Circuit for a switched mode power supply

1. A circuit for a switched-mode-power-supply, wherein the switched-mode-power-supply is configured to: receive a current-control-signal; and provide an output-voltage based on the current-control-signal, the circuit comprising:

a controller, configured to:

generate a control-voltage based on a difference between: (i) a sense-voltage, which is representative of the output-voltage of the switched-mode-power-supply; and (ii) a reference-voltage;

generate a target-current-control-signal based on the control-voltage, wherein the target-current-control-signal is configured to adjust a current through the switched-mode-power-supply in order to bring a magnitude of the sense-voltage closer to a magnitude of the reference-voltage;

a current-limiter configured to provide the current-control-signal as the target-current-control-signal limited to a max-current-control-value; and

a clamp-circuit configured to set the control-voltage to a clamp-voltage-value when the current-limiter provides the current-control-signal having the limited value of the max-current-control-value;

wherein the controller includes a transconductance-amplifier-control-block, which incorporates a functionality of the current-limiter and the clamp-circuit such that the transconductance-amplifier-control-block is configured to:

receive the control-voltage;

prevent the control-voltage from increasing when the current-control-signal has the limited value of the max-current-control-value; and

convert the control-voltage to the current-control-signal.

2. The circuit of claim 1 ,

wherein the clamp-circuit comprises a voltage regulator,

wherein the voltage regulator is configured to regulate the control-voltage to the clamp-voltage-value for all values of the sense-voltage and the reference-voltage that would cause the target-current-control-signal to be set to a value that is equal to or greater than the max-current-control-value.

3. The circuit of claim 1 , wherein the transconductance-amplifier-control-block comprises:

a voltage amplifier,

a bias-voltage-source configured to provide a saturation-voltage;

a clamp-transistor; and

a first-mirror-second-transistor;

wherein the voltage amplifier in combination with the clamp-transistor is configured to regulate the voltage drop across the first-mirror-second-transistor to the saturation-voltage provided by the bias-voltage-source.

4. The circuit of claim 1 , wherein:

the transconductance-amplifier-control-block comprises an additional transistor, and

the transconductance-amplifier-control-block is configured to prevent the control-voltage from increasing when the voltage drop across the transistor exceeds a saturation-voltage of the transistor.

5. The circuit of claim 3 ,

wherein the saturation-voltage is representative of the additional transistor being in a saturated state of operation.

6. The circuit of claim 1 ,

wherein the transconductance-amplifier-control-block is configured prevent the control-voltage from increasing when a transistor in the transconductance-amplifier-control-block is in saturation.

7. The circuit of claim 1 , wherein the controller comprises:

the transconductance-amplifier-control-block, which incorporates the functionality of the current-limiter and the clamp-circuit such that the transconductance-amplifier-control-block is configured to:

receive the control-voltage;

provide a non-zero over-current-signal when the current-control-signal has the limited value of max-current-control-value,

wherein the over-current-signal is configured to change the sense-voltage independently of the current through the switched-mode-power-supply; and

convert the control-voltage to the current-control-signal.

8. The circuit of claim 1 ,

wherein the clamp-voltage-value is a value of the control-voltage before the current-limiter provides the current-control-signal with the limited value of the max-current-control-value.

9. The circuit of claim 8 ,

wherein the clamp-circuit is configured to clamp the control-voltage to a current value when the current-limiter provides the current-control-signal with the limited value of the max-current-control-value.

10. The circuit of claim 1 ,

wherein the controller is configured to generate the control-voltage by integrating the difference between: (i) the sense-voltage; and (ii) the reference-voltage.

11. The circuit of claim 1 ,

wherein the target-current-control-signal is configured to adjust the current through the switched-mode-power-supply by setting the peak current through an inductor in the switched-mode-power-supply.

12. The circuit of claim 1 , wherein:

the clamp-circuit is configured to provide a flag-signal that is representative of whether or not the control-voltage is set to the clamp-voltage-value; and

the circuit comprises a controllable-block that is configured to be automatically controlled based on the flag-signal.

13. An audio amplifier circuit comprising:

the circuit of claim 1 ,

wherein the clamp-circuit is configured to provide a flag-signal that is representative of whether or not the control-voltage is set to the clamp-voltage-value; and

a controllable-block that is configured to be automatically controlled based on the flag-signal.

14. The audio amplifier circuit of claim 13 ,

wherein the controllable-block comprises an amplifier, and wherein the amplifier is configured to automatically control an audio level of an output signal of the audio amplifier circuit based on the flag-signal.

15. A circuit for a switched-mode-power-supply, wherein the switched-mode-power-supply is configured to: receive a current-control-signal; and provide an output-voltage based on the current-control-signal, the circuit comprising:

a controller, configured to:

generate a control-voltage based on a difference between: (i) a sense-voltage, which is representative of the output-voltage of the switched-mode-power-supply; and (ii) a reference-voltage;

generate a target-current-control-signal based on the control-voltage, wherein the target-current-control-signal is configured to adjust a current through the switched-mode-power-supply in order to bring a magnitude of the sense-voltage closer to a magnitude of the reference-voltage;

a current-limiter configured to provide the current-control-signal as the target-current-control-signal limited to a max-current-control-value; and

a clamp-circuit configured to set the control-voltage to a clamp-voltage-value when the current-limiter provides the current-control-signal having the limited value of the max-current-control-value;

wherein the controller includes a transconductance-amplifier-control-block, which incorporates a functionality of the current-limiter and the clamp-circuit such that the transconductance-amplifier-control-block is configured to:

receive the control-voltage;

provide a non-zero over-current-signal when the current-control-signal has the limited value of max-current-control-value,

wherein the over-current-signal is configured to change the sense-voltage independently of the current through the switched-mode-power-supply; and

convert the control-voltage to the current-control-signal.

16. A circuit for a switched-mode-power-supply, wherein the switched-mode-power-supply is configured to: receive a current-control-signal; and provide an output-voltage based on the current-control-signal, the circuit comprising:

a controller, configured to:

generate a control-voltage based on a difference between: (i) a sense-voltage, which is representative of the output-voltage of the switched-mode-power-supply; and (ii) a reference-voltage;

generate a target-current-control-signal based on the control-voltage, wherein the target-current-control-signal is configured to adjust a current through the switched-mode-power-supply in order to bring a magnitude of the sense-voltage closer to a magnitude of the reference-voltage;

a current-limiter configured to provide the current-control-signal as the target-current-control-signal limited to a max-current-control-value; and

a clamp-circuit configured to set the control-voltage to a clamp-voltage-value when the current-limiter provides the current-control-signal having the limited value of the max-current-control-value;

wherein the circuit in included in an audio amplifier circuit;

wherein the clamp-circuit is configured to provide a flag-signal that is representative of whether or not the control-voltage is set to the clamp-voltage-value; and a controllable-block that is configured to be automatically controlled based on the flag-signal;

wherein the controllable-block comprises an amplifier, and wherein the amplifier is configured to automatically control an audio level of an output signal of the audio amplifier circuit based on the flag-signal.