COMPENSATION NETWORK FOR A REGULATOR CIRCUIT

摘要

A linear regulator includes a drive circuit having an input and an output, with the output configured to drive a control terminal of a power transistor for the delivery of a load current. An error amplifier functions to amplify a difference between a reference signal and a feedback signal to generate an error signal at the input of the drive circuit. A compensation circuit includes a series circuit formed by a compensation capacitor and a variable resistance circuit, where the series circuit is coupled to the input of the drive circuit. A current sensing circuit operates to sense the load current. The resistance of the variable resistance circuit is varied in response to the sensed load current.

主权项

1. A circuit, comprising:
a control circuit for a linear regulator comprising a drive circuit having an input and an output, said output configured to drive a control terminal of a power transistor for the delivery of a load current, said control circuit further comprising an error amplifier configured to amplify a difference between a reference signal and a feedback signal to generate an error signal at the input of the drive circuit; a load capacitor coupled to an output of the power transistor; and a compensation circuit comprising:
a series circuit formed by a compensation capacitor and a variable resistance circuit, said series circuit coupled to the input of the drive circuit; anda current sensing circuit configured to sense the load current and vary a resistance of the variable resistance circuit in response to the sensed load current, wherein the current sense circuit is further configured to generate a sense current that is a fraction of the load current, and wherein said fraction has a value that is set dependent on a ratio of a capacitance of the load capacitor to a capacitance of the compensation capacitor.