TRIAC low-dimming quick starting circuit

Abstract

The utility model discloses a TRIAC low-dimming quick start circuit, which comprises an alternating current input circuit, a rectification output circuit, a low-current quick start circuit and a power conversion circuit, and is characterized in that the rectification output circuit is electrically connected with the alternating current input circuit, the low-current quick start circuit and the power conversion circuit respectively; the rectification output circuit comprises a diode D5, an electrolytic capacitor EC1 and an electrolytic capacitor EC2. According to the TRIAC low-dimming quick start circuit disclosed by the utility model, the AC input circuit, the rectification output circuit, the low-current quick start circuit and the power conversion circuit are linked, and a dimming pin of the power management chip IC1 is utilized, so that the charging current of a capacitor is increased during startup, and the charging current of the capacitor is reduced during startup; and after the power supply works normally, the charging function is closed, so that the time for starting to turn on the lamp is provided, and the dimming depth is low enough.

Description

Technical Field

[0001] The utility model belongs to a quick start circuit for an LED lamp, in particular to a TRIAC low-profile quick start circuit. Background Art

[0002] When designing TRIAC dimming LED driver power supply, in order to enable LED lamps to dim over a wide range, the dimming range is generally designed to be 3%-100%. At this time, the tangential angle of TRIAC is very small, and the amplitude of the input AC voltage will be less than 50% of the normal voltage. For example, if the input voltage is 100V, the actual voltage entering the LED driver power supply through the TRIAC phase cutting is 50V. At this time, the LED driver power supply operates at the minimum dimming rate. Due to the low input voltage and the minimum dimming rate, the user may have to wait for more than 5 seconds from pressing the switch to the LED lamp lighting up, and the customer experience is quite poor. When the phase dimming lamp is dimmed to the lowest, the output current is very low, and it often takes a few seconds for the lamp to light up after turning on the lamp switch. The main reason is that the lamp driver output has a large electrolytic. In the low dimming state, the current output by the power supply is small, and it takes a long time to charge the electrolytic.

[0003] Therefore, further improvements are made to the above problems. Utility Model Content

[0004] The main purpose of the utility model is to provide a TRIAC low-voltage dimming fast-start circuit, which is linked through an AC input circuit, a rectifier output circuit, a low-current fast-start circuit and a power conversion circuit, and utilizes the dimming pin of the power management chip IC1 itself to increase the charging current of the capacitor when starting up and reduce the startup current. After the power supply works normally, the charging function is turned off, so that both the start-up time and the dimming depth are sufficiently low.

[0005] To achieve the above purpose, the utility model provides a TRIAC low-light fast start circuit, including an AC input circuit, a rectifier output circuit, a low-current fast start circuit and a power conversion circuit, wherein the rectifier output circuit is electrically connected to the AC input circuit, the low-current fast start circuit and the power conversion circuit respectively, wherein:

[0006] The rectifier output circuit includes a diode D5, an electrolytic capacitor EC1 and an electrolytic capacitor EC2, the cathode of the diode D5 is grounded through the electrolytic capacitor EC1 and the electrolytic capacitor EC2 respectively, and the cathode of the diode D2 is connected to the output terminal VOUT (also connected to LED+, and LED- is grounded);

[0007] The low current fast start circuit includes a photocoupler OP1 and a field effect transistor Q2, the anode of the photocoupler OP1 is connected to the output terminal VOUT through a diode ZD2 and a resistor R24, and the cathode of the photocoupler OP1 is grounded, the collector of the photocoupler OP1 is grounded through a resistor R27 in one way and electrically connected to the gate of the field effect transistor Q2 in another way, the drain of the field effect transistor Q2 is connected to the power supply terminal Vbus through resistors R26, R14 and R13 in sequence, and the source of the field effect transistor Q2 is electrically connected to the common terminal of the resistor R26 and the resistor R14 through a resistor R15, the source of the field effect transistor Q2 is grounded, and the two ends of the resistor R15 are connected in parallel with a capacitor C4;

[0008] The power conversion circuit includes a power management chip IC1 and a field effect transistor Q1, wherein pin 1 of the power management chip IC1 is electrically connected to the common terminal of the resistor R14 and the resistor R15, pin 3 of the power management chip IC1 is connected to the power supply terminal Vaux through a diode D2 and a resistor R8 and is grounded through an electrolytic capacitor EC4, pin 5 of the power management chip IC1 is electrically connected to the source of the field effect transistor Q1 and the drain of the field effect transistor Q1 is electrically connected to the anode of the diode D5.

[0009] As a further preferred technical solution of the above technical solution, one of the 2 pins of the power management chip IC1 is electrically connected to the anode of the diode D2 through resistors R12, R10 and R9 in sequence, and the other pin is grounded through resistors R12 and diode D3 in sequence, and resistors R11 are connected in parallel at both ends of the diode D3.

