PWM drive circuit, LED lamp and electronic equipment

Abstract

The utility model discloses a PWM (Pulse Width Modulation) driving circuit. The PWM driving circuit comprises an input stage; an output stage; and a discharge circuit connected in parallel with the output stage. The discharge loop is connected in parallel with the output stage, namely, the discharge loop is connected between the base electrode and the emitter electrode of the triode, so that the discharge speed can be improved.

Description

Technical Field

[0001] The present application relates to the field of drive technology, and in particular to a PWM drive circuit, an LED lamp and an electronic device. Background Art

[0002] Pulse Width Modulation (PWM) technology is a very effective control technology that uses the digital output of a microprocessor to control analog circuits. It has been widely used in many fields such as measurement, communication, and power conversion. For PWM drive, if an ordinary primary circuit is used to achieve PWM output, the discharge is fast, but the charging is slow, and only low-frequency signal transmission can be achieved, such as Figure 1 , Figure 2 shown. Utility Model Content

[0003] In view of the above-mentioned shortcomings of the prior art, an object of the present application is to provide a digital programmable gain integrated instrumentation amplifier to solve at least one problem existing in the prior art.

[0004] In order to achieve the above-mentioned purpose and other related purposes, the utility model provides a PWM drive circuit, the PWM drive circuit comprising:

[0005] Input stage;

[0006] Output stage;

[0007] A discharge circuit is connected in parallel with the output stage.

[0008] Preferably, the input stage includes: a first resistor, a second resistor and a first transistor; one end of the first resistor is connected to the PWM signal, the other end of the first resistor is connected to the base of the first transistor, the emitter of the first transistor is connected to a first voltage, the collector of the first transistor is connected to one end of the second resistor, and the other end of the second resistor is connected to the second voltage.

[0009] Preferably, the output end includes: a third resistor, a fourth resistor and a second transistor; the base of the second transistor is connected to the collector of the first transistor to form a first electrical node, the collector of the second transistor is connected to a second voltage, the emitter of the second transistor is connected to one end of the third resistor, the other end of the third resistor is connected to one end of the fourth resistor to form a second electrical node, and a PWM signal is outputted from the second electrical node, and the other end of the fourth resistor is connected to the first voltage.

[0010] Preferably, the output stage further comprises a capacitor, one end of the capacitor is connected to the second electrical node, and the other end of the capacitor is connected to the first voltage.

[0011] Preferably, the discharge circuit includes: a fifth resistor and a third transistor, the base of the third transistor is connected to the first electrical node, the collector of the third transistor is connected to the first voltage, the emitter of the third transistor is connected to one end of the fifth resistor, and the other end of the fifth resistor is connected to the second electrical node.

[0012] Preferably, the first transistor is an NPN transistor, the second transistor is an NPN transistor, and the third transistor is a PNP transistor.

[0013] To achieve the above-mentioned purpose and other related purposes, the utility model provides an LED lamp, including: the PWM drive circuit and the light-emitting unit, the output end of the PWM drive circuit is connected to the input end of the light-emitting unit, the light-emitting unit receives the drive signal output by the PWM drive circuit, and emits light based on the drive signal.

[0014] To achieve the above-mentioned purpose and other related purposes, the utility model provides an electronic device, including the PWM drive circuit.

[0015] As described above, the PWM drive circuit, LED lamp and electronic device provided by the present application have the following beneficial effects:

[0016] A PWM drive circuit of the present application includes: an input stage; an output stage; a discharge circuit connected in parallel with the output stage; by connecting a discharge circuit in parallel with the output stage, that is, connecting the discharge circuit between the base and the emitter of the transistor, the discharge speed can be increased.

