CN116390288A

CN116390288A - Driving control circuit, driving control method thereof and LED driving circuit

Info

Publication number: CN116390288A
Application number: CN202310420244.4A
Authority: CN
Inventors: 白浪; 王曙光
Original assignee: Xiamen Biyi Micro Electronic Technique Co ltd
Current assignee: Xiamen Biyi Micro Electronic Technique Co ltd
Priority date: 2023-04-19
Filing date: 2023-04-19
Publication date: 2023-07-04

Abstract

The invention provides a drive control circuit, a drive control method thereof and an LED drive circuit. The drive control circuit includes an arithmetic circuit and a drive circuit. The operation circuit is used for generating a load voltage representation signal according to the detection voltage and a signal representing the period of the direct current input voltage, and generating a first voltage according to the detection voltage and the load voltage representation signal. The input end of the driving circuit is coupled with the operation circuit, and the driving circuit is used for controlling the power tube according to the first voltage and the sampling signal representing the current flowing through the power tube. The driving control method includes: generating a load voltage representation signal according to the detection voltage and a signal representing the period of the direct current input voltage, and generating a first voltage according to the detection voltage and the load voltage representation signal; and controlling the power tube according to the first voltage and the sampling signal. The driving control circuit, the driving control method thereof and the LED driving circuit provided by the invention have better circuit reliability and can save a chip pin.

Description

Driving control circuit, driving control method thereof and LED driving circuit

Technical Field

The invention belongs to the technical field of power electronics, relates to an LED driving technology, and in particular relates to a driving control circuit, a driving control method thereof and an LED driving circuit.

Background

The linear LED driving circuit is widely applied to the LED driving circuit due to the advantages of simpler circuit structure, fewer components, low cost and the like.

As shown in fig. 1, the linear LED driving circuit generally includes a rectifying circuit, a power tube Q, and a driving control circuit for controlling the power tube Q. The first input end of the driving control circuit is coupled to the direct current input voltage end to receive the direct current input voltage Vin, and the output end of the driving control circuit is coupled to the control end of the power tube Q to control the power tube Q. In a linear LED constant current driving circuit directly driven by a power frequency ac power supply, in order to suppress total harmonic distortion (THD for short), it is necessary to control the phase of the LED load current to be identical to the phase of the dc input voltage Vin, and the waveform of the LED load current is as close to a sine-like wave as possible. The common practice is to sample the voltage waveform of the dc input voltage Vin, and control the conduction degree of the power tube Q according to the dc input voltage Vin under different LED load voltages, so that load currents with approximately the same phase and waveform can be generated. When the dc input voltage Vin is greater than the LED load voltage Vled, the LED load current is greater than zero, and the magnitude of the LED load current is proportional to the dc input voltage. However, the technical scheme needs direct sampling of direct current input voltage or power frequency alternating current power supply, and strong surge resistance is needed, so that the reliability of the circuit is affected. In addition, this solution requires a new chip pin, which is disadvantageous for miniaturization of the circuit.

In view of the foregoing, there is a need to provide a new architecture or control method for solving at least some of the problems described above.

Disclosure of Invention

Aiming at one or more problems in the prior art, the invention provides a drive control circuit, a drive control method thereof and an LED drive circuit, which have better circuit reliability and can save one chip pin.

According to one aspect of the present invention, a drive control circuit is disclosed for controlling a power tube, a first end of the power tube being used for coupling to an LED load, the drive control circuit comprising:

the input end of the operation circuit is coupled with the first end of the power tube to obtain a detection voltage, and is used for generating a load voltage representation signal according to the detection voltage and a signal representing the period of the direct current input voltage, and generating a first voltage according to the detection voltage and the load voltage representation signal; and

and the input end of the driving circuit is coupled with the operation circuit and is used for controlling the power tube according to the first voltage and the sampling signal representing the current flowing through the power tube.

As an embodiment of the present invention, the operation circuit obtains a maximum value of the detection signal and a time signal representing the on-time of the LED according to the detection voltage.

As one embodiment of the invention, the time signal representing the LED on time is the duration of the detected voltage greater than zero in the period of the DC input voltage.

