Adaptive constant on time adjustment circuit and method for adaptively adjusting constant on time
AssigneeRichteck Technology Corporation
InventorsYi-Cheng Wan, Hung-Chun Peng, Jian-Rong Huang, Kuo-Lung Tseng
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Abstract
The present invention discloses an adaptive constant ON time adjustment circuit, which generates a square wave signal having a constant normal ON time during normal operation, for controlling a power stage circuit to convert an input voltage to an output voltage. When the output voltage is shifted from low to high, during the transient period, the ON time is adjusted longer; and when the output voltage is shifted from high to low, during the transient period, the ON time is adjusted shorter.
Claims10
An adaptive constant ON time adjustment circuit for controlling a power stage circuit to convert an input voltage to an output voltage and to provide an output current to a load, the output voltage including at least a high voltage stable status and a low voltage stable status and being capable of shifting between the high and low voltage stable statuses, wherein a time period for shifting from one stable status to another stable status is a transient period, the adaptive constant ON time adjustment circuit comprising:
- a transient period detection circuit detecting a transient period indication signal and generating a transient ON time (transient TON) control signal;
- an ON time (TON) generation circuit generating a constant normal ON time and a longer or shorter transient ON time, the TON generation circuit determining an ON time of a square wave signal according to the transient TON control signal;
- and
- a driver circuit controlling the power stage according to the square wave signal,
- wherein when the transient period indication signal indicates that the power stage circuit is not in the transient period, the square wave signal generated by the TON generation circuit has the constant normal ON time;
- and
- wherein when the transient period indication signal indicates that the output voltage is shifted from high to low, during the transient period, the square wave signal generated by the TON generation circuit has the shorter transient ON time;
- and when the transient period indication signal indicates that the output voltage is shifted from low to high, during the transient period, the square wave signal generated by the TON generation circuit has the longer transient ON time.
An method for adaptively adjusting constant ON time to control a power stage circuit to convert an input voltage to an output voltage and to provide an output current to a load, the output voltage including at least a high voltage stable status and a low voltage stable status and being capable of shifting between the high and low voltage stable statuses, wherein a time period for shifting from one stable status to another stable status is a transient period, the method for adaptively adjusting constant ON time comprising:
- detecting a transient period indication signal and generating a transient ON time (transient TON) control signal accordingly;
- determining an ON time of a square wave signal according to the transient TON control signal, the square wave signal having a constant normal ON time and a longer or shorter transient ON time;
- and
- controlling the power stage according to the square wave signal,
- wherein when the transient period indication signal indicates that the power stage circuit is not in the transient period, the square wave signal generated by the TON generation circuit has the constant normal ON time;
- and
- wherein when the transient period indication signal indicates that the output voltage is shifted from high to low, during the transient period, the square wave signal generated by the TON generation circuit has the shorter transient ON time;
- and when the transient period indication signal indicates that the output voltage is shifted from low to high, during the transient period, the square wave signal generated by the TON generation circuit has the longer transient ON time.
Dependencies are inferred from the claim text.