RU214510U1 - Switched choke power supply - Google Patents

Abstract

The device relates to the field of electrical engineering, in particular to power supplies for LED lighting devices based on ballast chokes. The technical result consists in increasing the service life of electric lighting LED devices (reliability, reliability) by increasing the series reactance to alternating current when the set voltage threshold of the supply network to the device is exceeded. The technical result is achieved due to the fact that the power supply of the electric LED lighting device includes two series-connected ballast chokes L1, L2, the middle connection point of which is switched by an electromechanical relay K1, with a normally closed contact, which, in turn, is connected by a control coil to the opto-triac VU1 connected to the comparison block. The comparison unit includes an operational amplifier DA1 with a positive feedback formed by resistor R8, circuits for generating a reference voltage and a measured one, formed by a controlled zener diode D2 connected to the inverting input of the op-amp DA1, respectively, in the cathode of which a current-limiting resistor R7 is connected in series, and series-connected resistors R5, R6 and P1, forming a voltage divider, the middle point of which is connected to the non-inverting input of the operational amplifier (op-amp) DA1. Also, the power supply additionally contains a parametric voltage regulator that feeds the comparison circuit, which includes a zener diode D1, the cathode of which is connected in series with a current-limiting resistor R3, and a storage capacitor C3 and a load resistor R4 are connected in parallel with the zener diode D1. In this case, the limiting capacitor C1 is connected in series with the phase of the AC supply network, the shunt resistor R1 is connected in parallel with C1, and the resistor R2 is connected in series with the neutral conductor of the supply network to limit the initial charge current of the capacitor C1. 1 ill.

Description

The device relates to the field of electrical engineering, in particular to power supplies for LED lighting devices based on ballast chokes.

Known power supply lamp [Patent RU No. 2313199, IPC H05B 33/02, F21S 4/00, publ. 20.12.2007], containing a series-connected power converter and ballast chokes, made in the form of at least two ballast chokes connected in parallel through a normally closed contact of the temperature sensor, while the temperature sensor and LED sections are installed on the cooling radiator.

The disadvantage of this power supply is the lack of protection of LED lighting devices from high voltage in the power supply network of the device and a decrease in the life of lighting devices.

The task is to create a power supply unit that is easy to set up due to the fact that the measuring circuits and power circuits of ballast chokes do not have common elements that provide increased

The technical result consists in increasing the service life of electric lighting LED devices (reliability, reliability), by increasing the series reactance to alternating current, when the set voltage threshold of the supply network to the device is exceeded.

The technical result is achieved due to the fact that the power supply of the electric LED lighting device includes two series-connected ballast chokes L1, L2, the middle connection point of which is switched by an electromechanical relay K1, with a normally closed contact, which in turn is connected by a control coil to the VU1 optotriac connected with a comparison unit that includes an operational amplifier DA1 with a positive feedback formed by a resistor R8, a circuit for generating a reference voltage and a measured one, formed by a controlled zener diode D2 connected to the inverting input of the operational amplifier (op-amp) DA1, respectively, in the cathode of which a current-limiting resistor R7 is connected in series, and series-connected resistors R5, R6 and P1, forming a voltage divider, the middle point of which is connected to the non-inverting input of the op-amp DA1, the power supply also additionally contains a parametric voltage regulator that supplies a comparison circuit that includes a zener diode D1, the cathode of which is connected in series with a current-limiting resistor R3, and in parallel with the zener diode D1, a storage capacitor C3 and a load resistor R4 are connected, an electrolytic capacitor C2 connected to the positive output of a full-wave rectifier VD1 and the voltage divider input formed by resistors R5 , R6, P1, while the limiting capacitor C1 is connected in series with the phase of the AC supply network, the shunt resistor R1 is connected in parallel with C1, and the resistor R2 is connected in series with the neutral conductor of the supply network to limit the initial charge current of the capacitor C1.

In FIG. the diagram of the power supply is shown.

