Accurate UMTS power transition with power alignment loop between two different modulation modes for polar transmitter

Generally low power region is very dominant for current consumption on UMTS handsets. However, a polar modulation architecture has a little bit lager current consumption in this region. So, we propose polar/quadrature modulation architecture with a fast-feedback power control technique “power alignment loop (PAL)”. The PAL can realize accurate UMTS power transition over the two different modulation modes. Measurement results shows that the power accuracy between the two modes can satisfy the 3GPP standard within 25 µs from the slot boundary. The average current consumption of the transmitter is 128 mA at the battery.