[0010] As a further preferred technical solution of the above technical solution, the AC input circuit includes an input terminal ACL, an input terminal ACN, a rectifier bridge BD1 and a common-mode inductor L2, the input terminal ACL and the input terminal ACN are electrically connected to the input terminal of the rectifier bridge BD1 respectively, and the output terminal of the rectifier bridge BD1 is electrically connected to the anode of the diode D5 through the common-mode inductor L2.

[0011] As a further preferred technical solution of the above technical solution, the gate of the field effect transistor Q1 is electrically connected to the output end of the rectifier bridge BD1 (connected to the power supply end Vbus) through resistors R6, R5 and R4 in sequence.

[0012] As a further preferred technical solution of the above technical solution, a capacitor C7 is connected in parallel to both ends of the resistor R27. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1The utility model discloses a circuit diagram of a TRIAC low-light fast-start circuit. DETAILED DESCRIPTION

[0014] The following description is used to disclose the utility model so that those skilled in the art can implement the utility model. The preferred embodiments described below are only examples, and those skilled in the art can think of other obvious variations. The basic principles of the utility model defined in the following description can be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not deviate from the spirit and scope of the utility model.

[0015] The utility model discloses a TRIAC low-light fast-start circuit. The specific embodiments of the utility model are further described below in conjunction with preferred embodiments.

[0016] In the embodiments of the present invention, those skilled in the art will note that the input terminal and the like involved in the present invention may be regarded as prior art.

[0017] Preferred embodiments.

[0018] The utility model discloses a TRIAC low-light fast-start circuit, comprising an AC input circuit, a rectifier output circuit, a low-current fast-start circuit and a power conversion circuit, wherein the rectifier output circuit is electrically connected to the AC input circuit, the low-current fast-start circuit and the power conversion circuit respectively, wherein:

[0019] The rectifier output circuit includes a diode D5, an electrolytic capacitor EC1 and an electrolytic capacitor EC2, the cathode of the diode D5 is grounded through the electrolytic capacitor EC1 and the electrolytic capacitor EC2 respectively, and the cathode of the diode D2 is connected to the output terminal VOUT (also connected to LED+, and LED- is grounded);

[0020] The low current fast start circuit includes a photocoupler OP1 and a field effect transistor Q2, the anode of the photocoupler OP1 is connected to the output terminal VOUT through a diode ZD2 and a resistor R24, and the cathode of the photocoupler OP1 is grounded, the collector of the photocoupler OP1 is grounded through a resistor R27 in one way and electrically connected to the gate of the field effect transistor Q2 in another way, the drain of the field effect transistor Q2 is connected to the power supply terminal Vbus through resistors R26, R14 and R13 in sequence, and the source of the field effect transistor Q2 is electrically connected to the common terminal of the resistor R26 and the resistor R14 through a resistor R15, the source of the field effect transistor Q2 is grounded, and the two ends of the resistor R15 are connected in parallel with a capacitor C4;

[0021] The power conversion circuit includes a power management chip IC1 and a field effect transistor Q1, wherein pin 1 of the power management chip IC1 is electrically connected to the common terminal of the resistor R14 and the resistor R15, pin 3 of the power management chip IC1 is connected to the power supply terminal Vaux through a diode D2 and a resistor R8 and is grounded through an electrolytic capacitor EC4, pin 5 of the power management chip IC1 is electrically connected to the source of the field effect transistor Q1 and the drain of the field effect transistor Q1 is electrically connected to the anode of the diode D5.

[0022] Specifically, one of the two pins of the power management chip IC1 is electrically connected to the anode of the diode D2 through resistors R12, R10 and R9 in sequence, and the other pin is grounded through resistors R12 and diode D3 in sequence. Both ends of the diode D3 are connected in parallel with resistors R11.

[0023] More specifically, the AC input circuit includes an input terminal ACL, an input terminal ACN, a rectifier bridge BD1 and a common-mode inductor L2. The input terminal ACL and the input terminal ACN are electrically connected to the input terminal of the rectifier bridge BD1 respectively, and the output terminal of the rectifier bridge BD1 is electrically connected to the anode of the diode D5 through the common-mode inductor L2.

[0024] Furthermore, the gate of the field effect transistor Q1 is electrically connected to the output end of the rectifier bridge BD1 (connected to the power supply end Vbus) through the resistor R6, the resistor R5 and the resistor R4 in sequence.

[0025] Furthermore, two ends of the resistor R27 are connected in parallel with a capacitor C7.

[0026] For this utility model:

[0027] If there is only an AC input circuit and a rectifier output circuit, when the phase dimming lamp is dimmed to the lowest setting, the output current is very low, and it often takes several seconds for the lamp to light up after turning on the lamp switch. The main reason is that there is a large electrolytic capacitor in the lamp driver output. In the low dimming state, the current output by the power supply is small, and it takes a long time to charge the electrolyte.

