A type of data among road data, route search data and route guidance data or a type of background data is specified to be updated. The composition of the cullet, or portions thereof, can be certified for use by a party other than the beneficiator andor the MRF. The frequency of a PWM input clock signal is increased to N times of the original frequency of the PWM input clock signal by the frequency multiplier, so that the counting cycle of the PWM counter is shortened to 1N of the original counting cycle of the PWM counter.