The power supply contains:

- two serially connected ballast chokes L1, L2;

- electromechanical relay K1 with two groups of contacts;

- optosimistor VU1;

- comparison unit (not indicated in the figure);

- resistors R1-R8;

- resistive voltage divider (not marked in the figure), presented in the form of three series-connected resistors R5 and R6, and a trimmer multi-turn resistor P1;

- thermostabilized precision zener diode D2;

- block parametric voltage stabilizer (not marked in the figure);

- full-wave bridge rectifier VD1;

- limiting capacitor C1;

- electrolytic capacitor C2;

- storage capacitor C3;

- zener diode D1.

Consider an example implementation of the block.

At the connection point of the chokes, an electromechanical relay K1 with two groups of contacts is switched on, so that in the initial state the current flows only through the choke L1. When crossing the set threshold, the comparison unit switches the electromechanical relay K1, the current flows through the inductor L2 and L1, thereby achieving the required limitation of the flowing current of the power supply, with an increased supply voltage, due to an increase in series reactance.

The control coil of the electromechanical relay K1 is connected to the terminal of the optotriac VU1, the LED of which is powered by the output of the operational amplifier DA1.

The measuring circuit consists of an operational amplifier DA1, connected according to the comparator circuit with hysteresis. The hysteresis window is set by resistor R8. The measured voltage is supplied to the non-inverting input through a resistive voltage divider, presented in the form of three series-connected resistors R5 and R6, and a trimmer multi-turn resistor P1. The setting threshold can be varied by changing the resistance of the trimmer P1. The reference voltage of the op-amp is set by a thermally stabilized precision zener diode D2, the current of which is limited by the resistor R7. Zener diode D2 is connected to the inverting input of the op-amp. The circuit is powered by a parametric voltage regulator, consisting of a zener diode D1, a current-limiting resistor R3 and storage capacitors C2 and C3, and a full-wave bridge rectifier VD1. The limitation of the mains voltage is provided by a capacitor C1 connected in series with the phase. Resistor R1 serves to discharge the capacitor C1 after the voltage is removed. Resistor R2 limits the inrush current when voltage is applied to the input power lines of the circuit.

With an increase in the input voltage of the mains supply, the voltage at the divider R5, R6, P1 increases proportionally. When the voltage at the non-inverting input DA1 passes through the reference voltage level at the inverting input, the current from the comparator output begins to flow through the LED of the optotriac VU1 and the positive feedback resistor R8. In turn, the triac channel opens, switching the mains supply voltage through the control coil of the electromechanical relay K1 of alternating voltage. The electromechanical relay K1 switches the phase of the power supply to the input of the ballast choke L2, which leads to an increase in the series reactance of the circuit and a drop in the current flowing through the power supply.

When the input voltage drops below the reference level, the comparator output feeds the optotriac LED until the threshold is reached, determined by the feedback formed by the resistor R8, which protects the circuit from false switching near the setpoint level.

Claims (1)

Power supply unit on switchable chokes, including two series-connected ballast chokes L1, L2, connected at the midpoint with a normally closed contact of an electromechanical relay, which, in turn, is connected by a control coil to an optotriac VU1 connected to a comparison unit that includes an operational amplifier DA1 and blocks for generating the reference voltage and the measured voltage, formed respectively by a thermally stabilized zener diode D2 connected to the inverting input DA1, the current-limiting resistor R7 is connected in series to the cathode, and resistors R5, R6 and P1 connected in series, forming a voltage divider, the middle point of which is connected to the non-inverting input DA1, moreover, the power supply additionally contains a block of parametric voltage regulator that feeds the comparison circuit, a zener diode D1, the cathode of which is connected in series with the current-limiting resistor R3, and in parallel with the zener diode D1, a storage circuit is connected capacitor C3 and load resistor R4, electrolytic capacitor C2 connected to the positive output of the full-wave rectifier VD1 and the voltage divider input formed by resistors R5, R6, P1, while the limiting capacitor C1 is connected in series with the phase of the AC power supply, resistor R1 is connected in parallel, and resistor R2 is connected in series with the neutral conductor of the supply network to limit the initial charge current of capacitor C1.

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