Power factor correction circuit for regulating operating frequency control circuit of power factor correction circuit and control method thereof, electronic apparatus, and power adapter
First Claim
1. A control circuit of a power factor correction circuit constituted by two channels, each of which includes a switching transistor, an inductor and a rectification element, comprising:
- an error amplifier configured to amplify an error of a feedback signal according to an output voltage of the power factor correction circuit and a target value of the feedback signal and generate an error signal;
a pulse modulator configured to generate a first pulse modulated signal and a second pulse modulated signal in a current critical mode in response to the error signal;
a first driver configured to drive the switching transistor of a first channel based on the first pulse modulated signal;
a second driver configured to drive the switching transistor of a second channel based on the second pulse modulated signal; and
a mode controller configured to monitor a total current of the first channel and the second channel and generate a mode control signal based on the total current,wherein the pulse modulator switches between a first mode in which a phase difference between the first pulse modulated signal and the second pulse modulated signal is 180° and
a second mode in which the first channel and the second channel are exclusively and alternately used every switching period, in response to the mode control signal.
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Abstract
A control circuit of a power factor correction circuit including two channels, each of which includes a switching transistor, an inductor and a rectification element, includes: an error amplifier amplifying an error of a feedback signal according to output voltage of the power factor correction circuit and target value of the feedback signal and generating an error signal; a pulse modulator generating first and second pulse modulated signals in current critical mode in response to the error signal; a first driver driving the switching transistor of first channel based on the first pulse modulated signal; and a second driver driving the switching transistor of second channel based on the second pulse modulated signal, wherein the pulse modulator switches between a first mode where phase difference between the first and second pulse modulated signals is 180° and a second mode where the first and second channels are exclusively and alternately used.
11 Citations
17 Claims
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1. A control circuit of a power factor correction circuit constituted by two channels, each of which includes a switching transistor, an inductor and a rectification element, comprising:
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an error amplifier configured to amplify an error of a feedback signal according to an output voltage of the power factor correction circuit and a target value of the feedback signal and generate an error signal; a pulse modulator configured to generate a first pulse modulated signal and a second pulse modulated signal in a current critical mode in response to the error signal; a first driver configured to drive the switching transistor of a first channel based on the first pulse modulated signal; a second driver configured to drive the switching transistor of a second channel based on the second pulse modulated signal; and a mode controller configured to monitor a total current of the first channel and the second channel and generate a mode control signal based on the total current, wherein the pulse modulator switches between a first mode in which a phase difference between the first pulse modulated signal and the second pulse modulated signal is 180° and
a second mode in which the first channel and the second channel are exclusively and alternately used every switching period, in response to the mode control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A control circuit of a power factor correction circuit constituted by M (M being an integer of two or more) channels, each of which includes a switching transistor, an inductor and a rectification element, the control circuit comprising:
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an error amplifier configured to amplify an error of a feedback signal according to an output voltage of the power factor correction circuit and a target value of the feedback signal and generate an error signal; a pulse modulator configured to generate pulse modulated signals of the M channels in a current critical mode in response to the error signal; M drivers which correspond respectively to the M channels and are configured to drive the respective corresponding switching transistors based on the respective corresponding pulse modulated signals; and a mode controller configured to monitor a total current of the first channel and the second channel and generate a mode control signal based on the total current, wherein the pulse modulator is further configured to switch between a first mode in which the pulse modulated signals of the M channels sequentially transition to an on-level with a phase difference of 360°
/M and a second mode in which a plurality of consecutive switching periods are set as a period group, in response to the mode control signal, and, in each switching period included in the period group, a pulse modulated signal of one channel transitions to an on-level and then an off-level and pulse modulated signals of the remaining (M−
1) channels are kept at an off-level, and, during one period group, each pulse modulated signal transitions to the off-level at least once after transitioning to the on-level. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A control method of a power factor correction circuit constituted by two channels, each of which includes a switching transistor, an inductor and a rectification element, the method comprising:
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monitoring a total current of the two channels; generating a mode control signal based on the total current; amplifying an error of a feedback signal according to an output voltage of the power factor correction circuit and a target value of the feedback signal and generating an error signal; generating a first pulse modulated signal and a second pulse modulated signal in a current critical mode in response to the error signal; driving the switching transistor of a first channel based on the first pulse modulated signal; and driving the switching transistor of a second channel based on the second pulse modulated signal, wherein the act of generating a first pulse modulated signal and a second pulse modulated signal includes switching between a first mode in which a phase difference between the first pulse modulated signal and the second pulse modulated signal is 180° and
a second mode in which the phase difference between the first pulse modulated signal and the second pulse modulated signal is 360° and
the first channel and the second channel are exclusively and alternately used, in response to the mode control signal.
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17. A control method of a power factor correction circuit constituted by M (M being an integer of two or more) channels, each of which includes a switching transistor, an inductor and a rectification element, the method comprising:
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monitoring a total current of the two channels; generating a mode control signal based on the total current; amplifying an error of a feedback signal according to an output voltage of the power factor correction circuit and a target value of the feedback signal and generating an error signal; generating pulse modulated signals of the M channels in a current critical mode in response to the error signal; and driving the corresponding switching transistors of the M channels based on the corresponding pulse modulated signals, respectively, wherein the act of generating pulse modulated signals of the M channels includes switching between a first mode in which the pulse modulated signals of the M channels sequentially transition to an on-level with a phase difference of 360°
/M and a second mode in which a plurality of consecutive switching periods are set as a period group, in response to the mode control signal, and, in each switching period included in the period group, a pulse modulated signal of one channel transitions to an on-level and then an off-level and pulse modulated signals of the remaining (M−
1) channels are kept at an off-level, and, during one period group, each pulse modulated signal transitions to the off-level at least once after transitioning to the on-level.
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Specification