Inductor current emulation circuit for multi-level switching conversion circuit and emulation control method thereof

Abstract

An inductor current simulation circuit is disclosed to simulate the inductor current of a multi-stage switching converter circuit. The multi-stage switching converter circuit periodically switches a capacitor and an inductor between multiple electrical connection states based on complex switching signals, thereby performing power conversion between a first and a second voltage. The inductor current simulation circuit includes: a selection circuit that selects multiple candidate voltages based on the complex state signals to generate a first simulation signal; and a filtering circuit that generates a second simulation signal based on the difference between the first simulation signal and a bias voltage value to simulate the inductor current. The multiple state signals are related to the multiple switching signals, each of the multiple state signals corresponding to each of the multiple electrical connection states. The multiple candidate voltages are related to a linear superposition of the first voltage, the second voltage, ground potential, and combinations thereof.

Claims

1. An inductor current simulation circuit for simulating an inductor current in a multi-stage switching converter circuit, wherein the multi-stage switching converter circuit periodically switches a capacitor and an inductor between multiple electrical connection states based on a duty cycle according to a complex switching signal, thereby performing a power conversion between a first voltage and a second voltage; the inductor current simulation circuit includes: a selection circuit for selecting a complex number of candidate voltages according to a complex state signal to generate a first simulation signal; and a filter circuit for generating a second simulation signal based on the difference between the first simulation signal and a bias voltage value to simulate the inductor current; wherein the difference between the first simulation signal and the bias voltage value is positively correlated with an inductor voltage corresponding to the multiple electrical connection states of the inductor; The complex state signal is related to the complex switching signal, each of the complex state signals corresponds to each of the complex electrical connection states, and the complex candidate voltage is related to the linear superposition of the first voltage, the second voltage, a ground potential, and combinations thereof.

2. The inductor current simulation circuit as described in claim 1, wherein the bias voltage value is positively correlated with an average voltage value of the second simulation signal.

3. The inductor current simulation circuit as described in claim 2, wherein the average voltage value of the second simulation signal is positively correlated with the second voltage.

4. The inductor current simulation circuit as described in claim 1, wherein the complex state signals include a first state signal, a second state signal, a third state signal, a fourth state signal, and a fifth state signal, which respectively correspond to the following states: (1) when the first state signal is enabled, the first simulation signal is positively correlated with the first voltage; (2) when the second state signal is enabled, the first simulation signal is positively correlated with the difference between the first voltage and the second voltage; (3) when the third state signal is enabled, the first simulation signal is positively correlated with the difference between the first voltage and half of the second voltage; (4) when the fourth state signal is enabled, the first simulation signal is positively correlated with the difference between the first voltage and half of the second voltage; or (5) when the fifth state signal is enabled, the first simulation signal is positively correlated with the ground potential.

5. The inductor current simulation circuit as described in claim 4, wherein the multiple electrical connection states of the capacitor and the inductor correspond to the following: (1) When the first state signal is enabled, the inductor is electrically connected between the first voltage and the ground potential, and the upper end and lower end of the capacitor are respectively floating and electrically connected to the ground potential; (2) When the second state signal is enabled, the inductor is electrically connected between the first voltage and the second voltage, and the upper end and lower end of the capacitor are respectively electrically connected to the second voltage and floating; (3) When the third state signal is enabled, the inductor and the capacitor are connected in series between the first voltage and the ground potential; (4) When the fourth state signal is enabled, the inductor and the capacitor are connected in series between the first voltage and the second voltage; or (5) When the fifth state signal is enabled, the inductor is connected between the first voltage and floating, and the capacitor is floating.

6. The inductor current simulation circuit as claimed in claim 2, wherein the complex state signals include a first state signal, a second state signal, a third state signal, and a fourth state signal; wherein the first simulation signal has a first simulation voltage value during the uniformity period of the first state signal, a second simulation voltage value during the uniformity period of the second state signal, and a third simulation voltage value during the uniformity period of the third state signal or the fourth state signal, wherein the average voltage value of the second simulation signal is determined according to one of the following: when the duty cycle is greater than half, the average voltage value is determined according to the first simulation voltage value, the third simulation voltage value, and the corresponding duty cycle; or when the duty cycle is less than half, the average voltage value is determined according to the second simulation voltage value, the third simulation voltage value, and the corresponding duty cycle.

7. The inductor current simulation circuit as described in either claim 1 or claim 3, wherein the filter circuit comprises: A voltage-to-current conversion circuit is used to generate a filtered current based on the difference between an average voltage value of the first analog signal and the second analog signal, thereby simulating the inductor voltage; and an integrating capacitor is used to generate the second analog signal based on the integration of the filtered current, thereby simulating the inductor current.

8. The inductor current simulation circuit as described in claim 7, wherein the voltage-to-current conversion circuit includes a filter resistor for generating the filter current, wherein one end of the filter resistor receives the first simulation signal to generate the second simulation signal at the other end of the filter resistor, wherein the other end of the filter resistor is coupled to the integrating capacitor.

