal to the third input terminal of the current limiting unit;

The first output end of the current limiting unit is the third end of the constant current drive module, the second output end is the fourth end of the constant current drive module, and the third output end is the third end of the constant current drive module. The fifth terminal: the current limiting unit is used to limit the current of the first driving signal and the second driving signal.

Preferably, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, the step-down unit includes a third resistor, a fourth resistor and a third capacitor;

The first end of the third resistor is the first end of the constant current drive module, and the second end is connected to the first end of the fourth resistor;

The second end of the fourth resistor is connected to the power supply end of the single-chip microcomputer;

The first end of the third capacitor is connected to the second end of the fourth resistor, and the second end is grounded.

Preferably, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, the current limiting unit includes a first diode, a second diode, a third diode, a fifth resistor, a Six resistors and a seventh resistor;

The anode of the first diode is connected to the first driving end of the single-chip microcomputer, and the cathode is connected to the first end of the fifth resistor;

The anode of the second diode is connected to the second drive terminal of the single-chip microcomputer, and the cathode is connected to the first end of the sixth resistor;

The anode of the third diode is connected to the third drive terminal of the single-chip microcomputer, and the cathode is connected to the first end of the seventh resistor;

The second end of the fifth resistor is the third end of the constant current drive module;

The second end of the sixth resistor is the fourth end of the constant current drive module;

The second end of the seventh resistor is the fifth end of the constant current driving module.

Preferably, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, the first control module includes a first switching transistor and a second switching transistor;

The gate of the first switching transistor is connected to the third terminal of the constant current drive module, the source is connected to the positive output terminal of the DC conversion module, and the drain is connected to the anode of the second LED light string;

The gate of the second switching transistor is connected to the fourth terminal of the constant current drive module, the source is connected to the cathode of the first LED light string, and the drain is connected to the negative output terminal of the DC conversion module.

Preferably, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, the second control module includes a third switching transistor;

The gate of the third switching transistor is connected to the fifth terminal of the constant current driving module, the source is connected to the cathode of the first LED light string, and the drain is connected to the anode of the second LED light string.

Preferably, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, the first switching transistor, the second switching transistor and the third switching transistor are all thin film transistors or metal oxide semiconductors FET.

Preferably, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, both the first LED light string and the second LED light string include a plurality of LEDs connected in series or a plurality of LEDs connected in parallel.

An adaptive dual-voltage LED lamp driving circuit provided by the present invention is used to drive the first LED light string and the second LED light string, including: a rectification and filtering module, a DC conversion module, a voltage sampling module, a constant current driving module, The first control module and the second control module; wherein, the rectification and filtering module is used to rectify and filter the alternating current; the input end of the DC conversion module is connected to the rectification and filtering module, and the positive output end is respectively connected to the anode and the first LED light string The first end of the constant current drive module is connected, and the negative output end is connected to the cathode of the second LED light string and grounded; the DC conversion module is used to convert the alternating current output by the rectification and filtering module into direct current; the input end of the voltage sampling module is connected to the rectification and filtering The module is connected, and the output end is connected to the second end of the constant current drive module; the voltage sampling module is used to sample and filter the alternating current output by the rectification and filtering module; the third end and the fourth end of the constant current drive module are respectively connected to the first The control terminal of the control module is connected, the fifth terminal is connected to the control terminal of the second control module, and the sixth terminal is grounded; the constant current drive module is used to convert the first drive signal Provided to the control terminal of the first control module, when the voltage output by the voltage sampling module is greater than the preset voltage threshold, the second drive signal is provided to the control terminal of the second control module; the input terminals of the first control module are respectively converted to DC The positive output end of the module is connected to the cathode of the first LED light string, and the output end is respectively connected to the negative output end of the DC conversion module and the anode of the second LED light string; the first control module is used to control the first LED light string and the second LED light string Parallel connection of two LED light strings; the input end of the second control module is connected to the cathode of the first LED light string, and the output end is connected to the anode of the second LED light string; the second control module is used to control the first LED light string and the second LED light string A series connection of two LED light strings.

