Linear constant-current and current-sharing LED drive circuit and circuit board structure thereof

Abstract

The invention discloses a linear constant-current and current-sharing LED drive circuit and a circuit board structure thereof, relating to a drive circuit of a vehicle LED illuminating device and configuration of elements of the drive circuit. The linear constant-current and current-sharing LED drive circuit comprises a reference voltage unit, a constant current feedback unit and a multi-channel sampling and current sharing unit, wherein the multi-channel sampling and current sharing unit is correspondingly connected to all channels of LED strings of the multi-channel LED light emitting module; all channels of current sampling feedback ends are connected in parallel to the feedback signal input end of the constant current feedback unit; and LED currents are automatically regulated according to an LED gear resistor arranged on an LED circuit board, one constant current feedback unit is used for controlling the currents of the multiple channels of LED strings, has multiple functions of constant current, current sharing, LED gear and PWM (Pulse Width Modulation) dimming, and can meet various practical demands in electronic illumination of automobile; and the complexity of design and production of the LED drive circuit is greatly lowered, and error probability is lowered. Any parameter of any element on the control circuit board is not needed to be changed in a production or maintenance process, high interchangeability of the circuit board can be realized, and the production efficiency is increased.

Description

technical field [0001] The present invention relates to arrangements for general vehicle lighting or signaling devices, and in particular to arrangements for driving circuits and components thereof for LED lighting devices. Background technique [0002] LED has significant advantages such as fast response speed, low power consumption, energy saving, and long life. Due to the fast response speed of LED, it is especially suitable for the application of automobile brake lights and turn signals, which can reduce the probability of traffic accidents such as rear-end collisions. With the improvement of semiconductor materials and packaging technology, the luminous flux and light output efficiency of LED light sources have gradually increased. LED light sources have been widely used in special lighting fields such as traffic lights, automotive lighting, and billboards. LED driving technology has gradually developed along with the development of LED application technology. [0003...

AI Technical Summary

Problems solved by technology

However, the technical solution of this invention is to use multiple transistors or MOSFETs integrated on the same substrate and with the same structure to form a multi-output current mirror to realize the current sharing function. Connect a sampling resistor in series after parallel connection, so that the sum of the currents of multiple LED strings can only be changed at the same time by changing the value of the sampling resistor, which lacks flexibility and cannot adapt to the matching of LEDs with different brightness levels.

[0005] In addition, there is a problem with LED gears. LED manufacturers cannot only supply LEDs with the same brightness gear. LEDs with different brightness gears must match different LED currents to ensure the consistency of light emission.

In production, if a control board with different currents is designed for LEDs of each brightness level, it will not only be time-consuming and labor-intensive, but also error-prone, and will cause the lack of interchangeability of the products, which will bring troubles to the after-sales service of the products.

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