CN116056281B - LED dimming circuit with selectable driving mode - Google Patents
LED dimming circuit with selectable driving mode Download PDFInfo
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- CN116056281B CN116056281B CN202310206244.4A CN202310206244A CN116056281B CN 116056281 B CN116056281 B CN 116056281B CN 202310206244 A CN202310206244 A CN 202310206244A CN 116056281 B CN116056281 B CN 116056281B
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Classifications
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/32—Pulse-control circuits
- H05B45/325—Pulse-width modulation [PWM]
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/30—Driver circuits
- H05B45/345—Current stabilisation; Maintaining constant current
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Abstract
The invention disclosesThe LED dimming circuit with the selectable driving mode is provided for solving the problems of single dimming mode and poor ripple suppression in the prior art. Taking a voltage value obtained by sampling the duty ratio of the PWM signal as a reference voltage V ref Or the PWM signal is used as a reference voltage V ref To regulate the current flowing through the LED. The dimming circuit has the advantage that only one PWM signal and one enabling control signal are needed for external control signals needed for dimming. The dimming mode can be switched between constant current dimming and PWM dimming modes as required.
Description
Technical Field
The invention relates to a new generation of information technology, in particular to an LED dimming circuit with an optional driving mode, which is used for a circuit device of a general electric light source.
Background
LEDs (Light-Emitting diodes) are a new generation of illumination Light sources, and research on LEDs and driving circuits thereof is a hot spot of current research. In the existing LED driving circuit, it is often a necessary function to adjust the brightness of the light source. From the characteristics of the LED, it is known that the brightness of the LED is proportional to the current flowing through the LED. Thus, the manner in which LED driving achieves dimming is actually to adjust the magnitude of the current flowing through the LED.
In FIG. 1, a DC-DC LED step-down driving circuit structure is shown, which is commonly used at present, and provides working voltage of an LED through a DC-DC BUCK circuit, a sampling resistor is connected in series between the LED and the ground, and the resistor samples current flowing through the LED and converts the current into feedback voltage V fb . The amplifier at the front end of the DC-DC BUCK circuit feeds back the voltage V fb And reference voltage V ref Comparing, and further maintaining V through feedback adjustment fb Stable and sum V ref And the LEDs are driven by constant current.
Based on the above driving architecture, the current commonly used LED dimming method includes constant current dimming and PWM dimming, as shown in fig. 2:
the constant current dimming mode is to change the reference voltage V ref Is changed by feedback control of the driving circuitVarying the current flowing through the LED such that V fb Equal to new V ref And the brightness adjustment of the LED is realized. The dimming mode can be used in an LED lamp product taking eye protection and flicker-free as a selling point, because the current flowing through the LED is constant before and after adjustment, and the brightness of the LED is constant and flicker-free.
However, when the constant current dimming is performed by using the framework, certain ripple exists in the current output by the step-down driving circuit, the magnitude of the ripple is about five thousandths of the load current, and the LED is enabled to be slightly flickering as a light source. These flicker, although subtle, can still have a bad effect on the human eye after long-term acceptance, so people often want to reduce current ripple when designing a constant current dimming mode. This dimming approach has a further disadvantage: external control instructions for dimming are generally generated by a digital circuit module, such as an MCU, and the digital circuit is difficult to generate a DC analog voltage with adjustable voltage, so that the constant current dimming is difficult to directly generate available V through the digital module ref External control is performed.
And the second PWM dimming mode is to control the switch of the driving circuit through a PWM square wave with fixed frequency. When the PWM square wave is at a high level in one period, the driving circuit works, and the LED lamp is lighted; and on the contrary, when the PWM square wave is at a low level, the driving circuit is turned off, and the LED lamp is turned off. The LED lamp is thus switched on and off in rapid succession, and if the switching frequency is >100Hz, the human eye considers the LED lamp brightness to be constant. If one wants to change the brightness of an LED, one can change the duty cycle D of the PWM square wave, then the average current through the LED in one PWM period can be expressed as:
I avg =I LED ×D（0＜D＜1）；
wherein I is LED For driving a preset maximum current of LEDs. By varying the duty cycle D, the current of the LED can be varied from 0 to I LED And (5) adjusting the position. PWM dimming can preserve the color of an LED lamp, and has certain advantages in scenes with requirements on the color of a light source, such as automobile tail lamps, signal indication lamps and PWM dimming.
