Hybrid control circuit and method
AssigneeRichtek Technology Corporation
InventorsHung-Shou Nien, Kuang-Yao Cheng, Yi-Chiang Fu, Wei-Hsu Chang
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Abstract
A hybrid control circuit and method combine analog circuit and digital circuit to generate digital PWM signals for a multiphase DC-DC converter to generate an output voltage. For current balance control, analog current error signals are generated by the analog circuit from analog phase current signals of the multiphase DC-DC converter and then converted into digital current error signals for calculating the duties of each phase of the multiphase DC-DC converter. Therefore, fewer bit devices can be used to achieve precise current balance control and the size and cost of the circuit can be reduced.
Claims21
A hybrid control circuit for providing a plurality of digital PWM signals to control a multiphase DC-DC converter to generate an output voltage, the hybrid control circuit comprising:
- a current balance controller including:
- an analog average-current generator for averaging analog phase-current signals of all phases of the multiphase DC-DC converter to generate an analog average-current signal;
- a first analog error generator connected to the analog average-current generator for comparing each of the analog phase-current signals with the analog average-current signal to generate an analog current error signal for each of the phases;
- and
- a first analog-to-digital converter connected to the first analog error generator for converting each of the analog current error signals into a digital current error signal;
- a voltage controller for monitoring the output voltage to generate a digital voltage error signal;
- a combiner connected to the current balance controller and the voltage controller for combining each of the digital current error signals with the digital voltage error signal to generate duty control signals for each of the phases;
- and
- a digital pulse-width modulator connected to the combiner for calculating duties for each of the phases according to the duty control signals, so as to generate the plurality of digital PWM signals.
A hybrid control method for providing a plurality of digital PWM signals to control a multiphase DC-DC converter to generate an output voltage, the hybrid control method comprising:
- (A) averaging analog phase-current signals of all phases of the multiphase DC-DC converter for generating an analog average-current signal;
- (B) comparing each of the analog phase-current signals with the analog average-current signal for generating an analog current error signal for each of the phases;
- (C) converting each of the analog current error signals into a digital current error signal;
- (D) monitoring the output voltage for generating a digital voltage error signal;
- (E) combining each of the digital current error signals with the digital voltage error signal for generating duty control signals for each of the phases;
- and
- (F) calculating duties for each of the phases according to the duty control signals for generating the plurality of digital PWM signals.
Dependencies are inferred from the claim text.