As one embodiment of the invention, the time signal representing the LED on time is the time period of the detected voltage increasing from zero to the maximum value in the period of the direct current input voltage or the time period of the detected voltage decreasing from the maximum value to zero in the period of the direct current input voltage.

As an embodiment of the present invention, an arithmetic circuit includes:

the input end of the characterization signal generation circuit is coupled with the first end of the power tube to acquire detection voltage, and the characterization signal generation circuit is used for generating a load voltage characterization signal according to the detection voltage; and

the first input end of the adder is coupled with the characterization signal generating circuit to receive the load voltage characterization signal, the second input end of the adder receives the detection signal, and the output end of the adder outputs the first voltage.

As an embodiment of the present invention, a driving circuit includes:

the input end of the proportional circuit is coupled with the operation circuit and is used for generating a reference signal after the proportional operation of the first voltage; and

the first input end of the operational amplifier circuit is coupled with the output end of the proportional circuit, the second input end of the operational amplifier circuit receives a sampling signal representing the current flowing through the power tube, and the output end of the operational amplifier circuit is coupled with the control end of the power tube.

As an embodiment of the present invention, the driving control circuit is provided with a preset pin, the preset pin is coupled to an input end of the operation circuit, the preset pin is used for being coupled to a first end of the power tube, and the preset pin is used as a power supply pin of the driving control circuit and a sampling pin for obtaining the detection signal.

According to another aspect of the present invention, a drive control circuit is disclosed for controlling a power tube, a first end of the power tube being used for coupling to an LED load, the drive control circuit comprising:

the input end of the operation circuit is coupled with the first end of the power tube to obtain a detection voltage, the operation circuit is used for calculating a second voltage representing the direct current input voltage according to the detection voltage and a signal representing the period of the direct current input voltage, generating a first voltage according to the second voltage, wherein the first voltage is zero when the detection voltage is zero, and the first voltage is in direct proportion to the second voltage when the detection voltage is greater than zero; and

According to yet another aspect of the present invention, an LED driving circuit is disclosed, the LED driving circuit comprising a rectifying circuit and any one of the above driving control circuits, the rectifying circuit being coupled to the driving control circuit.

According to one aspect of the present invention, a driving control method is disclosed, the driving control method is used for controlling a power tube, a first end of the power tube is used for coupling an LED load, and the driving control method includes:

acquiring a detection voltage representing the terminal voltage of a first end of a power tube, generating a load voltage representing signal according to the detection voltage and a signal representing the period of a direct current input voltage, and generating a first voltage according to the detection voltage and the load voltage representing signal; and

the power tube is controlled in accordance with the first voltage and a sampling signal representative of a current flowing through the power tube.

As an embodiment of the present invention, the step of generating the load voltage characterization signal from the detected voltage and the signal characterizing the period of the dc input voltage specifically includes: and obtaining the maximum value of the detection signal and a time signal representing the LED on time according to the detection voltage, and generating a load voltage representation signal according to the maximum value of the detection signal, the time signal representing the LED on time and a signal representing the period of the direct current input voltage.

As an embodiment of the present invention, the step of controlling the power tube according to the first voltage and the sampling signal characterizing the current flowing through the power tube comprises: and performing proportional operation on the first voltage to generate a reference signal, and generating a driving signal according to the reference signal and the sampling signal to control the power tube.

The invention provides a drive control circuit, a drive control method thereof and an LED drive circuit. The driving control circuit is used for controlling the power tube, the first end of the power tube is used for being coupled with the LED load, and the driving control circuit comprises an operation circuit and a driving circuit. The input end of the operation circuit is used for being coupled with the first end of the power tube to obtain detection voltage, and the operation circuit is used for generating a load voltage representation signal according to the detection voltage and a signal representing the period of the direct current input voltage and generating a first voltage according to the detection voltage and the load voltage representation signal. The input end of the driving circuit is coupled with the operation circuit, and the driving circuit is used for controlling the power tube according to the first voltage and the sampling signal representing the current flowing through the power tube. The driving control method includes: acquiring a detection voltage representing the terminal voltage of a first end of a power tube, generating a load voltage representing signal according to the detection voltage and a signal representing the period of a direct current input voltage, and generating a first voltage according to the detection voltage and the load voltage representing signal; and controlling the power tube according to the first voltage and a sampling signal representing the current flowing through the power tube. According to the drive control circuit, the drive control method thereof and the LED drive circuit, direct sampling of alternating current power supply voltage or direct current input voltage is not needed, and as the pin for sampling the terminal voltage of the first end of the power tube is coupled to the alternating current power supply through the LED load, the working voltage is lower, the circuit reliability is better, the circuit works stably, and a chip pin can be saved.