PWM dimming has the disadvantage that frequencies in the range of 100Hz to 2kHz can cause humans to perceive that the LED is blinking and causing visual fatigue. Although the light source with high-frequency dimming (> 2 kHz) can not be perceived by people to flicker, research shows that the long-term exposure of the light source can have bad influence on the eyesight of people, and the eye protection effect is inferior to that of constant-current dimming. In addition, high-frequency dimming has a requirement on the switching response speed of the driving circuit, and the driving circuit is required to pay more design cost and device cost to realize the high-frequency dimming.
Both LED dimming approaches discussed above have their own advantageous usage scenarios and usage characteristics on the market. With the expansion of the LED lighting market and the complexity of the usage scenario, there is a need for an LED dimming circuit that can integrate two dimming modes in one main circuit.
Disclosure of Invention
The invention aims to provide an LED dimming circuit with an optional driving mode, so as to solve the problems in the prior art.
The LED dimming circuit with the optional driving mode in the invention takes a voltage value obtained by sampling the duty ratio of PWM signals as a reference voltage V ref Or the PWM signal is used as a reference voltage V ref To regulate the current flowing through the LED.
The specific structure is as follows:
the drain electrode of the first transistor is connected with a current source, the source electrode of the first transistor is connected with a first capacitor in series and then grounded, and the grid electrode of the first transistor is externally connected with a PWM signal;
the drain electrode of the third transistor is connected with the source electrode of the first transistor, the source electrode of the third transistor is grounded, and the grid electrode of the third transistor is externally connected with a second control signal;
the drain electrode of the second transistor is connected with the source electrode of the first transistor, the source electrode of the second transistor is connected with the second capacitor in series and then grounded, and the grid electrode of the second transistor is externally connected with a first control signal;
the non-inverting input end of the first amplifier is connected with the source electrode of the second transistor after being connected with the first resistor R1 in series, and the output end of the first amplifier is in short circuit with the self inverting input end;
the drain electrode of the fifth transistor is connected with the output end of the first amplifier, the source electrode of the fifth transistor is connected with the non-inverting input end of the second amplifier, and the grid electrode of the fifth transistor is externally connected with an enabling signal;
the non-inverting input end of the second amplifier is also used for gating the PWM signal, the inverting input end of the second amplifier is connected with a second resistor in series and then grounded, and the output end of the second amplifier is connected with the grid electrode of the fourth transistor;
the drain electrode of the fourth transistor is connected with the cathode of the LED, and the source electrode of the fourth transistor is connected with the inverting input end of the second amplifier;
the anode of the LED is connected with a voltage-reducing circuit for constant voltage output;
the falling edge of the PWM signal is synchronous with the rising edge of the first control signal; the rising edge of the PWM signal is synchronous with the falling edge of the second control signal;
the first control signal and the second control signal are both short pulses.
The non-inverting input end of the second amplifier gates the PWM signal specifically as follows: when the enabling signal is in a high level, the PWM signal is disconnected with the non-inverting input end of the second amplifier; when the enable signal is at a low level, the PWM signal is conducted with the non-inverting input terminal of the second amplifier.
The LED dimming circuit with the selectable driving mode has the advantage that only one path of PWM signal and one path of enabling control signal are needed for external control signals required by dimming. The dimming mode can be switched between constant current dimming and PWM dimming modes as required. When constant current dimming is used, the LED ripple can also be suppressed to three parts per million of load current or even lower.
Drawings
Fig. 1 is a schematic diagram of a prior art LED dimmer circuit.