Through the interaction of the above-mentioned six modules, the present invention automatically detects and judges the input voltage when there are two kinds of multiple input voltages (for example, 120/240V, 12/24V), thereby automatically adjusting the circuit and switching the LEDs in series and parallel. , so that the resistance-capacitance step-down drive circuit and linear drive circuit (same as the DC conversion module) can be applied in a wide voltage range, with a wide range of adaptation, suitable for both AC and DC, high and low voltage, and is not affected by the capacitance or the AC-DC change circuit itself Inductive influence, good stability, high accuracy.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only It is an embodiment of the present invention, and those skilled in the art can also obtain other drawings according to the provided drawings without creative work.

FIG. 1 is a schematic structural diagram of an adaptive dual-voltage LED lamp driving circuit provided by an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an adaptive dual-voltage LED lamp driving circuit provided by an embodiment of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The present invention provides an adaptive dual-voltage LED lamp driving circuit, as shown in Figure 1 and Figure 2, used to drive the first LED light string 01 and the second LED light string 02, including: a rectification and filtering module 1, a DC conversion module 2. Voltage sampling module 3, constant current drive module 4, first control module 5 and second control module 6; wherein,

The rectification and filtering module 1 is used to rectify and filter the alternating current;

The input end of the DC conversion module 2 (DC-DC) is connected to the rectification and filtering module 1, the positive output end is respectively connected to the anode of the first LED light string 01 and the first end of the constant current drive module 4, and the negative output end is connected to the second The cathode of the LED light string 02 is connected and grounded; the DC conversion module 2 is used to convert the AC power output by the rectification and filtering module 1 into DC power; it should be noted that the DC conversion module 2 is similar to the conventional RC buck drive circuit and linear The driving circuit works on the principle of converting the input AC voltage into a DC voltage through a resistance-capacitance circuit/linear voltage regulator circuit;

The input end of the voltage sampling module 3 is connected to the rectification and filtering module 1, and the output end is connected to the second end of the constant current drive module 4; the voltage sampling module 3 is used for sampling and filtering and shaping the alternating current output by the rectification and filtering module 1; It is understood as the effect of partial pressure;

The third end and the fourth end of the constant current drive module 4 are respectively connected to the control end of the first control module 5, the fifth end is connected to the control end of the second control module 6, and the sixth end is grounded; the constant current drive module 4 is used When the voltage output by the voltage sampling module 3 is less than the preset voltage threshold, the first drive signal is provided to the control terminal of the first control module 5, and when the voltage output by the voltage sampling module 3 is greater than the preset voltage threshold, the second The driving signal is provided to the control terminal of the second control module 6;

The input end of the first control module 5 is respectively connected to the positive output end of the DC conversion module 2 and the cathode of the first LED light string 01, and the output end is respectively connected to the negative output end of the DC conversion module 2 and the anode of the second LED light string 02. connection; the first control module 5 is used to control the parallel connection of the first LED light string 01 and the second LED light string 02;

The input end of the second control module 6 is connected to the cathode of the first LED light string 01, and the output end is connected to the anode of the second LED light string 02; the second control module 6 is used to control the first LED light string 01 and the second LED light string Series connection of light string 02.

In the above self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, through the interaction of the above six modules, the input voltage is automatically detected and judged, thereby automatically adjusting the circuit, and switching the LEDs in series and parallel, so that the resistance and capacitance Step-down drive circuit and linear drive circuit (same as the DC conversion module) can be applied in a wide voltage range, with a wide range of application, and are suitable for application environments where the input voltage is twice the relationship (such as 120/240V, 12/24V), AC and DC, high It is suitable for low voltage and is not affected by the capacitance or inductance of the AC-DC changing circuit itself. It has good stability, high accuracy and low cost.

The present invention will be described in detail below in conjunction with specific embodiments. It should be noted that this embodiment is for better explaining the present invention, but not limiting the present invention.

