DVS-Buck converter used for digitally controlling output voltage and provided with timed self-calibration function

Abstract

The invention relates to a DVS-Buck converter used for digitally controlling output voltage and provided with a timed self-calibration function. The DVS-Buck converter comprises a main circuit and a control loop, wherein the main circuit comprises a power switch MP, a power switch MN and an inductor L; a source of the power switch MP is connected with the input voltage, and a drain of the power switch MP is connected with a node A; a source of the power switch MN is grounded, and a drain of the power switch MN is connected with the node A; the node A passes through the inductor L and outputs the voltage Vout; and the control loop comprises an analog to digital converter (ADC), a compensator, a clock generator, a timed self-calibration module, a digital pulse width modulator, a dead zone controller and a power metal oxide semiconductor (MOS) driver. According to the digitally controlled DVS function, a power module can be compatible with a digital control system such as a micro control unit, and the high dynamic loss is avoided; and moreover, the clock setting of the system, the timed self-calibration of the digital pulse width modulator (DPWM) and the like are unified, and the stability of the control system is improved.

Description

【Technical field】 [0001] The invention belongs to the technical field of converters, in particular to a Buck converter with a dynamic voltage adjustment (DVS) function. 【Background technique】 [0002] Digitally controlled Buck converter includes Buck main circuit, ADC, digital compensator and digital pulse width modulator (DPWM), such as figure 1 shown. [0003] By controlling the switching action of the power transistor NMOS and PMOS in the Buck main circuit, the power output of the converter is controlled; the ADC completes the signal sampling and converts it into a digital quantity for processing by the lower-level module, which is a digital-analog interface; the digital compensator converts the digital signal. Filtering and other processing, through the embedded PID algorithm to process the signal, to achieve system stability and fast response; the digital pulse width modulator converts the output digital signal of the compensator into a duty ratio signal, controls the ...

AI Technical Summary

Problems solved by technology

[0008] First, the system clock problem

The existing circuit structure uses independent clocks to control each module, which is not conducive to system synchronization and is prone to error accumulation

The delay due to different clocks will produce a phase shift in the discrete time domain, causing system stability problems, and this problem will bring great difficulty to the design of compensation due to the randomness of the delay.

[0009] Second, the control signal problem

However, when high-frequency signals are used to control switching converters, a series of problems will arise. For example, the frequency detection module will generate signal oscillation inside the power supply, and high-frequency noise will affect the stability of the system loop; at the same time, high-frequency signals (usually reaching hundreds of MHz) also produces a higher dynamic power loss

[0010] Third, the traditional DPWM modulator does not have a self-calibration function, which will cause the error signal to deviate from the correct value after a large number of cycles, resulting in unacceptable system errors

[0011] Fourth, the soft start circuit problem

In existing converters, an additional soft-start circuit needs to be designed, which increases the design workload and complexity

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