Adaptive frequency compensation for DC-to-DC converter
View Patent ↗One embodiment of the invention is a compensation circuit that includes a comparator that is coupled to receive a reference voltage. The compensation circuit can also include a capacitance coupled to receive a feedback voltage associated with an output voltage of a converter. Furthermore, the compensation circuit can include an adjustable resistance that is coupled to the capacitance and to the comparator.
1. A compensation circuit comprising:
a comparator coupled to receive a reference voltage;
a first capacitance coupled to receive a feedback voltage associated with an output voltage of a converter; and
an adjustable resistance coupled to said first capacitance and to said comparator.
2. The compensation circuit of claim 1 , wherein said first capacitance is coupled in parallel with said adjustable resistance.
3. The compensation circuit of claim 2 , further comprising:
a second capacitance coupled in series with said first capacitance; and
a resistance coupled in series with said second capacitance and coupled to an output of said comparator.
4. The compensation circuit of claim 1 , further comprising:
a control circuit coupled to change said adjustable resistance.
5. The compensation circuit of claim 1 wherein said compensation circuit is coupled to a duty cycle controller of said converter.
6. The compensation circuit of claim 5 , wherein said duty cycle controller is coupled to a power stage of said converter.
7. The compensation circuit of claim 1 , wherein said adjustable resistance comprises a plurality of resistors and a switch, said switch coupled to a resistor of said plurality of resistors.
8. A compensation circuit comprising:
a comparator coupled to receive a reference voltage;
a capacitance coupled to receive a feedback voltage associated with an output voltage of a converter; and
an adjustable capacitance coupled to said capacitance.
9. The compensation circuit of claim 8 , wherein said capacitance is coupled in parallel with a first resistance coupled to said comparator.
10. The compensation circuit of claim 9 , further comprising:
a second resistance coupled to said adjustable capacitance and an output of said comparator.
11. The compensation circuit of claim 8 , further comprising:
a control circuit coupled to change said adjustable capacitance.
12. The compensation circuit of claim 8 , wherein said compensation circuit is coupled to a duty cycle controller of said converter.
13. The compensation circuit of claim 12 , wherein said duty cycle controller is coupled to a power stage of said converter.
14. The compensation circuit of claim 8 , wherein said adjustable capacitance comprises a plurality of capacitors and a switch, said switch coupled to a capacitor of said plurality of capacitors.
15. A method comprising:
establishing an adjustable resistance of a compensation circuit at an upper value;
determining whether a transient feedback voltage exceeds a predefined range, said transient feedback voltage is associated with an output voltage of a converter circuit; and
establishing said adjustable resistance at a lower value, in response to said transient feedback voltage exceeding said predefined range.
16. The method of claim 15 , further comprising:
increasing said adjustable resistance to a higher value when said transient feedback voltage crosses a reference voltage value, after said transient feedback voltage exceeds said predefined range.
17. The method of claim 16 , wherein said increasing is performed at each odd numbered occurrence that said transient feedback voltage crosses said reference voltage value.
18. The method of claim 17 , wherein said increasing is performed until said upper value is reached.
19. The method of claim 15 , wherein said compensation circuit is part of a buck converter or a boost converter.
20. The method of claim 15 , wherein said predefined range is a delta percentage plus or minus said reference voltage.