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Abstract
| Voltage regulator modules are dc–dc converters that
power modern microprocessors. They must exhibit a fast dynamic
response, in order to achieve satisfactory regulation performance
in spite of the rapid load current variations. The pulsewidth modulator is one of the elements that determine the converter transient
response. This letter introduces a dual-edge modulator that outperforms conventional modulation schemes in terms of both small- and
large-signal dynamic performances: first, its small-signal transfer
function exhibits a phase boost action in the high-frequency range,
enabling the design of robust, wide-bandwidth control loops. Furthermore, it introduces a reduced expected delay in response to a
large-signal perturbation. The modulator transfer function is derived in this letter using the describing function approach, and it
is validated by comparing its predictions to SIMPLIS simulations
and to the measured loop transfer function of a synchronous buck
converter, designed in a 130 nm CMOS technology. |