Single-inductor multi-output DC-DC converter and control method thereof

Abstract

The invention discloses a single-inductor multi-output DC-DC converter and a control method thereof. The converter comprises a single-inductor multi-output DC-DC converter power stage, a current / voltage sampling circuit, a voltage analog-to-digital converter (ADC) module, an error signal generation module, a multi-path circuit proportional integral (PI) module, a duty ratio re-allocation module, a multi-path digital pulse width modulation module, a summator / subtracter, a current PI module, a digital pulse width modulation module, a new duty ratio total sum generation module, a switch logic and a dead zone control and driving circuit. By stretching and contracting an old duty ratio signal according to proportion to further control, and the cross regulation rate of the converter is reduced; meanwhile, the signal bit width is reduced by Sigma-Delta truncation during telescopic conversion, meanwhile, the precision is ensured, hardware calculation resources are saved, the calculation speed is increased, and the cost is reduced. The single-inductor multi-output DC-DC converter and the control method thereof can be widely applied to the technical field of electronics.

Description

technical field [0001] The invention relates to the field of electronic technology, in particular to a single-inductance multi-output DC-DC converter and a control method thereof. Background technique [0002] Single-Inductor Multiple-output (Single-InductorMultiple-output, SIMO) DC-DC converter is a new topology of switching power supply. In this type of converter, each output channel shares the same inductance, thereby achieving the purpose of saving inductance, reducing the size of the converter, and saving costs. [0003] At present, there are mainly two charging and discharging schemes for single-inductor multi-output DC-DC converters: one is Time Multiplexing (TM) control method, that is, in one cycle, for each channel, the first Charge the inductor, and then the inductor discharges the channel. For an n-channel converter, the number of times the inductor is charged is n, and the number of times it is discharged is also n. The characteristic of this control method i...

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Problems solved by technology

However, this control method also has disadvantages. Since each channel shares the same inductor, and the duty cycle of each channel is not independent of each other, when the output load current of one of the channels changes, the average value of the inductor current and the The duty cycle of the channel will also change accordingly, and the changing average value of the inductor current and the duty cycle of the channel will affect the output voltage of other channels, thus resulting in cross adjustment

Cross adjustment will not only increase the voltage ripple of other channels, but in severe cases, it will make the system unstable and affect the normal operation of the system

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