Drawings

The accompanying drawings are included to provide a further understanding of the invention, and together with the description serve to explain the embodiments of the invention, and do not constitute a limitation of the invention. In the drawings:

fig. 1 shows a schematic circuit diagram of a prior art LED driving circuit;

fig. 2 is a schematic circuit diagram of an LED driving circuit according to an embodiment of the present invention;

fig. 3 is a schematic circuit diagram showing a driving control circuit according to an embodiment of the present invention;

fig. 4 is a schematic circuit diagram showing a driving control circuit according to another embodiment of the present invention;

FIG. 5 shows a waveform diagram of a portion of signals of a drive control circuit according to an embodiment of the present invention;

FIG. 6 is a schematic waveform diagram showing a portion of signals of a drive control circuit according to another embodiment of the present invention;

fig. 7 shows a waveform diagram of a part of signals of a driving control circuit according to still another embodiment of the present invention.

Detailed Description

For a further understanding of the present invention, preferred embodiments of the invention are described below in conjunction with the examples, but it should be understood that these descriptions are merely intended to illustrate further features and advantages of the invention, and are not limiting of the claims of the invention.

The description of this section is intended to be illustrative of only a few exemplary embodiments and the invention is not to be limited in scope by the description of the embodiments. Combinations of the different embodiments, and alternatives of features from the same or similar prior art means and embodiments are also within the scope of the description and protection of the invention.

"coupled" or "connected" in the specification includes both direct and indirect connections. An indirect connection is a connection via an intermediary, such as a connection via an electrically conductive medium, such as a conductor, where the electrically conductive medium may contain parasitic inductance or parasitic capacitance, or may be a connection via an intermediary circuit or component described in the embodiments of the specification; indirect connections may also include connections through other active or passive devices, such as through circuits or components such as switches, signal amplification circuits, follower circuits, and the like, that may perform the same or similar functions. "plurality" or "multiple" means two or more. In addition, in the present invention, terms such as first and second are mainly used to distinguish one technical feature from another technical feature, and do not necessarily require or imply a certain actual relationship or order between the technical features.

As shown in fig. 2, an embodiment of the present invention discloses an LED driving circuit, which includes a rectifying circuit and a driving control circuit 10, wherein the rectifying circuit is coupled to the driving control circuit 10. The rectifying circuit comprises a rectifying bridge. In an embodiment, the driving control circuit 10 is configured to control the power tube Q, a first end of the power tube Q is configured to be coupled to the LED load, a second end of the power tube Q is coupled to the ground, and a control end of the power tube is coupled to an output end of the driving control circuit 10. The first end of the LED load is coupled with the rectifier bridge, and the second end of the LED load is coupled with the first end of the power tube Q. The drive control circuit 10 acquires a detection voltage vdrain representing a terminal voltage of a first terminal of the power transistor Q and a sampling signal representing a current flowing through the power transistor to control the power transistor Q. In an embodiment of the present invention, as shown in fig. 2, the power transistor Q is disposed outside the driving control circuit 10. In another embodiment, the drive control circuit 10 includes a power transistor Q.

As shown in fig. 3, the drive control circuit includes an arithmetic circuit 100 and a drive circuit 200. The input end of the operation circuit 100 is coupled to the first end of the power tube Q to obtain the detection voltage Vdrain, which may be a terminal voltage of the first end of the power tube Q or a voltage signal proportional to the terminal voltage of the first end of the power tube Q. The operation circuit 100 is configured to generate a load voltage characterization signal according to the detection voltage Vdrain and a signal that characterizes a period of the dc input voltage, and generate a first voltage V1 according to the detection voltage Vdrain and the load voltage characterization signal. The load voltage characterization signal may characterize the LED load voltage Vled. In an embodiment, the load voltage characterization signal is proportional to the LED load voltage Vled or the load voltage characterization signal is equal to the LED load voltage Vled. An input terminal of the driving circuit 200 is coupled to an output terminal of the operation circuit 100, and the driving circuit 200 is configured to control the power transistor Q according to the first voltage V1 and a sampling signal Vcs indicating a current flowing through the power transistor Q.

