Load transient detection circuit and method

A method of operating a Universal Serial Bus (USB)-Power Delivery (PD) integrated circuit (IC) controller, the method comprising:

• controlling, via a driver circuit of the USB-PD IC controller, operation of a buck-boost converter electrically coupled to a USB voltage bus power line;
• controlling the driver circuit in a first mode, wherein changes in duty cycle are limited to a predetermined number of cycles in the first mode;
• generating a sense signal proportional to current flowing in the USB voltage bus power line;
• detecting, via an analog detection circuit, whether a slew rate of the sense signal exceeds a reference slew rate;
• and
• overriding the limit placed on the changes in duty cycle in the first mode responsive to the analog detection circuit indicating that the slew rate of the sense signal exceeds the reference slew rate.

A Universal Serial Bus (USB)-Power Delivery (PD) device, comprising:

• a buck-boost converter electrically coupled to a USB voltage bus power line;
• and
• a USB-PD integrated circuit (IC) controller coupled to control operation of the buck-boost converter, the USB-PD IC controller comprising:
• a gate driver controller configured to control the buck-boost converter in a first mode, wherein changes in duty cycle are limited to a predetermined number of cycles in the first mode;
• a sense circuit configured to generate a sense signal proportional to current flowing in the USB voltage bus power line;
• and
• an analog detection circuit configured to detect whether a slew rate of the sense signal exceeds a reference slew rate,
• wherein the gate driver controller is configured to override the limit placed on the changes in duty cycle in the first mode responsive to the analog detection circuit indicating that the slew rate of the sense signal exceeds the reference slew rate.