Current feed circuit and current control circuit of light emitting diode

Abstract

The invention relates to a current feed circuit and a current control circuit of a light emitting diode. The current feed circuit is used for driving a first group and a second group of light emitting diodes, and the invention comprises a main power source rectification circuit, a primary DC-DC converting circuit, a first current control circuit and a second current control circuit, wherein the primary DC-DC converting circuit is used for respectively converting rectification input voltage into a first and a second pulsewidth modulating voltage; the input end of the first current control circuit is connected with the first output end of the primary DC-DC converting circuit, and the output end of the first current control circuit is connected with the first group of light emitting diodes; and the input end of the second current control circuit is connected with the second output end of the primary DC-DC converting circuit, and the output end thereof is connected with the second group of light emitting diodes. The first current control circuit and the second current control circuit respectively receive the first and the second pulsewidth modulating voltage so as to generate a first and a second currents with specific current values. The invention can reduce the integral cost of the circuits, increase the density and the running efficiency of the circuits, ensuring the currents of the light emitting diodes to be balanced and ensuring the brightness to be identical.

Description

technical field [0001] The invention relates to a current supply circuit and a current control circuit, in particular to a current supply circuit and a current control circuit of a light emitting diode. Background technique [0002] In recent years, due to breakthroughs in light emitting diode (Light Emitting Diode, LED) manufacturing technology, the luminous brightness and luminous efficiency of light emitting diodes have been greatly improved, thus making light emitting diodes gradually replace traditional lamps and become new lighting components, widely used in For example, lighting applications such as household lighting devices, automotive lighting devices, handheld lighting devices, LCD panel backlights, traffic signal lights, and signage boards. [0003] In the application of multiple light-emitting diodes, since the characteristics of each light-emitting diode are different from each other, the magnitude of the current flowing through each light-emitting diode is dif...

AI Technical Summary

Problems solved by technology

[0005] The current control circuit of traditional LEDs needs to be used in conjunction with the secondary DC-DC conversion circuit to make the current of each group of LEDs the same, which results in high overall circuit cost and low circuit density

In addition, the traditional LED power supply circuit needs to first generate a specific DC voltage on the DC bus by the primary DC-DC conversion circuit, and then convert the specific DC voltage into the DC current required by the LED through the secondary DC-DC conversion circuit and the current control circuit. It can be seen that the traditional LED power supply circuit requires a two-stage DC-DC conversion circuit, and there is a fixed voltage difference between the input and output of the secondary DC-DC conversion circuit, resulting in loss, and this loss will follow the output. The lower the voltage, the larger the diode, therefore, the traditional LED power supply circuit has low efficiency, high circuit cost and low circuit density

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