Whole-course adjustable digital pulse width modulator based on oscillation ring circuit

Abstract

The invention relates to a whole-course adjustable digital pulse width modulator based on an oscillation ring circuit, which comprises an oscillation ring-counting comparator circuit and an output logic circuit, wherein the oscillation ring circuit is formed by connecting k stages of D triggers end to end and used for generating a reset signal required by the D trigger and output by the output logic circuit together with a multi-channel gating device and the counting comparator circuit according to an digital duty cycle control signal externally input, thereby resetting an output signal of the output D trigger to a low level; and the clock end of the output D trigger is used for controlling a high level at the input end to be transferred to the output end, and the reset signal and a clock signal act jointly for finally generating a duty cycle signal at the output end. The whole-course adjustable digital pulse width modulator can not only keep the advantages of a conventional oscillation ring structure digital pulse width modulator, but also enlarge the adjustable range of output duty cycle, thereby being very applicable to being integrated in high-frequency DC(direct current)-DC switching mode power supplies (SMPS) in power supply management systems of miniature handheld devices.

Description

technical field [0001] The invention relates to an integrated electronic circuit design of a digital pulse width modulator, which is especially suitable for a high-frequency DC-DC switching power supply integrated in a power management system of a small hand-held device, and belongs to the field of electronic technology. Background technique [0002] Due to the flexible digital control method, low sensitivity to external influences, and can be realized with a small number of external passive components, the application of digital control to switching power supplies can also simplify the design configuration of diverse load power supplies, and automatic digital design tools Allows rapid modification of existing designs to accommodate new requirements, enabling significant improvements in power system performance in portable consumer electronics and the like. [0003] In the application of low-power digitally controlled switching power supply, the switching frequency of digita...

AI Technical Summary

Problems solved by technology

However, the DPWM with the oscillation ring structure uses the RS latch in the output logic circuit, and its set (S) terminal signal is obtained by several signal logics such as a counter and a comparator. The secondary setting error, and then the output pulse width signal is wrong when the duty ratio is small

Therefore, the output pulse width signal in this structure is affected by the number of counter bits m limit, cannot correctly generate lower than (1 / 2 m )×100% duty cycle signal, which reduces the effective resolution of DPWM, thereby affecting the adjustment speed and accuracy of the output voltage of the power supply

[0005] Therefore, when using the DPWM with an oscillatory ring structure, it needs to be optimized to solve the problem that the duty cycle of the output pulse width signal cannot be adjusted in a full range while ensuring the advantages of the structure

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