Fig. 2 is a schematic diagram of two dimming modes in the prior art.
Fig. 3 is a schematic diagram of a structure of the LED dimming circuit according to the present invention.
Fig. 4 is a timing diagram of signals when the LED dimming circuit is in a constant current dimming mode in the present invention.
Fig. 5 is a voltage change chart of each signal when the LED dimming circuit is in the constant current dimming mode, and the duty ratio of the PWM signal is 30% in the present invention.
Fig. 6 is a graph showing a current change of an LED when the LED dimming circuit according to the present invention is in a constant current dimming mode, and the duty ratio of the PWM signal is 30%.
Fig. 7 is a voltage change chart of each signal when the LED dimming circuit is in the constant current dimming mode, and the duty ratio of the PWM signal is 60% in the present invention.
Fig. 8 is a graph showing a current change of an LED when the LED dimming circuit according to the present invention is in a constant current dimming mode, and the duty ratio of the PWM signal is 60%.
Fig. 9 is a graph showing a current change of an LED when the LED dimming circuit according to the present invention is in a PWM dimming mode, and the duty ratio of the PWM signal is 30%.
Fig. 10 is a graph showing a current change of an LED when the LED dimming circuit according to the present invention is in a PWM dimming mode, and the duty ratio of the PWM signal is 60%.
Reference numerals:
V ref -reference voltage, V fb -a feedback voltage;
s1-a first control signal, S2-a second control signal and an EN-enabling signal;
m1-first transistor, M2-second transistor, M3-third transistor, M4-fourth transistor, M5-fifth transistor;
c1-a first capacitor and C2-a second capacitor;
r1-a first resistor and R2-a second resistor;
AMP 1-first amplifier, AMP 2-second amplifier;
and a connection point of the drain electrode of the a 1-fourth transistor and the cathode of the LED, and a connection point of the source electrode of the a 2-fourth transistor and the second resistor.
Detailed Description
As shown in fig. 3, the LED dimming circuit with an optional driving mode in the present invention has the following structure:
the drain electrode of the first transistor M1 is connected with a current source, the source electrode of the first transistor M1 is connected with the first capacitor C1 in series and then grounded, and the grid electrode of the first transistor M1 is externally connected with a PWM signal.
The drain electrode of the third transistor M3 is connected to the source electrode of the first transistor M1, the source electrode of the third transistor M3 is grounded, and the gate electrode of the third transistor M3 is externally connected to the second control signal S2.
The drain electrode of the second transistor M2 is connected to the source electrode of the first transistor M1, the source electrode of the second transistor M2 is connected in series with the second capacitor C2 and then grounded, and the gate electrode of the second transistor M2 is externally connected with the first control signal S1.
The non-inverting input end of the first amplifier AMP1 is connected with the source electrode of the second transistor M2 after being connected with the first resistor R1 in series, and the output end of the first amplifier AMP1 is short-circuited with the inverting input end of the first amplifier AMP 1.
The drain of the fifth transistor M5 is connected to the output terminal of the first amplifier AMP1, the source of the fifth transistor M5 is connected to the non-inverting input terminal of the second amplifier AMP2, and the gate of the fifth transistor M5 is externally connected to the enable signal EN.
The non-inverting input terminal of the second amplifier AMP2 is also gated with the PWM signal, the inverting input terminal of the second amplifier AMP2 is connected in series with the second resistor R2 and then grounded, and the output terminal of the second amplifier AMP2 is connected to the gate of the fourth transistor M4.
The drain electrode of the fourth transistor M4 is connected to the cathode of the LED, and the source electrode of the fourth transistor M4 is connected to the inverting input terminal of the second amplifier AMP 2.
In the present invention, the LEDs include, but are not limited to, single LED beads, LED strings, or other well known LED combination modules. Under the guidance of the inventive concept, those skilled in the art can undoubtedly know that the present LED dimming circuit can be directly used for various known structures of the LED.
