LED current-supplying circuit and LED current-controlling circuit

摘要

A LED current-controlling circuit includes a first magnetic amplifier, a first current detecting circuit, a first magnetic amplifier controller and a first diode. The first magnetic amplifier is connected to an input terminal of the LED current-controlling circuit and the first LED string. The first current detecting circuit is connected to the first LED string in series for detecting the first current flowing through the first LED string. The first magnetic amplifier controller is used for controlling on/off statuses of the first magnetic amplifier. The first diode is connected to an output terminal of the first magnetic amplifier, the first LED string and the first magnetic amplifier controller. The first magnetic amplifier controller controls on/off statuses of the first magnetic amplifier according to the magnitude of the first current, thereby maintaining the first current at a specified DC current level.