CN211669737U

CN211669737U - Voltage analog quantity isolation module

Info

Publication number: CN211669737U
Application number: CN202020693900.XU
Authority: CN
Inventors: 邵勇; 徐春岩
Original assignee: Anyang Anjia Electric Co ltd
Current assignee: Anyang Anjia Electric Co ltd
Priority date: 2020-04-30
Filing date: 2020-04-30
Publication date: 2020-10-13
Anticipated expiration: 2030-04-30

Abstract

The utility model discloses a voltage analog quantity isolation module, keep apart chip, PAC chip including APC chip, digit, 0V is connected to the analog voltage input of VCC to the input of APC chip, and the PWM signal of 0-100% duty cycle of PWM output of APC chip arrives the signal input part of chip is kept apart to digit, keeps apart the chip through digit and keeps apart the back, and the signal output part who keeps apart the chip from digit is exported and is connected to the PWM input of PAC chip, PAC chip converts the PWM signal of 0-100% duty cycle of input into analog voltage after its output, and the analog voltage scope of its output is 0-5/10V. The utility model discloses obviously improved isolation module's precision and reliability, had high speed and low-cost advantage concurrently.

Description

Voltage analog quantity isolation module

Technical Field

The utility model relates to an analog quantity isolation module, concretely relates to voltage analog quantity isolation module belongs to the electrical automation control technology field.

Background

In many industrial electrical control systems, an analog signal is often used to control a terminal, and in order to ensure indexes of reliability, safety, interference resistance and the like of the system, the analog signal is often required to be isolated, however, the isolation of analog models is usually complex to implement, for example, the isolation can be implemented by a "voltage-PWM-isolation-PWM-voltage" method, where PWM is a pulse width modulation signal, and the PWM signal has the advantage of interference resistance of a digital signal and is also easily restored to an analog signal. At present, the mainstream voltage signal-to-PWM technology is realized through an analog circuit formed by discrete components or a singlechip chip integrated with an ADC (analog to digital converter), wherein the components are numerous, errors can be introduced into an operational amplifier, a capacitor, a resistor and the like, so that the system precision is not high, and the calibration is difficult; the singlechip of the latter is operated based on a program, the system is easy to be interfered to cause instability, and the precision of the system cannot meet the requirement; when the PWM signal is reduced into the analog quantity, the response speed is low when an RC low-pass filter circuit scheme is adopted, and the cost for acquiring a duty ratio scheme by adopting the high-frequency clock sampling of the singlechip is high.

In addition, the isolation method generally adopts optical coupling isolation: the optical coupler is a device for transmitting signals by taking light as a medium, a light emitter and a receiver are usually packaged in the same tube shell, when a current signal is applied to an input end, the light emitter emits light, and after the receiver receives the light, photocurrent is generated and is output from an output end, so that 'electricity-light-electricity' conversion is realized. Although the optical coupler realizes electrical isolation between two voltage domains simply in an optical transmission mode, the optical coupler has the defects of poor temperature characteristic, large power consumption, short aging period, difficulty in semiconductor process integration, low transmission rate and the like, and the reliability is not high.

Disclosure of Invention

Problem to prior art existence, the utility model provides a voltage analog quantity isolation module aims at improving isolation module's precision and reliability, has high speed and low cost concurrently.

The technical scheme of the utility model is that: a voltage analog quantity isolation module comprises an APC chip, a digital isolation chip and a PAC chip, wherein the input end of the APC chip is connected with an analog voltage input from 0V to VCC, the PWM output end of the APC chip outputs a PWM signal with 0-100% duty ratio to the signal input end of the digital isolation chip, after being isolated by the digital isolation chip, the APC chip outputs from the signal output end of the digital isolation chip and is connected to the PWM input end of the PAC chip, the PAC chip converts the input PWM signal with 0-100% duty ratio into an analog voltage and then outputs from the output end of the analog voltage, and the output analog voltage range is 0-5/10V.

Preferably, the model of the APC chip is GP 9105.

Preferably, the type of the digital isolation chip is pi 120.

Preferably, the model of the PAC chip is GP 8101.

The utility model has the advantages that: the utility model adopts the scheme of 'analog voltage signal-PWM-isolation-PWM-analog voltage signal' to realize the conversion isolation of the analog voltage signal, adopts a GP9105 chip as APC conversion and GP8101 as PAC conversion, can realize the PWM signal linear conversion with 0-100% duty ratio, and has high conversion precision and stable and reliable performance; the pi 120 is used as a digital isolation chip, the chip is based on the principle of a capacitive coupling technology, the integrated on-chip capacitor can realize faster data transmission and higher signal integrity, the capability of resisting magnetic interference is much better than that of an inductive coupling technology, the power consumption is much lower than that of a photoelectric coupling technology with higher performance, and the defect of temperature drift of the photoelectric coupling is avoided.

