Power supply systems and methods

1. A power supply system comprising:

an error amplifier system configured to generate an error voltage based on a feedback voltage associated with an output voltage of the power supply system relative to a reference voltage;

a pulse-width modulation (PWM) generator configured to generate a PWM signal based on the error voltage;

a power stage configured to generate the output voltage based on the PWM signal; and

an output voltage tuning circuit configured to set a desired magnitude of the output voltage in response to a first digital signal and a second digital signal, the first digital signal being configured to set a magnitude of the reference voltage and the second digital signal being configured to adjust a magnitude of the feedback voltage.

2. The system of claim 1 , wherein the output voltage tuning circuit comprises a first digital-to-analog converter (DAC) configured to generate the reference voltage in response to the first digital signal and a second DAC configured to generate a fine adjust voltage in response to the second digital signal, the feedback voltage having a magnitude that is based on the fine adjust voltage and the output voltage.

3. The system of claim 1 , wherein the power stage comprises a voltage divider configured to generate the feedback voltage, the voltage divider comprising at least one variable resistor, wherein a resistance magnitude of the at least one variable resistor is set based on the second digital signal to adjust the magnitude of the feedback voltage.

4. The system of claim 3 , wherein the voltage divider comprises:

a static resistor coupled to a feedback node associated with the feedback voltage; and

an variable resistor interconnecting the feedback node and an output node associated with the output voltage, wherein a resistance magnitude of the variable resistor is set based on the second digital signal to adjust the magnitude of the feedback voltage.

5. The system of claim 1 , further comprising an oscillator system configured to generate a clock signal at a clock node, wherein the PWM generator is configured to generate the PWM signal based on the error voltage and the clock signal.

6. The system of claim 5 , wherein the oscillator system comprises:

a capacitor that is configured to be repeatedly charged and discharged based on a state of the clock signal; and

a comparator configured to compare a first voltage associated with the capacitor at a first comparator node and a second voltage at a second comparator node, the second voltage having a magnitude that changes based on the state of the clock signal.

7. The system of claim 6 , wherein the oscillator system further comprises:

a feedback circuit element interconnecting the clock node and the first comparator node and which is configured as a first discharge current path to substantially discharge the capacitor during the logic-low state of the clock signal, and is configured as a charging current path to substantially charge the capacitor during a logic-high state of the clock signal; and

a transistor that is configured to be activated during the logic-low state of the clock signal to provide a second discharge current path to substantially discharge the capacitor in parallel with the first discharge current path during the logic-low state of the clock signal.

8. The system of claim 6 , wherein the oscillator system further comprises a feedback circuit element interconnecting the clock node and the second comparator node, the second voltage having a first magnitude during the logic-high state of the clock signal and having a second magnitude during the logic-low state of the clock signal, the first magnitude being greater than the second magnitude.

9. The system of claim 1 , wherein the PWM generator is configured to generate the PWM signal based on the error voltage and a ramp signal, and wherein the power stage comprises a transconductance amplifier configured to generate a temperature-compensated sense current associated with a magnitude of an output current associated with the power stage, the ramp signal being generated based on the temperature-compensated sense current.

10. The system of claim 9 , further comprising an oscillator system configured to generate a clock signal, wherein the ramp signal is generated based on the temperature-compensated current and a ramp current associated with the clock signal.

11. An integrated circuit (IC) comprising the power supply system of claim 1 , the IC being configured as a backward compatible retrofit for an analog power supply controller.

12. A method for generating an output voltage via a power supply system, the method comprising:

setting a magnitude of a reference voltage based on a value of a first digital signal;

adjusting a scale factor of a feedback voltage that is associated with the output voltage based on a second digital signal;

generating an error voltage based on a magnitude of the feedback voltage associated with the output voltage relative to the reference voltage;

generating a pulse-width modulation (PWM) signal based on the error voltage and a clock signal; and

controlling at least one switch based on the PWM signal to generate the output voltage.

13. The method of claim 12 , wherein setting the magnitude of the reference voltage comprises setting the magnitude of the reference voltage based on providing the first digital signal to a digital-to-analog converter (DAC) configured to generate the reference voltage.

14. The method of claim 12 , wherein adjusting the scale factor of the feedback voltage comprises:

providing the second digital signal to a digital-to-analog converter (DAC) to generate a fine adjust voltage; and

adjusting at least one variable resistor associated with a voltage divider coupled to an output node associated with the power supply system, the voltage divider being configured to generate the feedback voltage.

15. The method of claim 12 , further comprising:

providing a charging current via a first current path that interconnects a first comparison node and a clock node associated with the clock signal during a logic-high state of the clock signal;

charging a capacitor via the charging current to generate a first comparison voltage at the first comparison node;

setting the clock signal to a logic-low state in response to the first comparison voltage being greater than a second comparison voltage;

activating a discharge switch in response to the logic-low state of the clock signal to provide a second current path;

discharging the capacitor via the first current path and the second current path during the logic-low state of the clock signal; and

setting the clock signal to the logic-high state and deactivating the discharge switch in response to the second comparison voltage being greater than the first comparison voltage.

16. The method of claim 15 , further comprising:

decreasing the second comparison voltage in response to the clock signal being set to the logic-low state via a feedback current path that interconnects the second comparison node and the clock node; and

increasing the second comparison voltage in response to the clock signal being set to the logic-high state via the feedback current path.

17. The method of claim 12 , further comprising:

generating a temperature-compensated current associated with a magnitude of an output current associated with a power stage of the power supply system, the PWM signal being generated based on the error voltage and a ramp signal that is generated based on the temperature-compensated current and a ramp current associated with the clock signal.