A control to change the pulse width control method according to the output-pulse frequency.
There are two methods to control the pulse width: fixed duty-ratio method and fixed pulse-width method.
There are advantages and disadvantages. When duty-ratio is fixed, there is no restriction at high speed, but the final pulse width can be long at low speed, therefore, the waiting time for OFF state becomes long.
When pulse width is fixed, the final pulse width can be shortened at low speed, so the waiting time can be shortened.
However, the higher the speed, the shorter the OFF state, so there is a limit. In the output-pulse width control, the method is switched automatically to the pulse-width fixed method when the speed is lower than the specified speed and to the duty-ratio fixed method when the speed is higher than one.