WO2019024877A1 - Signal conversion circuit, dimming led driving source and lamp - Google Patents

Abstract

Provided are a signal conversion circuit, a dimming LED driving source and a lamp, relating to the field of illumination. The signal conversion circuit comprises a reference source, a PWM acquisition circuit, a push-pull circuit and a charging and discharging circuit. The reference source is used for providing a supply voltage; the PWM acquisition circuit is connected to a PWM output port, for acquiring a PWM signal; the push-pull circuit is connected to the reference source and the PWM acquisition circuit, for realising line conversion according to the PWM signal; and the charging and discharging circuit is connected to the push-pull circuit, for realising charging or discharging according to the conversion of the push-pull line, thereby adjusting a reference voltage by means of the PWM signal. Since no sampling operational amplifier with a complex scheme is used in the circuit structure of the present invention, the present invention has simple lines and can effectively reduce the cost of the circuit.

Description

Signal conversion circuit, dimming LED driving power source and lamp Technical field

The invention relates to the field of illumination, in particular to a signal conversion circuit, a dimming LED driving power source and a lamp.

Background technique

In the use of the LED dimming driving power supply, it is necessary to convert the external PWM (Pulse Width Modulation) signal into the reference voltage signal of the secondary side sampling chip through a signal conversion circuit to realize the circuit change. The function of the sampling reference adjusts the output current of the power supply to achieve the dimming effect.

Existing signal conversion circuits are implemented by sampling operational amplifiers. Due to the complexity of the sampling op amp solution, the circuit cost is high.

Summary of the invention

The invention provides a signal conversion circuit, a dimming LED driving power source and a lamp to overcome the above-mentioned problem of high circuit cost in the prior art.

In particular, the present invention proposes a signal conversion circuit for adjusting a reference voltage by a PWM signal, including:

a reference source for providing a supply voltage;

a PWM acquisition circuit connected to the PWM output port for acquiring a PWM signal;

a push-pull circuit connected to the reference source and the PWM acquisition circuit for implementing line conversion according to the PWM signal; and

a charge and discharge circuit connected to the push-pull circuit for charging or discharging according to conversion of a push-pull line;

Wherein, the PWM output port outputs a square wave with an adjustable duty ratio, and when the square wave is in a high level segment, the charging and discharging circuit is charged; when the square wave is in a low level segment, the charging and discharging The circuit is discharged.

Further, the PWM acquisition circuit includes a first transistor.

Further, the first transistor is an NMOS transistor, a gate of the first transistor is connected to the PWM output port, a drain of the first transistor is connected to the reference source, and a source of the first transistor is grounded .

Further, the PWM acquisition circuit further includes a pull-up resistor connected in parallel between the gate of the first transistor and the reference source,

The signal conversion circuit outputs at full load when the PWM output port has no PWM signal through the pull-up resistor.

Further, the push-pull circuit includes a second transistor and a third transistor connected in series.

Further, the second transistor and the third transistor are both NMOS transistors, the gate of the second transistor is connected to the drain of the first transistor, and the source of the second transistor is grounded, the A drain of the second transistor is connected to a source of the third transistor, a gate of the third transistor is connected to a gate of the first transistor, and a drain of the third transistor is connected to a reference voltage.

Further, the charge and discharge circuit includes a first resistor, a second resistor, a third resistor, and a capacitor.

The first resistor is connected between the drain of the third transistor and the reference voltage, and the second resistor is connected at one end to a source connection point of the drain of the second transistor and the third transistor The other end of the second resistor is connected to the capacitor, the other end of the capacitor is grounded, and the third resistor is connected in parallel with the capacitor;

When the square wave is in a high level segment, the first transistor is turned on, the second transistor is turned off, the third transistor is turned on, and the reference voltage is passed through the first resistor and the second resistor Charging the capacitor;

When the square wave is in a low level segment, the first transistor is turned off, the second transistor is turned on, the third transistor is turned off, and the capacitor is discharged through the second resistor and the third resistor.

