Light-emitting diode current balance circuit

Abstract

The invention discloses a light-emitting diode current balance circuit, and belongs to the technical field of light-emitting diode driving. The light-emitting diode current balance circuit comprises a reference current generator, a current mirror and a voltage compensation circuit. The reference current generator provides reference current with a robust power voltage disturbance resistant characteristic for the current mirror to generate absorption current to each lamp string, and a framework used in the current mirror is not influenced by a transistor gain ratio, so the current mirror can stably control the current flowing through each lamp string. The voltage compensation circuit detects the voltage at end points of each lamp string so as to compensate forward conduction voltage drop. Lamp strings with different forward conduction voltage drops can be lightened, and the current flowing through the lamp strings is more balanced. In addition, a special light-emitting diode (LED) controller is not needed, and the light-emitting diode current balance circuit is low in cost and competitive.

Description

technical field [0001] The invention relates to a light-emitting diode driving technology, in particular to a light-emitting diode current balance circuit. Background technique [0002] The ideal forward voltage drop of LED (Light-Emitting Diode, light-emitting diode) marked on the specification is 3.3V, but the actual forward voltage drop after the LED is connected to the line will inevitably exist with the ideal value of 3.3V Error, if there is a 5% error, the actual forward conduction voltage drop of the LED may be between 3.135V and 3.465V. Therefore, even if the same number and the same type of LEDs are connected in series to form a light string (light bar), there will still be different forward conduction voltage drops on each light string. If the same voltage is applied to each light string The voltage of the light strings, each light string will have different currents flowing through each light string due to the different actual forward conduction voltage drop, and...

AI Technical Summary

Problems solved by technology

Although the integrated circuit can achieve more precise control and smaller circuit area, the reliability of the integrated circuit is not as good as that of the traditional circuit, and because the current and power loss that the integrated circuit can withstand is limited (generally less than 60mA), in the high voltage and high current In the application of LED light strings, it is necessary to add transistors and other components to balance the current. For designers, not only cannot save costs, but the circuit is more complicated and difficult to control.

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