Patent ID: 8866456
Filing Date: 2014-10-21
Classification: G05F

Abstract:
1. A linear power supply controller comprising: a series pass transistor coupled to receive an input voltage and to control an input current to regulate an output voltage to a desired value, the series pass transistor having a control electrode, a first current carrying electrode and a second current carrying electrode; a feedback node configured to form a feedback signal that is representative of the output voltage wherein the linear power supply controller is configured to regulate a voltage on the control electrode of the series pass transistor in response to the feedback signal; an enable input configured to receive an enable signal wherein the linear power supply controller is configured to inhibit enabling the series pass transistor in response to a negated state of the enable signal; a soft-start circuit configured to form a ramp signal that varies at a first rate responsively to an asserted state of the enable signal; an enable transistor coupled to the control electrode of the series pass transistor wherein the enable transistor is configured to vary a voltage on the control electrode of the series pass transistor responsively to the variation of the ramp signal and independently of a value of the feedback signal until a difference between the ramp signal and a deviation from the desired value of the output voltage reaches a threshold voltage of the enable transistor; and wherein the soft-start circuit configured to vary the ramp signal at a second rate responsively to a first value of the ramp signal.