The invention also provides a dimming LED driving power source, comprising the signal conversion circuit and a PWF dimming circuit, the PWF dimming circuit having the PWM output port.

The invention also provides a light fixture comprising the dimming LED driving power source;

A light source device as a load is connected to the dimming LED driving power source.

The signal conversion circuit, the dimming LED driving power source and the lamp of the invention acquire the PWM signal through the PWM acquisition circuit, realize the line conversion according to the PWM signal through the push-pull circuit, realize charging or discharging through the charging and discharging circuit, and further pass the PWM Signal adjustment reference voltage. Since the circuit structure of the present invention does not employ a sampling operational amplifier with complicated schemes, the circuit of the present invention is simple and can effectively reduce the circuit cost.

The above description is only an overview of the technical solutions of the present invention, and the above-described and other objects, features and advantages of the present invention can be more clearly understood. Specific embodiments of the invention are set forth below.

The above as well as other objects, advantages and features of the present invention will become apparent to those skilled in the <

DRAWINGS

Various other advantages and benefits will become apparent to those skilled in the art from a The drawings are only for the purpose of illustrating the preferred embodiments and are not to be construed as limiting. Throughout the drawings, the same reference numerals are used to refer to the same parts. In the drawing:

1 is a schematic structural block diagram of a signal conversion circuit according to an embodiment of the present invention;

2 is a schematic circuit diagram of a signal conversion circuit in accordance with one embodiment of the present invention;

3 is a schematic structural block diagram of a dimming LED driving power supply according to an embodiment of the present invention;

4 is a schematic block diagram of a luminaire in accordance with one embodiment of the present invention.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While the embodiments of the present invention have been shown in the drawings, the embodiments Rather, these embodiments are provided so that this disclosure will be more fully understood and the scope of the disclosure will be fully disclosed.

1 is a schematic block diagram of a signal conversion circuit in accordance with one embodiment of the present invention. A signal conversion circuit 100 is used to adjust a reference voltage by a PWM signal, and may generally include a reference source VCC, a PWM acquisition circuit 10, a push-pull circuit 20, and a charge and discharge circuit 30. The reference source VCC is used to supply the supply voltage. The PWM acquisition circuit 10 is connected to the PWM output port for acquiring the PWM signal. The push-pull circuit 20 is connected to the reference source VCC and the PWM acquisition circuit 10 for implementing line conversion according to the PWM signal. A charge and discharge circuit 30 is connected to the push-pull circuit 20 for charging or discharging according to the conversion of the push-pull line. Wherein, the PWM output port outputs a square wave with an adjustable duty ratio, and when the square wave is in a high level segment, the charging and discharging circuit 30 is charged; when the square wave is in a low level segment, the charging The discharge circuit 30 is discharged.

The signal conversion circuit 100 of the present invention acquires a PWM signal through the PWM acquisition circuit 10, realizes line conversion according to the PWM signal through the push-pull circuit 20, performs charging or discharging through the charging and discharging circuit 30, and further adjusts the reference voltage through the PWM signal. . Since the circuit structure of the present invention does not employ a sampling operational amplifier with complicated schemes, the circuit of the present invention is simple and can effectively reduce the circuit cost.

2 is a schematic circuit diagram of a signal conversion circuit in accordance with one embodiment of the present invention. In this embodiment, the PWM acquisition circuit 10 includes a first transistor Q3.

Further, the first transistor Q3 is an NMOS transistor, the gate of the first transistor Q3 is connected to the PWM output port, and the drain of the first transistor Q3 is connected to the reference source VCC, the first transistor The source of Q3 is grounded. The PWM signal is inverted by the first transistor Q3 to ensure that the push-pull output of the push-pull circuit is in phase with the PWM signal.