9. The inductor current simulation circuit as described in claim 4, wherein the selection circuit includes a plurality of selection switches, the plurality of selection switches including a first group of selection switches, a second group of selection switches and a third group of selection switches, wherein the plurality of candidate voltages includes a first candidate voltage, a second candidate voltage, a third candidate voltage, a fourth candidate voltage and a fifth candidate voltage; wherein the plurality of selection switches operate as follows: the first group of selection switches selects the first candidate voltage when the second state signal is enabled, and selects the second candidate voltage when the first state signal, the third state signal or the fourth state signal is enabled, to generate a first sub-simulation signal; The second set of selector switches selects the third candidate voltage when the first state signal is enabled, and selects the fourth candidate voltage when the second state signal, the third state signal, or the fourth state signal is enabled, to generate a second sub-analog signal; and the third set of selector switches selects the fifth candidate voltage when the fifth state signal is enabled, based on the complex state signals; wherein the first analog signal is generated based on the voltage division between the first sub-analog signal and the second sub-analog signal when the first state signal, the second state signal, the third state signal, or the fourth state signal is enabled, and the first analog signal is generated based on the fifth candidate voltage when the fifth state signal is enabled.

10. The inductor current simulation circuit as described in claim 9, wherein the selection circuit further includes a logic circuit for generating a complex control signal based on the complex state signal to control the switching of the complex selection switch, thereby selecting the complex candidate voltage.

11. An analog control method for simulating an inductor current in a multi-stage switching circuit, wherein the multi-stage switching circuit periodically switches a capacitor and an inductor between multiple electrical connection states based on a duty cycle according to a complex switching signal, thereby performing a power conversion between a first voltage and a second voltage; the analog control method includes: selecting a complex number of candidate voltages based on a complex number of state signals to generate a first analog signal; and generating a second analog signal based on the difference between the first analog signal and a bias voltage value to simulate the inductor current; wherein the difference between the first analog signal and the bias voltage value is positively correlated with an inductor voltage corresponding to the multiple electrical connection states; wherein the complex number of state signals is related to the complex switching signals, each of the complex number of state signals corresponding to each of the complex electrical connection states, and wherein the complex candidate voltages are related to a linear superposition of the first voltage, the second voltage, a ground potential, and combinations thereof.

12. The simulation control method as described in claim 11, wherein the bias voltage value is positively correlated with an average voltage value of the second simulation signal.

13. The simulation control method as described in claim 12, wherein the average voltage value of the second simulation signal is positively correlated with the second voltage.

14. The analog control method as described in claim 11, wherein the plurality of state signals includes a first state signal, a second state signal, a third state signal, a fourth state signal, and a fifth state signal, each corresponding to one of the following states: (1) when the first state signal is enabled, the first analog signal is positively correlated with the first voltage; (2) when the second state signal is enabled, the first analog signal is positively correlated with the difference between the first voltage and the second voltage; (3) when the third state signal is enabled, the first analog signal is positively correlated with the difference between the first voltage and half of the second voltage; (4) when the fourth state signal is enabled, the first analog signal is positively correlated with the difference between the first voltage and half of the second voltage; or (5) when the fifth state signal is enabled, the first analog signal is positively correlated with the ground potential.

15. The analog control method as described in claim 14, wherein the electrical connection states of the capacitor and the inductor correspond to the following: (1) when the first state signal is enabled, the inductor is electrically connected between the first voltage and the ground potential, and the upper end and lower end of the capacitor are respectively floating and electrically connected to the ground potential; (2) when the second state signal is enabled, the inductor is electrically connected between the first voltage and the second voltage, and the upper end and lower end of the capacitor are respectively electrically connected to the second voltage and floating; (3) when the third state signal is enabled, the inductor and the capacitor are connected in series between the first voltage and the ground potential; (4) when the fourth state signal is enabled, the inductor and the capacitor are connected in series between the first voltage and the second voltage; or (5) when the fifth state signal is enabled, the inductor is electrically connected between the first voltage and floating, and the capacitor is floating.

16. The analog control method as claimed in claim 12, wherein the plurality of state signals includes a first state signal, a second state signal, a third state signal, and a fourth state signal; wherein the first analog signal has a first analog voltage value during the consistency energy period of the first state signal, a second analog voltage value during the consistency energy period of the second state signal, and a third analog voltage value during the consistency energy period of the third state signal or the fourth state signal; wherein the step of determining the average voltage value of the second analog signal includes one of the following: when the duty cycle is greater than half, determining the average voltage value based on the first analog voltage value, the third analog voltage value, and the corresponding duty cycle; or when the duty cycle is less than half, determining the average voltage value based on the second analog voltage value, the third analog voltage value, and the corresponding duty cycle.

17. The emulation control method as described in either claim 11 or claim 13, wherein the step of generating the second emulation signal includes: A filter signal is generated based on the difference between an average voltage value of the first analog signal and the second analog signal, thereby simulating the inductor voltage. And the second analog signal is generated based on the integration of the filtered signal, thereby simulating the inductor current.

18. The simulation control method as described in claim 14, wherein the step of selecting the complex candidate voltages includes: The plurality of candidate voltages includes a first candidate voltage, a second candidate voltage, a third candidate voltage, a fourth candidate voltage, and a fifth candidate voltage; based on the plurality of state signals, the first candidate voltage is selected when the second state signal is enabled, and the second candidate voltage is selected when the first state signal, the third state signal, or the fourth state signal is enabled, to generate a first sub-analog signal; based on the plurality of state signals, the third candidate voltage is selected when the first state signal is enabled, and the fourth candidate voltage is selected when the second state signal, the third state signal, or the fourth state signal is enabled, to generate a second sub-analog signal; and based on the plurality of state signals, the fifth candidate voltage is selected when the fifth state signal is enabled.

19. The emulation control method as described in claim 18, wherein the step of generating the first emulation signal includes: When the first state signal, the second state signal, the third state signal, or the fourth state signal is enabled, the first analog signal is generated based on the voltage division between the first sub-analog signal and the second sub-analog signal; and when the fifth state signal is enabled, the first analog signal is generated based on the fifth candidate voltage.

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