Synthetic ripple regulator
First Claim
1. A synthetic ripple voltage generator for a DC-DC regulator having a hysteretic comparator that develops a pulse width modulation (PWM) signal provided to a switching circuit that switches an input voltage via a phase node through an output inductor to develop an output voltage at an output node, said synthetic ripple voltage generator comprising:
- a transconductance amplifier circuit having an input for coupling to the output inductor and an output for coupling to an input of the hysteretic comparator; and
a ripple capacitor coupled to said output of said transconductance amplifier circuit;
wherein said transconductance amplifier circuit provides current to said ripple capacitor which develops a voltage indicative of ripple current through the output inductor.
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Accused Products
Abstract
A synthetic ripple regulator including a synthetic ripple voltage generator that generates a synthetic ripple voltage indicative of the ripple current through an output inductor. The regulator uses the synthetically generated ripple voltage to control toggling of a hysteretic comparator for developing the pulse width modulation (PWM) signal that controls switching of the regulator. In a non-limiting implementation, a transconductance amplifier monitors the phase node voltage of the inductor and supplies an inductor voltage-representative current to a ripple capacitor, which produces the synthetic ripple voltage. Using the replicated inductor current for ripple regulation results in low output ripple, input voltage feed forward, and simplified compensation.
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Citations
38 Claims
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1. A synthetic ripple voltage generator for a DC-DC regulator having a hysteretic comparator that develops a pulse width modulation (PWM) signal provided to a switching circuit that switches an input voltage via a phase node through an output inductor to develop an output voltage at an output node, said synthetic ripple voltage generator comprising:
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a transconductance amplifier circuit having an input for coupling to the output inductor and an output for coupling to an input of the hysteretic comparator; and a ripple capacitor coupled to said output of said transconductance amplifier circuit; wherein said transconductance amplifier circuit provides current to said ripple capacitor which develops a voltage indicative of ripple current through the output inductor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of synthetically generating ripple voltage for a DC-DC regulator including a hysteretic comparator that develops a pulse width modulation (PWM) signal provided to a switching circuit that switches an input voltage via a phase node through an output inductor to develop an output voltage at an output node, said method comprising:
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developing a ripple voltage indicative of current through the output inductor; and applying the ripple voltage to an input of the hysteretic comparator. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A synthetic ripple regulator, comprising:
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a hysteretic comparator having a first input and having an output that provides a pulse width modulation (PWM) signal; a switching circuit that alternately couples a phase node to opposite polarities of an input voltage source based on said PWM signal; an output inductor coupled between said phase node and an output node that develops a regulated output signal; a transconductance amplifier circuit having an input coupled to said output inductor and an output coupled to said first input of said hysteretic comparator; and a capacitor, coupled to said output of said transconductance amplifier circuit, that develops a ripple voltage indicative of ripple current through said output inductor. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28)
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29. A synthetic ripple voltage generator for a DC-DC regulator having a hysteretic comparator that develops a pulse width modulation signal provided to a switching circuit that controls switching of voltage across an output inductor which is coupled to an output node developing an output voltage, said synthetic ripple voltage generator comprising:
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a transconductance amplifier circuit having an input for coupling to the output inductor and an output for coupling to an input of the hysteretic comparator; and a ripple capacitor coupled to said output of said transconductance amplifier circuit; wherein said transconductance amplifier circuit provides current to said ripple capacitor which develops a voltage indicative of tipple current through the output inductor. - View Dependent Claims (30, 31, 32)
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33. A method of synthetically generating ripple voltage for a DC-DC regulator including a hysteretic comparator that develops a pulse width modulation signal provided to a switching circuit that controls switching of voltage applied to an output inductor coupled to an output node which develops an output voltage, said method comprising:
- developing a ripple voltage indicative of current through the output inductor; and
applying the ripple voltage to an input of the hysteretic comparator. - View Dependent Claims (34, 35, 36, 37, 38)
- developing a ripple voltage indicative of current through the output inductor; and
Specification