Zero Current Detecting Circuit and Related Synchronous Switching Power Converter
First Claim
1. A zero current detecting circuit, comprising:
- a first 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 switching power converter;
a second zero current comparator for determining whether the first zero current comparator turns off the down-bridge transistor too early or too late, and outputting a comparison result;
a counter coupled to the second zero current comparator for ascending or descending a control bit according to the comparison result; and
an adjustable voltage source coupled to the first zero current comparator and the counter for adjusting a offset voltage according to the control bit.
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Accused Products
Abstract
A zero current detecting circuit is disclosed. The zero current detecting circuit includes a first 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; a second zero current comparator for determining whether the first zero current comparator turns off the down-bridge transistor too early or too late and outputting a comparison result, and a counter coupled to the second zero current comparator for ascending or descending a control bit according to the comparison result.
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Citations
13 Claims
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1. A zero current detecting circuit, comprising:
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a first 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 switching power converter; a second zero current comparator for determining whether the first zero current comparator turns off the down-bridge transistor too early or too late, and outputting a comparison result; a counter coupled to the second zero current comparator for ascending or descending a control bit according to the comparison result; and an adjustable voltage source coupled to the first zero current comparator and the counter for adjusting a offset voltage according to the control bit. - View Dependent Claims (2, 3, 4, 5)
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6. A synchronous switching power converter with zero current detecting, comprising:
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an up-bridge transistor comprising; a first terminal coupled to an input power supply; a second terminal; and a third terminal for receiving a turned-on signal; a down-bridge transistor comprising; a first terminal coupled to a ground; a second terminal coupled to the second terminal of the up-bridge transistor; and a third terminal for receiving a turned-off signal; an inductor coupled between the second terminal of the down-bridge transistor and an output capacitor; and a zero current detecting circuit comprising; a first zero current comparator for determining current variation on the inductor of a synchronous switching power converter so as to accordingly turn off a down-bridge transistor of the synchronous switching power converter; a second zero current comparator for determining whether the first zero current comparator turns off the down-bridge transistor too early or too late and outputting a comparison result; a counter coupled to the second zero current comparator for ascending or descending a control bit according to the comparison result; and an adjustable voltage source coupled to the first zero current comparator and the counter for adjusting an offset voltage according to the control bit. - View Dependent Claims (7, 8, 9, 10)
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11. A zero current detecting method for a synchronous switching power converter, comprising:
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determining current variation on an inductor of a synchronous switching power converter to accordingly turn off a down-bridge transistor of the synchronous switching power converter; determining whether the down-bridge transistor is turned off too early or too late and outputting a comparison result; ascending or descending a control bit according to the comparison result; and adjusting an offset voltage according to the control bit. - View Dependent Claims (12, 13)
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Specification