Multiphase switching converter and control circuit thereof

A multiphase switching converter, comprising:

• a plurality of switching circuits coupled in parallel, wherein each switching circuit has an input coupled to an input voltage and an output coupled to a load to provide an output voltage;
• and
• a plurality of control circuits, configured in a daisy chain architecture, respectively coupled to the plurality of switching circuits, wherein each control circuit has a first terminal, a second terminal and a third terminal, the first terminal is coupled to the second terminal of a pre-stage control circuit to receive a preparatory input signal, the second terminal is coupled to the first terminal of a post-stage control circuit to provide a preparatory output signal, and the third terminal is coupled to a communication bus to receive a clock signal,
• wherein each control circuit is configured to operate in a preparatory state when receiving the preparatory input signal, and to generate the preparatory output signal and a switching control signal for controlling a corresponding switching circuit when receiving the clock signal in the preparatory state,
• wherein each control circuit comprises:
• a reset controller, configured to transmit a state feedback signal to a host controller through the communication bus, the host controller judging whether only one control circuit in a cyclic chain is in the preparatory state according to the state feedback signal,
• wherein the reset controller receives a reset signal from the host controller through the communication bus and executes circuit reset when one or more than one control circuit in the cyclic chain is in the preparatory state,
• a counter, configured to count pulses of the clock signal in the preparatory state, obtain a total phase number in the cyclic chain at a current time, and transmit the total phase number to the host controller through the communication bus,
• a phase-cutting controller, configured to receive a phase-cutting instruction from the host controller through the communication bus in the preparatory state, and determine whether to make the corresponding switching circuit stop outputting power or start to output power based on the phase-cutting instruction, and
• a detection and control module, configured to compare a current sampling signal of the corresponding switching circuit with a current threshold value to obtain a comparison result, judge whether an inductor current in the corresponding switching circuit is reversed according to the comparison result, and transmit an inductor current reverse indication signal to the host controller through the communication bus,
• wherein the detection and control module is further configured to receive a threshold setting signal from the host controller through the communication bus and set the current threshold value according to the threshold setting signal.