Method and apparatus for regulating power in a flyback converter
AssigneeInfineon Technologies AG
InventorsJing Hu, Kok Kee Lim, Meng Kiat Jeoh, Xiao Wu Gong, Yi He
Life of this patent
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Abstract
An integrated circuit includes an operational amplifier configured to receive a current sense voltage (VCS) at a first input and an offset voltage at a second input. A comparator is coupled to the operational amplifier and adapted to receive at a first input an output voltage signal (VOUT) of the operational amplifier. A voltage limiting circuit is configured to receive a regulation voltage. A fold back correction circuit is coupled to the voltage limiting circuit and to a second input of the comparator. A pulse width modulator circuit is coupled to the comparator and is adapted to receive the output of comparator.
Claims19
An integrated circuit, comprising:
- an operational amplifier configured to receive a current sense voltage (VCS) at a first input and an offset voltage at a second input;
- a comparator coupled to the operational amplifier and adapted to receive at a first input an output voltage signal (VOUT) of the operational amplifier;
- a voltage limiting circuit configured to receive a regulation voltage;
- a fold back correction circuit coupled to the voltage limiting circuit, the foldback correction circuit coupled to a second input of the comparator;
- and
- a pulse width modulator circuit coupled to the comparator and adapted to receive the output of the comparator.
A method, comprising:
- receiving a current sense voltage at a first pin and a regulation voltage at a second pin of an integrated circuit;
- off-setting the current sense voltage using an offset voltage source and an operational amplifier and generating an off-setted current sense voltage;
- limiting the regulation voltage using a limiting voltage and providing a limited regulation voltage to a fold back correction circuit;
- performing a fold back correction on the limited regulation voltage to generate a fold back corrected regulation voltage;
- comparing the fold back corrected regulation voltage and the off-setted current sense voltage;
- and
- generating a PWM switch-off signal based on comparing the fold back regulation voltage and the off-setted current sense voltage.
A circuit comprising:
- means for receiving a current sense voltage at a first pin and a regulation voltage at a second pin of an integrated circuit;
- means for off-setting the current sense voltage using an offset voltage source and an operational amplifier and generating an off setted current sense voltage;
- means for limiting the regulation voltage using a limiting voltage and providing a limited regulation voltage to a fold back correction circuit;
- means for performing a fold back correction on the limited regulation voltage to generate a fold back corrected regulation voltage;
- means for comparing the fold back corrected regulation voltage and the off-setted current sense voltage;
- and
- means for generating a PWM switch-off signal based on comparing the fold back regulation voltage and the off setted current sense voltage.
A system comprising:
- a flyback controller circuit configured to provide a switching signal used to activate a switch;
- a current source coupled to the flyback controller circuit and configured to be operational during a burst mode based on the switching signal;
- and
- a resistive load coupled to the current source at one end and the switch at the other end, wherein the flyback controller circuit comprising:
- an operational amplifier configured to receive a current sense voltage (VCS) at a first input and an offset voltage at a second input;
- a comparator coupled to the operational amplifier and adapted to receive at a first input an output voltage signal (VOUT) of the operational amplifier;
- a current limiting circuit configured to receive a regulation voltage;
- a fold back correction circuit coupled to the current limiting circuit, the foldback correction circuit coupled to a second input of the comparator;
- and
- a pulse width modulator circuit coupled to the comparator and adapted to receive the output of comparator.
Dependencies are inferred from the claim text.