A single inductor multiple output DC-DC converter and its control method

Abstract

The invention discloses a single-inductance multi-output DC-DC converter and a control method thereof. The converter includes a single-inductance multi-output DC-DC converter power stage, a current / voltage sampling circuit, a voltage ADC module, and an error signal generator. module, multi-channel voltage PI module, duty ratio redistribution module, multi-channel digital pulse width modulation module, adder / subtractor, current PI module, digital pulse width modulation module, new duty cycle sum generation module, switch logic, dead Zone control and drive circuits. In the present invention, the old duty cycle signal is stretched and controlled in proportion to reduce the cross adjustment rate of the converter; at the same time, the Sigma-Delta truncation is used to reduce the bit width of the signal while ensuring accuracy and saving hardware calculations. resources, increase computing speed, and save costs. As a single-inductance multi-output DC-DC converter and a control method thereof, the present invention can be widely applied in the field of electronic technology.

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 (SIMO) DC-DC converter is a new type of switching power supply topology. In this type of converter, each output channel shares the same inductor, so as to save inductance, reduce the volume of the converter, and save costs. [0003] At present, there are two main charging and discharging schemes for single-inductor multi-output DC-DC converters: one is the Time Multiplexing (TM) control method, that is, in one cycle, for each channel, it is Charge the inductor first, 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 discharges is also n. The characteristic of this control method is that there are too many switching actions in the cycle and the switchi...

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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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