Drive circuit of keyboard lamp of mobile terminal

Abstract

The invention discloses a drive circuit of a keyboard lamp of a mobile terminal. The drive circuit comprises a keyboard lamp module, a battery, a voltage regulating module, a switch control module and a baseband chip, wherein the keyboard lamp module is used for supplying keyboard backlights; the battery is used for supplying power to the mobile terminal; the voltage regulating module is used for transforming a battery voltage into a constant voltage and outputting the voltage; the switch control module is used for controlling the open and closure of the voltage regulating module; the baseband chip is used for outputting high and low electric levels to correspondingly control the open and closure of the switch control module; the battery is connected with the voltage regulating module; the baseband chip is connected with the voltage regulating module by the switch control module; and the voltage regulating module is connected with the keyboard lamp module. According to the invention, the voltage regulating module is arranged at the front ends of the battery and the keyboard lamp module; and the voltage regulating module transforms the battery voltage into a constant voltage to drive a keyboard lamp, so that the drive voltage of the keyboard lamp is not changed along with the change of the battery voltage, thereby improving the consistency of the keyboard lamp and meeting user requirements.

Description

technical field [0001] The invention relates to the field of electronic products, in particular to a driving circuit for a keyboard light of a mobile terminal. Background technique [0002] see figure 1 , which is the circuit diagram of the keyboard light of the existing mobile phone. As shown in the figure, it includes two light-emitting diodes, two resistors and a MOS tube. The positive poles of the two light-emitting diodes are connected to the battery, and the negative poles are connected to the MOS tube through a resistor. The source of the MOS transistor, the gate of the MOS transistor is connected to the baseband chip, and the drain is grounded. In the keyboard light circuit, the battery directly drives two light-emitting diodes, and limits the current of the light-emitting diodes through a resistor, and the switch of the light-emitting diodes is controlled by a MOS tube. However, this circuit design will cause the current of the LED to change with the battery volta...

AI Technical Summary

Problems solved by technology

[0004] From the above analysis, it can be known that in the design of the keyboard light circuit of the existing mobile phone, the brightness of the keyboard light will change significantly with the change of the battery voltage, causing the keyboard light to fail to meet the needs of users under certain battery voltages.

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