Circuit for eliminating LCD backlight black frame insertion noises and wearable device

Abstract

The invention discloses a circuit for eliminating LCD backlight black frame insertion noises. The circuit comprises a first phase modulation module, and / or a second phase modulation module, wherein the first phase modulation module is disposed between a first backlight control module and a first backlight IC, and the second phase modulation module is arranged between a second backlight control module and a second backlight IC; the first phase modulation module modulates PWM signals outputted by the first backlight control module to the first backlight IC; the second phase modulation module modulates PWM signals outputted by the second backlight control module to the second backlight IC; and therefore, the phases of the PWM signals received by the first backlight IC and the second backlightIC are different, namely, the PWM signals received by the first backlight IC and the second backlight IC have phase difference. According to the prior art, sound generated by two output capacitors has the same phase and contains large noises, while, with the circuit provided by the technical schemes of the invention adopted, the sound generated by the two output capacitors can be partially offset, and therefore, noises are reduced, and user experience can be improved. The invention also discloses a head-mounted device. The noises of the head-mounted device can be decreased, and an audiovisualeffect can be improved.

Description

technical field [0001] The invention relates to the technical field of noise processing, in particular to a circuit and a wearable device for eliminating black noise from an LCD backlight. Background technique [0002] Black insertion technology is a display technology commonly used in LCDs. One method of black insertion technology is to turn off the backlight power supply for a certain period of time, so as to eliminate screen smear. figure 1 It is a schematic diagram of an LCD backlight black insertion control system in the prior art. When implementing the black insertion technology, the first backlight control module will output a PWM (Pulse Width Modulation, pulse width modulation) signal of a predetermined frequency to the first backlight IC U1, and the second backlight control module will output a PWM signal of the same predetermined frequency to the second backlight IC U2 to control the dimming pins of U1 and U2 (i.e. figure 1 The dimming control pin in the module) ...

AI Technical Summary

Problems solved by technology

In addition, since the PWM signals output by the first backlight control module and the second backlight control module are of the same frequency and phase, that is, the PWM signals received by U1 and U2 are of the same phase, resulting in the output capacitors C1 and C2 The sound is also in the same phase, superimposed in the same phase, further increasing the noise

When the black insertion technology is applied to wearable devices, this phenomenon will cause the user to hear the whistling sound of the wearable device, seriously affecting the audio-visual effect

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