Constant on-time (cot) control in isolated converter

A constant on-time (COT) isolated converter, connected to an input terminal for receiving an input voltage, the constant on-time isolated converter comprises:

• a transformer comprising a primary side and a secondary side, wherein the primary side is connected to an input terminal and the secondary side is connected to a load, wherein a ripple signal on the secondary side generates an output voltage and an output current on the load;
• a processor connected to the secondary side of the transformer and the load, wherein the processor captures an AC voltage of an AC component of the ripple signal and the output current, the processor converts the output current to a process voltage and generates a control signal based on a preset reference voltage, the AC voltage and the process voltage;
• at least one coupling element connected to the processor, wherein the coupling element connects to the primary side and the secondary side of the transformer respectively to transmit the control signal from the secondary side to the primary side;
• a driver connected to the primary side of the transformer and the coupling element, wherein the driver receives and amplifies the control signal to generate a digital signal;
• and
• an electronic switch connected to the primary side and the driver, wherein the electronic switch receives the digital signal and accordingly changes its ON/OFF state to control the input voltage transmitted to the transformer from the input terminal, thereby regulating the output voltage and the output current.