Pulse width signal duty ratio detection circuit

Abstract

The invention discloses a pulse width signal duty ratio detection circuit, which comprises a slope generating circuit, a pulse generating circuit and a sampling hold circuit, wherein the slope generating circuit generates a constant slope signal; the pulse generating circuit outputs a pulse signal by monitoring a detected pulse width signal; the sampling hold circuit samples the slope signal under the control of the pulse signal, and holds the voltage value of the slope signal at each falling edge moment of the detected pulse width signal as an output signal of the sampling hold circuit; the held voltage value and the duty ratio of the detected pulse width signal have a direct functional relationship; and the magnitude of the held voltage value reflects the magnitude of the duty ratio of the pulse width signal, and the held voltage value has the function of reflecting the magnitude of the duty ratio of the pulse width signal in real time. The detection circuit can detect the magnitude of the duty ratio of the pulse width signal cycle by cycle so that the reliability of the pulse width signal duty ratio detection circuit is improved; and meanwhile, because the detection circuit does not need high resistance or capacitance, the integration degree of the circuit is greatly improved.

Description

technical field [0001] The invention relates to a duty ratio (Duty Ratio) detection technology, in particular to a pulse width signal duty ratio detection circuit. Background technique [0002] The traditional pulse width signal duty cycle detection circuit such as Figure 7 As shown, it includes a resistor 71 and a capacitor 72. The resistor 71 and capacitor 72 form an RC integrator. One end of the resistor 71 is connected to the measured pulse width signal, and the other end of the resistor 71 is connected to one end of the capacitor 72. The other end of the capacitor 72 is grounded, and the common connection end of the resistor 71 and the capacitor 72 is the output end of the detection circuit. Figure 7 The basic working principle of the traditional pulse width signal duty ratio detection circuit shown is to use the RC integrator to directly integrate the measured pulse width signal, and its steady-state output is a voltage signal similar to a triangular wave, such as F...

AI Technical Summary

Problems solved by technology

However, in practical applications, the triangular wave voltage signal is often required to have very small ripples. According to the basic working principle of the traditional pulse width signal duty cycle detection circuit, a large resistor 71 and a capacitor 72 are required to meet the actual requirements.

However, the large resistor 71 and the large capacitor 72 not only occupy a large area and reduce the integration level of the integrated circuit, but also the zero-state response of this RC integrator takes a long time to stabilize

Therefore, when the duty ratio of the pulse width signal changes, the traditional pulse width signal duty ratio detection circuit cannot monitor the duty ratio of the pulse width signal in real time.

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