Fecha de publicación: -- Fuente: Wipo "digitalization" A protection circuit includes: a first gain module, configured to receive a first input signal, scale the first input signal according to a first scaling factor, to obtain a first analog signal, receive a third scaling factor from a processing module, and scale the second input signal according to the third scaling factor, to obtain a second analog signal; an analog-to-digital converter, configured to convert the first analog signal into a first digital signal, and convert the second analog signal into a second digital signal; the processing module, configured to determine, according to a voltage value of the first digital signal and a preset scaling factor determining rule, the third scaling factor and a fourth scaling factor; and a second gain module, configured to scale the first digital signal according to a second scaling factor, and scale the second digital signal according to the fourth scaling factor.