In specific implementation, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, as shown in FIG. 2 , the rectification and filtering module 1 may include a rectification bridge and a first capacitor C1; The positive input terminal L of the alternating current is connected, the negative input terminal is connected with the negative input terminal N of the alternating current, the positive output terminal V+ is respectively connected with the input terminal of the voltage sampling circuit 3 and the positive input terminal of the DC conversion module 2, and the negative output terminal V- is connected with the positive input terminal of the DC conversion module 2. The negative input terminal of the DC conversion module 2 is connected; the first capacitor C1 is connected between the positive output terminal V+ and the negative output terminal V− of the rectifier bridge. The function of the rectifier bridge is to rectify the alternating current, and the function of the first capacitor C1 is to filter the alternating current.

The above is just an example to illustrate the specific structure of the rectification and filtering module. In the actual implementation, the specific structure of the rectification and filtering module is not limited to the above-mentioned structure provided by the embodiment of the present invention, and can also be other structures known to those skilled in the art, which will not be described here. limited.

During specific implementation, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, as shown in FIG. 2 , the voltage sampling module 3 may include a first resistor R1, a second resistor R2, and a second capacitor C2; The first end of the first resistor R1 is the input end of the voltage sampling module 3 (that is, the first end of the first resistor R1 is connected to the positive output terminal V+ of the rectifier bridge), and the second end is respectively connected to the first end of the second resistor R2 It is connected to the second end of the constant current driving module 4; the second end of the second resistor R2 is grounded; the second capacitor C2 is connected to both ends of the second resistor R2.

Specifically, the working principle of the voltage sampling module is to divide and sample the input voltage according to a certain ratio through the voltage dividing circuit, and send it to the second terminal of the constant current driving module, so that the constant current driving module can detect and determine the input voltage value.

The above is just an example to illustrate the specific structure of the voltage sampling module. In the actual implementation, the specific structure of the voltage sampling module is not limited to the above-mentioned structure provided by the embodiment of the present invention, and can also be other structures known to those skilled in the art, which will not be described here. limited.

During specific implementation, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, as shown in FIG. ,

The input end of the step-down unit 41 is the first end of the constant current drive module 4 (that is, the input end of the step-down unit 41 is connected to the positive output end of the DC conversion module 2 (DC-DC), and the first output end is connected to the single-chip microcomputer 42 The power supply terminal is connected, and the second output terminal is grounded; the step-down unit 41 is used to step down the DC power output by the DC conversion module 2, and supply power to the single-chip microcomputer 42;

The voltage detecting end of the single-chip microcomputer 42 is the second end of the constant current drive module 4 (that is, the voltage detecting end of the single-chip microcomputer 42 is connected with the second end of the first resistor R1), and the first driving end is connected with the first input end of the current limiting unit 43 connected, the second drive terminal is connected to the second input terminal of the current limiting unit 43, the third drive terminal is connected to the third input terminal of the current limiting unit 43, and the ground terminal is grounded; the single chip microcomputer 42 is used to output the voltage of the voltage sampling module 3 Compare with the preset voltage threshold, and according to the comparison result, transmit the first drive signal to the first input terminal and the second input terminal of the current limiting unit 43, and transmit the second drive signal to the third input terminal of the current limiting unit 43;

The first output end of the current limiting unit 43 is the third end of the constant current drive module 4, the second output end is the fourth end of the constant current drive module 4, and the third output end is the fifth end of the constant current drive module 4; The current limiting unit 43 is used to limit the current of the first driving signal and the second driving signal.

Specifically, when the voltage detection terminal of the single-chip microcomputer detects the voltage value output by the voltage sampling module, the voltage value is judged by the internal comparison circuit, and when the judged voltage value is greater than the preset voltage threshold, the comparison circuit outputs a corresponding level signal (such as a high-level signal) to the internal logic circuit of the single-chip microcomputer. When the determined voltage value is less than the preset voltage threshold, the internal comparison circuit outputs a corresponding level signal (such as a low-level signal) to the internal logic circuit of the single-chip microcomputer. The single-chip microcomputer The circuit outputs corresponding level signals to its logic circuit, and sends corresponding driving signals to the first control module or the second control module. It should be noted that the preset voltage threshold can be set to 200V (when AC power is input), and the preset voltage threshold can also be adjusted. The setting of the voltage sampling module should ensure that its output voltage value is not higher than the upper limit of the preset voltage threshold and not lower than the lower limit of the preset voltage threshold, so as to ensure the normal operation of the single-chip microcomputer input voltage detection circuit.

