Dual-phase constant on-time power converter and control method
AssigneeM3 Technology Inc.
InventorsBo Yang, Xiaoyu Xi, David Meng
Life of this patent
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Abstract
An apparatus includes a ramp generator configured to produce a set signal for determining a phase shift between a first phase and a second phase of a power converter, a first phase on-timer configured to produce a first reset signal for determining a turn-on time of a high-side switch of the first phase of the power converter, a second phase on-timer configured to produce a second reset signal for determining a turn-on time of a high-side switch of the second phase of the power converter, and a control logic block configured to generate gate drive signals for the first phase and the second phase of the power converter based on the set signal, the first reset signal and the second reset signal.
Claims18
An apparatus comprising:
- a ramp generator configured to produce a set signal for determining a phase shift between a first phase and a second phase of a power converter;
- a first phase on-timer configured to produce a first reset signal for determining a turn-on time of a high-side switch of the first phase of the power converter, wherein the first phase on-timer comprises a first current source and a first capacitor connected in series between an input of the power converter and ground, and wherein a current flowing through the first current source is proportional to an input voltage of the power converter, and wherein the input of the power converter is directly connected to the high-side switch of the first phase of the power converter, and wherein the first phase on-timer further comprises a switch connected in parallel with the first capacitor, and wherein a gate of the switch is controlled by a gate drive signal of a low-side switch of the first phase of the power converter, and a comparator having a non-inverting input connected to a common node of the first current source and the first capacitor, an inverting input configured to receive a reference voltage equal to a product of the input voltage of the power converter and a duty cycle of the power converter, and an output configured to generate the first reset signal;
- a second phase on-timer configured to produce a second reset signal for determining a turn-on time of a high-side switch of the second phase of the power converter;
- and
- a control logic block configured to generate gate drive signals for the first phase and the second phase of the power converter based on the set signal, the first reset signal and the second reset signal.
A method comprising:
- generating a ramp for determining a phase shift between a first phase and a second phase of a power converter;
- generating a plurality of set signals, wherein two adjacent set signals are used to determine a turn-on instant of a high-side switch of the first phase and a turn-on instant of a high-side switch of the second phase of the power converter, respectively, wherein generating the plurality of set signals comprises converting the ramp into a first current, converting a difference between an error signal and a feedback signal into a second current, feeding a combination of the first current and the second current into a resistor to generate a triangular waveform and comparing the triangular waveform with a predetermined reference to generate the plurality of set signals;
- generating a plurality of first reset signals for determining turn-off instants of the high-side switch of the first phase, wherein the plurality of first reset signals is generated by an on-timer comprising a current source and a capacitor connected in series between an input of the power converter and ground, and wherein a current flowing through the current source is proportional to an input voltage of the power converter, and wherein the input of the power converter is directly connected to high-side switches of the power converter;
- and
- generating a plurality of second reset signals for determining turn-off instants of the high-side switch of the second phase.
Dependencies are inferred from the claim text.