[0017] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0019] Figure 1 This is a waveform diagram of the output signal with a frequency of 1KHz when there is only one level of driving circuit in the prior art;

[0020] Figure 2 This is a waveform diagram of the output signal with a frequency of 10KHz when there is only one level of driving circuit in the prior art;

[0021] Figure 3A circuit diagram of a PWM driving circuit according to an embodiment of the present application;

[0022] Figure 4 This is a waveform diagram of an output signal with a frequency of 1KHz according to an embodiment of the present application;

[0023] Figure 5 The output signal of one embodiment of the present application is a waveform diagram with a frequency of 100 KHz. DETAILED DESCRIPTION

[0024] The following describes the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0025] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0026] Although the terms "first", "second", "A", "B", etc. may be used herein to describe various elements, these elements should not be limited by these terms and are only used to distinguish one element from another. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the following technology. The term "and / or" includes a combination of multiple related items or any item in the multiple related items.

[0027] As used herein, unless the context indicates otherwise, the singular form is intended to include the plural form, and it will be understood that the term "comprising" means the presence of stated features, quantities, steps, operations, elements, or combinations thereof, but does not exclude the presence or addition of one or more other features, quantities, steps, operations, elements, components, or combinations thereof.

[0028] Before describing the drawings in detail, it is intended to clarify that the division of components in this specification is divided only by the main function of each component. That is, two or more components to be described below can be combined into one component, or can be divided into two or more components according to more detailed functions. In addition to the main function of the component, each component to be described below can also perform some or all of the functions of other components, and some of the main functions of each component can be exclusively performed by other components.

[0029] See also Figure 1 The utility model provides a PWM drive circuit, the PWM drive circuit comprising:

[0030] Input stage;

[0031] Output stage;

[0032] A discharge circuit is connected in parallel with the output stage.

[0033] In one embodiment, the input stage includes: a first resistor R1, a second resistor R2 and a first transistor Q1; one end of the first resistor R1 is connected to the PWM signal, the other end of the first resistor R1 is connected to the base of the first transistor Q1, the emitter of the first transistor Q1 is connected to a first voltage, the collector of the first Q1 is connected to one end of the second resistor R2, and the other end of the second resistor R2 is connected to the second voltage.

[0034] It should be noted that the second voltage is generally a power supply voltage, which can be represented by VCC, and the first voltage is 0V, represented by GND, which is achieved through grounding.

[0035] In one embodiment, the output end includes: a third resistor R3, a fourth resistor R4 and a second transistor Q2; the base of the second transistor Q2 is connected to the collector of the first transistor Q1 to form a first electrical node, the collector of the second transistor Q2 is connected to a second voltage, the emitter of the second transistor Q2 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to one end of the fourth resistor R4 to form a second electrical node, and the PWM signal is output by the second electrical node, and the other end of the fourth resistor R4 is connected to the first voltage.

[0036] It should be noted that the second voltage is generally a power supply voltage, which can be represented by VCC, and the first voltage is 0V, represented by GND, which is achieved through grounding.

[0037] In one embodiment, the output stage further includes a capacitor CL, one end of the capacitor CL is connected to the second electrical node, and the other end of the capacitor CL is connected to the first voltage.

[0038] It should be noted that the first voltage is 0V, represented by GND, and is achieved by grounding.

[0039] In one embodiment, the discharge circuit includes: a fifth resistor R5 and a third transistor Q3, the base of the third transistor Q3 is connected to the first electrical node, the collector of the third transistor Q3 is connected to the first voltage, the emitter of the third transistor Q3 is connected to one end of the fifth resistor R5, and the other end of the fifth resistor R5 is connected to the second electrical node.

[0040] It should be noted that the first voltage is 0V, represented by GND, and is achieved by grounding.

[0041] In one embodiment, the first transistor is an NPN transistor, the second transistor is an NPN transistor, and the third transistor is a PNP transistor.

[0042] An embodiment of the present application also provides an LED lamp, comprising: the PWM drive circuit and a light-emitting unit, wherein the output end of the PWM drive circuit is connected to the input end of the light-emitting unit, the light-emitting unit receives a drive signal output by the PWM drive circuit, and emits light based on the drive signal.

[0043] In one embodiment, the utility model provides an electronic device, including the PWM drive circuit.

[0044] In summary, a PWM driving circuit of the present application includes: an input stage; an output stage; and a discharge circuit connected in parallel with the output stage; by connecting a discharge circuit in parallel with the output stage, the discharge speed can be increased.

