This invention generally relates to electronic systems and in particular it relates to a switch mode regulator with a hybrid hysteretic controller.
The classical prior art voltage mode control for a switch mode regulator does not perform to tight output voltage tolerance requirements during load transients. The standard prior art hysteretic control for a switch mode regulator maintains a better regulation of voltage tolerance, but causes extreme switching frequencies.
A switch mode controller circuit includes: a hysteretic comparator for monitoring an output of a switch mode circuit; a standard comparator for monitoring a phase of the switch mode circuit; a logic block having a first input coupled to a clock signal generator, a second input coupled to an output of the hysteretic comparator, and a third input coupled to an output of the standard comparator, wherein the logic block generates switching cycles based on a fixed ON/OFF time during a first part of a cycle and based on a hysteretic control during a second part of the cycle.