Switch control circuit and buck converter comprising the same
First Claim
1. A switch control circuit for a power switch and a synchronous switch that are connected to an inductor, the switch control circuit comprising:
- a comparator configured to compare a detection voltage indicating a present magnitude of an inductor current flowing through the inductor with a predetermined reference voltage;
a delay unit configured to delay an output of the comparator by a zero voltage delay time; and
a dead time calculation unit configured to;
produce, by measuring an OFF time of the power switch using an OFF counter, a TOFF signal having a value corresponding to the OFF time, andcalculate a dead time based on the zero voltage delay time, the TOFF signal, and an input voltage that is input to the power switch,wherein the switch control circuit is configured to control a turn-off time of the synchronous switch according to an output of the delay unit, and turn on the power switch when the dead time passes following the turn-off time of the synchronous switch.
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Accused Products
Abstract
A buck converter includes a power switch having a first end to receive an input voltage, a synchronous switch connected between a second end of the power switch and the ground, an inductor having a first end connected to the other end of the power switch, and a switch control circuit configured to turn off the synchronous switch when a zero voltage delay time passes after an inductor current flowing through the inductor reaches a predetermined reference value, calculate a dead time based on the input voltage and the zero voltage delay time, and turn on the power switch when the dead time passes following the turn-off time of the synchronous switch.
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Citations
20 Claims
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1. A switch control circuit for a power switch and a synchronous switch that are connected to an inductor, the switch control circuit comprising:
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a comparator configured to compare a detection voltage indicating a present magnitude of an inductor current flowing through the inductor with a predetermined reference voltage; a delay unit configured to delay an output of the comparator by a zero voltage delay time; and a dead time calculation unit configured to; produce, by measuring an OFF time of the power switch using an OFF counter, a TOFF signal having a value corresponding to the OFF time, and calculate a dead time based on the zero voltage delay time, the TOFF signal, and an input voltage that is input to the power switch, wherein the switch control circuit is configured to control a turn-off time of the synchronous switch according to an output of the delay unit, and turn on the power switch when the dead time passes following the turn-off time of the synchronous switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A buck converter comprising:
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a power switch having a first end to receive an input voltage; a synchronous switch connected between a second end of the power switch and ground; an inductor having a first end connected to the second end of the power switch; and a switch control circuit configured to; receive an indication of a present magnitude of an inductor current flowing through the inductor, turn off the synchronous switch when a zero voltage delay time passes after the inductor current flowing through the inductor reaches a predetermined reference value, measure an OFF time of the power switch using an off counter, calculate a dead time based on the input voltage, the OFF time, and the zero voltage delay time, and turn on the power switch when the dead time passes following the turn-off time of the synchronous switch. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification