ADC transfer function providing improved dynamic regulation in a switched mode power supply
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Accused Products
Abstract
A power supply comprises at least one power switch adapted to convey power between input and output terminals of the power supply, and a digital controller adapted to control operation of the at least one power switch responsive to an output measurement of the power supply. The digital controller comprises an analog-to-digital converter providing a digital error signal representing a voltage difference between the output measurement and a reference value, a digital filter providing a digital control output based on a sum of previous error signals and previous control outputs, an error controller adapted to modify operation of the digital filter upon an error condition, and a digital pulse width modulator providing a control signal to the power switch having a pulse width corresponding to the digital control output. The analog-to-digital converter further comprises a windowed flash analog-to-digital converter having a transfer function defining a relationship between the voltage difference and corresponding digital values. The transfer function provides a substantially linear region at a center of a corresponding error window, including a first step size in the center of the error window and at least one other step size in a peripheral region of the error window that is larger than the first step size. The first step size and the other step sizes may each reflect a linear relationship between the voltage difference and the corresponding digital values. Alternatively, the first step size reflects a linear relationship between the voltage difference and the corresponding digital values, and the other step sizes each reflect a non-linear relationship between the voltage difference and the corresponding digital values.
107 Citations
55 Claims
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1-25. -25. (canceled)
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26. A switched mode power supply comprising:
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at least one power switch adapted to convey power between input and output terminals of said power supply; and
a digital controller adapted to control operation of said at least one power switch responsive to an output measurement of said power supply, said digital controller comprising;
an analog-to-digital converter providing a digital error signal representing a voltage difference between said output measurement and a reference value, said analog-to-digital converter further comprises a windowed flash analog-to-digital converter having a transfer function defining a relationship between said voltage difference and corresponding digital values, said transfer function having a substantially linear region at a center of a corresponding error window, said transfer function further comprises a first step size in said center of said error window and at least one additional step size in a peripheral region of said error window, each said at least one additional step size being larger than said first step size;
a digital filter transforming the digital error signal to a digital control output; and
a digital pulse width modulator providing a control signal to said at least one power switch, said control signal having a pulse width corresponding to said digital control output. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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47. A method of controlling a switched mode power supply comprising at least one power switch adapted to convey power between input and output terminals of said power supply, said method comprising:
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receiving an output measurement of said power supply;
sampling said output measurement to provide a digital error signal representing a voltage difference between said output measurement and a reference value in accordance with a transfer function defining a relationship between said voltage difference and corresponding digital values, said transfer function having a substantially linear region at a center of a corresponding error window, said transfer function further comprising a first step size in said center of said error window and at least one other step size in a peripheral region of said error window, each said at least one other step size being larger than said first step size;
filtering said digital error signal to provide a digital control output based on said digital error signal; and
providing a control signal to said at least one power switch, said control signal having a pulse width corresponding to said digital control output. - View Dependent Claims (48, 49, 50, 51, 52, 53, 54, 55)
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Specification