Control method for switched-mode power supplies

1 . A switched-mode power supply comprising:

a voltage source;

an output device;

a converter including an inductor and a switch, the converter configured to convert unregulated direct current (DC) voltage received from the voltage source to a regulated DC voltage used for powering the output device; and

a controller including one or more electronic processors, the controller configured to:

receive a first signal indicative of a voltage across the output device;

receive a second signal indicative of a current flowing into the converter; and

estimate an impedance of the output device based on the voltage across the output device and the current flowing through the output device using a state estimator;

wherein the state estimator comprises a discrete state space model of the converter and is configured to determine a full-state estimation of the converter from incomplete state information;

wherein a value of the current flowing into the converter is measured or estimated,

wherein the controller is further configured to:

determine a setpoint for the current flowing through the inductor based on the impedance of the output device; and

determine a predicted value of the current flowing through the inductor based on the setpoint;

determine, in response to the predicted value of the current, an operating mode of the converter, wherein the determined operating mode is a continuous conduction mode (CCM) when the predicted value of the current is greater than zero, and wherein the determined operating mode is a discontinuous conduction mode (DCM) when the predicted value of the current is less than zero; and

control the switch in response to the determined operating mode, wherein a first duty cycle is used to control the switch when the converter is operating in CCM and a second duty cycle is used to control the switch when the converter is operating in DCM.

2 . The switched-mode power supply according to claim 1 , wherein the controller is further configured to determine the first duty cycle based on a property of the switch during CCM operation of the converter.

3 . The switched-mode power supply according to claim 2 , wherein the property of the switch is an on-time of the switch during one cycle of operation of the converter; and

wherein the controller is further configured determine the on-time of the switch based on a predicted or an estimated average of current flowing through the inductor.

4 . The switched-mode power supply according to claim 1 , wherein the controller is further configured to determine the second duty cycle based on a property of the switch during DCM operation of the converter.

5 . The switched-mode power supply according to claim 4 , wherein the property of the switch is an on-time of the switch during one cycle of operation of the converter; and

wherein the controller is further configured determine the on-time of the switch based on an estimated value of current flowing through the inductor or an exact value of current flowing through the inductor.

6 . The switched-mode power supply according to claim 2 , wherein the property of the switch is an on-time of the switch during one cycle of operation of the converter.

7 . The switched-mode power supply according to claim 6 , wherein the controller is further configured to determine the on-time of the switch based on an exact value of current flowing through the inductor.

8 . The switched-mode power supply of claim 1 , wherein the switched-mode power supply is included in a portable speaker.

9 . The switched-mode power supply of claim 1 , wherein the converter is non-synchronous boost converter.

10 . A method for controlling a switched-mode power supply, the switched-mode power supply including a converter circuit that includes an inductor and a switch, the method comprising:

receiving a first signal indicative of a voltage across the output device;

receiving a second signal indicative of a current flowing into the converter circuit; and

estimating an output impedance of the converter circuit based on the output voltage and the current flowing into the converter circuit using a state estimator;

wherein the state estimator comprises a discrete state space model of the converter and is configured to determine a full-state estimation of the converter from incomplete state information;

wherein a value of the current flowing into the converter circuit is measured or estimated,

determining a setpoint for the current flowing through the inductor based on the output impedance; and

determining a predicted value of the current flowing through the inductor based on the setpoint;

determining, in response to the predicted value of the current, an operating mode of the converter, wherein the determined operating mode is a continuous conduction mode (CCM) when the predicted value of the current is greater than zero, and wherein the determined operating mode is a discontinuous conduction mode (DCM) when the predicted value of the current is less than zero; and

controlling the switch in response to the determined operating mode, wherein a first duty cycle is used to control the switch when the determined operating mode is CCM and a second duty cycle is used to control the switch when the converter is operating in DCM.

11 . The method according to claim 10 , further comprising determining the first duty cycle based on an on-time of the switch during CCM operation of the converter circuit.

12 . The method according to claim 11 , further comprising determining the on-time of the switch based on a predicted or an estimated average of current flowing through the inductor.

13 . The method according to claim 10 , further comprising determining the second duty cycle based on an on-time of the switch during DCM operation of the converter.

14 . The method according to claim 13 , further comprising determining the on-time of the switch based on an estimated value of current flowing through the inductor or an exact value of current flowing through the inductor.

15 . A non-transitory computer-readable medium storing instructions that, when executed by an electronic processor, cause the electronic processor to perform operations comprising the method according to 10 .

16 . The switched-mode power supply according to claim 1 , wherein the second duty cycle is different from the first duty cycle.

17 . The switched-mode power supply according to claim 2 , wherein the property of the switch is an on-time of the switch during one cycle of operation of the converter.

18 . The method according to claim 10 , wherein the second duty cycle is different from the first duty cycle.