LED driving device, driving circuit and driving method thereof

Abstract

The invention discloses an LED driving device, a driving circuit and a driving method thereof. The LED driving circuit comprises a reference voltage output module, a control signal output module, a plurality of driving modules, and switching modules corresponding to the driving modules. The reference voltage output module outputs a corresponding reference voltage to the driving modules according to a dimming signal, and the driving modules drive corresponding lamp strings to be turned on or turned off in sequence according to a line voltage and the corresponding reference voltage. The controlsignal output module compares the dimming signal with a preset signal of each switching module and outputs a corresponding control signal to each switching module according to a comparison result so as to make each driving module switched on or switched off. The preset signals of all the switching modules are decreased progressively according to the conduction sequence of all the driving modules,and the preset signal of each switching module is larger than the offset voltage signal of the driving module connected with the switching module, so that the problem that part of the lamp strings areturned on and part of the lamp strings are not when the brightness is reduced is avoided.

Description

technical field [0001] The invention relates to the technical field of LEDs, in particular to an LED driving device, a driving circuit and a driving method thereof. Background technique [0002] see figure 1 , LED dimming is accomplished by changing the dimming signal to change the output of the reference voltage generating circuit, and then controlling the output of the operational amplifier to adjust the current flowing through the light string. In the multi-segment linear constant current dimming driving scheme, the reference voltage generation circuit generates and outputs multiple reference voltages according to the dimming signal, and then controls the output of the corresponding operational amplifier to adjust the current flowing through the corresponding light string. In the process of lowering the LED brightness, when the dimming signal is lowered enough to turn on the MOS tubes under all the light strings, because the offset voltage of each op amp is inconsistent,...

AI Technical Summary

Problems solved by technology

[0004] In view of the shortcomings of the prior art above, the object of the present invention is to provide an LED driving device, a driving circuit and a driving method thereof, which solve the problem that the MOS tubes connected in series with the light string cannot The predetermined sequence is turned off, which causes the problem that some light strings are lit and some light strings are not lit

Images