Centro de Electrónica Industrial (CEI) | Universidad Politécnica de Madrid | [email protected] | www.cei.upm.es Buck derived converters operating in open loop can improve its dynamic response by using higher order output filters. The MIBuck with 4 th order Bessel filter is presented here. A multiphase MIBuck is also proposed. Experimental results are shown. Why 4 th order Bessel? Mission of the output filter in ET: Bessel filter has flat pass-band and flat group-delay. Reject the switching frequency . Keep waveform. The use of a higher order Bessel output filter can yield a significant improvement in the slew rate and bandwidth of the MIBuck converter. A multiphase configuration has been demonstrated to further improve the capabilities of this converter for ET applications. The former MIBuck presents a slew rate around 6 V/ s. By properly designing the filter means multiplying by 3 the slew rate and up to 4 times in the Multiphase MIBuck. CONCLUSIONS Enhancements of the Multiple Input Buck Converter for Envelope Tracking Applications P. Fernández Grupo de Sistemas Electrónica de Alimentación Switching frequency rejection (40 dB) Design Hints: Guarantee CCM Filter adapted to the Switching Network Impedance 4 th ORDER MIBuck 4th ORDER Multiphase MIBuck Multiphase operation introduces a notch at the switching frequency, so the cutt-off frequency of the filter can be increased with less switching noise f s = 4 MHz f cutt-off = 1 MHz f s = 4 MHz f cutt-off = 2 MHz Angular switching frequency for 40 dB Rejection Boundary angular switching frequency for MCC