Further, an eighth resistor R8 is connected between the gate of the first transistor Q3 and the PWM output port, and the eighth resistor R8 is a current limiting resistor. Further, a second diode D2 is connected in parallel between the PWM output port and the source of the first transistor Q3, and the second diode D2 is a clamp diode. Further, a fifth resistor R5 is connected between the drain of the first transistor Q3 and the reference source VCC, and the fifth resistor R5 is a current limiting resistor. A tenth resistor R10 is connected in parallel between the gate of the first transistor Q3 and the source of the first transistor Q3, and the tenth resistor R10 is a discharge resistance between the gate and the source of the first transistor Q3.

Further, the PWM acquisition circuit 10 further includes a pull-up resistor R4 for current limiting, the pull-up resistor R4 being connected in parallel between the gate of the first transistor Q3 and the reference source VCC, The pull-up resistor R4 causes the signal conversion circuit 100 to output at full load when the PWM output port has no PWM signal. Further, a first diode D1 is connected between the pull-up resistor R4 and the gate of the first transistor Q3, and the first diode D1 is a reverse-biased diode.

In this embodiment, the push-pull circuit 20 includes a second transistor Q2 and a third transistor Q1 connected in series.

Further, the second transistor Q2 and the third transistor Q1 are both NMOS transistors, the gate of the second transistor Q2 is connected to the drain of the first transistor Q3, and the source of the second transistor Q2 Grounding, the drain of the second transistor Q2 is connected to the source of the third transistor Q1, the gate of the third transistor Q1 is connected to the gate of the first transistor Q3, and the third transistor Q1 is The drain is connected to the reference voltage Vref.

Further, a sixth resistor R6 is connected between the gate of the second transistor Q2 and the drain of the first transistor Q3, and the sixth resistor R6 is a current limiting resistor. A ninth resistor R9 is connected in parallel between the gate of the second transistor Q2 and the source of the second transistor Q2, and the ninth resistor R9 is a discharge resistance between the gate and the source of the second transistor Q3.

Further, the charge and discharge circuit 30 includes a first resistor R1, a second resistor R2, a third resistor R7, and a capacitor C1. The first resistor R1 is connected to the drain of the third transistor Q1 and the reference voltage. Between Vref, one end of the second resistor R2 is connected to a source connection point of the drain of the second transistor Q2 and the third transistor Q1, and the other end of the second resistor R2 is connected to the capacitor C1. The other end of the capacitor C1 is grounded, and the third resistor R7 is connected in parallel with the capacitor C1.

The first resistor R1, the second resistor R2 and the capacitor C1 form an RC filter circuit. The RC filter is used to provide a stable reference voltage to the reference and filter out the interference signal.

The PWM output port output PWM signal is inverted by the first transistor Q3, so that the PWM signal is in phase with the push-pull output of the push-pull circuit, and the push-pull line composed of the third transistor Q1 and the second transistor Q2 can achieve 0-100% Dimming control. The dimming signal outputted by the PWM output port is a square wave whose duty ratio D is adjustable, and the square wave signal directly controls the gate of the first transistor Q3. When in the high-level range of the square wave, the first transistor Q3 is turned on, the VDS voltage of the first transistor Q3 becomes low, the VGS of the second transistor Q2 goes low, the second transistor Q2 turns off, and the third transistor Q1 is turned on. The reference voltage Vref charges the capacitor C1 after passing through the first resistor R1 and the second resistor R2. When in the low-level range of the square wave, the first transistor Q3 is turned off, the VGS of the second transistor Q2 goes high, the second transistor Q2 is turned on, and the third transistor Q1 is turned off, and the capacitor C1 passes through the second resistor R2 and the third resistor. R7 discharge. Repeatedly, the duty ratio D of the PWM input terminal is an adjustable square wave signal. After the push-pull circuit composed of the third transistor Q1 and the second transistor Q2, the relationship between the voltage Vninv across the capacitor C1 and the PWM dimming signal is :Vninv=Vref*D, where D is the duty cycle of the PWM signal. Thereby, the signal conversion circuit of the present invention has the characteristics of high precision of signal conversion.