The above is just an example to illustrate the specific structure of the constant current drive module. In actual implementation, the specific structure of the constant current drive module is not limited to the above structure provided by the embodiment of the present invention, and may also be other structures known to those skilled in the art. Here No limit.

In specific implementation, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, as shown in FIG. 2 , the step-down unit 43 may include a third resistor R3, a fourth resistor R4, and a third capacitor C3; The first end of the third resistor R3 is the first end of the constant current drive module 4, and the second end is connected to the first end of the fourth resistor R4; the second end of the fourth resistor R4 is connected to the power supply end of the single-chip microcomputer 42; The first end of the third capacitor C3 is connected to the second end of the fourth resistor R4, and the second end is grounded.

The above is just an example to illustrate the specific structure of the decompression unit. In actual implementation, the specific structure of the decompression unit is not limited to the above-mentioned structure provided by the embodiment of the present invention, and may also be other structures known to those skilled in the art, which will not be described here. limited.

In specific implementation, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, as shown in FIG. 2 , the current limiting unit 43 may include a first diode D1, a second diode D2, a second Three diodes D3, the fifth resistor R5, the sixth resistor R6 and the seventh resistor R7; the anode of the first diode D1 is connected to the first driving end of the single chip microcomputer 42, and the cathode is connected to the first end of the fifth resistor R5 ; The anode of the second diode D2 is connected with the second drive end of the single-chip microcomputer 42, and the cathode is connected with the first end of the sixth resistor R6; the anode of the third diode D3 is connected with the third drive end of the single-chip microcomputer 42, and the cathode Connected to the first end of the seventh resistor R7; the second end of the fifth resistor R5 is the third end of the constant current drive module 4; the second end of the sixth resistor R6 is the fourth end of the constant current drive module 4; The second terminal of the seven resistors R7 is the fifth terminal of the constant current driving module 4 .

Specifically, the setting of the first diode D1, the second diode D2, and the third diode D3 can prevent the devices in the first control module and the second control module from affecting the single-chip microcomputer when leakage occurs; The driving voltages of the devices in the first control module and the second control module may be inconsistent, and the settings of the fifth resistor R5, the sixth resistor R6 and the seventh resistor R7 can control the output of different voltage values to limit the current.

The above is just an example to illustrate the specific structure of the current limiting unit. In actual implementation, the specific structure of the current limiting unit is not limited to the above-mentioned structure provided by the embodiment of the present invention, but may also be other structures known to those skilled in the art, which will not be described here. limited.

In specific implementation, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, as shown in FIG. 2 , the first control module 5 may include a first switching transistor T1 and a second switching transistor T2; The gate of the switching transistor T1 is connected to the third terminal of the constant current drive module 4, the source is connected to the positive output terminal of the DC conversion module 2, and the drain is connected to the anode of the second LED light string 02; the second switching transistor T2 The grid is connected to the fourth end of the constant current drive module 4 , the source is connected to the cathode of the first LED light string 01 , and the drain is connected to the negative output terminal of the DC conversion module 2 .

Specifically, both the first switch transistor T1 and the second switch transistor T2 may be N-type transistors. At this time, when the first driving signal is at a high potential, the first switch transistor T1 and the second switch transistor T2 are in a conduction state, When the first driving signal is at a low potential, the first switch transistor T1 and the second switch transistor T2 are in an off state; or, the first switch transistor T1 and the second switch transistor T2 can also be P-type transistors, at this time, when the second switch transistor T1 When a driving signal is at a low potential, the first switch transistor T1 and the second switch transistor T2 are in an on state, and when the first driving signal is at a high potential, the first switch transistor T1 and the second switch transistor T2 are in an off state.

The above is just an example to illustrate the specific structure of the first control module. In actual implementation, the specific structure of the first control module is not limited to the above-mentioned structure provided by the embodiment of the present invention, and may also be other structures known to those skilled in the art. Here No limit.

