Voltage converting controller, voltage converting circuit, and control method for voltage converting

A switching voltage converting circuit, used to convert an input voltage into a regulated secondary-side output voltage, wherein, the switching voltage converting circuit comprises:

• a primary coil, coupled to an input terminal and receiving the input voltage;
• a secondary coil, coupled to a secondary-side output terminal and outputting the secondary-side output voltage, wherein an output current is provided on the secondary-side output terminal;
• a switch, coupled to the primary coil;
• wherein when the switch is turned on, a current is generated on the primary coil, and when the switch is turned off, no current is generated on the primary coil;
• and
• a voltage converting controller, generating a control signal, wherein the control signal has a variable control frequency to separately and periodically control the switch to be turned on or off by using a first state and a second state;
• wherein, when the output current increases from a first current value to a second current value, the voltage converting controller starts a transient reaction period and sets the control frequency to a maximum frequency value;
• and when the transient reaction period ends, the voltage converting controller sets the control frequency to a target control frequency corresponding to the second current value.

A control method for voltage converting, applied to a switching voltage converting circuit, wherein the switching voltage converting circuit converts an input voltage into a regulated secondary-side output voltage, and a voltage converting controller generates a control signal, and the control signal has a variable control frequency to separately and periodically control a switch to be turned on or off by using a first state and a second state, and the control method comprises the following steps:

• detecting an output current of the switching voltage converting circuit;
• when the output current of the switching voltage converting circuit increases from a first current value to a second current value, the voltage converting controller starts a transient reaction period, and setting the control frequency to a maximum frequency value;
• and
• when the transient reaction period ends, setting the control frequency to an output control frequency corresponding to the second current value.