DIRECT DRIVE LED LIGHTING

摘要

A direct drive LED lighting circuit includes a LED current control circuit with a power switching device; a current sensing device, an averaging circuit, and an error amplifier. A LED chain circuit is formed by connecting several LEDs in series with a capacitor connecting in parallel with the series of LEDs, with a current flowing in side as a positive terminal, and a current leaving terminal as a negative terminal. The LED chain circuit and the LED current control circuit are connecting in series and the whole circuit is connected between the positive and negative terminals of a rectified AC power source.

主权项

1. A direct drive LED lighting circuit comprising:
a LED current control circuit with a power switching device; a current sensing device, an averaging circuit, and an error amplifier; wherein the power switching device with a control terminal to control the amount of current flowing through the switching channel, a current inflow terminal and a current outflow terminal as the positive channel terminal and the negative channel terminal of the power switching device respectively; and a current sensing device for sensing the current flowing through the power switching device is connecting between the negative channel terminal of the power switching device and the reference node (lowest voltage) of the control circuit, the output of the current sensing device (or negative channel terminal of the power switching device for particular implementation) is also connecting to the input of an averaging circuit; and the averaging circuit with an input connected to the output of the current sensing device, and an output connected to one of the inputs of an error amplifier; and the error amplifier with an output of the averaging circuit as one of the inputs, and reference voltage serving for setting of an average LED current as another input, and an output connected to the control terminal of the power switching device; and a LED chain circuit by connecting several LEDs in series with a capacitor connecting in parallel with the series of LEDs, with a current flowing in terminal as a positive terminal, and a current leaving terminal as a negative terminal; the LED chain circuit and the LED current control circuit are connecting in series and the whole circuit is connected between the positive and negative terminals of a rectified AC power source.