3 is a schematic block diagram of a dimming LED driving power supply in accordance with one embodiment of the present invention. The present invention also provides a dimming LED driving power supply 1, which may generally include the signal conversion circuit 100 and the PWF dimming circuit 200 described in the above embodiments, and the PWF dimming circuit 200 has the PWM output port.

The dimming LED driving power supply of the present invention includes all the technical features of the signal conversion circuit, so that it acquires a PWM signal through a PWM acquisition circuit, realizes line conversion according to the PWM signal through a push-pull circuit, and realizes charging through a charging and discharging circuit. Or discharge, and then adjust the reference voltage through the PWM signal. Since the circuit structure of the present invention does not employ a sampling operational amplifier with complicated schemes, the circuit of the present invention is simple and can effectively reduce the circuit cost. In addition, the dimming LED driving power supply of the invention has the advantages of high signal conversion accuracy.

4 is a schematic block diagram of a luminaire in accordance with one embodiment of the present invention. The present invention also provides a luminaire I, which may generally include the dimming LED driving power source 1 in the above embodiment, and a light source device 2 as a load, the loaded light source device 2 being connected to the dimming LED Drive power supply 1.

The lamp of the invention comprises all the technical features of the signal conversion circuit, so that the PWM signal is obtained by the PWM acquisition circuit, the line conversion is realized according to the PWM signal by the push-pull circuit, the charging or discharging is realized by the charging and discharging circuit, and then the The PWM signal adjusts the reference voltage to achieve dimming of the luminaire. Since the circuit structure of the present invention does not employ a sampling operational amplifier with complicated schemes, the circuit of the present invention is simple and can effectively reduce the circuit cost.

In the description provided herein, numerous specific details are set forth. However, it is understood that the embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of the description.

Similarly, the various features of the invention are sometimes grouped together into a single embodiment, in the above description of the exemplary embodiments of the invention, Figure, or a description of it. However, the method disclosed is not to be interpreted as reflecting the intention that the claimed invention requires more features than those specifically recited in the claims. Rather, as the following claims reflect, inventive aspects reside in less than all features of the single embodiments disclosed herein. Therefore, the claims following the specific embodiments are hereby explicitly incorporated into the embodiments, and each of the claims as a separate embodiment of the invention.

Those skilled in the art will appreciate that the modules in the devices of the embodiments can be adaptively changed and placed in one or more devices different from the embodiment. The modules or units or components of the embodiments may be combined into one module or unit or component, and further they may be divided into a plurality of sub-modules or sub-units or sub-components. In addition to such features and/or at least some of the processes or units being mutually exclusive, any combination of the features disclosed in the specification, including the accompanying claims, the abstract and the drawings, and any methods so disclosed, or All processes or units of the device are combined. Each feature disclosed in this specification (including the accompanying claims, the abstract and the drawings) may be replaced by alternative features that provide the same, equivalent or similar purpose.

Moreover, those skilled in the art will appreciate that, although some embodiments described herein include certain features that are not included in other embodiments, and other features, combinations of features of different embodiments are intended to be within the scope of the present invention. Different embodiments are formed and formed. For example, in the claims, any one of the claimed embodiments can be used in any combination.

The various component embodiments of the present invention may be implemented in hardware, or in a software module running on one or more processors, or in a combination thereof. Those skilled in the art will appreciate that a microprocessor or digital signal processor (DSP) may be used in practice to implement some or all of the functionality of some or all of the components of a luminaire in accordance with embodiments of the present invention. The invention can also be implemented as a device or device program (e.g., a computer program and a computer program product) for performing some or all of the methods described herein. Such a program implementing the invention may be stored on a computer readable medium or may be in the form of one or more signals. Such signals may be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

It is to be noted that the above-described embodiments are illustrative of the invention and are not intended to be limiting, and that the invention may be devised without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as a limitation. The word "comprising" does not exclude the presence of the elements or steps that are not recited in the claims. The word "a" or "an" The invention can be implemented by means of hardware comprising several distinct elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means can be embodied by the same hardware item. The use of the words first, second, and third does not indicate any order. These words can be interpreted as names.

