Synchronous Switching Power Converter with Zero Current Detection, and Method Thereof
First Claim
1. A synchronous switching power converter with zero current detection, comprising:
- an inductor;
a down bridge transistor coupled to the inductor and a ground as a synchronous rectifier as the synchronous switching power converter; and
a zero current detecting circuit comprising;
a zero current comparator coupled between the inductor and the down bridge transistor for changing state of a turn off signal to turn off the down bridge transistor when determining current on the inductor is zero;
a transient state adjusting circuit coupled to the zero current comparator for indicating a transient period when detecting state of the turn off signal is changed; and
an integrator coupled to the zero current comparator and the transient state adjusting circuit for integrating a compensation voltage by analog manner to adjust value of the compensation voltage and providing to an input end of the zero current comparator within the transient period;
wherein the zero current comparator determines the integrator to integrate positively or negatively within the transient period.
1 Assignment
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Accused Products
Abstract
Zero current detecting circuit includes a zero current comparator for determining current variation on an inductor of a synchronous switching power converter so as to accordingly turn off a down bridge transistor of the synchronous power converter; an integrator for executing integration to the signal on an input end of the zero current comparator within a transient period after the down bridge transistor is turned off, for eliminating the effect from the offset voltage of the zero current comparator; and an integration controller for determining if the down bridge transistor is turned off too early or too late so as to control the integrator to positively or negatively integrate.
9 Citations
13 Claims
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1. A synchronous switching power converter with zero current detection, comprising:
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an inductor; a down bridge transistor coupled to the inductor and a ground as a synchronous rectifier as the synchronous switching power converter; and a zero current detecting circuit comprising; a zero current comparator coupled between the inductor and the down bridge transistor for changing state of a turn off signal to turn off the down bridge transistor when determining current on the inductor is zero; a transient state adjusting circuit coupled to the zero current comparator for indicating a transient period when detecting state of the turn off signal is changed; and an integrator coupled to the zero current comparator and the transient state adjusting circuit for integrating a compensation voltage by analog manner to adjust value of the compensation voltage and providing to an input end of the zero current comparator within the transient period; wherein the zero current comparator determines the integrator to integrate positively or negatively within the transient period. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for controlling a down bridge transistor of a synchronous switching power converter, comprising:
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detecting size of current on an inductor coupled to the down bridge transistor of the synchronous switching power converter for generating a current information; when the current information and a compensation voltage meets to a predetermined relation, turning off the down bridge transistor; and within a transient period after turning off the down bridge transistor, integrating the compensation voltage in analog manner to adjust value of the compensation voltage to expected ideal value. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification