RU2735022C1 - Driver for led lighting fixture - Google Patents

Abstract

FIELD: electrical engineering.SUBSTANCE: invention relates to drivers for LED lighting fixtures. Driver includes a board, on which a rectifying diode bridge is installed, power switches, diodes, capacitors, output current stabilization unit, filter for suppression of in-phase and differential noise, current-measuring resistors, disconnected discharge resistors, light-emitting diode module, transformer, unit for analysis and control of power switch according to PFM/PWM algorithm, high-voltage capacitor. Driver additionally comprises an electromagnetic compatibility unit consisting of a unit for protection from microsecond pulse interferences of high energy of more than 1500 V, which includes varistors, a thermistor and a discharger, located on the printed-circuit board, filter for suppression of in-phase and differential noise, which includes throttles and capacitors. Unit for protection against microsecond pulse interferences of high energy of less than 1500 V consists of a capacitor, varistors and a discharger connected in parallel to the input power circuit. Output current stabilization unit includes high-voltage protection unit in the network, thermal protection unit, unit for analysis and stabilization of current through the LED module by means of control of the power switch according to PFM/PWM algorithm. Primary winding of the transformer, current-measuring resistors and the power switch are connected in series to the input circuit, and the unit for analysis and control of the power switch according to the PFM/PWM algorithm and the high-voltage capacitor are connected in parallel to the driver output. Output current stabilization unit further comprises output current pulsation smoothing unit.EFFECT: technical result is creation of driver with protection function of LED lamp from voltage surges, higher power factor, higher driver efficiency, ruled out ripple of output current.3 cl, 2 dwg

Description

The present invention relates to power supply devices for LED luminaires, in particular to LED luminaire drivers for lighting applications.

Drivers for LED luminaires must provide current limiting and some degree of current control. LED current control has two tasks: current limiting to prevent thermal failure due to increased temperature of the LED, and current regulation to keep the LED current within a certain range to account for fluctuations in LED parameters and fluctuations in the input voltage of the LED luminaire driver.

Another approach to creating a driver for an LED luminaire was to use pulse width modulation (PWM) feedback to measure the LED array current and actively control the LED array current.

As used herein to disclose the essence of the present invention, the term "LED" should be understood as any electroluminescent diode or other type of carrier injection / combining system that is capable of generating radiation under the action of an electrical signal. Thus, the term "LED" includes various semiconductor structures that emit light in response to current, light emitting polymers, organic light emitting diodes (OLEDs), electroluminescent strips, and the like.

Note that LEDs can be configured (and / or controlled) to generate radiation with different bandwidths (for example, full width at half maximum or duration at half amplitude) for a given spectrum range (for example, in a narrow frequency band, in a wide frequency band) and with a variety of dominant wavelengths that determine the fundamental color tone.

Known LED light source for utility model patent No. RU113105 (IPC Н05В 37/02, 01/27/2012), which is aimed at eliminating voltage surges, increasing the reliability and service life of the LED illuminator, reducing power consumption from a stationary AC network. The LED light source contains a step-down voltage converter, which is connected to at least one LED through a rectifier diode bridge, and a capacitive filter is connected in parallel with it between the rectifier diode bridge and the LED, the voltage step-down converter is made of a chain of series-connected capacitors, where the rectifier the diode bridge is connected to break the chain of series-connected capacitors of the voltage converter.

The disadvantages of this solution are: low power factor (less than 0.9), low efficiency, high dependence of the LED supply current on changes in the supply voltage of the 220V network, weak protection against high-energy microsecond impulse noise, high luminous flux ripple, lack of protection against overheating.

A useful model is known under patent No. 128433 (IPC Н05В 33/02, 20.05.13), where the problems of protecting the lamp from voltage surges, increasing the power factor, eliminating the pulsation of the output current at a frequency of up to 1 kHz are solved. A driver for an LED lamp, which includes a board on which a mains rectifier, a power switch, a diode, capacitors, a unit for analyzing and stabilizing the output current by controlling the power switch of the output current stabilization circuit are installed, while the board additionally contains:

- mains power connector (2),

- protective element against voltage surges (3),

- common mode filter (4),

- output voltage stabilization unit (7) by controlling the power switch according to the PFM / PWM algorithm (6),

- high frequency step-down transformer (8),

- power switch (transistor) of the output current stabilization circuit (11),

- resistors for measuring current on the LED bar (12),

- unit for analyzing the output voltage and transmitting the control signal (power switch) to the voltage stabilization unit,

- the block for stabilizing the output voltage and the power switch are connected in parallel;

the diode and the power switch are connected in series with each other and in parallel with the rest of the circuit elements; a diode and one or two capacitors connected in parallel make up a rectifier circuit; the unit for analyzing the output voltage is connected in parallel with the rectifier circuit; the unit for analyzing and stabilizing the output current, the power switch of the output current stabilization circuit are included in the serial circuit.

