Single-path constant-current drive circuit for controlling multiple LED pixel points

Abstract

The invention provides a single-path constant-current drive circuit for controlling multiple LED pixel points. The circuit comprises an LED lamp string and a logic control circuit for driving the LED lamp string, wherein the LED lamp string is formed by connecting more than two LED lamp beads in series; the logic control circuit comprises more than two electronic switches and a driver for controlling the electronic switches to be turned on; and the electronic switches correspond to the LED lamp beads one by one and are connected with the corresponding LED lamp beads in parallel. According to the working principle, multiple LED lamp beads are connected in series, one path of constant-current source is used for driving and each LED lamp bead is connected with one electronic switch in parallel, so that the target that each LED lamp bead is individually lightened or extinguished can be achieved. The average current which flows through each LED lamp bead can be adjusted through adjusting the duty ratio of each electronic switch period as long as the switching speed of each electronic switch is high enough, so that output power of each LED pixel point is controlled and individual lightening and extinguishing and dimming of each LED lamp bead are achieved.

Description

technical field [0001] The invention relates to the field of LED lighting fixtures, in particular to a constant current drive circuit that needs to output and control multiple LED pixels. Background technique [0002] At present, most of the LED lighting fixtures on the market use a constant current drive circuit to drive the LED and adjust the LED drive current. Generally, one constant current drive can only drive one LED light string, and multiple LED light strings require more road constant current drive circuit. When this constant current driving scheme is used to control dot matrix LED pixels, multiple constant current driving circuits must be used. N pixels need N constant current driving circuits, which seems to take up more space and cost more. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a single-channel constant current drive circuit for controlling multiple LED pixels, reduce the cost of the LED do...

AI Technical Summary

Problems solved by technology

This constant current drive scheme needs to use multiple constant current drive circuits when controlling dot matrix LED pixels. N pixels need N constant current drive circuits, which is more space-consuming and costly.

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