The LED drive circuit of the present invention is a high-
voltage LED linear
constant current drive circuit, which is composed of two parts, an AC / DC conversion circuit AC / DC and a linear
constant current source circuit, in addition to the LED
light source module. The linear
constant current source circuit part mainly includes
amplifier A, constant current output adjustment tube T, reference reference power supply Vfer, working power supply VDD, output current sampling
resistor R F and output current shunt
resistor R. The LED drive circuit of the present invention, when the constant current output adjustment tube T is subjected to
voltage rise, bypasses a part of the output current through the shunt
resistor R connected in parallel with the output terminal of the constant current adjustment tube T, so as to reduce the power dissipation of the constant current adjustment tube T , reduce temperature rise and improve stability. The higher the
voltage withstood by the output end of the constant current adjusting tube T, the greater the bypass current of the shunt resistor R. As long as you choose the appropriate shunt resistor resistance, and arrange the shunt resistor reasonably to keep it away from thermally sensitive devices, and control the temperature rise of the constant
current regulator tube within a safe range, the stability of the constant current drive circuit can be improved and the expansion can be extended. scope of application.