Patent ID: 9496781
Filing Date: 2016-11-15
CPC Classification: H02M,Y02B

Claim Text:
1. A soft start circuit for a switching converter, the soft start circuit comprising: an internal soft start voltage generating circuit having an output terminal configured to provide an internal soft start voltage; an amplifier circuit having a first input terminal, a second input terminal and an output terminal, wherein the first input terminal is coupled to the output terminal of the internal soft start voltage generating circuit to receive the internal soft start voltage, and the second input terminal is configured to receive a soft start reference signal or a feedback signal indicative of the soft start reference signal; and a buffer circuit having an input terminal and an output terminal, wherein the input terminal is coupled to the output terminal of the amplifier circuit, and the output terminal is configured to provide the soft start reference signal; wherein when the output terminal of the amplifier circuit is coupled to an external soft start capacitor, the external soft start capacitor is charged by the amplifier circuit to provide an external soft start voltage, and the soft start circuit is configured to provide the soft start reference signal based on the internal soft start voltage and the external soft start voltage.