Lighting drive circuit and lighting system

Abstract

The invention discloses a lighting drive circuit and a lighting system. The constant current control circuit of the invention has the function of instantaneous value current limiting, and can not only output current under a certain range of input voltage without a thyristor dimmer Both achieve the effect of constant current; in the case of a silicon controlled rectifier dimmer, when the conduction angle is greater than a certain value, the instantaneous value of the output current does not reach the current limit value, then it works in the output constant current state; in the conduction When the angle is less than a certain value, the instantaneous value of the output current reaches the current limit value, then the output current is limited, and the average value of the output current decreases, thereby realizing dimming. Therefore, the solution is compatible with the two situations of whether there is a thyristor dimmer or not, and the compatibility is high; by adding a bleeder circuit, it can prevent the thyristor from being turned off by mistake because the output current is lower than the maintenance current, so as to ensure the output of the system. The current is stabilized to prevent 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 current of the dimmer, so as to solve the problems existing in the prior art. The technical problems of being unable to meet the requirements of high linear adjustment rate and being difficult to be compatible with different types of thyristor dimmers

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