In this regard, it will be appreciated by those skilled in the <RTIgt;the</RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; The content directly determines or derives many other variations or modifications consistent with the principles of the invention. Therefore, the scope of the invention should be understood and construed as covering all such other modifications or modifications.

Claims (9)

A signal conversion circuit (100) for adjusting a reference voltage by a PWM signal, comprising: a reference source (VCC) for providing a supply voltage; a PWM acquisition circuit (10) connected to the PWM output port for acquiring a PWM signal; a push-pull circuit (20) connected to the reference source (VCC) and the PWM acquisition circuit (10) for implementing line conversion according to the PWM signal; a charge and discharge circuit (30) connected to the push-pull circuit (20) for charging or discharging according to conversion of the push-pull line; Wherein, the PWM output port outputs a square wave with an adjustable duty ratio, and when the square wave is in a high level segment, the charging and discharging circuit (30) is charged; when the square wave is in a low level segment, The charging and discharging circuit (30) is discharged. The signal conversion circuit according to claim 1, characterized in that said PWM acquisition circuit (10) comprises a first transistor (Q3). The signal conversion circuit according to claim 2, wherein said first transistor (Q3) is an NMOS transistor, and a gate of said first transistor (Q3) is connected to said PWM output port, said first transistor The drain of (Q3) is connected to the reference source (VCC), and the source of the first transistor (Q3) is grounded. The signal conversion circuit according to claim 3, wherein said PWM acquisition circuit (10) further comprises a pull-up resistor (R4), said pull-up resistor (R4) being connected in parallel with said first transistor (Q3) Between the gate and the reference source (VCC), The signal conversion circuit outputs at full load when the PWM output port has no PWM signal through the pull-up resistor (R4). The signal conversion circuit according to claim 3, characterized in that said push-pull circuit (20) comprises a second transistor (Q2) and a third transistor (Q1) connected in series. The signal conversion circuit according to claim 5, wherein said second transistor (Q2) and said third transistor (Q1) are both NMOS transistors, and the gate of said second transistor (Q2) is connected. a drain of the first transistor (Q3), a source of the second transistor (Q2) is grounded, and a drain of the second transistor (Q2) is connected to a source of the third transistor (Q1) The gate of the third transistor (Q1) is connected to the gate of the first transistor (Q3), and the drain of the third transistor (Q1) is connected to a reference voltage (Vref). The signal conversion circuit according to claim 6, wherein the charge and discharge circuit (30) comprises a first resistor (R1), a second resistor (R2), a third resistor (R7), and a capacitor (C1), The first resistor (R1) is connected between a drain of the third transistor (Q1) and the reference voltage (Vref), and one end of the second resistor (R2) is connected to the second transistor (Q2) a drain connected to a source of the third transistor (Q1), the other end of the second resistor (R2) being connected to the capacitor (C1), and the other end of the capacitor (C1) being grounded, a third resistor (R7) is connected in parallel with the capacitor (C1); When the square wave is in a high level segment, the first transistor (Q3) is turned on, the second transistor (Q2) is turned off, the third transistor (Q1) is turned on, and the reference voltage (Vref) is turned on. Charging the capacitor (C1) via the first resistor (R1) and the second resistor (R2); When the square wave is in a low level segment, the first transistor (Q3) is turned off, the second transistor (Q2) is turned on, the third transistor (Q1) is turned off, and the capacitor (C1) passes through The second resistor (R2) and the third resistor (R7) are discharged. A dimming LED driving power supply (1), comprising the signal conversion circuit (100) and the PWF dimming circuit (200) according to any one of claims 1-7, wherein the PWF dimming circuit has The PWM output port. A luminaire (I), comprising the dimming LED driving power source (1) of claim 8; A light source device (2) as a load is connected to the dimming LED driving power source (1).

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