An EMI-Reduction design with Charge Pump Circuit and Hybrid Modulation
Technology for a Motor Driver Applications in 0.18um BiCMOS process
Abstract
An EMI-reduction charge pump circuit with hybrid modulation is proposed
for the motor driver circuits. Periodic modulation technique changes the
range of spread spectrum as coarse modulation. Random modulation
technique, as fine-tuning, changes its edge delay to slow the speed of
switch-edge. Simultaneously, the proposed buffer circuit can limit the
charge and discharge current of the charge pump and reduces the
variation of the current peak. Compared with the circuit without
modulation, EMI is reduced by up to 28dB. The proposed design fabricated
in a 0.18um BiCMOS process occupies an area of 0.173mm$^{2}$, and
its power consumption is 5.677mW.