Current sample converting circuit and LED constant current power supply

The utility model discloses a current sample converting circuit and LED constant current power supply, this current sample converting circuit include constant -current chip control circuit, current sample unit, first resistance, second resistance, and the one end and the one end of sample current port and second resistance of first resistance are connected, the other end ground connection of firstresistance, the other end of second resistance and constant -current chip control circuit and the current sample unit connection, constant -current chip control circuit utilizes the output of cut -offfing on -off control sample current of current sample unit, constant current power supply includes that current sampling circuit, EMI filter circuit, half -bridge harmonic circuit, rectification filtered output circuit and power factor correct the circuit. The utility model discloses an each circuit cooperation work, hoisting power factor value and harmonic restrain. Furthermore, the utility model discloses the electric