A battery charger circuit is intended to deliver a desired current into a battery and then maintain a fixed "float voltage" when full charge is reached. For a small car battery, a reasonable scenario would be to deliver 5 A to the battery until it reaches 13.8 V and then to maintain the converter output at 13.8 V indefinitely. Required:
a. What duty ratio will be needed to deliver 5 A of current when the battery is at low charge and has a terminal voltage of 11.5 V?
b. What duty ratio will be needed when the battery voltage reaches 13.8 V?