Current sense circuit and method for a DC-to-DC converter
First Claim
1. A current sense circuit for a DC-to-DC converter having a controller for switching a high side switch and a low side switch connected to each other by a phase node to generate an output current, the current sense circuit comprising:
- a first transconductive amplifier responsive to the output current for generating a first current for the controller to switch the high side and low side switches;
a second transconductive amplifier for generating a second current from a first voltage;
variable resistor for adjustably generating a second voltage from the second current; and
a bias apparatus for generating a bias signal from a difference between the second voltage and a third voltage to adjust a first transconductance of the first transconductive amplifier and a second transconductance of the second transconductive amplifier, whereby the first and second transconductances are adaptively adjusted in value responsive to variation of the variable resistor.
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Accused Products
Abstract
In a DC-to-DC converter, a current sense circuit and method generate a first current by a first transconductive amplifier responsive to the output current of the converter for a controller to switch a high side switch and a low side switch, a second current from a first voltage by a second transconductive amplifier, a second voltage from the second current by an adjustable resistor, and a bias signal from a difference between the second voltage and a third voltage by a bias apparatus to adjust the transconductances of the first and second transconductive amplifiers.
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Citations
17 Claims
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1. A current sense circuit for a DC-to-DC converter having a controller for switching a high side switch and a low side switch connected to each other by a phase node to generate an output current, the current sense circuit comprising:
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a first transconductive amplifier responsive to the output current for generating a first current for the controller to switch the high side and low side switches; a second transconductive amplifier for generating a second current from a first voltage; variable resistor for adjustably generating a second voltage from the second current; and a bias apparatus for generating a bias signal from a difference between the second voltage and a third voltage to adjust a first transconductance of the first transconductive amplifier and a second transconductance of the second transconductive amplifier, whereby the first and second transconductances are adaptively adjusted in value responsive to variation of the variable resistor. - View Dependent Claims (3, 4, 5, 6)
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2. A current sense circuit for a DC-to-DC converter having a controller for switching a high side switch and a low side switch connected to each other by a phase node to generate an output current, the current sense circuit comprising:
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a first transconductive amplifier responsive to the output current for generating a first current for the controller to switch the high side and low side switches; a second transconductive amplifier for generating a second current from a first voltage; a variable resistor for adjustably generating a second voltage from the second current; and a bias apparatus for generating a bias signal from a difference between the second voltage and a third voltage to adjust a first transconductance of the first transconductive amplifier and a second transconductance of the second transconductive amplifier; wherein the third voltage is substantially equal to the first voltage.
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7. A current sense method for a DC-to-DC converter having a controller for switching a high side switch and a low side switch connected to each other by a phase node to generate an output current, the method comprising the steps of:
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sensing the output current for generating a first current for the controller to switch the high side and low side switches; generating a second current from a first voltage; generating a second voltage from the second current; generating a third voltage substantially equal to the first voltage; and adaptively generating a bias signal from a difference between the second voltage and a third voltage to adjust the first and second currents, the second voltage being adjusted responsive to variation of a variable resistor. - View Dependent Claims (8)
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9. A current sense circuit for a DC-to-DC converter having a controller for modulating a plurality of channels each having a high side switch and a low side switch connected to each other by a phase node to be switched to generate a channel current, the current sense circuit comprising:
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a first transconductive amplifier responsive to each of the plurality of channel currents in turn for generating a first current for the controller to switch the high side and low side switches of each respective one of the plurality of channels; a second transconductive amplifier for generating a second current from a first voltage; variable resistor for adjustably generating a second voltage from the second current; and a bias apparatus for generating a bias signal from a difference between the second voltage and a third voltage to adjust a first transconductance of the first transconductive amplifier and a second transconductance of the second transconductive amplifier. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A current sense method for a DC-to-DC converter having a controller for modulating a plurality of channels each having a high side switch and a low side switch connected to each other by a phase node to be switched to generate a channel current, the method comprising the steps of:
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sensing the plurality of channel currents in turn for generating a first current for the controller to switch the high side and low side switches of each respective one of the plurality of channels; generating a second current substantially proportional to the first current from a first voltage; generating a second voltage from the second current; and adaptively generating a bias signal from a difference between the second voltage and a third voltage to adjust the first and second currents, the second voltage being adjusted responsive to variation of a variable resistor. - View Dependent Claims (17)
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Specification