This type of lamps is one of the most expensive, but also more durable and safe (it should be, but like others fail), these are 220 Volt LED lamps with a pulse driver.The driver in the lamps is the power source for the LEDs, the current on which the LEDs operate depends on it.In total, there are three types of LED lamps on sale, distinguished by the driver, where the driver is made on a ballast capacitor (the cheapest lamps), with a linear driver and a pulse driver.Here in this article I will tell you what is so good about lamps with a pulse driver.
There is a mandatory “attribute” on the boards of such lamps, this is a throttle and a chip that provides several protections for LEDs: this is protection against overheating of LEDs, the chip will reduce the current to the LEDs as soon as they heat up above a certain temperature, although the chip is not always installed on a radiator with LEDs.There is also a short circuit protection on the LEDs and other protections, it all depends on the chip.Such lamps have fewer pulsations on LEDs, unlike lamps where a capacitor serves as a driver.
Here I will take as an example the kp1052x chip from the jazzway GX53 lamp.This chip provides a quasi-resonant mode of operation, outputs a stable current to the LEDs with an error of 4%,protection against undervoltage,cycle-by-cycle current limitation,overheating protection,short circuit protection of LEDs,the operating current of the chip is only 140 µA, etc.The driver on the capacitor does not have all this, and not everything is on the linear driver.
In the photo, the ripple check on the LEDs.The ripples make up a level of about 6 volts.
How do such drivers work and why do they have a inductance choke .On the circuits of such lamps, at least which I have come across, there is such an interesting resistor as Rcs.Its resistance is literally several ohms, it monitors the current on the LEDs and a certain voltage drop occurs on it.If the voltage on the resistor becomes less than permissible, then the field-effect transistor-key, which is located in the chip (Drain pin), opens and the current goes through the choke and the LEDs shine, the diode is locked.This is the first bar.As soon as the current that passes through the LEDs increases, the Rcs resistor will give the signal to the chip and the field-effect transistor closes.But the current also passed through the throttle and energy accumulated in it.And when the transistor is closed, this throttle energy (EMF) will go through the diode and onto the LEDs and everything repeats again.This is the second cycle.Here with the help of this Rcs resistor, you can set the current through the LEDs, basically it is better to reduce it, and the maximum current can be found out from the instruction on the chip.
Of course, such pulse drivers have a disadvantage in the form of interference that the lamp emits.
How to find out such a lamp at the time of purchase? This is of course the price and maximum power.Basically, powerful 20 or 25 watt LED lamps are made on such a driver.You can take a radio receiver and bring it to the lamp when checking in the store, a buzz should be heard on long or medium waves.The best of these lamps, those that have an impressive heat sink-radiator.It is due to excessive heating of the LEDs that the lamps fail without having worked out the required service life.You could say that the heavier such a lamp is, the better.
