Zero Current Detecting Circuit and Related Synchronous Switching Power Converter
AssigneeAnpec Electronics Corporation
InventorsKe-Horng Chen, Tzu-Yang Yen
Life of this patent
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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.
Claims13
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.
A synchronous switching power converter with zero current detecting, comprising:
- 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.
A zero current detecting method for a synchronous switching power converter, comprising:
- 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.
Dependencies are inferred from the claim text.