Controlled adaptive power limiter
View Patent ↗A power limiter for a switched mode power supply includes an operational amplifier and a comparator circuit. The operational amplifier is configured to receive an input voltage supplied to the SMPS as a first input and a reference voltage as a second input. The comparator circuit is configured to receive an output of the operational amplifier, receive a current sense signal, and generate an output signal configured to control a power generator. The output signal is based on a comparison between the output of the operational amplifier and the current sense signal.
1. A power limiter for a switched mode power supply (SMPS), comprising:
an operational amplifier configured to:
receive an input voltage supplied to the SMPS as a first input; and
a reference voltage as a second input;
a comparator circuit configured to:
receive an output of the operational amplifier;
receive a current sense signal; and
generate an output signal configured to control a power generator, the output signal based on a comparison between the output of the operational amplifier and the current sense signal;
wherein the operational amplifier is further configured to lower a maximum current input limit of the SMPS as input voltage increases.
2. The power limiter of claim 1 , wherein the output of the operational amplifier is a current limit.
3. The power limiter of claim 1 , wherein the comparator circuit is further configured to generate the output signal based on a comparison between a set current limit and a measured current by comparing the output of the operational amplifier and the current sense signal.
4. The power limiter of claim 1 , wherein the output signal is configured to overwrite a feedback signal from output of the SMPS.
5. The power limiter of claim 1 , wherein:
the output signal is configured to overwrite a feedback signal from output of the SMPS; and
the comparator circuit is further configured to generate the output signal before reception of the feedback signal.
6. The power limiter of claim 1 , wherein the operational amplifier and the comparator unit are incorporated into a microcontroller.
7. The power limiter of claim 1 , wherein the operational amplifier is further configured to lower a current input limit as input voltage increases according to a slope defined by one or more resistors connected between an input voltage source and the operational amplifier.
8. The power limiter of claim 1 , wherein the operational amplifier is further configured to maintain a current limit above zero based upon the reference voltage.
9. A switched mode power supply (SMPS), comprising:
an operational amplifier configured to:
receive an input voltage supplied to the SMPS as a first input; and
a reference voltage as a second input;
a pulse-width modulation power generator circuit configured to produce an output voltage based on a duty cycle of a pulse-width modulation output; and
a comparator circuit configured to:
receive an output of the operational amplifier;
receive a current sense signal based on output of the pulse-width modulation power generator circuit; and
generate an output signal configured to control the pulse-width modulation power generator, the output signal based on a comparison between the output of the operational amplifier and the current sense signal;
wherein the operational amplifier is further configured to lower a maximum current input limit of the SMPS as input voltage increases.
10. The SMPS of claim 9 , wherein the output of the operational amplifier is a current limit.
11. The SMPS of claim 9 , wherein the comparator circuit is further configured to generate the output signal based on a comparison between a set current limit and a measured current by comparing the output of the operational amplifier and the current sense signal.
12. The SMPS of claim 9 , wherein the output signal is configured to overwrite a feedback signal from output of the SMPS.
13. The SMPS of claim 9 , wherein:
the output signal is configured to overwrite a feedback signal from output of the SMPS; and
the comparator circuit is further configured to generate the output signal before reception of the feedback signal.
14. The SMPS of claim 9 , wherein the operational amplifier and the comparator unit are incorporated into a microcontroller.
15. The SMPS of claim 9 , wherein the operational amplifier is further configured to lower a current input limit as input voltage increases according to a slope defined by one or more resistors connected between an input voltage source and the operational amplifier.
16. The SMPS of claim 9 , wherein the operational amplifier is further configured to maintain a current limit above zero based upon the reference voltage.
17. A microcontroller, comprising:
a switched mode power supply (SMPS);
an operational amplifier configured to:
receive an input voltage supplied to the SMPS as a first input; and
a reference voltage as a second input; and
a comparator circuit configured to:
receive an output of the operational amplifier;
receive a current sense signal;
and
generate an output signal configured to control a power generator, the output signal based on a comparison between the output of the operational amplifier and the current sense signal;
wherein the operational amplifier is further configured to lower a maximum current input limit of the SMPS as input voltage increases.
18. The microcontroller of claim 17 , wherein the output of the operational amplifier is a current limit.