Driver and LED lamp comprising driver

An LED lamp for connecting to an external power supply, comprising:

• a lighting source including a plurality of LEDs;
• and
• a driver, configured for driving the lighting source, the driver comprising:
• a front-end stage comprising a front-end main circuit and a front-end controller, and configured to rectify an AC input voltage from the external power supply and output a DC bus voltage through output terminals,
• a back-end stage comprising a buck circuit, and configured to receive the DC bus voltage from the front-end stage and output a desired DC drive voltage to the load according to an operating voltage of the load, wherein the DC bus voltage is greater than the desired DC drive voltage, and
• an intermediate controller, configured to obtain a difference voltage signal indicative of an electric potential difference between the bus voltage and the drive voltage, and provide a feedback signal which is generated based on the difference voltage signal to the front-end controller, wherein the front-end controller controls the front-end main circuit based on the feedback signal to change the bus voltage with change of the drive voltage.

A driver for driving a load, comprising:

• a front-end stage, a back-end stage, and an intermediate controller, wherein
• the front-end stage comprises a front-end main circuit and a front-end controller, and is configured to rectify an AC input voltage from an external power supply and output a DC bus voltage through output terminals;
• the back-end stage comprises a buck circuit, and configured to receive the bus voltage from the front-end stage and output a desired DC drive voltage to the load according to an operating voltage of the load, wherein the buck circuit comprises a controllable switch, a diode and an inductor, and the buck circuit adopts a switch floated topology structure or an output floated topology structure;
• and
• the intermediate controller is configured to obtain a difference voltage signal indicative of an electric potential difference between the bus voltage and the drive voltage, and provide a feedback signal which is generated based on the difference voltage signal to the front-end controller, wherein the front-end controller controls the front-end main circuit based on the feedback signal to change the bus voltage with change of the drive voltage;
• wherein the intermediate controller comprises a first module configured to generate the difference voltage signal, and the first module comprising:
• a differential sampling circuit, wherein a first electrode of the controllable switch is connected with one input terminal of the differential sampling circuit and a second electrode of the controllable switch is connected with the other input terminal of the differential sampling circuit and the differential sampling circuit outputs a scaled potential difference between the first electrode of the controllable switch and the second electrode of the controllable switch;
• and
• a filter circuit which filters an output of the differential sampling circuit and outputs the difference voltage signal.