Signal processing method and circuit and led dimming circuit with the circuit

Abstract

The invention relates to the field of electronics, and discloses a signal processing method, a circuit and an LED dimming circuit with the circuit. The method includes: sampling the first pulse width modulation signal according to the frequency of the first clock signal, obtaining sampling pulses, and counting the number of pulses of the second clock signal from zero until the current cumulative number of pulses is consistent with the number of high-level sampling pulses Until now, store the current cumulative number of pulses as the first pulse number, and output the first pulse signal; count the number of second clock signal pulses from zero until the current cumulative number of pulses is consistent with the number of low-level sampling pulses So far, the current accumulated pulse number is stored as the second pulse number, the second pulse signal is output, and the second pulse width modulation signal is generated according to the first pulse signal and the second pulse signal. The application of this technical solution is beneficial to increase the frequency of the PMW signal while keeping its duty cycle unchanged, and realize the miniaturization and integration of the circuit under the condition of low modulation frequency.

Description

technical field [0001] The invention relates to the field of electronics, in particular to a signal processing method and circuit and an LED dimming circuit with the circuit. Background technique [0002] In LED lighting applications, pulse width modulation (Pulse Width Modulation, PWM for short) signals are mostly used as dimming signals to adjust the luminance of LEDs. The dimming process of the LED by using the PWM signal is mainly to convert the information of the duty ratio in the PWM signal into a linear level signal, thereby simulating the linear output of the LED. [0003] The LED dimming circuit in the prior art is mainly implemented by a first-order RC filter circuit, and the cut-off frequency f of the filter circuit is c is: 1 / 2πRC, where the cut-off frequency f of the filter circuit is required c Less than the dimming frequency of the PWM signal, that is, the cut-off frequency f c The smaller the value, the larger the required parameter R*C should be. [0004...

AI Technical Summary

Problems solved by technology

[0006] In this case, it is difficult to integrate resistors and capacitors with large resistance and capacitance in the chip, especially when the capacitance of the capacitor is large, the capacitor cannot be integrated in the chip

Moreover, at this time, the response speed of the RC filter circuit is slow, and it often takes several cycles to respond to the information of the dimming signal, resulting in the inability to realize a miniaturized integrated circuit, and there is a problem of slow response speed of the circuit.

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