Lighting driving circuit and lighting system

Abstract

The invention discloses a lighting driving circuit and a lighting system. A constant current control circuit of the invention is provided with an instantaneous value current-limiting function; the output current under a certain range of input voltage achieves the constant current effect in the absence of a silicon controlled light dimmer; with the help of the silicon controlled light dimmer, when a conduction angle is greater than a certain value, the instantaneous value of the output current does not achieve the current-limiting value, the circuit is worked at an constant current output state; when the conduction angle is less than a certain value, the instantaneous value of the output current achieves the current-limiting value, the output current is limited, the average value of the output current is reduced, thereby realizing the light-dimming. Therefore, the scheme can be compatible with two conditions of the existence of inexistence of the silicon controlled light dimmer, the compatibility is high; through the adding of a leakage circuit, the error shutoff of the controlled silicon caused by the condition that the output current is lower than the maintenance current can be prevented, thereby guaranteeing the stabilization of the output current of the system and preventing the system from flickering.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to an illumination driving circuit and an illumination system. Background technique [0002] In the lighting driving circuit, LED is a common lighting source. Taking the LED driving circuit as an example, the linear LED driving circuit in the prior art is widely used in the LED driving circuit due to its simple circuit and low cost. However, when LED lamps replace traditional incandescent lamps, they not only need to be compatible with thyristor dimmers, but also have certain requirements for their linear adjustment rate (that is, the rate of change of LED current with input voltage). [0003] Such as figure 1 Shown is the schematic diagram of the prior art linear LED drive circuit. The sampling resistor R00 samples the current flowing through the LED. The sampled value of the current is equal to VREF0, that is, the LED current is equal to VREF0 / R00. [0004] The above ...

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Problems solved by technology

[0005] In view of this, the purpose of the present invention is to provide a lighting drive circuit and lighting system that can improve the linear adjustment rate and prevent false shutdown caused by the load current being lower than the holding cu

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