[0045] For PWM drive circuit, if ordinary primary circuit (i.e. input stage of the above circuit) is used to realize PWM output, the discharge is fast but the charge is slow, and only the transmission frequency of 1-10KHz can be realized. If PWM output is realized by output stage, the charge is fast but the discharge is slow, and only the transmission frequency of 1-10KHz can be realized. For the input signal with frequency of 1KHz, PWM output can be realized by primary circuit, and a better PWM signal can be output, such as Figure 1 As shown; for an input signal with a frequency of 10KHz, a PWM output can be achieved through a primary circuit, and a relatively good PWM signal can be output. However, the output signal is deformed and cannot drive the subsequent circuits at all, such as Figure 2 shown.

[0046] for Figure 3For the PWM drive circuit in the embodiment, by adding a discharge circuit (including transistor Q3 and resistor R5) to the output stage of the ordinary PWM drive circuit, the discharge speed is increased by about 8-10 times. By simply adding devices, the transmission frequency of 80-100KHz can be achieved. For an input signal with a frequency of 1KHz, the present application Figure 3 The PWM shown in the figure realizes PWM output and can output a better PWM signal, such as Figure 4 As shown; for an input signal with a frequency of 100KHz, the PWM output is realized by the driving circuit of the present application, and a PWM signal with a good ratio can be output, such as Figure 5 shown.

[0047] The present application significantly improves the discharge speed by adding a discharge circuit (third transistor Q3 and fifth resistor R5) at the output stage. By simply adding devices, 80-100KHz frequency transmission can be achieved. It has the characteristics of low cost and fast discharge speed, and can achieve isolation between input and output.

[0048] The above is a detailed description of the implementation process and working details of a specific embodiment of the present application in combination with the drawings in the specification. For a general technician in this field, there will be flexible changes in the specific implementation of the application scheme based on the design architecture proposed in this application. Therefore, this specification should not be a limitation of the present application and does not exhaust the scope of the present application.

[0049] The above embodiments are merely illustrative of the principles and effects of the present application, and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A PWM drive circuit, characterized in that: The PWM driving circuit comprises: Input stage; Output stage; a discharge circuit connected in parallel with the output stage; The input stage comprises: a first resistor, a second resistor and a first transistor; one end of the first resistor is connected to the PWM signal, the other end of the first resistor is connected to the base of the first transistor, the emitter of the first transistor is connected to a first voltage, the collector of the first transistor is connected to one end of the second resistor, and the other end of the second resistor is connected to the second voltage; The output stage includes: a third resistor, a fourth resistor and a second transistor; the base of the second transistor is connected to the collector of the first transistor to form a first electrical node, the collector of the second transistor is connected to a second voltage, the emitter of the second transistor is connected to one end of the third resistor, the other end of the third resistor is connected to one end of the fourth resistor to form a second electrical node, and a PWM signal is outputted from the second electrical node, and the other end of the fourth resistor is connected to the first voltage.

2. The PWM driving circuit according to claim 1, characterized in that: The output stage further includes a capacitor, one end of which is connected to the second electrical node, and the other end of which is connected to the first voltage.

3. The PWM driving circuit according to claim 1, characterized in that: The discharge circuit includes: a fifth resistor and a third transistor, the base of the third transistor is connected to the first electrical node, the collector of the third transistor is connected to the first voltage, the emitter of the third transistor is connected to one end of the fifth resistor, and the other end of the fifth resistor is connected to the second electrical node.

4. The PWM driving circuit according to claim 3, characterized in that: The first transistor is an NPN transistor, the second transistor is an NPN transistor, and the third transistor is a PNP transistor.

5. An LED lamp, characterized in that: include: According to the PWM drive circuit and the light-emitting unit as described in any one of claims 1 to 4, the output end of the PWM drive circuit is connected to the input end of the light-emitting unit, the light-emitting unit receives the drive signal output by the PWM drive circuit, and emits light based on the drive signal.

6. An electronic device, characterized in that: It comprises the PWM drive circuit as described in any one of claims 1 to 4.

Images