Buck-Store and Boost-Restore Converter

A system, comprising:

• a first converter for receiving a pre-stage input DC voltage from a power source, and providing a pre-stage output DC voltage which includes a first DC voltage or a second DC voltage;
• a modulator, coupled to the first converter, the modulator controlling the first converter;
• a second converter, coupled to the first converter;
• and
• a controller, coupled to the second converter, the controller controlling an operation mode of the second converter and notifying the modulator about the operation mode of the second converter,
• wherein:
• the modulator and the controller receive an external voltage indication signal indicating whether the pre-stage output DC voltage is the first DC voltage or the second DC voltage;
• the modulator controls the first converter to output the pre-stage output DC voltage based on the voltage indication signal;
• and
• the modulator notifies the controller about whether the pre-stage output DC voltage reaches a target level.