Method for generating an internal compensation network of a pole and two zeros to compensate high frequency voltage mode switching regulators
AssigneeAdvanced Analogic Technologies, Inc.
InventorRobert Wrathall
Life of this patent
Estimating the term…
Abstract
A method for controlling a switching voltage regulator that includes generating a feedback voltage that is proportional to the output voltage of the voltage regulator; generating a voltage proportional to the duty-cycle of the inductor charging and discharging phases as a function of the difference between the feedback voltage and a reference voltage; and adding a dominate pole and two zeros to the function used to generate the voltage proportional to the duty-cycle of the inductor charging and discharging phases.
Claims20
A method for operating a switching regulator, the switching regulator including a high-side switch connected between an input voltage and a first node, a low-side switch connected between the first node and a ground, and an inductor connected between the first node and an output node, the method comprising:
- driving the high and low-side switches in a repeating sequence including activating the high-side switch to connect the first node to the input voltage in an inductor charging phase and activating the low-side switch to connect the first node to the ground in an inductor discharging phase;
- generating a feedback voltage proportional to an output voltage of the switching regulator;
- generating a voltage proportional to the duty-cycle of the inductor charging and discharging phases as a function of a difference between the feedback voltage and a reference voltage;
- and adding a dominate pole and two zeros to the function used to generate the voltage proportional to a duty-cycle of the inductor charging and discharging phases, by using a compensation network connected between a negative input and an output of an error amplifier but not being connected to the feedback voltage, the negative input of the error amplifier being connected to the reference voltage, the compensation network including
- a first capacitor and a first resistor connected in series between the negative input of the error amplifier and a second node,
- a second resistor connected between the second node and the output of the error amplifier, and
- a second capacitor connected between the second node and the ground.
A circuit for controlling a switching regulator, the switching regulator including a high-side switch connected between an input voltage and a first node, a low-side switch connected between the first node and a ground, and an inductor connected between the first node and an output node, the circuit comprising:
- a control circuit for driving the high and low-side switches in a repeating sequence that includes activating the high-side switch to connect to the first node to the input voltage in an inductor charging phase and activating the low-side switch to connect the first node to the ground in an inductor discharging phase;
- a resistor divider for generating a feedback voltage that is proportional to an output voltage of the switching regulator;
- an error amplifier for generating a voltage proportional to a duty-cycle of the inductor charging and discharging phases as a function of a difference between the feedback voltage and a reference voltage, a negative input of the error amplifier being connected to the reference voltage;
- and
- a compensation network for adding a dominate pole and two zeros to an output of the error amplifier, the compensation network being connected between the negative input and the output of the error amplifier but not being connected to the feedback voltage, the compensation network including
- a first capacitor and a first resistor connected in series between the negative input of the error amplifier and a second node,
- a second resistor connected between the second node and the output of the error amplifier, and
- a second capacitor connected between the second node and the ground.
A method for operating a switching regulator, the switching regulator including an inductor connected between an input voltage and a first node, a high-side switch connected between the first node and an output node, and a low-side switch connected between the first node and a ground, the method comprising:
- driving the high and low-side switches in a repeating sequence including activating the low-side switch to connect the first node to the ground in an inductor charging phase and activating the high-side switch to connect the first node to the output node in an inductor discharging phase;
- generating a feedback voltage that is proportional to an output voltage of the switching regulator;
- generating a voltage proportional to a duty-cycle of the inductor charging and discharging phases as a function of a difference between the feedback voltage and a reference voltage;
- and
- adding a dominate pole and two zeros to the function used to generate the voltage proportional to the duty-cycle of the inductor charging and discharging phases by using a compensation network connected between a negative input and an output of an error amplifier but not being connected to the feedback voltage, the negative input of the error amplifier being connected to the reference voltage, the compensation network including
- a first capacitor and a first resistor connected in series between the negative input of the error amplifier and a second node,
- a second resistor connected between the second node and the output of the error amplifier, and
- a second capacitor connected between the second node and the ground.
A circuit for controlling a switching regulator, the switching regulator including an inductor connected between an input voltage and a first node, a high-side switch connected between the first node and an output node, and a low-side switch connected between the first node and a ground, the circuit comprising:
- a control circuit for driving the high and low-side switches in a repeating sequence including activating the low-side switch to connect the first node to the ground in an inductor charging phase and activating the high-side switch to connect the first node to the output node in an inductor discharging phase;
- a resistor divider for generating a feedback voltage that is proportional to an output voltage of the switching regulator;
- an error amplifier for generating a voltage proportional to a duty-cycle of the inductor charging and discharging phases as a function of a difference between the feedback voltage and a reference voltage, a negative input of the error amplifier being connected to the reference voltage;
- and
- a compensation network for adding a dominate pole and two zeros to an output of the error amplifier, the compensation network being connected between the negative input and the output of the error amplifier but not being connected to the feedback voltage, the compensation network including
- a first capacitor and a first resistor connected in series between the negative input of the error amplifier and a second node,
- a second resistor connected between the second node and the output of the error amplifier, and
- a second capacitor connected between the second node and the ground.
Dependencies are inferred from the claim text.