Patent ID: 7274178
Filing Date: 2007-09-25
Classification: G09G,H05B

Abstract:
1. An active current regulator circuit, comprising: a. a first input node for receiving a first reference electrical signal; b. a second input node for receiving a second reference electrical signal; c. a ground node; d. an output node for outputting an output electrical signal with respect to the ground node; e. a PI controller having a first input node, a second input node, and an output node, wherein the PI controller comprises an amplifier having a first input connected to the first input node of the PI controller, a second input connected to the second input node of the PI controller, an output connected to the output node of the PI controller, and a first capacitor with a capacitance C f. a linear regulator having a first input node, a second input node, a first output node and a second output node, wherein the linear regulator comprises a first transistor with a base, an emitter and a collector, and a second transistor with a base, an emitter and a collector, wherein the emitter of the first transistor is electrically connected to the collector of the second transistor, and the collector of the first transistor is electrically connected to the emitter of the second transistor, respectively, and wherein the base of the first transistor is electrically coupled to the output of the PI controller through the first input node of the linear regulator, the base of the second transistor is electrically coupled to the output of the PI controller through the second input node of the linear regulator, the collector of the first transistor and the emitter of the second transistor are electrically connected to the first output node of the linear regulator, and the emitter of the first transistor and the collector of the second transistor are electrically connected to the second output node of the linear regulator, respectively; g. a rectifier having a first input, a second input, and a first output, wherein the first input of the rectifier is electrically connected to the second output node of the linear regulator, the second input of the rectifier is electrically coupled to the ground node, and the first output of the rectifier is electrically coupled to the second input of the amplifier, respectively; h. an RC filter having an input and an output, wherein the input of the RC filter is electrically connected to the first output of the rectifier, and the output of the RC filter is electrically coupled to the ground node; and i. a dimmer having an input and an output, wherein the input of the dimmer is electrically connected to the second input node, and the output of the dimmer is electrically connectable to the first input node or the second input node of the PI controller, wherein in operation, a voltage signal V 0 , which is generated at the output node of the PI controller responsive to at least one input voltage signal applied to the first input of the second input of the amplifier, drives the linear regulator to have a controlled electrical signal at the output node accordingly.