And the anode of the LED is connected with a voltage-reducing circuit for constant voltage output.
As shown in fig. 4, the falling edge of the PWM signal is synchronized with the rising edge of the first control signal S1. The rising edge of the PWM signal is synchronized with the falling edge of the second control signal S2. The first control signal S1 and the second control signal S2 are both short pulses.
The non-inverting input terminal of the second amplifier AMP2 gates the PWM signal specifically: when the enable signal EN is at a high level, the PWM signal is disconnected from the non-inverting input terminal of the second amplifier AMP 2; when the enable signal EN is at a low level, the PWM signal is turned on with the non-inverting input terminal of the second amplifier AMP 2.
The working principle of the LED dimming circuit with the selectable driving mode in the invention is as follows:
constant current dimming: the enable signal EN is outputted to high level to control the fifth transistor M5 to be turned on, and the PWM signal is disconnected from the non-inverting input terminal of the second amplifier AMP 2.
When the circuit is operating stably, the fourth transistor M4, the second amplifier AMP2 and the second resistor R2 together form a negative feedback loop similar to the low dropout linear regulator (low dropout regulator, LDO). The loop is clamped by negative feedback to make the voltage V of the a2 node a2 Is equal to the reference voltage V of the non-inverting input terminal of the second amplifier AMP2 ref . Thus the current I flowing through the LED LED The method comprises the following steps:
I LED =V a2 /R2=V ref /R2 ；
it can be seen that the regulation V ref Can adjust I LED To achieve dimming.
The PWM signal is input from the outside, which controls the on and off of the first transistor M1. When the input is at a high level, the first transistor M1 is turned on, and the current source charges the first capacitor C1, so that the voltage across the first capacitor C1 increases linearly with time. During one PWM period, since the current of the current source is constant, i.e., the amount of charge charged into the first capacitor C1 per unit time is fixed. Therefore, the voltage on the first capacitor C1 increases with the duty ratio of the PWM signal; conversely, when the duty cycle of the PWM signal is reduced, the voltage will also drop in equal proportion.
When the high level time of the PWM signal is over, the first control signal S1 outputs a short high level to drive the second transistor M2 to be turned on. At this time, the voltage in the first capacitor C1 is sampled to the second capacitor C2. At the end of the whole PWM period, the second control signal S2 drives the third transistor M3 to be turned on, releasing the charge in the first capacitor C1, and the voltage on the first capacitor C1 becomes 0 to prepare for the next sampling period.
The voltage on the second capacitor C2 is output after being sampled again by the first resistor R1 and the first amplifier AMP1, namely the reference voltage V ref . From the above analysis, it can be found that V ref The voltage on the first capacitor C1 is output after sampling and is in direct proportion to the duty ratio of the PWM signal. Thus the external signal can change V by changing the duty cycle of the PWM waveform ref The dimming function is realized.
When the LED dimming circuit disclosed by the invention realizes constant current dimming, I LED Is very small, and can reach the minimum I LED Three parts per million. The principle analysis is as follows:
from the above analysis, I LED Mainly subject to V a2 And R2. Wherein R2 is not changed as a resistance value in a certain circuit, and thus the variable factor affecting ripple is voltage V a2 Is a ripple of (a). V (V) a2 The ripple source of the LED lamp is mainly that the voltage V is obtained after the output of the step-down circuit passes through the LED lamp a1 Is a ripple of (a). I is reduced in the present invention LED The ripple method of (a) is to reduce V a1 Voltage ripple vs V of (2) a2 Is a function of (a) and (b).
Since the fourth transistor M4, the second amplifier AMP2 and the second resistor R2 form a negative feedback loop, V a1 For V a2 The effect of (2) may be equivalent to the effect of the supply voltage on the output voltage. Due to PSRR CS =ΔV a2 /ΔV a1 Wherein PSRR CS The smaller PSRRcs is the ratio of the voltage change of the node a1 to the voltage change of the node a2, which means that the smaller the influence of the voltage of the node a1 on the voltage of the node a2 is. The power supply rejection ratio expression of the analog LDO can be obtained by:
；
；
；
wherein PSRR POW A power supply rejection ratio for the fourth transistor M4; beta is a feedback coefficient, which is 1 in the circuit; a is that POW Gain for the fourth transistor M4; a is that EA Is the gain of the second amplifier AMP 2.