Drawings

Fig. 1 is a schematic circuit diagram of the present invention.

Fig. 2 is a circuit diagram of a 3.3V power supply.

Detailed Description

In order to explain the utility model more fully, the utility model provides an implementation example. The embodiment is merely illustrative of the present invention, and does not limit the scope of the present invention.

As shown in FIG. 1, the voltage analog quantity isolation module circuit mainly comprises three chips, from left to right, an APC chip IC1-GP9105, a digital isolation chip IC 3-pi 120 and a PAC chip IC2-GP8101 are arranged in sequence, and a T1 at the rightmost end is a wiring terminal.

The APC (APC to PWM Converter) chip is an abbreviation of an Analog signal to PWM signal Converter chip, the APC chip has the function of converting Analog quantity in a certain amplitude into proportional PWM signals, the duty ratio of the PWM and the amplitude of the Analog quantity are in a linear relation, and the APC module is internally provided with a high-precision ADC module and a PWM algorithm module. Specifically, the GP9105 chip inputs the analog voltage from 0V to VCC into a 3-pin VIN of the GP, linearly converts the analog voltage into a PWM signal with 0 to 100 percent duty ratio, and outputs the PWM signal to a digital isolation chip from a 6 pin, wherein the frequency range of the output PWM signal is 1Hz to 1MHz, the linearity error of the PWM duty ratio is less than 0.5 percent, and the maximum PWM duty ratio error is less than 1 percent.

The digital isolation chip pi 120 is a surge semiconductor product and is designed by adopting a standard CMOS technology and an intelligent voltage division technology, and the intelligent voltage division technology utilizes a capacitance voltage division principle to realize accurate transmission of voltage signals across an isolation gate under the condition of not needing modulation and demodulation; the two-channel product with the withstand voltage grade of 3.0KV rms can realize signal transmission from DC to 600Mbps, and the series of products support 3V to 5.5V working voltage and 3V to 5.5V signal level conversion. When the input power supply does not supply power or has no input signal and the output power supply supplies power normally, the isolator outputs default level; the isolator is superior to optical couplers and other digital isolator products in the aspects of performance and reliability.

The PAC chip (PWM to Analog Converter) is an abbreviation of a PWM signal to Analog signal Converter chip, and functions to convert a PWM signal into an Analog quantity of equal proportion according to a duty ratio, and an amplitude of the Analog quantity is in a linear relation with the duty ratio of the PWM. The PAC chip integrates a PWM sampling algorithm and a high-performance DAC. Specifically, for a GP8101 chip, isolated PWM signals with 0% -100% duty ratio are input to 3 pins of the chip, the signals are linearly converted into analog voltages of 0-5V or 0-10V and output from 6 pins VOUT, and the amplitude of the output voltage VOUT is selected as follows: 0-5V when the 7 pin SEL is grounded, and 0-10V when the 7 pin SEL is connected with the 8 pin V5V; input PWM signal high level: 3.0V-5.5V, output voltage error:<1% output voltage linearity error<0.5 percent. The duty cycle of the PWM signal is 0% to 100%, VOUT =5V × D when selecting 0-5V output_PWM(ii) a VOUT =10V D when selecting 0-10V output_PWM，D_PWMIs the duty cycle of the input signal PWM. The power supply voltage: 10V to 40V, and in the example, 24V is adopted for power supply.

In the embodiment, GP9105 and pi 120 are supplied by a 3.3V power supply, a power supply circuit is shown in FIG. 2, the core is that an AMS1117-3.3 chip is used as a forward low dropout regulator, 3.3V is output, and the precision is 1%.

The utility model discloses a but the wide application in the field that the conversion need be kept apart to analog voltage signal in various industrial control scene to voltage analog quantity isolation module, for example can be used to the drive execution of electric proportional valve to the realization is to the continuous stepless regulation of various fluidic.

Claims

1. A voltage analog quantity isolation module is characterized in that: the input end of the APC chip is connected with an analog voltage input from 0V to VCC, the PWM output end of the APC chip outputs a PWM signal with 0-100% duty ratio to the signal input end of the digital isolation chip, the PWM signal is isolated by the digital isolation chip and then is output from the signal output end of the digital isolation chip and connected to the PWM input end of the PAC chip, the PAC chip converts the input PWM signal with 0-100% duty ratio into an analog voltage and then outputs from the output end of the PAC chip, and the range of the output analog voltage is 0-10V.

2. The voltage analog isolation module of claim 1, wherein: the model of the APC chip is GP 9105.

3. The voltage analog isolation module of claim 1, wherein: the model of the digital isolation chip is pi 120.

4. The voltage analog isolation module of claim 1, wherein: the model of the PAC chip is GP 8101.