Controllers and related control methods for generating signals representing an output current to a load in a switched mode power supply

摘要

Controllers and related control methods for a switched mode power supply are disclosed. The switched mode power supply has an inductive device and a power switch connected in series. An output current estimator in a controller is configured for receiving a current-sense signal representing an inductor current flowing through the inductive device and a discharge-time signal indicating a discharge time of the inductive device. The output current estimator generates a charge current in response to the discharge-time signal and the current-sense signal, thereby the charge current substantially corresponding to an output current that the switched mode power supply outputs to a load. The charge current is limited not to exceed a maximum value. A current limiter is configured for limiting the current-sense signal when the charge current is the maximum value.

主权项

1. A controller for a switched mode power supply with an inductive device and a power switch connected in series, the controller comprising:
an output current estimator, configured for receiving a current-sense signal representing an inductor current flowing through the inductive device and a discharge-time signal indicating a discharge time of the inductive device, and for generating a charge current in response to the discharge-time signal and the current-sense signal, thereby the charge current substantially corresponding to an output current that the switched mode power supply outputs to a load, wherein the charge current is limited not to exceed a maximum value; and a current limiter, configured for limiting the current-sense signal when the charge current is the maximum value; wherein the inductive device includes an auxiliary winding, the switched mode power supply has a resistor connected to the auxiliary winding, and the controller further comprises a load compensator configured for draining an offset current from the resistor in response to the charge current.