System and method providing over current protection based on duty cycle information for power converter
First Claim
1. A signal generator for protecting a power converter, the signal generator comprising:
- a modulation and drive component configured to generate a modulation signal to output a drive signal to a switch in order to affect a primary current flowing through a primary winding of a power converter, the modulation signal including an on-time period, the switch being closed during the on-time period;
a ramping-signal generator configured to receive the modulation signal and generate a ramping signal based on at least information associated with the modulation signal;
a sampling-signal generator configured to receive the modulation signal and generate a sampling signal including a pulse in response to a falling edge of the modulation signal; and
a sample-and-hold component configured to receive the sampling signal and the ramping signal and output a sampled-and-held signal associated with a magnitude of the ramping signal corresponding to the pulse of the sampling signal;
wherein;
the falling edge of the modulation signal is at a first time;
the pulse of the sampling signal starts at a second time and ends at a third time;
the first time and the second time are the same; and
the on-time period ends at the first time.
1 Assignment
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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.
166 Citations
31 Claims
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1. A signal generator for protecting a power converter, the signal generator comprising:
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a modulation and drive component configured to generate a modulation signal to output a drive signal to a switch in order to affect a primary current flowing through a primary winding of a power converter, the modulation signal including an on-time period, the switch being closed during the on-time period; a ramping-signal generator configured to receive the modulation signal and generate a ramping signal based on at least information associated with the modulation signal; a sampling-signal generator configured to receive the modulation signal and generate a sampling signal including a pulse in response to a falling edge of the modulation signal; and a sample-and-hold component configured to receive the sampling signal and the ramping signal and output a sampled-and-held signal associated with a magnitude of the ramping signal corresponding to the pulse of the sampling signal; wherein; the falling edge of the modulation signal is at a first time; the pulse of the sampling signal starts at a second time and ends at a third time; the first time and the second time are the same; and the on-time period ends at the first time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A signal generator for protecting a power converter, the signal generator comprising:
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a modulation and drive component configured to generate a modulation signal to output a drive signal to a switch in order to affect a primary current flowing through a primary winding of a power converter; a ramping-signal generator configured to receive the modulation signal and generate a ramping signal based on at least information associated with the modulation signal; a sampling-signal generator configured to receive the modulation signal and generate a sampling signal including a pulse in response to a falling edge of the modulation signal; a sample-and-hold component configured to receive the sampling signal and the ramping signal and output a sampled-and-held signal associated with a magnitude of the ramping signal corresponding to the pulse of the sampling signal; a comparator configured to receive a threshold signal associated with the sampled-and-held signal and a current sensing signal associated with the primary current and output a comparison signal to the modulation and drive component based on at least information associated with the sampled-and-held signal and the current sensing signal; and a low-pass filter configured to receive the sampled-and-held signal and output the threshold signal based on at least information associated with the sampled-and-held signal; wherein the sample-and-hold component includes; a first switch configured to be closed and open in response to the sampling signal; and a first capacitor configured to be charged in response to the ramping signal when the first switch is closed; wherein the low-pass filter includes; a first resistor including a first resistor terminal and a second resistor terminal, the first resistor terminal being coupled to the first switch; and a second capacitor coupled to the second resistor terminal; wherein; the falling edge of the modulation signal is at a first time; the pulse of the sampling signal starts at a second time and ends at a third time; and the first time and the second time are the same.
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14. A signal generator for protecting a power converter, the signal generator comprising:
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a modulation and drive component configured to generate a modulation signal to output a drive signal to a switch in order to affect a primary current flowing through a primary winding of a power converter; a ramping-signal generator configured to receive the modulation signal and generate a ramping signal based on at least information associated with the modulation signal; a sample-and-hold component configured to receive the ramping signal and the modulation signal and output a sampled-and-held signal associated with a magnitude of the ramping signal in response to the modulation signal; a filter-signal generator configured to receive the modulation signal and generate a filter signal based on at least information associated with the modulation signal; and a low-pass filter configured to receive the filter signal and the sampled-and-held signal and, in response to the filter signal, generate a first signal based on at least information associated with the sampled-and-held signal; wherein the filter-signal generator is further configured to change the filter signal from a first logic level to a second logic level in response to the modulation signal changing from a third logic level to a fourth logic level. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for generating a signal for protecting a power converter, the method comprising:
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generating a modulation signal to output a drive signal to a switch in order to affect a primary current flowing through a primary winding of a power converter, the modulation signal including an on-time period, the switch being closed during the on-time period; receiving the modulation signal; processing information associated with the modulation signal; generating a ramping signal based on at least information associated with the modulation signal; generating a sampling signal including a pulse in response to a falling edge of the modulation signal; receiving the sampling signal and the ramping signal; and outputting a sampled-and-held signal associated with a magnitude of the ramping signal corresponding to the pulse of the sampling signal; wherein; the falling edge of the modulation signal is at a first time; the pulse of the sampling signal starts at a second time and ends at a third time; the first time and the second time are the same; and the on-time period ends at the first time.
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30. A method for generating a signal for protecting a power converter, the method comprising:
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generating a modulation signal to output a drive signal to a switch in order to affect a primary current flowing through a primary winding of a power converter; receiving the modulation signal; processing information associated with the modulation signal; generating a ramping signal based on at least information associated with the modulation signal; generating a filter signal based on at least information associated with the modulation signal; receiving the ramping signal and the modulation signal; outputting a sampled-and-held signal associated with a magnitude of the ramping signal in response to the modulation signal; receiving the filter signal and the sampled-and-held signal; and generating, in response to the filter signal, a first signal based on at least information associated with the sampled-and-held signal; wherein the generating a filter signal based on at least information associated with the modulation signal includes; changing the filter signal from a first logic level to a second logic level in response to the modulation signal changing from a third logic level to a fourth logic level. - View Dependent Claims (31)
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Specification