Under-voltage protection circuit for programmable power supplies
View Patent ↗A control circuit of a power supply is provided. The power supply includes a current-sense circuit, a voltage-sense circuit, an output voltage regulation circuit, and a current regulation circuit. The current-sense circuit generates a current-sense signal in response to an output current of the power supply. The voltage-sense circuit generates a voltage-sense signal in response to an output voltage of the power supply. The output voltage regulation circuit is coupled to regulate the output voltage of the power supply according to a voltage reference signal and the voltage-sense signal. The output current regulation circuit is coupled to regulate the output current of the power supply according to a current reference signal and the current-sense signal. The output voltage of said power supply is programmable.
1. A control circuit of a programmable power supply, comprising:
a current-sense circuit generating a current-sense signal in response to an output current of said programmable power supply;
a voltage-sense circuit generating a voltage-sense signal in response to an output voltage of said programmable power supply;
an output voltage regulation circuit coupled to regulate said output voltage of said programmable power supply according to a voltage reference signal and said voltage-sense signal; and
an output current regulation circuit, coupled to regulate said output current of said programmable power supply according to a current reference signal and said current-sense signal,
wherein said current reference signal is changed in response to a level of said output voltage of the programmable power supply, and said output current of said power supply is decreased in response to a decrement of said current reference signal, and
wherein said output voltage of said programmable power supply is programmable.
2. The control circuit as claimed in claim 1 further comprising a time-delay circuit coupled to said output current regulation circuit for changing said current reference signal.
3. The control circuit as claimed in claim 1 , wherein a level of said current reference signal is decreased in response to a decrement of said level of said output voltage of said programmable power supply.
4. The control circuit as claimed in claim 1 , wherein a level of said current reference signal is decreased once said output voltage is lower than a protection threshold.
5. The control circuit as claimed in claim 4 , wherein a level of said protection threshold is decreased in response to a decrement of said voltage reference signal.
6. A method of regulating a programmable power supply, comprising:
generating a current-sense signal in response to an output current of said programmable power supply;
generating a voltage-sense signal in response to an output voltage of said programmable power supply;
regulating said output voltage in response to a voltage reference signal and said voltage-sense signal; and
regulating said output current in response to a current reference signal and said current-sense signal,
wherein said current reference signal is changed in response to said output voltage of said programmable power supply, and said output current is decreased in response to a decrement of said current reference signal, and
wherein said output voltage of said programmable power supply is programmable.
7. The method as claimed in claim 6 further comprising generating a delay time to change said current reference signal.
8. The method as claimed in claim 6 , wherein a level of said current reference signal is decreased in response to a decrement of said output voltage of said programmable power supply.
9. The method as claimed in claim 6 , wherein a level of said current reference signal is decreased once said output voltage is lower than a protection threshold.
10. The method as claimed in claim 9 , wherein a level of said protection threshold is decreased in response to a decrement of said voltage reference signal.
11. A method of under-voltage protection for a programmable power supply, comprises:
regulating an output voltage of said power supply at a regulated level;
regulating an output current of said programmable power supply approximately at a first current level whenever said output voltage is below said regulated level and higher than a lower limit of a protection threshold; and
regulating said output current of said programmable power supply approximately at a second current level whenever said output voltage is below an upper limit of said protection threshold,
wherein said output voltage of said programmable power supply is programmable.
12. The method as claimed in claim 11 , said first current level is higher than said second current level.
13. The method as claimed in claim 11 , said upper limit of said protection threshold is higher than said lower limit of said protection threshold.