Digital average input current control in power converter
First Claim
1. A method, comprising:
- transferring a converter from a boost mode to an alternating buck-boost mode in response to a duty cycle dropping below a first predetermined value for at least a first predetermined number of cycles; and
transferring the converter from the alternating buck-boost mode to the boost mode in response to the duty cycle climbing above a second predetermined value for at least a second predetermined number of cycles.
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Accused Products
Abstract
A digital average-input current-mode control loop for a DC/DC power converter. The power converter may be, for example, a buck converter, boost converter, or cascaded buck-boost converter. The purpose of the proposed control loop is to set the average converter input current to the requested current. Controlling the average input current can be relevant for various applications such as power factor correction (PFC), photovoltaic converters, and more. The method is based on predicting the inductor current based on measuring the input voltage, the output voltage, and the inductor current. A fast cycle-by-cycle control loop may be implemented. The conversion method is described for three different modes. For each mode a different control loop is used to control the average input current, and the control loop for each of the different modes is described. Finally, the algorithm for switching between the modes is disclosed.
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Citations
23 Claims
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1. A method, comprising:
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transferring a converter from a boost mode to an alternating buck-boost mode in response to a duty cycle dropping below a first predetermined value for at least a first predetermined number of cycles; and transferring the converter from the alternating buck-boost mode to the boost mode in response to the duty cycle climbing above a second predetermined value for at least a second predetermined number of cycles. - View Dependent Claims (2, 3, 4, 5, 22, 23)
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6. An apparatus, comprising:
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an inductor; and control logic configured to; switch the apparatus from a boost mode to an alternating buck-boost mode in response to a duty cycle dropping below a first predetermined value for at least a first predetermined number of cycles; switch the apparatus from a buck mode to an alternating buck-boost mode in response to the duty cycle climbing above a second predetermined value for at least a second predetermined number of cycles; switch the apparatus from an alternating buck-boost mode to a boost mode in response to the duty cycle climbing above a third predetermined value for at least a third predetermined number of cycles; and switch the apparatus from an alternating buck-boost mode to a buck mode in response to the duty cycle dropping below a fourth predetermined value for at least a fourth predetermined number of cycles. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A DC to DC converter, comprising:
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an inductor; one or more switches; and control logic configured to; switch the converter from a boost mode to an alternating buck-boost mode in response to a duty cycle dropping below a first predetermined value for at least a first predetermined number of cycles; switch the converter from a buck mode to an alternating buck-boost mode in response to the duty cycle climbing above a second predetermined value for at least a second predetermined number of cycles; switch the converter from an alternating buck-boost mode to a boost mode in response to the duty cycle climbing above a third predetermined value for at least a third predetermined number of cycles; and switch the converter from an alternating buck-boost mode to a buck mode in response to the duty cycle dropping below a fourth predetermined value for at least a fourth predetermined number of cycles. - View Dependent Claims (18, 19, 20, 21)
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Specification