In specific implementation, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, as shown in FIG. 2 , the second control module 6 may include a third switching transistor T3; the gate of the third switching transistor T3 It is connected to the fifth terminal of the constant current driving module 4 , the source is connected to the cathode of the first LED light string 01 , and the drain is connected to the anode of the second LED light string 02 .

Specifically, the third switch transistor T3 may be an N-type transistor. At this time, when the second drive signal is at a high potential, the third switch transistor T3 is in an on state, and when the second drive signal is at a low potential, the third switch transistor The transistor T3 is in an off state; or, the third switching transistor T3 can also be a P-type transistor. At this time, when the second driving signal is a low potential, the third switching transistor T3 is in a conducting state, and when the second driving signal is high potential, the third switching transistor T3 is in a cut-off state.

The above is only an example to illustrate the specific structure of the second control module. In actual implementation, the specific structure of the second control module is not limited to the above-mentioned structure provided by the embodiment of the present invention, and may also be other structures known to those skilled in the art. Here No limit.

In specific implementation, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, the first switching transistor, the second switching transistor and the third switching transistor may be thin film transistors (TFT, Thin Film Transistor), or It is a Metal Oxide Semiconductor Field Effect Transistor (MOS, Metal Oxide Scmiconductor), which is not limited here. In a specific implementation, the functions of the sources and drains of these switch transistors can be interchanged according to different transistor types and input signals, and no specific distinction is made here. It should be noted that the first switch transistor, the second switch transistor and the third switch transistor may all be N-type transistors or all be P-type transistors, and the types of the above transistors may be determined according to actual conditions, and are not limited herein.

During specific implementation, in the above-mentioned self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention, both the first LED light string and the second LED light string include a plurality of LEDs connected in series or a plurality of LEDs connected in parallel.

The following uses Fig. 2 as an example to describe the working process of the self-adaptive dual-voltage LED lamp driving circuit provided by the embodiment of the present invention:

In Figure 2, all switching transistors are N-type transistors, and each N-type transistor is turned on under the action of a high level, and is turned off under the action of a low level; the working voltage of the first LED light string 01 and the second LED light string 02 same;

In the initial state of the circuit, the first switch transistor T1, the second switch transistor T2 and the third switch transistor T3 are all in an off state due to power failure;

When the circuit is connected to the AC input voltage, when the single-chip microcomputer 42 detects that the voltage value output by the voltage sampling module is higher than the preset voltage threshold, the single-chip microcomputer 42 turns on the third switching transistor T3, while the first switching transistor T1 and the second switching transistor T2 remains in the cut-off state. At this time, the first LED light string 01 and the second LED light string 02 are in a series connection state, the circuit is turned on, and the LEDs work normally; when the single-chip microcomputer 42 detects that the voltage value output by the voltage sampling module is lower than the preset voltage threshold , the MCU turns off the third switching transistor T3, and turns on the first switching transistor T1 and the second switching transistor T2. At this time, the first LED light string 01 and the second LED light string 02 are in parallel state, the circuit is turned on, and the LED is normal. Work.

