CN102751853B - A Novel Push-Pull PWM Signal Generation Circuit for Digital Power Supply - Google Patents

Abstract

A kind of production method for recommending pwm signal of novel digital power.It is for the scheme designed by many single-chip microcomputers containing PWM module, this single-chip microcomputer can produce the complementary pwm signal of two-way and dead time is adjustable, but it can not produce and recommend pwm signal needed for push-pull circuit, can produce this single-chip microcomputer by the method for the present invention and recommend pwm signal.The invention is characterized in produce the complementary pwm signal of two-way first, the dutycycle for setting the complementary pwm signal of two-way again is 50%, two-way dutycycle is thus obtained and has recommended pwm signal for 50%, then the dutycycle for recommending pwm signal is changed between 0~50% by adjusting the size of dead time.

Description

A Novel Push-Pull PWM Signal Generation Circuit for Digital Power Supply

Technical field:

In a power electronic circuit, a circuit that generates a push-pull PWM (pulse width modulation) signal.

Background technique:

In power electronic circuits, digital power supply is a hot spot and trend of recent research, and it is also very common to use single-chip microcomputer control. Many microcontrollers with PWM modules cannot generate the push-pull PWM signal required by the push-pull circuit, but they can generate two complementary PWM signals with adjustable dead time. The invention can make the above-mentioned single-chip microcomputer generate the push-pull PWM signal required by the push-pull circuit. Among them, the push-pull PWM signal mentioned in the present invention refers to the PWM signal with the same two-way cycle, the duty ratio is equal, and the phase difference is half a cycle, as shown in Figure 2; the two-way complementary PWM signal refers to the two-way PWM signal. The cycle of the signal is the same, and the signal level state is opposite at any moment, as shown in Figure 1; the dead time means that the PWM signal should jump from low level to high level (high level is active) at time _t1 , But in fact, after a delay time, it jumps from low level to high level at time t ₂ , this delay time t _d =t ₂ -t ₁ is the dead time, as shown in Figure 3 .

Invention content:

In the field of digital power control, many single-chip microcomputers containing PWM modules cannot generate push-pull PWM signals required by push-pull circuits, but they can generate two complementary PWM signals with adjustable dead time. In order to allow the aforementioned single-chip microcomputer to generate a push-pull PWM signal, the present invention proposes a novel generating circuit for a push-pull PWM signal of a digital power supply.

Technical solutions:

In the field of digital power control, many single-chip microcomputers containing PWM modules cannot generate push-pull PWM signals required by push-pull circuits, but they can generate two complementary PWM signals with adjustable dead time. The present invention is a novel scheme for making the aforementioned single-chip microcomputer generate the PWM signal required by the push-pull circuit. The specific steps of the program are: first, make the PWM module of the single-chip microcomputer output two complementary PWM signals; second, set the duty cycle of the two complementary PWM signals to be 50%, so that the complementary PWM signals becomes a push-pull PWM signal, and the duty cycle of the push-pull PWM signal at this time is 50%; thirdly, the duty cycle of the push-pull PWM signal can be changed between 0 and 50% by adjusting the dead time, thus required by the push-pull PWM signal. The core of the present invention is to set the duty cycle of two complementary PWM signals to be 50%, so that it becomes a push-pull PWM signal with a duty cycle of 50%, and then the duty cycle of the push-pull PWM signal is adjusted by adjusting the dead time. The ratio varies from 0 to 50%.

Beneficial effects of the present invention:

In the field of digital power control, many single-chip microcomputers containing PWM modules cannot generate push-pull PWM signals required by push-pull circuits, but they can generate two complementary PWM signals with adjustable dead time. The present invention is a novel scheme for making the aforementioned single-chip microcomputer generate the PWM signal required by the push-pull circuit. The scheme not only meets the actual needs, but also is simple and economical.

Description of drawings:

Figure 1 is a waveform diagram of two complementary PWM signals.

Figure 2 is a waveform diagram of a push-pull PWM signal.

Figure 3 is a waveform diagram of the dead time.

detailed description:

Below in conjunction with PIC16F616 single-chip microcomputer illustrate the implementation method of the present invention.

PIC16F616 has a PWM module, and the dead time is adjustable. The following settings allow the PIC16F616 microcontroller to output two push-pull PWM signals with a period of 40us and an adjustable duty cycle between 0 and 50%. Its specific implementation plan is: the first step, in the PWM module that comes with PIC16F616, select the half-bridge mode by setting the register CCP1CON to 0x8c, and output two complementary PWM signals; the second step, set the register PR2 to 119, CCPR1L is 60, so that the period of the two complementary PWM signals is 40us, and the duty cycle is 50%. Such a signal is also a push-pull PWM signal with a duty cycle of 50%. The dead time is adjusted so as to output the push-pull PWM signal whose duty cycle required by the push-pull circuit varies between 0% and 50%. The core point of the present invention is to set the duty cycle of two complementary PWM signals to 50%, and then output the push-pull PWM signal required by the push-pull circuit by adjusting the dead time. .

Claims (2)

1. a kind of novel digital power recommends pwm signal generation circuit, it is characterized in that：Including hardware and software, its hardware It is made up of the interior single-chip microcomputer containing PWM module, and the PWM module can not produce the pwm signal of recommending needed for push-pull circuit, but The complementary pwm signal of two-way can be produced and dead time is adjustable；Its software algorithm is, the first step, by setting single-chip microcomputer Register the single-chip microcomputer is exported the complementary pwm signal of two-way, second step, by setting the register of single-chip microcomputer to make two-way The dutycycle of complementary PWM signals is 50%, such signal be also two-way dutycycle for 50% pwm signal of recommending, the 3rd step, Dead time is adjusted by the value for the register for changing single-chip microcomputer, by adjusting dead time can make to recommend pwm signal Dutycycle changes between 0~50%, so that recommending of changing between 0~50% of the dutycycle needed for exporting push-pull circuit Pwm signal.

2. according to claim 1 recommend pwm signal generation circuit, it is characterized in that：Single-chip microcomputer is PIC16F616.