[0028] After adding the low-current fast start-up circuit and the power conversion circuit, the dimming pin of the power management chip IC1 is used to increase the charging current of the capacitor when starting up and reduce the power. After the power supply works normally, the charging function is turned off. In this way, there is both a starting time for the light and a sufficiently low dimming depth. The specific implementation is as follows:

[0029] After the power is turned on, R24 and ZD2 detect VOUT (lamp supply voltage). Before the power reaches the VF value of the lamp LED, ZD2 is not turned on, no current flows through the photocoupler OP1 control stage, no current flows through the OP1 controlled stage, Q2 is low level, so Q2 is turned off. The voltage-divided current of IC1's pin 1 is formed by VBUS, R13, R14, and R15. R15 can be selected with a larger resistor so that IC1's pin 1 has a larger voltage, and the power supply output current is larger to quickly complete the charging of the output electrolytic.

[0030] When the voltage on the output electrolytic capacitor reaches the VF value, ZD2 is turned on, the controlled stage of the optocoupler is also turned on, the current flowing through R27 increases, so Q2 is also turned on, and R26 participates in the voltage division of the 1 pin of the IC to reduce the output current of the power supply. In this way, by adjusting the parameters of R26, R15 and DZ2, the charging time and the minimum dimming rate can be well adjusted. In short, when the output voltage does not reach the voltage of the LED lamp, the speed of charging the electrolytic capacitor EC is accelerated to reduce the startup time.

[0031] It is worth mentioning that the technical features such as the input end involved in this utility model patent application should be regarded as the prior art. The specific structure, working principle and possible control method and spatial layout method of these technical features can be selected by conventional methods in the field and should not be regarded as the invention point of this utility model patent. This utility model patent will not be further elaborated.

[0032] For those skilled in the art, it is still possible to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present utility model should be included in the protection scope of the present utility model.

Claims

1. A TRIAC low-light fast-start circuit, characterized in that: It includes an AC input circuit, a rectifier output circuit, a low current fast start circuit and a power conversion circuit, wherein the rectifier output circuit is electrically connected to the AC input circuit, the low current fast start circuit and the power conversion circuit respectively, wherein: The rectifier output circuit includes a diode D5, an electrolytic capacitor EC1 and an electrolytic capacitor EC2, the cathode of the diode D5 is grounded through the electrolytic capacitor EC1 and the electrolytic capacitor EC2 respectively, and the cathode of the diode D5 is connected to the output terminal VOUT; The low current fast start circuit includes a photocoupler OP1 and a field effect transistor Q2, the anode of the photocoupler OP1 is connected to the output terminal VOUT through a diode ZD2 and a resistor R24, and the cathode of the photocoupler OP1 is grounded, the collector of the photocoupler OP1 is grounded through a resistor R27 in one way and electrically connected to the gate of the field effect transistor Q2 in another way, the drain of the field effect transistor Q2 is connected to the power supply terminal Vbus through resistors R26, R14 and R13 in sequence, and the source of the field effect transistor Q2 is electrically connected to the common terminal of the resistor R26 and the resistor R14 through a resistor R15, the source of the field effect transistor Q2 is grounded, and the two ends of the resistor R15 are connected in parallel with a capacitor C4; The power conversion circuit includes a power management chip IC1 and a field effect transistor Q1, wherein pin 1 of the power management chip IC1 is electrically connected to the common terminal of the resistor R14 and the resistor R15, pin 3 of the power management chip IC1 is connected to the power supply terminal Vaux through a diode D2 and a resistor R8 and is grounded through an electrolytic capacitor EC4, pin 5 of the power management chip IC1 is electrically connected to the source of the field effect transistor Q1 and the drain of the field effect transistor Q1 is electrically connected to the anode of the diode D5.

2. A TRIAC low-light fast-start circuit according to claim 1, characterized in that: Pin 2 of the power management chip IC1 is electrically connected to the anode of the diode D2 through resistors R12, R10 and R9 in sequence, and is grounded through resistors R12 and diode D3 in sequence in another path. Both ends of the diode D3 are connected in parallel with resistors R11.

3. A TRIAC low-light fast-start circuit according to claim 2, characterized in that: The AC input circuit includes an input terminal ACL, an input terminal ACN, a rectifier bridge BD1 and a common-mode inductor L2. The input terminal ACL and the input terminal ACN are electrically connected to the input terminal of the rectifier bridge BD1 respectively, and the output terminal of the rectifier bridge BD1 is electrically connected to the anode of the diode D5 through the common-mode inductor L2.

4. A TRIAC low-light fast-start circuit according to claim 3, characterized in that: The gate of the field effect transistor Q1 is electrically connected to the output end of the rectifier bridge BD1 through the resistor R6, the resistor R5 and the resistor R4 in sequence.

5. A TRIAC low-light fast-start circuit according to claim 4, characterized in that: The two ends of the resistor R27 are connected in parallel with a capacitor C7.

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