VOLT-SECOND INTEGRATION CABLE COMPENSATION CIRCUIT

摘要

A power converter (such as a battery charger) includes a cable configured to deliver a source voltage and current to a load, where the cable is anticipated to drop some voltage as the load current increases. The power converter also includes a regulator having a feedback-adjusting transistor configured to gradually compensate for the dropped cable voltage as the load current increases. The transistor has a gate capacitance and a resistance forming an integrator configured to filter a volt-second product of an output waveshape of the converter to derive an average voltage correlated to the load current as the load current increases. The regulator is configured to increase a gate voltage of the transistor through a threshold region of the transistor and gradually turn the transistor on. The transistor is configured to apply an adjusting resistance coupled to a feedback sensing node of the regulator to increase the source voltage to compensate for the cable voltage drop and improve the load voltage regulation.

主权项

1. For use in a converter configured to provide a source voltage to a cable extending between the source voltage and a load where the cable drops a cable voltage as a load current to the load increases, a method comprising:
providing an output waveshape to a regulator having a feedback adjusting transistor configured to gradually compensate for the dropped cable voltage as the load current increases; and using a gate capacitance of the transistor and a resistance as an integrator to filter a volt-second product of an output waveshape of the converter to derive an average voltage correlated to the load current as the load current increases; wherein the transistor is a signal-level MOSFET and a gate voltage of the transistor increases through a threshold region of the transistor and gradually turns the transistor on, the transistor applying an adjusting resistance coupled to a feedback sensing node of the regulator to increase the source voltage.