Switching power converter circuit and control method thereof

Abstract

A switching power converter circuit includes a power stage circuit for converting an input voltage into an output voltage according to a control signal; a control circuit that receives a first ramp signal and a reference voltage at a first input terminal, and receives a second ramp signal and the output voltage at a second input terminal, for comparing the signal at the first input terminal with the signal at the second input terminal to generate the control signal, thereby controlling the power stage circuit; and a dual ramp signal generation circuit for generating the first ramp signal according to a first voltage and a working cycle of the control signal, and for generating the second ramp signal according to a second voltage and the working cycle of the control signal; wherein the first voltage and the second voltage are selected from the input voltage and the output voltage.

Claims

1. A switching power converter circuit, comprising: an input terminal for receiving an input voltage; an output terminal for outputting an output voltage; a power stage circuit coupled to the input terminal and the output terminal for converting the input voltage into the output voltage according to a control signal; a control circuit coupled to the power stage circuit, receiving a first ramp signal and a reference voltage at a first input terminal, and receiving a second ramp signal and the output voltage at a second input terminal, for comparing the signal at the first input terminal with the signal at the second input terminal to generate the control signal, thereby controlling the power stage circuit; and a dual ramp signal generation circuit coupled to the first input terminal and the second input terminal for generating the first ramp signal according to a first voltage and a working cycle of the control signal, and for generating the second ramp signal according to a second voltage and the working cycle of the control signal; wherein... The first voltage is selected from the input voltage and the output voltage, and the second voltage is the other of the input voltage and the output voltage that is not selected as the first voltage.

2. The switching power converter circuit as described in claim 1, wherein the dual-ramp signal generation circuit includes a first ramp signal generation circuit and a second ramp signal generation circuit; wherein, The first ramp signal generating circuit includes: a first current generating circuit for generating a first current based on the first voltage; a first switch coupled between the first current generating circuit and the first input terminal of the control circuit, for switching the connection between the first current generating circuit and the first input terminal of the control circuit according to the operating cycle of the control signal; and a first capacitor coupled between a node and the first input terminal of the control circuit; wherein, the second ramp signal generating circuit includes: a second current generating circuit for generating a second current based on the second voltage; a second switch coupled between the second current generating circuit and the second input terminal of the control circuit, for switching the connection between the second current generating circuit and the second input terminal of the control circuit according to the operating cycle of the control signal; and a second capacitor coupled between the node and the second input terminal of the control circuit; The first current generating circuit is composed of one of a current source and a resistor, and the second current generating circuit is composed of the other of the current source and the resistor that is not selected to generate the first current; wherein the node is coupled to one of the output voltage, the reference voltage, or a ground voltage.

3. The switching power converter circuit as claimed in claim 2, wherein the current source is an active current source that converts the first voltage into the first current or the second voltage into the second current according to a coefficient, and a resistance value of the resistor is related to the coefficient.

4. The switching power converter circuit as claimed in claim 2, wherein when the first voltage is the output voltage, the first current generating circuit generates the first current based on a weighted result of the first voltage; and when the second voltage is the output voltage, the second current generating circuit generates the second current based on a weighted result of the second voltage.

5. The switching power converter circuit as described in claim 2, wherein the node is coupled to the output voltage to respond to changes in the output voltage to the control circuit in order to improve the load transient response speed.

6. The switching power converter circuit as described in claim 1, wherein the dual ramp signal generation circuit further includes a level adjustment module, the level adjustment module including: an error amplifier coupled to the output terminal, the reference voltage and the second input terminal of the control circuit, for comparing the output voltage with the reference voltage to generate an error signal, and outputting the error signal to the second input terminal of the control circuit to adjust the level of the second ramp signal.

7. The switching power converter circuit as described in claim 1, wherein the dual-ramp signal generation circuit further includes a level adjustment module, the level adjustment module including: an error amplifier coupled to the output terminal and the reference voltage, for comparing the output voltage with the reference voltage to generate an error signal; and an active current source coupled to the error amplifier and the second input terminal of the control circuit, for generating an error current based on the error signal and outputting the error signal to the second input terminal of the control circuit to adjust a level of the second ramp signal.

8. The switching power converter circuit as claimed in claim 1, wherein the combination of the signal at the first input terminal and the signal at the second input terminal is related to a weighted result of the output voltage and the combination of the input voltage.

9. The switching power converter circuit as claimed in claim 1, further comprising: a first resistor coupled between the reference voltage and the first input terminal of the control circuit for transmitting the reference voltage to the first input terminal; and a second resistor coupled between the output terminal and the second input terminal of the control circuit for transmitting the output voltage to the second input terminal.

10. A control method for a switching power converter, comprising: receiving an input voltage; converting the input voltage into an output voltage through a power stage circuit according to a control signal; generating a first ramp signal according to a first voltage and a duty cycle of the control signal; generating a second ramp signal according to a second voltage and the duty cycle of the control signal; and receiving the first ramp signal and a reference voltage at a first input terminal of a control circuit, and receiving the second ramp signal and the output voltage at a second input terminal of the control circuit, to compare the signal at the first input terminal with the signal at the second input terminal, thereby generating the control signal; wherein, The first voltage is selected from the input voltage and the output voltage, and the second voltage is the other of the input voltage and the output voltage that is not selected as the first voltage.

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