Fecha de publicación: 15/02/2023 Fuente: Wipo "digitalization" Disclosed are a digital output circuit, a digital output device and a digital output system. The digital output circuit includes: a digital output functional circuit; and a digital output leakage current detection circuit electrically connected to the digital output functional circuit. The digital output functional circuit is configured to turn on electrical connection between an input power supply and an upper computer to provide digital signal for the upper computer, and the digital output leakage current detection circuit is configured to perform leakage current detection on the digital signal, to control a switching state of the input power supply based on the leakage current detection result. The leakage current is detected on the digital signal of the digital output functional circuit through the digital output leakage current detection circuit, which improves the functional safety of the digital output.