The disadvantages of this solution are protection against microsecond impulse noise, which can withstand pulses up to 2 kV, lower efficiency (about 87%), limitation of the maximum output power up to 70-80W

The technical result, the solution of which is aimed at the claimed invention is the creation of a driver with the function of protecting the LED lamp from voltage surges, increasing the power factor, increasing the efficiency of the driver, eliminating the ripple of the output current, protection against an open circuit in the load circuit, protection against polarity reversal.

This technical result is achieved by the fact that the driver for the LED luminaire includes a board on which a network rectifier diode bridge is installed, power switches, diodes, capacitors, an output current stabilization unit, a filter for suppressing common-mode and differential noise, current-measuring resistors, disconnectable discharge resistors , LED module, transformer, PFM / PWM power switch analysis and control unit, high-voltage capacitor. At the same time, the driver additionally contains an electromagnetic compatibility unit, consisting of a protection unit against microsecond impulse noise of high energy more than 1500V, including varistors, a thermistor and a spark gap located on the printed circuit board, a filter for suppression of common-mode and differential noise, including chokes and capacitors , the protection unit against microsecond impulse noise of high energy less than 1500 V, consists of a capacitor, varistors and a spark gap connected in parallel with the input power circuit, while the output current stabilization unit includes a high voltage protection unit, a thermal protection unit, an analysis unit and stabilization of the current through the LED module by controlling the power switch according to the PFM / PWM algorithm, and the primary winding of the transformer, current measuring resistors and the power switch are connected in series in the input circuit, and the analysis and control unit of the power switch according to the PFM / PWM algorithm and the high-voltage capacitor are connected in parallel on the driver's output, in addition, the output current stabilization unit additionally contains an output current ripple smoothing unit, consisting of an output current control unit by means of a specialized microcircuit for linear transistor control, in which high-voltage diodes, transistors and current-measuring resistors are connected in series with the LED module, the secondary winding of the transformer and a discharge circuit of disconnected discharge resistors ...

In addition, the transistor consists of a block of output capacitors discharge connected in parallel with the driver output.

In addition, the disconnectable discharge resistors are connected in parallel.

The essence of the invention is illustrated by drawings, where figure 1 shows a general view of the driver circuit. FIG. 2 is a block diagram of a driver for an LED luminaire.

The driver circuit for a LED luminaire includes the following elements located on a printed circuit board: varistors (1), a thermistor (2), an arrester (3) wired on a printed circuit board in the form of single triangles, an input filter (4) for suppression of common-mode and differential noise, an input filter (5) radio interference, interference suppression capacitors (6), rectifier diode bridge (7), high-voltage capacitor (8), output current stabilization unit, including a transformer (9), power switch (10), high-voltage diode (11), current measuring resistors (12) and unit (13) for analyzing and controlling the power switch according to the PFM / PWM algorithm, the power supply unit for the power switch control microcircuit, which includes a starting circuit of disconnected resistors (14), a transistor (15) for disconnecting the starting circuit, a transistor ( 16) control of the power circuit, high-voltage diode (17), unit for analyzing and smoothing the output current ripple, which consists of a specialized microcircuit (18) for analyzing the output current ripple, resistors (19) of the power supply circuit of the output current ripple analysis microcircuit, the power switch (20) and the current analysis resistors (21), the output capacitor discharge unit, which consists of resistors (22) and a switch (23).

In this case, the primary winding of the transformer, current measuring resistors (12) and the power switch (10) are connected in series to the input circuit, and the unit (13) for analyzing and controlling the power switch according to the PFM / PWM algorithm and the high-voltage capacitor (8) are parallel to the driver output.

In this case, the secondary winding of the transformer, high-voltage diodes (11), power switch (10), current-measuring resistors (12) are connected in series, and high-voltage capacitors (8), the unit for analyzing and smoothing the output current ripples and the output capacitor discharge unit in parallel with the driver output.

The driver for the LED device works as follows.

The alternating voltage of the 220V network is supplied to a protective element against common-mode and differential interference, made in the form of an (input) node (24) of electromagnetic compatibility . This unit (24) consists of a block (25) for protection against high-energy microsecond impulse noise (hereinafter μs.i.p.) and a block (26) for protection against high-energy microsecond impulse noise (μs.i.p.) less than 1500V, where the analysis of the presence of μs.i.p. as part of the 220V mains voltage, as well as the filter (27) for suppression of common-mode and differential interference, including chokes and capacitors. In the presence of a 220V mains voltage μs.i.p. with an amplitude from 300 to 1500V in the block (26) for protection against microsecond impulse noise of high energy less than 1500V, consisting of a capacitor, varistors and a spark gap connected in parallel with the input power circuit. In this case, the noise is smoothed out by the chokes and capacitors into the filter (27) for suppressing common-mode and differential noise, and the varistor is triggered, as a result of which the amplitude of μs decreases. up to 300V safe for driver operation. If the mains voltage is 220V μs. etc. with an amplitude of more than 1500V to 2kV in the block (25) of protection against microsecond impulse noise of high energy more than 1500V, the series-connected thermistor, arrester and varistor are triggered, and thereby the amplitude of the μs.i.p. to a value of 630V by means of power dissipation on the varistor, then μs.i.p. it is smoothed by chokes and capacitors into the filter (27) of common-mode and differential noise and then enters the protection unit against microsecond impulse noise of high energy less than 1500V, where the varistor is triggered and the amplitude of μs decreases. etc. up to a safe voltage for the driver to work 300 V.

