A sigma-delta DC-DC converter
A switching DC-DC converter is proposed that uses a Sigma-Delta Modulator (SDM) in place of the usual Pulse Width Modulator (PWM). One type of control method, voltage mode control used for switching regulators involves sensing the output voltage to servo the loop to regulate the output. Voltage mode control has inherently bad line response, which is the ability to filter out changes on the input so they don’t reach the output. The typical method to improve this response can put more noise on the output when a steady state ripple is present. The proposed architecture provides an advantage over a PWM based converter in that it does not put as many harmonics in the low frequency range when steady state ripple is present on the input.