It can be derived that by setting the appropriate fourth transistor M4 parameters, PSRR is reduced POW Increase A by a value of (2) POW The value of or increase A EA Can reduce PSRR CS I.e. reduce I LED Ripple waves. The gain of the second amplifier AMP2 is set to be greater than 80dB in this embodiment, while the fourth transistor M4 parameter is set appropriately according to the actual use of the circuit. By simulation result I LED The ripple is reduced to about one tenth compared to the conventional structure in fig. 1.
The main principle is that the output voltage of the step-down circuit is fixed to have voltage ripple, and in the conventional structure shown in fig. 1, the ripple of the node between the resistor and the LED and the ripple of the output voltage are equal, and are also equal to the voltage ripple of the structural node a1 used in the present invention. But the structure in the invention has voltage V on the resistor a2 Through the actions of the second amplifier AMP2 and the fourth transistor M4, its voltage ripple is suppressed with respect to the node a 1.
Meanwhile, the problem that in the prior art, a digital circuit hardly generates direct current analog voltage with adjustable voltage, so that constant current dimming hardly directly generates available V through a digital module is solved ref An external control is performed.
(II) PWM dimming: the enable signal EN is outputted as low level to control the fifth transistor M5 to be turned off, and the PWM signal is conducted with the non-inverting input terminal of the second amplifier AMP2 to be directly used as V ref 。
When PWM is high level, V ref Equal to the PWM high level voltage, the driving circuit lights the LED. V when PWM is at zero level ref =0, LED is off. As is known in the art, the brightness of an LED can be adjusted by adjusting the duty cycle of PWM.
In the first embodiment, constant current dimming is performed by setting the PWM signal duty ratio to 30%: the signals are shown in fig. 5, where the enable signal EN remains 5V, and need not be shown in the figure. The current flowing through the LED at this time is about 500mA, and the current ripple is about 171uA, and the ripple is about 0.034% of the total current, as shown in fig. 6.
In the second embodiment, constant current dimming is performed by setting the PWM signal duty ratio to 60%: the signals are shown in fig. 7, where the enable signal EN remains 5V, and need not be shown in the figure. The current flowing through the LED at this time is 1A, and the current ripple is about 158uA in magnitude, and the ripple is about 0.016% in magnitude of the total current, as shown in fig. 8.
In the third embodiment, PWM dimming is performed by setting the PWM signal duty ratio to 30%: the PWM signal is related to the current through the LED as shown in fig. 9.
In the fourth embodiment, PWM dimming is performed by setting the PWM signal duty ratio to 60%: the PWM signal is related to the current through the LED as shown in fig. 10. It can be seen from fig. 9 and 10 that adjusting the duty cycle of the PWM adjusts the average current flowing through the LEDs, thereby adjusting the brightness.
It will be apparent to those skilled in the art from this disclosure that various other changes and modifications can be made which will be within the scope of the invention as defined in the following claims.
