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 circuits;
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.
81 Citations
24 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 circuits; 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)
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Specification