Current output digital-to-analog conversion circuit based on PWM (pulse width modulation)

An output digital-to-analog conversion technology, which is applied in the field of current output digital-to-analog conversion circuits, can solve the problems of D/A conversion module precision not meeting development requirements, high price, and increased product cost, and achieve good anti-interference and reliability The effect of high reliability, low cost and stable work

Inactive Publication Date: 2018-05-29
曹玲
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In the development process of automatic instruments and sensors, D/A converters are often involved. However, many control devices do not integrate D/A inside, or the accuracy of D/A conversion module

Method used

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  • Current output digital-to-analog conversion circuit based on PWM (pulse width modulation)
  • Current output digital-to-analog conversion circuit based on PWM (pulse width modulation)
  • Current output digital-to-analog conversion circuit based on PWM (pulse width modulation)

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Embodiment Construction

[0017] The present invention will be further described below in conjunction with drawings and embodiments.

[0018] Such as figure 1 , The current output digital-to-analog conversion circuit adds an optocoupler isolation chip at the output of the microcontroller. The circuit chip uses TP521 to isolate and shape the input PWM wave. Under the action of the 5V module power supply, the PWM output from different microcontrollers is shaped. It is a PWM optocoupler isolation with a high level of 5V and a low level of almost 0. The high and low level operating current output by the controller is related to the ambient temperature, and because the circuit may use different types of microcontroller devices, the obtained high and low level values ​​of PWM are also different.

[0019] Such as figure 2 , The function of the passive filter network is to filter out the high-frequency harmonics of the PWM wave, so that the back-end circuit can obtain a DC voltage with little fluctuation. T...

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PUM

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Abstract

The invention discloses a current output digital-to-analog conversion circuit based on PWM (pulse width modulation). The circuit is suitable for the field of the communication; a conversion circuit iscomposed of a current output digital-to-analog conversion circuit, a passive filtering network, an amplifying circuit, and a voltage-current conversion circuit. The circuit is compact in structure, small in volume, low in cost, stable in work, high in precision and resolution, and has good interference resistance and reliability.

Description

technical field [0001] The invention relates to a current output digital-to-analog conversion circuit based on PWM, which is suitable for the communication field. Background technique [0002] Digital-to-analog conversion is the conversion of discrete digital quantities into analog quantities with varying connections. Although voltage output type DA converters output voltage directly from the resistor array, they generally use a built-in output amplifier to output with low impedance. Devices that directly output voltage are only used for high-impedance loads, and are often used as high-speed DA converters because there is no delay in the output amplifier part. Digital-to-analog converter, also known as D / A converter, or DAC for short, is a device that converts digital quantities into analog. The D / A converter basically consists of 4 parts, namely weight resistor network, operational amplifier, reference power supply and analog switch. Digital-to-analog converters are gene...

Claims

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Application Information

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IPC IPC(8): H03M1/82
CPCH03M1/822
Inventor 曹玲
Owner 曹玲
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