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Application of APC&PAC chip in electronic system

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Mar 13, 2022
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APC&PAC IC is a kind of new signal chain IC, which based on ADC&DAC taking the PWM signal as its digital interface. APC= Analog to PWM Convertor;PAC=PWM to Analog Convertor. The characteristics of APC&PAC ICs are converting between analog value and the duty cycle of PWM signal according to the linear relation, which achieved analog-to-digital and digital-to-analog conversion

Which kind of electronic system will apply APC&PAC ICs?

Application 1: Occasions of signal isolation and acquisition

Analog signals usually depend on linear optocoupler or isolated operational amplifier to isolated transfer and acquire, but under comprehensive consideration on the linear velocity, congruence, reliability and cost, etc., APC&PAC chip can be seen as a cost-effective solution for this kind of application.

In instruments, sensors, transmitters, PLC and other equipment, 4-20mA、0-10V signals can be seen as the standard analog signal interface, and it is often necessary to electrically isolate analog signals for the signal interference of Industrial site.

Taking the isolated 4-20mA output as an example: the single chip MCU outputs the PWM signal, and the PWM signal isolated by the optocoupler is transmitted to the PAC GP8301, linearly convert the duty cycle of PWM signal into 4-20mA current output. In this solution, PAC chip GP8301 integrates 12bit DAC and 4-20mA drive circuit, and the overall circuit is very simple. The output current Iout=5V/Rset*Duty, Duty = The duty cycle of MCU outputs PWM signal.

Application 2: In DLP in laser TV controling, convert PWM to voltage for LED color adjuest

In the laser TV based on DLP technology, DLP IC output multichannel PWM signal, converting PWM signal into Voltage signal to adjust LED color. Due to the needs of display, the high speed PWM needs high speed capture and conversion, PAC IC GP8501 can help to achieve this function, which convert PWM signal of 0%-100% duty cycle into 0-2.5V/0-VCC voltage output.

Application 3: 0-10V speed regulating interface in EC electric machinery

In general, speed regulation relies on analog volume(0-10V/0-5V)or PWM signal, especially the new EC electric machinery. The driving motor is directly driven by 220V/110V/380V AC, however, the speed regulating interface is in low voltage environment, therefore, the electric isolation is needed. APC IC GP9301 will convert the 0-10V signal to PWM signal which will be input to MCU, and recognized after optocoupler isolation.

GP9301B not only supports 0-10V input, but also integrates 3in1 input interface of PWM and 100k resistance, optimizing the interface circuit.

Application 4: 0-10V 3in1 LED dimming power supply

In the application of LED dimming, 0-10V interface is one of the most common interfaces. In this type of power supply, 0-10V signal will be accessed to APC IC GP9301B and be converted into PWM to control AC-DC or DC-DC IC after optocoupler or capacitor isolation. Therefore, the output current and the LED brightness can be dimmed.

Interesting chips have good application opportunities if they can give consideration to both linearity and conversion speed. Especially in the scene of analog signal isolation. What is the frequency range of PWM signal of APC and PAC chip?

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