In an embodiment of the present invention, the power transistor Q is any one of a metal oxide semiconductor field effect transistor (MOS transistor for short), a triode, or other power devices capable of operating in a linear region. In one embodiment, the driving control circuit controls the power transistor Q to operate in a linear region to realize linear constant current driving control. In an embodiment as shown in fig. 3, the power tube Q is a MOS tube, a drain electrode of the power tube Q is coupled to the LED load, a gate electrode of the power tube Q is coupled to an output end of the driving control circuit, a source electrode of the power tube Q is coupled to a first end of the sampling resistor Rcs, and a second end of the sampling resistor Rcs is coupled to ground. In this embodiment, the detection voltage is the drain voltage of the power transistor Q.

As shown in fig. 4, the drive control circuit includes an arithmetic circuit 100 and a drive circuit 200. In one embodiment, the arithmetic circuit 100 includes a characterization signal generation circuit 101 and an adder. An input terminal of the characterization signal generating circuit 101 is coupled to a first terminal of the power transistor Q to obtain the detection voltage Vdrain, and the characterization signal generating circuit 101 is configured to generate the load voltage characterization signal Vled according to the detection voltage Vdrain. A first input terminal of the adder is coupled to the output terminal of the characterization signal generating circuit 101 to receive the load voltage characterization signal Vled, a second input terminal of the adder receives the detection signal Vdrain, and an output terminal of the adder outputs the first voltage V1. In another embodiment, the detected voltage and the load voltage representation signal may be respectively subjected to a scaling operation or a scaling operation and then added to obtain the first voltage V1. In another embodiment, the driving circuit 200 includes a scaling circuit 201 and an operational amplifier circuit 202. The input end of the scaling circuit 201 is coupled to the output end of the operation circuit, and the scaling circuit 201 is configured to perform scaling operation on the first voltage V1 to generate the reference signal Vref. In one embodiment, the scaling circuit 201 generates the reference signal Vref after scaling up the first voltage V1. As shown in fig. 4, a first input terminal of the operational amplifier circuit 202 is coupled to an output terminal of the proportional circuit 201, a second input terminal of the operational amplifier circuit 202 is coupled to the sampling resistor Rcs to receive the sampling signal Vcs representing the current flowing through the power transistor Q, and an output terminal of the operational amplifier circuit 202 is coupled to a control terminal of the power transistor Q.

In an embodiment of the present invention, a signal representing a period of the power frequency ac voltage is provided in the operation circuit, and the signal representing signal generating circuit generates the load voltage representing signal Vled according to the detected voltage and the signal representing the period of the power frequency ac voltage. The load voltage characterization signal Vled can be obtained based on the detection voltage and the signal operation that characterizes the period of the power frequency alternating voltage. The signal representing the period of the power frequency alternating voltage is the period of the power frequency alternating voltage or the period of the direct current input voltage. The period of the direct current input voltage is half of the period of the power frequency alternating current voltage. In another embodiment, the operation circuit includes a characterization signal generation circuit and a period acquisition circuit. The input end of the period acquisition circuit is coupled with the direct current input voltage, and the period acquisition circuit is used for acquiring the period of the direct current input voltage. The input end of the characterization signal generating circuit is coupled with the output end of the period acquisition circuit to acquire the period of the direct current input voltage. In yet another embodiment, the operation circuit includes a characterization signal generation circuit and a period acquisition circuit. The input end of the period acquisition circuit is coupled with the power frequency alternating voltage, and the period acquisition circuit is used for acquiring the period of the power frequency alternating voltage. The input end of the characterization signal generating circuit is coupled with the output end of the period acquisition circuit to acquire the period of the power frequency alternating voltage. In an embodiment, the period acquisition circuit is disposed outside the driving control circuit, and the calculation circuit is coupled to the period acquisition circuit to acquire a period of the power frequency ac voltage or a period of the dc input voltage.

In an embodiment of the present invention, as can be seen in fig. 4 and 5, the operation circuit obtains the maximum value vd_max of the detection signal and the time signal representing the on-time of the LED according to the detection voltage Vdrain. The operation circuit may generate the load voltage characterization signal Vled according to a maximum value of the detection signal, a time signal characterizing an LED on-time, and a signal characterizing a period of the dc input voltage. With reference to fig. 2, 4 and 5, equation (1) and equation (2) can be obtained, respectively:

Vin_max＝Vd_max+Vled(2)

wherein Vled is the LED load voltage, vin_max is the maximum value of the dc input voltage Vin, T is the time signal representing the LED on time, T is the signal representing the period of the dc input voltage, vd_max is the maximum value of the detection signal in the period of the dc input voltage.

In one embodiment of the present invention, the LED load voltage may be approximately considered to remain unchanged after the LED load in the LED drive circuit is selected. Taking a power tube as an MOS tube as an example, the drain voltage of the MOS tube is equal to the direct current input voltage Vin minus the LED load voltage. Therefore, according to the duration that the drain voltage of the MOS tube is greater than zero and the maximum value of the drain voltage of the MOS tube, the maximum value of the direct current input voltage can be calculated, so that the waveform of the whole direct current input voltage is calculated, and finally the LED load current waveform corresponding to the waveform of the direct current input voltage is obtained. In a specific embodiment, the LED load current is proportional to the dc input voltage when the dc input voltage is greater than the LED load voltage. When the direct current input voltage is smaller than the LED load voltage, the LED load current is equal to zero. As can be seen from the formulas (1) and (2), when the operation circuit obtains the maximum value vd_max of the detection signal, the time signal T representing the LED on time, and the signal T representing the period of the dc input voltage, the LED load voltage Vled can be obtained by operation.

In another embodiment of the present invention, the operation circuit calculates a waveform of the dc input voltage according to the waveform of the detection signal and a period of the dc input voltage, and obtains the load voltage characterization signal according to the dc input voltage and the detection signal. Specifically, the operation circuit obtains a dc input voltage value corresponding to a moment when the detection signal is about to be greater than zero, where the dc input voltage value at the moment is equal to the LED load voltage, and the LED load voltage may be used as a load voltage characterization signal. The operation circuit generates a first voltage according to the detection voltage and the load characterization signal.

In an embodiment of the invention, a driving control circuit is disclosed, the driving control circuit is used for controlling a power tube, a first end of the power tube is used for being coupled with an LED load, and the driving control circuit comprises an operation circuit and a driving circuit. The input end of the operation circuit is used for being coupled with the first end of the power tube to obtain detection voltage, and the operation circuit is used for calculating to obtain second voltage representing direct current input voltage according to the detection voltage and signals representing the period of the direct current input voltage. The second voltage may be equal to the dc input voltage or a voltage signal proportional to the dc input voltage. In a specific embodiment, the operation circuit can calculate the waveform of the dc input voltage according to the waveform of the detected voltage and in combination with the period of the dc input voltage. In another specific embodiment, the operation circuit obtains the LED on time and two detection voltage signals greater than zero according to the detection voltage, and obtains the waveform of the dc input voltage by combining the cycle fitting of the dc input voltage. In an embodiment, the operation circuit generates a first voltage according to the second voltage, the first voltage is zero when the detection voltage is zero, and the first voltage is proportional to the second voltage when the detection voltage is greater than zero. The input end of the driving circuit is coupled with the operation circuit, and the driving circuit is used for controlling the power tube according to the first voltage and the sampling signal representing the current flowing through the power tube.

In one embodiment, as shown in fig. 5, the dotted steamed bread wave is the dc input voltage Vin, and the solid steamed bread wave is the detection voltage vdrain. The time signal t representing the LED on time is equal to the LED on time t1, and the LED on time is the duration that the detection voltage is larger than zero in the period of the direct current input voltage. In the present embodiment, the signal T representing the period of the dc input voltage is the period of the dc input voltage Vin.

