Richtek Technology Corporation

Richtek Technology Corporation, R.o.c

Ricktek Technology Corporation, R.o.c.

Ting-Jung Tai

Chih-Hao Yang

An-Tung Chen

Li-Wen Fang

A control circuit of a switching DC-DC power supply includes a feedback circuit detecting an output voltage of the power supply to generate a feedback signal, an error comparator detecting an error between the output voltage and a design value of the output voltage, a control logic circuit generating a control signal according to the error for regulating the output voltage, and an offset and delay cancellation circuit generating an offset adjust signal according to the feedback signal and a second reference voltage for adjusting an offset of the error comparator to pull the output voltage toward the design value.

Offset and delay cancellation circuit for a switching DC-DC power supply

A constant frequency ON-time control system applied to a voltage regulator is disclosed. The voltage regulator determines a time length of an input voltage inputted thereto according to an ON-time and thereby regulates an output voltage. The constant frequency ON-time control system includes a constant frequency ON-time control circuit for computing the ON-time according to a system duty cycle of the voltage regulator and a frequency setting parameter and a frequency setting parameter adjusting circuit for generating a frequency setting parameter adjust value according to an OFF-time corresponding to the ON-time and taking a result of operation between the frequency setting parameter adjust value and a preset frequency setting parameter as the frequency setting parameter. The frequency setting parameter adjusting circuit uses the frequency setting parameter adjust value to change the result of operation for varying the frequency setting parameter when the OFF-time is shorter than a reference value.

Constant frequency on-time control system and method and voltage regulator using the same

The present invention discloses a constant on-time switching regulator, a control method therefor, and an on-time calculation circuit for calculating an on-time period of a constant on-time switching regulator. The on-time calculation circuit calculates on-time according to practical conditions. It includes: a driver gate receiving a gate signal of a power switch in a switching regulator, the driver gate operating between high and low levels of a first reference voltage and ground; a low pass filter receiving an output from the driver gate and generating a second reference voltage, a ratio between the second reference voltage and the first reference voltage being substantially the same as a duty ratio of the gate signal; and an on-time generator comparing the second reference voltage with a ramp signal to determine an on-time of the power switch.

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Hsinchu, Taiwan

Ting-Jung Tai