| CPC H03K 5/1565 (2013.01) [H03K 5/00006 (2013.01); H03K 5/135 (2013.01)] | 9 Claims |
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1. A duty cycle calibration circuit, comprising:
a driving circuit unit for outputting a clock signal to be calibrated;
a voltage dividing unit connected to the driving circuit unit for voltage dividing based on a target duty cycle to obtain a reference voltage, wherein one end of the voltage dividing unit is connected to a power supply and the other end of the voltage dividing unit is connected to an output end of the driving circuit unit, and when obtaining the reference voltage, the voltage at the output end of the driving circuit unit is at low level;
a low-pass filter connected to the driving circuit unit for receiving the clock signal and performing low-pass filtering on the clock signal;
a voltage controlled oscillator connected to the voltage dividing unit and the low-pass filter for generating a reference frequency corresponding to the reference voltage and a clock signal frequency corresponding to the clock signal based on the reference voltage and the filtered clock signal;
a digital processing unit connected to the voltage controlled oscillator for comparing the clock signal frequency with the reference voltage frequency in digital domain and generating a duty cycle adjustment control signal based on comparison result; and
a duty cycle adjustment unit connected to the digital processing unit for receiving the duty cycle adjustment control signal and calibrating duty cycle of the clock signal based on the duty cycle adjustment control signal to obtain the target duty cycle.
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