Abstract: An electronic apparatus is described. The apparatus includes a circuit element configured to output a signal comprising a modulated frequency component. The apparatus also includes a filter arrangement comprising first, second and third notch filter arrangements, wherein each of the first and second notch filter arrangements comprise a first series inductor, and a series shunt configuration comprising a second inductor and a capacitor coupled in series and the third notch filter arrangement comprises a series inductor and a shunt capacitor, wherein each of the notch filter arrangements are configured to generate a notch in a frequency response to attenuate the output signal at a frequency of the modulated frequency component.

Abstract: An error amplifier for a pulse width modulation circuit is described. The amplifier includes an operational amplifier configured as an integrator and a feedback loop coupled between a signal output of the operational amplifier and an inverting input of the operational amplifier. The feedback loop comprises a feedback capacitor coupled to the signal output, a feedback resistor coupled to the feedback capacitor, and an integrator resistor coupled to the feedback resistor and the inverting input of the operational amplifier. A junction between the feedback resistor and the integrator resistor is configured to receive an input signal and a junction between the feedback capacitor and the feedback resistor is configured to receive a feedback signal from the pulse width modulation circuit.

Abstract: An electronic apparatus is described. The apparatus includes a circuit element configured to output a signal comprising a modulated frequency component. The apparatus also includes a filter arrangement comprising first, second and third notch filter arrangements, wherein each of the first and second notch filter arrangements comprise a first series inductor, and a series shunt configuration comprising a second inductor and a capacitor coupled in series and the third notch filter arrangement comprises a series inductor and a shunt capacitor, wherein each of the notch filter arrangements are configured to generate a notch in a frequency response to attenuate the output signal at a frequency of the modulated frequency component.

Abstract: An error amplifier for a pulse width modulation circuit is described. The amplifier includes an operational amplifier configured as an integrator and a feedback loop coupled between a signal output of the operational amplifier and an inverting input of the operational amplifier. The feedback loop comprises a feedback capacitor coupled to the signal output, a feedback resistor coupled to the feedback capacitor, and an integrator resistor coupled to the feedback resistor and the inverting input of the operational amplifier. A junction between the feedback resistor and the integrator resistor is configured to receive an input signal and a junction between the feedback capacitor and the feedback resistor is configured to receive a feedback signal from the pulse width modulation circuit.