In another embodiment, as shown in fig. 6, the time signal t representing the LED on-time is a duration t2 of the detected voltage increasing from zero to the maximum value in the period of the dc input voltage, and the duration t2 is half of the LED on-time t 1. In the present embodiment, the signal T representing the period of the dc input voltage is half the period of the dc input voltage Vin. In another embodiment, the time signal T representing the on-time of the LED may also be a period of time in which the detected voltage decreases from the maximum value to zero in the period of the dc input voltage, and the signal T representing the period of the dc input voltage is half of the period of the dc input voltage Vin.

In one embodiment, as shown in fig. 7, the dc input voltage Vin is a steamed bread wave. When the direct current input voltage Vin is smaller than the LED load voltage Vled, the reference signal Vref generated by the drive control circuit is zero, and at this time, the LED load current iled is zero. When the dc input voltage Vin is greater than the LED load voltage Vled, the waveform of the reference signal Vref generated by the drive control circuit approximates to the waveform of the dc input voltage Vin, specifically, the waveform of the reference signal Vref greater than the zero-order segment approximates to the waveform of the dc input voltage Vin, and the waveform of the reference signal Vref greater than the zero-order segment is a sine-like wave. At this time, the waveform of the LED load current iled is also similar to the waveform of the dc input voltage Vin, specifically, the waveform of the LED load current iled greater than the zero-order is similar to the waveform of the dc input voltage Vin, and the waveform of the LED load current iled greater than the zero-order is a sine-like wave. When the dc input voltage Vin is greater than the LED load voltage Vled, the LED load current iled is proportional to the dc input voltage. The drive control circuit based on the invention can realize the optimization of total harmonic distortion, and meanwhile, the direct sampling of alternating current power supply voltage or direct current input voltage is not needed, and as the pin for sampling the terminal voltage of the first end of the power tube is coupled to the alternating current power supply through the LED load, the working voltage is lower, and the circuit reliability is better. If the LED load voltage is larger, the LED on time is shorter, and the value of the reference signal Vref at the LED on start time in the dc input voltage period is larger, so the LED load current at the LED on start time is larger. In an embodiment of the invention, the driving control circuit can adaptively adjust the reference signal Vref according to different LED loads, thereby adjusting the LED load current in each direct current input voltage period, effectively inhibiting total harmonic distortion and realizing macroscopic LED constant current output.

In an embodiment of the present invention, the driving control circuit is provided with a preset pin, the preset pin is coupled to an input end of the operation circuit, the preset pin is used for being coupled to a first end of the power tube, and the preset pin is used as a power supply pin of the driving control circuit and a sampling pin for obtaining the detection signal, so that a chip pin can be omitted.

The embodiment of the invention also discloses an LED driving circuit, which comprises a rectifying circuit and the driving control circuit according to any embodiment, wherein the rectifying circuit is coupled with the driving control circuit, and the driving control circuit controls the working state of the power tube.

An embodiment of the invention discloses a driving control method, which is used for controlling a power tube, wherein a first end of the power tube is used for being coupled with an LED load, and the driving control method comprises the following steps:

the power tube is controlled according to the first voltage and a sampling signal representing current flowing through the power tube so as to realize constant current output.

In an embodiment of the invention, the driving control method is used for controlling a driving control circuit, the driving control circuit is used for controlling a power tube, and a first end of the power tube is used for coupling with an LED load. The drive control circuit includes an arithmetic circuit and a drive circuit. The operation circuit obtains a detection signal, and the detection signal represents terminal voltage of a first end of the power tube. The operation circuit generates a load voltage representation signal according to the detection voltage and a signal representing the period of the direct current input voltage, and generates a first voltage according to the detection voltage and the load voltage representation signal. The driving circuit controls the conduction degree of the power tube according to the first voltage and a sampling signal representing the current flowing through the power tube, so as to control the LED load current.

In another embodiment of the present invention, the step of generating the load voltage characterization signal from the detected voltage and the signal characterizing the period of the dc input voltage specifically comprises: and obtaining the maximum value of the detection signal and a time signal representing the LED on time according to the detection voltage, and generating a load voltage representation signal according to the maximum value of the detection signal, the time signal representing the LED on time and a signal representing the period of the direct current input voltage.

In one embodiment of the present invention, the time signal representing the on-time of the LED is the duration of the detected voltage greater than zero in the period of the dc input voltage.