Claims (2)
1. An LED dimming circuit with an optional driving mode is characterized in that a voltage value obtained by sampling the duty ratio of PWM signals is used as a reference voltage V ref Or the PWM signal is used as a reference voltage V ref To regulate the current flowing through the LED;
the specific structure is as follows:
the drain electrode of the first transistor (M1) is connected with a current source, the source electrode of the first transistor (M1) is connected with a first capacitor (C1) in series and then grounded, and the grid electrode of the first transistor (M1) is externally connected with a PWM signal;
the drain electrode of the third transistor (M3) is connected with the source electrode of the first transistor (M1), the source electrode of the third transistor (M3) is grounded, and the grid electrode of the third transistor (M3) is externally connected with a second control signal (S2);
the drain electrode of the second transistor (M2) is connected with the source electrode of the first transistor (M1), the source electrode of the second transistor (M2) is connected with a second capacitor (C2) in series and then grounded, and the grid electrode of the second transistor (M2) is externally connected with a first control signal (S1);
the non-inverting input end of the first amplifier (AMP 1) is connected with the source electrode of the second transistor (M2) after being connected with the first resistor R1 in series, and the output end of the first amplifier (AMP 1) is in short circuit with the inverting input end of the first amplifier;
the drain electrode of the fifth transistor (M5) is connected with the output end of the first amplifier (AMP 1), the source electrode of the fifth transistor (M5) is connected with the non-inverting input end of the second amplifier (AMP 2), and the grid electrode of the fifth transistor (M5) is externally connected with an enable signal (EN);
the non-inverting input end of the second amplifier (AMP 2) is also used for gating the PWM signal, the inverting input end of the second amplifier (AMP 2) is connected with a second resistor (R2) in series and then grounded, and the output end of the second amplifier (AMP 2) is connected with the grid electrode of a fourth transistor (M4);
the drain electrode of the fourth transistor (M4) is connected with the cathode electrode of the LED, and the source electrode of the fourth transistor (M4) is connected with the inverting input end of the second amplifier (AMP 2);
the anode of the LED is connected with a voltage-reducing circuit for constant voltage output;
the falling edge of the PWM signal is synchronized with the rising edge of the first control signal (S1); the rising edge of the PWM signal is synchronized with the falling edge of the second control signal (S2);
the first control signal (S1) and the second control signal (S2) are both short pulses.
2. A driving-mode selectable LED dimming circuit according to claim 1, wherein the non-inverting input of the second amplifier (AMP 2) gates the PWM signal in particular: when the enable signal (EN) is at a high level, the PWM signal is disconnected from the non-inverting input of the second amplifier (AMP 2); when the enable signal (EN) is at a low level, the PWM signal is conducted with the non-inverting input terminal of the second amplifier (AMP 2).
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102196621A (en) * | 2010-03-19 | 2011-09-21 | 上海贝岭股份有限公司 | LED dimming circuit |
| CN103476184A (en) * | 2013-09-26 | 2013-12-25 | 矽力杰半导体技术(杭州)有限公司 | Power system with multiplexed output |
| CN105246212A (en) * | 2015-11-03 | 2016-01-13 | 佛山市南海区联合广东新光源产业创新中心 | Novel LED (Light Emitting Diode) dimming circuit |
| CN107071982A (en) * | 2017-05-19 | 2017-08-18 | 深圳市晟碟半导体有限公司 | LED drive device and its invariable power light adjusting circuit, light-dimming method |
| CN209767879U (en) * | 2019-02-20 | 2019-12-10 | 广州视源电子科技股份有限公司 | PCB compatible with multi-mode constant-current dimming circuit |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9572208B2 (en) * | 2008-08-29 | 2017-02-14 | Philips Lighting Holding B.V. | LED lighting system with accurate current control |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102196621A (en) * | 2010-03-19 | 2011-09-21 | 上海贝岭股份有限公司 | LED dimming circuit |
| CN103476184A (en) * | 2013-09-26 | 2013-12-25 | 矽力杰半导体技术(杭州)有限公司 | Power system with multiplexed output |
| CN105246212A (en) * | 2015-11-03 | 2016-01-13 | 佛山市南海区联合广东新光源产业创新中心 | Novel LED (Light Emitting Diode) dimming circuit |
| CN107071982A (en) * | 2017-05-19 | 2017-08-18 | 深圳市晟碟半导体有限公司 | LED drive device and its invariable power light adjusting circuit, light-dimming method |
| CN209767879U (en) * | 2019-02-20 | 2019-12-10 | 广州视源电子科技股份有限公司 | PCB compatible with multi-mode constant-current dimming circuit |
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