An improved high speed low-power dynamic comparator was proposed, which was used in minimum energy point tracking (MEPT) system. By introducing an extra positive feedback to the latch comparator, the proposed dynamic comparator had advantages of fast transient response and low power consumption. Meantime, the on-chip area was almost unchanged. Based on a 65 nm CMOS process, simulation results showed that the transport delay of the proposed dynamic comparator was just 1.82 ns when the input difference voltage was 1 mV, which was an exciting improvement compared with 3.57 ns transport delay of the conventional structure.