Abstract: A constant time buck-boost switching converter includes: a power switch circuit for switching a first terminal of an inductor between an input voltage and a ground, and for switching a second terminal of the inductor between an output voltage and the ground; and a modulation control circuit for generating a buck ramp signal and a boost ramp signal and for controlling the inductor according to comparisons of these two ramp signals with an error amplification signal, so as to convert the input voltage to the output voltage. The average levels of the buck ramp signal and the boost ramp signal are both equal to a product of the output voltage multiplied by a predetermined ratio. The upper limit of the buck ramp signal and the lower limit of the boost ramp signal are both equal to a product of the input voltage multiplied by the predetermined ratio.

Abstract: A multi-loop error amplifier circuit for generating an error amplification signal includes: a first operational transconductance amplifier (OTA) including a first current output stage which generates a first transconductance amplification current in a predetermined current direction according to a first voltage difference between a positive terminal and a negative input terminal of the first OTA; a second OTA including a second current output stage which generates a second transconductance amplification current in the predetermined current direction according to a second voltage difference between a positive terminal and a negative input terminal of the second OTA. The first and the second current output stages are coupled in series to generate a first error output current. The error amplification signal is generated according to the first error output current which is equal to the smaller one of the first and the second transconductance amplification currents.

Abstract: A multi-loop error amplifier circuit for generating an error amplification signal includes: a first operational transconductance amplifier (OTA) including a first current output stage which generates a first transconductance amplification current in a predetermined current direction according to a first voltage difference between a positive terminal and a negative input terminal of the first OTA; a second OTA including a second current output stage which generates a second transconductance amplification current in the predetermined current direction according to a second voltage difference between a positive terminal and a negative input terminal of the second OTA. The first and the second current output stages are coupled in series to generate a first error output current. The error amplification signal is generated according to the first error output current which is equal to the smaller one of the first and the second transconductance amplification currents.

Abstract: A constant time buck-boost switching converter includes: a power switch circuit for switching a first terminal of an inductor between an input voltage and a ground, and for switching a second terminal of the inductor between an output voltage and the ground; and a modulation control circuit for generating a buck ramp signal and a boost ramp signal and for controlling the inductor according to comparisons of these two ramp signals with an error amplification signal, so as to convert the input voltage to the output voltage. The average levels of the buck ramp signal and the boost ramp signal are both equal to a product of the output voltage multiplied by a predetermined ratio. The upper limit of the buck ramp signal and the lower limit of the boost ramp signal are both equal to a product of the input voltage multiplied by the predetermined ratio.