Method and apparatus of providing a biased current limit for limiting maximum output power of power converters
AssigneeSystem General Corp.
InventorsCheng-Chi Hsueh, Wei-Hsuan Huang, Ta-Yung Yang
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Abstract
A biased current-limit circuit for limiting a maximum output power of a power converter includes an oscillator for generating a pulse signal. A waveform generator generates a waveform signal in response to a switching signal and a second-sampling signal. A sample-hold circuit is used to sample the waveform signal to generate a hold signal in response to a first-sampling signal. The sample-hold circuit further samples the hold signal to generate a current-limit threshold in response to the second-sampling signal. A current comparator is utilized to compare a current-sensing signal with the current-limit threshold to limit a maximum on-time of the switching signal.
Claims12
A method of a biased current limit for limiting a maximum output power of a power converter, comprising:
- generating a pulse signal;
- generating a waveform signal in response to a switching signal and a second-sampling signal, wherein the switching signal is utilized to switch a transformer of the power converter, and the second-sampling signal is correlated to the pulse signal;
- comparing the waveform signal with a current-sensing signal to generate a first-sampling signal, wherein the current-sensing signal is correlated to a switching current of the transformer;
- sampling the waveform signal to generate a hold signal in response to the first-sampling signal;
- sampling the hold signal to generate a current-limit threshold in response to the second-sampling signal;
- and
- comparing the current-sensing signal with the current-limit threshold to limit a maximum on-time of the switching signal.
A biased current-limit circuit for limiting a maximum output power of a power converter, comprising:
- an oscillator, generating a pulse signal;
- a waveform generator, generating a waveform signal in response to a switching signal and a second-sampling signal, wherein the switching signal is utilized to switch a transformer of the power converter, and the second-sampling signal is correlated to the pulse signal;
- a sample-hold circuit, sampling the waveform signal to generate a hold signal in response to a first-sampling signal, the sample-hold circuit further sampling the hold signal to generate a current-limit threshold in response to the second-sampling signal, wherein the first-sampling signal is generated by comparing the waveform signal with a current-sensing signal, and the current-sensing signal is correlated to a switching current of the transformer;
- and
- a current comparator, comparing the current-sensing signal with the current-limit threshold to limit a maximum on-time of the switching signal.
Dependencies are inferred from the claim text.