Original question:
Hello,
The UCC256301 uses a form of constant current mode control. It is called hybrid hysteretic mode control. This makes for easier loop compensation easier.
Constant current control is generally when the converter is operating at it's peak no mater what the output voltage. This is most commonly used in battery chargers.
So when the converter is not operating at it's peak current limit this would be a form of constant voltage mode control.
When charging battery's from an LLC this is generally handled by a current regulator off of the LLC.
In low power applications of less than 250W to charge a battery you can use an active clamp flyback conveter (UCC28780) that was designed to operate in both in constant current and constant voltage. The following link will get you the UCC28780 product page where you can find the data sheet, design tools and reference design using the ACF in constant current/constant voltage. This device also achieves ZVS for high efficiency.
Regards,