An adaptive dual-voltage LED lamp driving circuit provided by an embodiment of the present invention is used to drive the first LED light string and the second LED light string, including: a rectification and filtering module, a DC conversion module, a voltage sampling module, and a constant current driving module , the first control module and the second control module; wherein, the rectification and filtering module is used to rectify and filter the alternating current; the input end of the DC conversion module is connected to the rectification and filtering module, and the positive output end is respectively connected to the anode of the first LED light string It is connected to the first end of the constant current drive module, and the negative output end is connected to the cathode of the second LED light string and grounded; the DC conversion module is used to convert the alternating current output by the rectification and filtering module into direct current; the input end of the voltage sampling module is connected to the rectification The filter module is connected, and the output end is connected to the second end of the constant current drive module; the voltage sampling module is used to sample and filter the alternating current output by the rectification filter module; the third end and the fourth end of the constant current drive module are connected to the second end of the constant current drive module respectively. The control terminal of the first control module is connected, the fifth terminal is connected to the control terminal of the second control module, and the sixth terminal is grounded; the constant current drive module is used to drive the first drive when the voltage output by the voltage sampling module is less than the preset voltage threshold. The signal is provided to the control terminal of the first control module, and when the voltage output by the voltage sampling module is greater than the preset voltage threshold, the second drive signal is provided to the control terminal of the second control module; the input terminals of the first control module are respectively connected to the DC The positive output end of the conversion module is connected to the cathode of the first LED light string, and the output end is respectively connected to the negative output end of the DC conversion module and the anode of the second LED light string; the first control module is used to control the first LED light string and the anode of the second LED light string. Parallel connection of the second LED light string; the input end of the second control module is connected to the cathode of the first LED light string, and the output end is connected to the anode of the second LED light string; the second control module is used to control the first LED light string and A series connection of a second LED string. Through the interaction of the above-mentioned six modules, the present invention automatically detects and judges the input voltage when there are two kinds of multiple input voltages (for example, 120/240V, 12/24V), thereby automatically adjusting the circuit and switching the LEDs in series and parallel. , so that the resistance-capacitance step-down drive circuit and linear drive circuit (same as the DC conversion module) can be applied in a wide voltage range, with a wide range of adaptation, suitable for both AC and DC, high and low voltage, and is not affected by the capacitance or the AC-DC change circuit itself Inductive influence, good stability, high accuracy.

Finally, it should also be noted that in this text, relational terms such as first and second etc. are only used to distinguish one entity or operation from another, and do not necessarily require or imply that these entities or operations, any such actual relationship or order exists. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The self-adaptive dual-voltage LED lamp driving circuit provided by the present invention has been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention. The descriptions of the above embodiments are only used to help understand the present invention. method and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. Invention Limitations.

Claims (10)

