A class d amplifier chip with duty ratio limiting functions and the device thereof

A class D amplifier chip with duty ratio limiting functions, wherein, comprising:

• a triangle wave module, configured to generate triangle wave signals;
• a PWM modulation module, configured to convert the input differential audio signals and the triangle wave signals generated by the said triangle wave module into low voltage pulsed PWM signals, and drive the said PWM signals to generate high voltage pulses;
• a duty ratio detection module, configured to real-time detect the duty ratio of the PWM signals generated by the said PWM modulation module;
• a logic control module, configured to control the PWM modulation module stop working while deciding the duty ratio of the PWM signals is larger than the preset maximum value;
• the said duty ratio detection module comprises:
• a mirror current unit, configured to convert the input bias current into charging current and discharging current, to the charging-discharging control unit, following the preset ratio;
• a charging-discharging control unit, configured to output charging-discharging commands, according to the PWM signals generated by the said PWM modulation module, convert the charging and discharging currents output from the said minor current unit into the according capacitor voltages then send to the logic control module.