Noise Countermeasures for LED Bulbs Using Medium and High Voltage Ceramic Capacitors
Recently, in addition to the requirements of small and thin, energy-saving, and low-noise, electronic equipment is expected to meet the ecological needs of the global warming. Under such market demand, the LED bulbs that have been popular since 2009 have become small and thin, and have achieved high eco-friendship due to their long service life. The electronic components mounted on them are also required to be small and thin. It has a long service life.
LED bulbs are equipped with a small power supply with a power of about 10W, mainly using electrolytic capacitors and film capacitors to achieve a smooth function, but the use of small and longer-life ceramic capacitors is also increasing. Ceramic capacitors with higher electrostatic capacity than conventional ceramic materials, this paper will introduce its characteristics, and introduce the recommended circuit for power supply of other electronic devices based on LED bulbs.
New material ceramic capacitor performance
The properties of the new material ceramics are compared with the conventional materials, and the Curie point is transferred to the low temperature side, so that it exhibits a paraelectric phase at normal temperature. Therefore, the new material product can achieve the following performance compared with the conventional product.
The maximum value of the capacitance when the DC voltage is applied is reduced, ensuring a high effective capacitance value. It ensures that the capacitance is twice that of conventional materials when DC600V is applied.
1: Electrostatic capacity - DC voltage characteristics
The loss is small, allowing a large ripple current. The ripple current is allowed to be approximately 1.6 times at a frequency of f = 250 kHz.
Murata's standard for allowing ripple current is that the ambient temperature is below 25 degrees and can be energized until the capacitor self-heating temperature reaches 20 degrees. Led lamp bead uses low voltage power supply, the supply voltage is between 2-4V, depending on the product, so it is a safer power supply than the use of high voltage power supply, especially suitable for public places; brightness changes with current Bright, low power LED lamp bead working current is 0-60mA, high power LED working current is above 150mA. The terminal voltage of the PN junction of the led lamp bead constitutes a certain barrier. When the forward bias voltage is applied, the barrier decreases, and the majority carriers in the P and N regions diffuse to each other. Since the electron mobility is much larger than the hole mobility, a large amount of electrons diffuse into the P region, which constitutes injection of minority carriers in the P region. These electrons recombine with the holes in the valence band, and the energy obtained during the recombination is released in the form of light energy. This is the principle of PN junction illumination. If the product has a capacitance of 1F, the frequency of f = 250kHz is 4.7Arms compared to the conventional material, and the new material is 4.7Arms.
2: Comparison of heating temperature
When the DC voltage is applied, the mechanical strain is relatively small and the click is small. The led lamp is an electroluminescent semiconductor material chip, which is cured with silver or white glue to the bracket, and then connected to the chip and the circuit board with silver wire or gold wire, and sealed with epoxy resin to protect the inner core wire. Function, and finally install the outer casing, so the LED lamp has good seismic performance. Compared to traditional materials, the new material has a sound pressure level of only one-fifth. The piezoelectric effect of new material ceramics is small. Therefore, mechanical vibration caused by changes in electrical signals is less likely to occur.
led grow lights
LED bulbs are equipped with a small power supply with a power of about 10W, mainly using electrolytic capacitors and film capacitors to achieve a smooth function, but the use of small and longer-life ceramic capacitors is also increasing. Ceramic capacitors with higher electrostatic capacity than conventional ceramic materials, this paper will introduce its characteristics, and introduce the recommended circuit for power supply of other electronic devices based on LED bulbs.
New material ceramic capacitor performance
The properties of the new material ceramics are compared with the conventional materials, and the Curie point is transferred to the low temperature side, so that it exhibits a paraelectric phase at normal temperature. Therefore, the new material product can achieve the following performance compared with the conventional product.
The maximum value of the capacitance when the DC voltage is applied is reduced, ensuring a high effective capacitance value. It ensures that the capacitance is twice that of conventional materials when DC600V is applied.
1: Electrostatic capacity - DC voltage characteristics
The loss is small, allowing a large ripple current. The ripple current is allowed to be approximately 1.6 times at a frequency of f = 250 kHz.
Murata's standard for allowing ripple current is that the ambient temperature is below 25 degrees and can be energized until the capacitor self-heating temperature reaches 20 degrees. Led lamp bead uses low voltage power supply, the supply voltage is between 2-4V, depending on the product, so it is a safer power supply than the use of high voltage power supply, especially suitable for public places; brightness changes with current Bright, low power LED lamp bead working current is 0-60mA, high power LED working current is above 150mA. The terminal voltage of the PN junction of the led lamp bead constitutes a certain barrier. When the forward bias voltage is applied, the barrier decreases, and the majority carriers in the P and N regions diffuse to each other. Since the electron mobility is much larger than the hole mobility, a large amount of electrons diffuse into the P region, which constitutes injection of minority carriers in the P region. These electrons recombine with the holes in the valence band, and the energy obtained during the recombination is released in the form of light energy. This is the principle of PN junction illumination. If the product has a capacitance of 1F, the frequency of f = 250kHz is 4.7Arms compared to the conventional material, and the new material is 4.7Arms.
2: Comparison of heating temperature
When the DC voltage is applied, the mechanical strain is relatively small and the click is small. The led lamp is an electroluminescent semiconductor material chip, which is cured with silver or white glue to the bracket, and then connected to the chip and the circuit board with silver wire or gold wire, and sealed with epoxy resin to protect the inner core wire. Function, and finally install the outer casing, so the LED lamp has good seismic performance. Compared to traditional materials, the new material has a sound pressure level of only one-fifth. The piezoelectric effect of new material ceramics is small. Therefore, mechanical vibration caused by changes in electrical signals is less likely to occur.
led grow lights
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