1. An adaptive dual-voltage LED lamp driving circuit, used to drive the first LED light string and the second LED light string, is characterized in that it includes: a rectification and filtering module, a DC conversion module, a voltage sampling module, and a constant current driving module , the first control module and the second control module; wherein, The rectification and filtering module is used to rectify and filter the alternating current; The input terminal of the DC conversion module is connected to the rectifying and filtering module, the positive output terminal is respectively connected to the anode of the first LED light string and the first terminal of the constant current drive module, and the negative output terminal is connected to the first terminal of the constant current drive module. The cathodes of the two LED light strings are connected and grounded; the DC conversion module is used to convert the AC power output by the rectification and filtering module into DC power; The input end of the voltage sampling module is connected to the rectification and filtering module, and the output end is connected to the second end of the constant current drive module; the voltage sampling module is used for sampling and summing the alternating current output by the rectification and filtering module filter shaping; The third terminal and the fourth terminal of the constant current drive module are respectively connected to the control terminal of the first control module, the fifth terminal is connected to the control terminal of the second control module, and the sixth terminal is grounded; The current drive module is used to provide a first drive signal to the control terminal of the first control module when the voltage output by the voltage sampling module is lower than a preset voltage threshold, and when the voltage output by the voltage sampling module is greater than a preset voltage threshold When the voltage threshold is reached, a second drive signal is provided to the control terminal of the second control module; The input terminal of the first control module is respectively connected to the positive output terminal of the DC conversion module and the cathode of the first LED light string, and the output terminal is respectively connected to the negative output terminal of the DC conversion module and the second The anode connection of the LED light string; the first control module is used to control the parallel connection of the first LED light string and the second LED light string; The input end of the second control module is connected to the cathode of the first LED light string, and the output end is connected to the anode of the second LED light string; the second control module is used to control the first LED light string string and the second LED light string in series. 2. The adaptive dual-voltage LED lamp driving circuit according to claim 1, wherein the rectification and filtering module comprises a rectification bridge and a first capacitor; The positive input end of the rectifier bridge is connected to the positive input end of the alternating current, the negative input end is connected to the negative input end of the alternating current, and the positive output end is respectively connected to the input end of the voltage sampling circuit and the positive input end of the DC conversion module connected, the negative output terminal is connected to the negative input terminal of the DC conversion module; The first capacitor is connected between the positive output terminal and the negative output terminal of the rectifier bridge. 3. The adaptive dual-voltage LED lamp driving circuit according to claim 1, wherein the voltage sampling module comprises a first resistor, a second resistor and a second capacitor; The first end of the first resistor is the input end of the voltage sampling module, and the second end is respectively connected to the first end of the second resistor and the second end of the constant current drive module; The second end of the second resistor is grounded; The second capacitor is connected to both ends of the second resistor. 4. The self-adaptive dual-voltage LED lamp drive circuit according to claim 1, wherein the constant current drive module includes a step-down unit, a single-chip microcomputer, and a current limiting unit; wherein, The input end of the step-down unit is the first end of the constant current drive module, the first output end is connected to the power supply end of the single-chip microcomputer, and the second output end is grounded; the step-down unit is used to convert the DC conversion module Stepping down the output direct current, and supplying power to the single-chip microcomputer; The voltage detection terminal of the single-chip microcomputer is the second terminal of the constant current driving module, the first driving terminal is connected with the first input terminal of the current limiting unit, and the second driving terminal is connected with the second input terminal of the current limiting unit. The third drive terminal is connected to the third input terminal of the current limiting unit, and the ground terminal is connected to the ground; the single-chip microcomputer is used to compare the voltage output by the voltage sampling module with the preset voltage threshold, and according to the comparison result , transmitting the first drive signal to the first input terminal and the second input terminal of the current limiting unit, and transmitting the second drive signal to the third input terminal of the current limiting unit; The first output end of the current limiting unit is the third end of the constant current drive module, the second output end is the fourth end of the constant current drive module, and the third output end is the third end of the constant current drive module. The fifth terminal: the current limiting unit is used to limit the current of the first driving signal and the second driving signal. 5. The adaptive dual-voltage LED lamp driving circuit according to claim 4, wherein the step-down unit comprises a third resistor, a fourth resistor and a third capacitor; The first end of the third resistor is the first end of the constant current drive module, and the second end is connected to the first end of the fourth resistor; The second end of the fourth resistor is connected to the power supply end of the single-chip microcomputer; The first end of the third capacitor is connected to the second end of the fourth resistor, and the second end is grounded. 6. The adaptive dual-voltage LED lamp driving circuit according to claim 4, wherein the current limiting unit comprises a first diode, a second diode, a third diode, a fifth resistor, The sixth resistor and the seventh resistor; The anode of the first diode is connected to the first driving end of the single-chip microcomputer, and the cathode is connected to the first end of the fifth resistor; The anode of the second diode is connected to the second drive terminal of the single-chip microcomputer, and the cathode is connected to the first end of the sixth resistor; The anode of the third diode is connected to the third drive terminal of the single-chip microcomputer, and the cathode is connected to the first end of the seventh resistor; The second end of the fifth resistor is the third end of the constant current drive module; The second end of the sixth resistor is the fourth end of the constant current drive module; The second end of the seventh resistor is the fifth end of the constant current driving module. 7. The adaptive dual-voltage LED lamp driving circuit according to claim 1, wherein the first control module comprises a first switching transistor and a second switching transistor; The gate of the first switching transistor is connected to the third terminal of the constant current drive module, the source is connected to the positive output terminal of the DC conversion module, and the drain is connected to the anode of the second LED light string; The gate of the second switching transistor is connected to the fourth terminal of the constant current drive module, the source is connected to the cathode of the first LED light string, and the drain is connected to the negative output terminal of the DC conversion module. 8. The adaptive dual-voltage LED lamp driving circuit according to claim 7, wherein the second control module comprises a third switching transistor; The gate of the third switching transistor is connected to the fifth terminal of the constant current driving module, the source is connected to the cathode of the first LED light string, and the drain is connected to the anode of the second LED light string. 9. The adaptive dual-voltage LED lamp driving circuit according to claim 8, wherein the first switching transistor, the second switching transistor and the third switching transistor are all thin film transistors or metal oxide Semiconductor Field Effect Transistor. 10. The adaptive dual-voltage LED lamp driving circuit according to claim 1, wherein the first LED light string and the second LED light string each comprise a plurality of LEDs connected in series or a plurality of LEDs connected in parallel .