In another embodiment of the present invention, the time signal representing the on-time of the LED is the duration of the detected voltage increasing from zero to a maximum value in the period of the dc input voltage or the duration of the detected voltage decreasing from a maximum value to zero in the period of the dc input voltage.

In one embodiment of the present invention, the step of controlling the power tube according to the first voltage and the sampling signal characterizing the current flowing through the power tube comprises: and performing proportional operation on the first voltage to generate a reference signal, and generating a driving signal according to the reference signal and the sampling signal to control the power tube. In a specific embodiment, the first voltage is scaled up to generate a reference signal, and a driving signal is generated according to the reference signal and the sampling signal to control the power tube.

It will be appreciated by those skilled in the art that the logic controls of the "high" and "low", "set" and "reset", "and" or "," in-phase input "and" anti-phase input "among the logic controls described in the specification or drawings may be interchanged or changed, and that the same functions or purposes as those of the above embodiments may be achieved by adjusting the subsequent logic controls.

The description and applications of the present invention herein are illustrative and are not intended to limit the scope of the invention to the embodiments described above. The relevant descriptions of effects, advantages and the like in the description may not be presented in practical experimental examples due to uncertainty of specific condition parameters or influence of other factors, and the relevant descriptions of effects, advantages and the like are not used for limiting the scope of the invention. Variations and modifications of the embodiments disclosed herein are possible, and alternatives and equivalents of the various components of the embodiments are known to those of ordinary skill in the art. It will be clear to those skilled in the art that the present invention may be embodied in other forms, structures, arrangements, proportions, and with other assemblies, materials, and components, without departing from the spirit or essential characteristics thereof. Other variations and modifications of the embodiments disclosed herein may be made without departing from the scope and spirit of the invention.

Claims

1. A drive control circuit for controlling a power tube having a first end for coupling to an LED load, the drive control circuit comprising:

2. The drive control circuit of claim 1, wherein the arithmetic circuit obtains a maximum value of the detection signal and a time signal indicative of an on time of the LED from the detection voltage.

3. The drive control circuit of claim 2 in which the time signal indicative of LED on time is a duration of greater than zero detected voltage during a period of the dc input voltage.

4. The drive control circuit of claim 2, wherein the time signal indicative of LED on-time is a duration of an increase in detected voltage from zero to a maximum value during a period of the dc input voltage or a duration of a decrease in detected voltage from a maximum value to zero during a period of the dc input voltage.

5. The drive control circuit according to claim 1, wherein the arithmetic circuit includes:

6. The drive control circuit of claim 1, wherein the drive circuit comprises:

7. The drive control circuit of claim 1, wherein the drive control circuit is provided with a preset pin coupled to an input of the operational circuit, the preset pin being configured to be coupled to a first end of the power tube, the preset pin being a power supply pin of the drive control circuit and a sampling pin for obtaining the detection signal.

8. A drive control circuit for controlling a power tube having a first end for coupling to an LED load, the drive control circuit comprising:

9. An LED driving circuit, comprising a rectifying circuit and a driving control circuit according to any one of claims 1-8, wherein the rectifying circuit is coupled to the driving control circuit.

10. A drive control method for controlling a power tube, a first end of the power tube being configured to be coupled to an LED load, the drive control method comprising:

11. The drive control method of claim 10, wherein the step of generating a load voltage characterization signal from the detected voltage and a signal characterizing the period of the dc input voltage comprises: and obtaining the maximum value of the detection signal and a time signal representing the LED on time according to the detection voltage, and generating a load voltage representation signal according to the maximum value of the detection signal, the time signal representing the LED on time and a signal representing the period of the direct current input voltage.

12. The drive control method of claim 11, wherein the time signal indicative of LED on-time is a duration of greater than zero detected voltage during a period of the dc input voltage.

13. The drive control method of claim 11, wherein the time signal indicative of the LED on-time is a duration of an increase in the detected voltage from zero to a maximum value during the period of the dc input voltage or a duration of a decrease in the detected voltage from a maximum value to zero during the period of the dc input voltage.

14. The drive control method of claim 10, wherein the step of controlling the power tube based on the first voltage and a sampling signal representative of a current flowing through the power tube comprises: and performing proportional operation on the first voltage to generate a reference signal, and generating a driving signal according to the reference signal and the sampling signal to control the power tube.