System and method providing over current protection based on duty cycle information for power converter
First Claim
1. A system for protecting a power converter, the system comprising:
- a threshold signal generator configured to generate a threshold signal; and
a drive signal generator coupled to the threshold signal generator and configured to receive at least a comparison signal, generate a drive signal based at least in part on the comparison signal, and output the drive signal to a switch in order to affect a primary current flowing through a primary winding of the power converter, the comparison signal being associated with the threshold signal, the drive signal being associated with one or more first switching periods and a second switching period following the one or more first switching periods, the one or more first switching periods corresponding to one or more first duty cycles, the second switching period including an on-time period and an off-time period;
wherein the threshold signal generator is further configured to, for the second switching period,determine a first threshold signal value based at least in part on the one or more first duty cycles;
set a time to zero at a beginning of the on-time period;
if the time satisfies one or more first predetermined conditions, generate the threshold signal equal to the determined first threshold signal value so that the threshold signal is constant in magnitude as a function of the time; and
if the time satisfies one or more second predetermined conditions, generate the threshold signal so that the threshold signal decreases with the increasing time in magnitude.
1 Assignment
0 Petitions
Accused Products
Abstract
System and method for protecting a power converter. An example system controller for protecting a power converter includes a signal generator, a comparator, and a modulation and drive component. The signal generator is configured to generate a threshold signal. The comparator is configured to receive the threshold signal and a current sensing signal and generate a comparison signal based on at least information associated with the threshold signal and the current sensing signal, the current sensing signal indicating a magnitude of a primary current flowing through a primary winding of a power converter. The modulation and drive component is coupled to the signal generator.
175 Citations
24 Claims
-
1. A system for protecting a power converter, the system comprising:
-
a threshold signal generator configured to generate a threshold signal; and a drive signal generator coupled to the threshold signal generator and configured to receive at least a comparison signal, generate a drive signal based at least in part on the comparison signal, and output the drive signal to a switch in order to affect a primary current flowing through a primary winding of the power converter, the comparison signal being associated with the threshold signal, the drive signal being associated with one or more first switching periods and a second switching period following the one or more first switching periods, the one or more first switching periods corresponding to one or more first duty cycles, the second switching period including an on-time period and an off-time period; wherein the threshold signal generator is further configured to, for the second switching period, determine a first threshold signal value based at least in part on the one or more first duty cycles; set a time to zero at a beginning of the on-time period; if the time satisfies one or more first predetermined conditions, generate the threshold signal equal to the determined first threshold signal value so that the threshold signal is constant in magnitude as a function of the time; and if the time satisfies one or more second predetermined conditions, generate the threshold signal so that the threshold signal decreases with the increasing time in magnitude. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A system for protecting a power converter, the system comprising:
-
a threshold signal generator configured to generate a threshold signal; and a drive signal generator coupled to the threshold signal generator and configured to receive at least a comparison signal, generate a drive signal based at least in part on the comparison signal, and output the drive signal to a switch in order to affect a primary current flowing through a primary winding of the power converter, the comparison signal being associated with the threshold signal, the drive signal being associated with one or more first switching periods and a second switching period following the one or more first switching periods, the one or more first switching periods corresponding to one or more first duty cycles, the second switching period including an on-time period and an off-time period; wherein the threshold signal generator is further configured to, for the second switching period, determine a first threshold signal value based at least in part on the one or more first duty cycles; set a time to zero at a beginning of the on-time period; and if the time satisfies one or more first predetermined conditions, generate the threshold signal so that the threshold signal decreases, from the determined first threshold signal value, with the increasing time in magnitude. - View Dependent Claims (10, 11, 12, 13, 14, 15)
-
-
16. A system for protecting a power converter, the system comprising:
-
a threshold signal generator configured to generate a threshold signal; and a drive signal generator coupled to the signal generator and configured to receive at least a comparison signal, generate a drive signal based at least in part on the comparison signal, and output the drive signal to a switch in order to affect a primary current flowing through a primary winding of a power converter, the comparison signal being associated with the threshold signal, the drive signal being associated with a plurality of switching periods, each of the plurality of switching periods including an on-time period and an off-time period; wherein the threshold signal generator is further configured to, for each of the plurality of switching periods, set a time to zero at a beginning of the on-time period; if the time satisfies one or more first predetermined conditions, generate the threshold signal so that the threshold signal increases with the increasing time in magnitude; and if the time satisfies one or more second predetermined conditions, generate the threshold signal so that the threshold signal decreases with the increasing time in magnitude. - View Dependent Claims (17, 18, 19, 20, 21)
-
-
22. A method for protecting a power converter, the method comprising:
-
generating a threshold signal; receiving at least a comparison signal, the comparison signal being associated with the threshold signal; generating a drive signal based at least in part on the comparison signal, the drive signal being associated with one or more first switching periods and a second switching period following the one or more first switching periods, the one or more first switching periods corresponding to one or more duty cycles, the second switching period including an on-time period and an off-time period; and outputting the drive signal to a switch in order to affect a primary current flowing through a primary winding of a power converter; wherein the process for generating a threshold signal includes, for the second switching period, determining a threshold signal value based on at least information associated with the one or more duty cycles; setting a time to zero at a beginning of the on-time period; if the time satisfies one or more first predetermined conditions, generating the threshold signal equal to the determined threshold signal value so that the threshold signal is constant in magnitude as a function of the time; and if the time satisfies one or more second predetermined conditions, generating the threshold signal so that the threshold signal decreases with the increasing time in magnitude.
-
-
23. A method for protecting a power converter, the method comprising:
-
generating a threshold signal; receiving at least the comparison signal, the comparison signal being associated with the threshold signal; generating a drive signal based at least in part on a comparison signal, the drive signal being associated with one or more first switching periods and a second switching period following the one or more first switching periods, the one or more first switching periods corresponding to one or more duty cycles, the second switching period including an on-time period and an off-time period; and outputting the drive signal to a switch in order to affect a primary current flowing through a primary winding of a power converter; wherein the process for generating a threshold signal includes, for the second switching period, determining a threshold signal value based on at least information associated with the one or more duty cycles; setting a time to zero at a beginning of the on-time period; and if the time satisfies one or more predetermined conditions, generating the threshold signal so that the threshold signal decreases, from the determined threshold signal value, with the increasing time in magnitude.
-
-
24. A method for protecting a power converter, the method comprising:
-
generating a threshold signal; receiving at least a comparison signal, the comparison signal being associated with the threshold signal; generating a drive signal based at least in part on the comparison signal, the drive signal being associated with a plurality of switching periods, each of the plurality of switching periods including an on-time period and an off-time period; and outputting the drive signal to a switch in order to affect a primary current flowing through a primary winding of a power converter; wherein the process for generating a threshold signal includes, for each of the plurality of switching periods, setting a time to zero at a beginning of the on-time period; if the time satisfies one or more first predetermined conditions, generating the threshold signal so that the threshold signal increases with the increasing time in magnitude; and if the time satisfies one or more second predetermined conditions, generating the threshold signal so that the threshold signal decreases with the increasing time in magnitude.
-
Specification