Patent ID: 8970271
Filing Date: 2015-03-03
Classification: H04N

Abstract:
1. A signal coupling circuit, configured to generate an output signal according to an input signal, comprising: a coupling capacitor, configured to generate a coupling signal at an output terminal of the coupling capacitor according to the input signal that varies and is provided at an input terminal of the coupling capacitor; a clock generating circuit, configured to generate a clock, and to determine a duty cycle of the clock by the coupling capacitor; a discharge circuit, coupled to the coupling capacitor and the clock generating circuit, for intermittently discharging the coupling capacitor according to the duty cycle of the clock, the discharge circuit comprising: a switch, coupled to the coupling capacitor, switching between an on state and an off state according to the duty cycle of the clock; and a discharge unit, coupled to the switch, discharging the coupling capacitor when the switch switches to the on state and stopping discharging the coupling capacitor when the switch switches to the off state; and an output circuit, coupled to the coupling capacitor, for generating the output signal according to the coupling signal, wherein the clock generating circuit adjusts the duty cycle of the clock within a range according to a capacitance value of the coupling capacitor.