METHOD AND APPARATUS FOR A CONTROL CIRCUIT WITH MULTIPLE OPERATING MODES
First Claim
1. A controller for a power converter, comprising:
- an oscillator coupled to a switch of the power converter to determine a time at which the switch is turned on at a beginning of a switching cycle of the switch, wherein the oscillator includes a capacitor, a charging current source coupled to charge the capacitor, and a discharging current source coupled to discharge the capacitor, wherein a time period for the capacitor to charge and discharge between first and second voltage levels is a time period of the switching cycle of the switch; and
a duty cycle mode control circuit coupled to operate in a first duty control mode in response to a feedback signal representative of an output of the power converter being between a first feedback signal value and a second feedback signal value, wherein the duty cycle mode control circuit is coupled to operate in a second duty control mode in response to the feedback signal being between the second feedback signal value and a third feedback signal value, wherein the duty cycle mode control circuit is coupled to operate in a third duty control mode in response to the feedback signal being between the third feedback signal value and a fourth feedback signal value.
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Abstract
A controller includes an oscillator coupled to a switch to determine a time at which the switch is turned on. The oscillator includes a capacitor, a charging current source and a discharging current source coupled to charge and discharge the capacitor. A time period for the capacitor to charge and discharge between first and second voltage levels is a time period of a switching cycle. A duty cycle mode control circuit is coupled to operate in a first duty control mode in response to a feedback signal being between first and second feedback signal values, operate in a second duty control mode in response to the feedback signal being a between the second and third feedback signal values, and operate in a third duty control mode in response to the feedback signal being between the third and fourth feedback signal values.
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Citations
19 Claims
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1. A controller for a power converter, comprising:
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an oscillator coupled to a switch of the power converter to determine a time at which the switch is turned on at a beginning of a switching cycle of the switch, wherein the oscillator includes a capacitor, a charging current source coupled to charge the capacitor, and a discharging current source coupled to discharge the capacitor, wherein a time period for the capacitor to charge and discharge between first and second voltage levels is a time period of the switching cycle of the switch; and a duty cycle mode control circuit coupled to operate in a first duty control mode in response to a feedback signal representative of an output of the power converter being between a first feedback signal value and a second feedback signal value, wherein the duty cycle mode control circuit is coupled to operate in a second duty control mode in response to the feedback signal being between the second feedback signal value and a third feedback signal value, wherein the duty cycle mode control circuit is coupled to operate in a third duty control mode in response to the feedback signal being between the third feedback signal value and a fourth feedback signal value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification