Electronic monitoring circuit for detecting a variation in the power or current absorbed by an electronic circuit under test, the circuit comprising: - an input terminal adapted to receive a pulse-width modulation control signal (S_pwm_ctrl), wherein said control signal is adapted to control the opening and closing of at least one power switch of a switch mode power supply of the electronic circuit under test; - a resistor having a first terminal connected to the input terminal; - a capacitor having a first terminal connected to a second terminal of the resistor and having a second terminal connected to a low reference voltage; - an output terminal adapted to generate an output signal (S_ΔT) as a function of the value of the voltage drop at the ends of the capacitor, said output signal (S_ΔT) being representative of a variation (ΔT+, ΔT-) in the pulse width of the pulse-width modulation control signal (S_pwm_ctrl), wherein said variation in the pulse width is a function of the power or current absorbed by the electronic circuit under test, characterized in the electronic monitoring circuit comprising: - a further resistor having a first terminal connected to the input terminal; - a further capacitor having a first terminal connected to a second terminal of the further resistor and having a second terminal connected to the low reference voltage; wherein: - the output terminal of the electronic monitoring circuit is adapted to generate the output signal (S_ΔT) as a function of the difference between the value of the voltage drop at the ends of the capacitor and the value of the voltage drop at the ends of the further capacitor; and wherein, alternatively: - the resistance value is equal for said resistor and said further resistor and the capacitance value differs between said capacitor and said further capacitor; - the resistance value differs between said resistor and said further resistor and the capacitance value is equal for said capacitor and said further capacitor. - an input terminal adapted to receive a pulse-width modulation control signal (S_pwm_ctrl), wherein said control signal is adapted to control the opening and closing of at least one power switch of a switch mode power supply of the electronic circuit under test; - a resistor having a first terminal connected to the input terminal; - a capacitor having a first terminal connected to a second terminal of the resistor and having a second terminal connected to a low reference voltage; - an output terminal adapted to generate an output signal (S_ΔT) as a function of the value of the voltage drop at the ends of the capacitor, said output signal (S_ΔT) being representative of a variation (ΔT+, ΔT-) in the pulse width of the pulse-width modulation control signal (S_pwm_ctrl), wherein said variation in the pulse width is a function of the power or current absorbed by the electronic circuit under test, characterized in the electronic monitoring circuit comprising: - a further resistor having a first terminal connected to the input terminal; - a further capacitor having a first terminal connected to a second terminal of the further resistor and having a second terminal connected to the low reference voltage; wherein: - the output terminal of the electronic monitoring circuit is adapted to generate the output signal (S_ΔT) as a function of the difference between the value of the voltage drop at the ends of the capacitor and the value of the voltage drop at the ends of the further capacitor; and wherein, alternatively: - the resistance value is equal for said resistor and said further resistor and the capacitance value differs between said capacitor and said further capacitor; - the resistance value differs between said resistor and said further resistor and the capacitance value is equal for said capacitor and said further capacitor. the electronic monitoring circuit comprising: - a further resistor having a first terminal connected to the input terminal; - a further capacitor having a first terminal connected to a second terminal of the further resistor and having a second terminal connected to the low reference voltage; - a further resistor having a first terminal connected to the input terminal; - a further capacitor having a first terminal connected to a second terminal of the further resistor and having a second terminal connected to the low reference voltage; wherein: - the output terminal of the electronic monitoring circuit is adapted to generate the output signal (S_ΔT) as a function of the difference between the value of the voltage drop at the ends of the capacitor and the value of the voltage drop at the ends of the further capacitor; - the output terminal of the electronic monitoring circuit is adapted to generate the output signal (S_ΔT) as a function of the difference between the value of the voltage drop at the ends of the capacitor and the value of the voltage drop at the ends of the further capacitor; and wherein, alternatively: - the resistance value is equal for said resistor and said further resistor and the capacitance value differs between said capacitor and said further capacitor; - the resistance value differs between said resistor and said further resistor and the capacitance value is equal for said capacitor and said further capacitor. - the resistance value is equal for said resistor and said further resistor and the capacitance value differs between said capacitor and said further capacitor; - the resistance value differs between said resistor and said further resistor and the capacitance value is equal for said capacitor and said further capacitor.