When the mains voltage passes through the filter (27) of common-mode and differential noise, noise from the network is suppressed, which can affect the operation of the driver, as well as to suppress noise to the 220V network up to the established standards, to prevent influence on third-party devices connected to the same network as the driver.

The alternating voltage is then rectified by means of an AC / DC rectifier (28), which is a diode bridge. The rectified voltage is fed to the combined unit (29) for stabilizing the output current and active power correction (hereinafter referred to as the STACS unit). The STACS unit (29) includes a network overvoltage protection unit (30), a thermal protection unit (31), a unit (32) for analyzing and stabilizing the current through the LED module by controlling the power switch using the PFM / PWM algorithm.

The STACS unit (29) analyzes the alternating voltage and the voltage value across the current-measuring resistors and, by controlling the power switch according to the PFM / PWM algorithm, maintains a stabilized current on the output capacitors of the driver and provides a power factor of more than 0.95.

From the output capacitors, the current flows to the LED module (33) through the unit (34) for suppressing low-frequency ripple current (hereinafter BPNP). In block (34) BPNP, the value of the output current ripple from the current-measuring resistors enters a specialized microcircuit, which, in a linear mode, by means of a power switch, creates an additional voltage drop at the driver output, converting the ripple into heat. Parallel to the BPNP, a circuit (35) of disconnectable discharge resistors is installed, which are disconnected from the output capacitors by means of a transistor during driver operation.

In the block (29) STACS there is a module (36) for controlling the output current, while the adjustment range varies in the range of the nominal value to completely off. The impact is carried out by means of a PWM signal at a frequency of 1 to 2 kHz, as well as a node (30) for protection against high voltage in the network (overvoltage) and a node (31) for thermal protection, integrated into the PFM / PWM signal chip, which is necessary to reduce the driver power and prevent overheating driver or LED module at a temperature higher than the maximum allowable for their operation.

When using the driver, it is achieved:

• operating range 160-265 V;

• input of brightness control in the range from 0 to 100%;

• high reliability and efficiency of the driver (efficiency = 92%) at a wide range of input voltage;

• combined two-level protection of the luminaire against overvoltage up to 430 V and protection against impulse noise up to 2 kV with a duration of 50 μs I.p. according to GOST R 51317.4.5-99 (IEC 61000-4-5-95) and emergency shutdown of the driver in case of overheating;

• protection against short circuit in the load, protection against open circuit in the load circuit, protection against polarity reversal.

• tested operating temperature from -60 ° С to + 50 ° С;

• driver service life up to 100,000 hours or more using electrolytic capacitors of increased operating temperature range.

Claims (3)

1. A driver for an LED lamp, which includes a board on which a network rectifier diode bridge, power switches, diodes, capacitors, an output current stabilizer, a filter for suppression of common-mode and differential noise, current-measuring resistors, disconnectable discharge resistors, an LED module, a transformer are installed , a unit for analyzing and controlling the power switch according to the PFM / PWM algorithm, a high-voltage capacitor, characterized in that the driver additionally contains an electromagnetic compatibility unit, consisting of a protection unit against high-energy microsecond impulse noise of more than 1500 V, including varistors, a thermistor and a spark gap, located on the printed circuit board, a common-mode and differential noise suppression filter, including chokes and capacitors, the protection unit against high-energy microsecond impulse noise less than 1500 V consists of a capacitor, varistors and an arrester connected in parallel with the input power circuit, while the stabilizer unit Ii of the output current includes a high-voltage protection unit in the network, a thermal protection unit, a unit for analyzing and stabilizing the current through the LED module by controlling the power switch using the PFM / PWM algorithm, and the primary winding of the transformer, current-measuring resistors and the power switch are connected in series to the input circuit , and the unit for analysis and control of the power switch according to the PFM / PWM algorithm and the high-voltage capacitor are connected in parallel with the driver output, in addition, the output current stabilization unit additionally contains an output current ripple smoothing unit, consisting of an output current control unit by means of a specialized microcircuit for linear transistor control, in which high-voltage diodes, transistors and current-measuring resistors are connected in series with the LED module, the secondary winding of the transformer and a discharge circuit of disconnected discharge resistors ... 2. The driver of claim. 1, characterized in that the transistor consists of a block of discharge of output capacitors connected in parallel with the output of the driver. 3. The driver of claim. 1, characterized in that the disconnected discharge resistors are connected in parallel.

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