The LED strip must cooperate with the driving power supply, and different working environments also have different requirements upon driving power supplies. For now, there are many categories of power supplies in the market. Here we classify them according to the driving method and circuit structure.
1. According to the driving method, there are mainly two kinds of power supplies for the flexible LED strip.
(1) The constant-current type: a. The current output by the constant-current driving circuit is steady, while the output voltage varies along with the load resistance within a certain range. The smaller the load resistance, the lower the output voltage; vice versa. b. The constant-current circuit has no load short circuit problems, but it must strictly prohibit open circuit. c. The constant-current driving circuit is ideal to drive LEDs, but the price is relatively high. d. Please pay attention to the maximum bearing current and voltage, which limits the number of LEDs.
(2) Voltage-stabilizing type: a. When the parameters of the voltage-stabilizing circuit are confirmed, the output voltage is steady, while the output current fluctuates along with the load. b. The voltage-stabilizing circuit has no open circuit problems, but it must avoid dead short circuit. c. If we adopt voltage-stabilizing circuit to drive LEDs, appropriate resistance is needed to make the brightness of LEDs uniform. d. The brightness may be influenced by fluctuations of the rectified voltage.
2. According to the circuit structure, there are six kinds of power supplies for the flexible LED strip.
(1) Capacitance buck type. During working, the instantaneous current may become so large that the chip will be damaged. This kind of power supplies may be easily influenced by the voltage fluctuation of the power grid. They have low efficiency and reliability.
(2) Resistance buck type. This kind of power supplies also will be influenced greatly by the voltage fluctuation of the power grid. Buck resistance needs to consume large quantity of energy, so this kind of powering method has low efficiency and reliability.
(3) Common transformer buck type. This kind of power supplies for the flexible LED strip has small volume, heavy weight, and low efficiency, generally 45%-60%. So they are not usually adopted and have low reliability.
(4) Electronic transformer buck type. The efficiency is low, and the voltage range is not wide, generally 180-240V. Meantime,