Yuan Power: DC-DC Converter & Signal Isolation Amplifier Module |
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Application Notes for Isolation Amplifier Modules
Key words:
Isolation Amplifier
ISO-AMP
isolation and switching
analog signal
0-10mA/0-20mA/4-20mA/0-5V/0-10V/0-±5V/1-5V
Notes:
ISO series isolation amplifier IC isolates and switches the analog signal pro rata, it is divided into two classifications: Internally powered and not powered.
Inside the not-powered IC contains current signal modulating circuit and signal coupling isolation & switching circuit. The very low input equivalent impendence allows the input voltage can be up to an ultra-wide range (7.5V~32V), so that it is able to meet the requirements for no distortion in long-distance signal transmission under the circumstance without any extra power supply.¡¡The internal ceramic PCB, printed impendence and new isolation technologies allow the IC for the 3KVAC insulated voltage and meets the industrial level for the extremely poor temperature, humidity and shaking conditions.
ISO 4-20Ma series is very easy for application. No extra components are needed to realize the performance of 4-20mA current loop isolation and signal switching of one in two out and two in two out.
The internally powered IC integrates a high isolated DC/DC Converter and high-performance linearity inter-coupler on a single chip. Except provides the power for the internal amplifying circuit, it also provides two-group isolated Positive-Negative power supply and two-group 5VDC nominal power supply for the outside signal input and output end, specially designed for the extending of outside circuits, like bridge circuit and small signal pre-amplifying circuit.
The IC contains 20KHz wide signal bandwidth that can isolate, modulate and switch 0~±10VDC bi-directional DC signal or 0~5VAC bi-directional AC signal. The IC is of small size, very easy to use. Only a few extra components are needed to realize the isolation and switching of analog signal¡¡(I/I, I/V, V/I, V/V).
Applications:
Analog signal data acquisition, Ground interference control, Signal long routed transmits, Equipment and sensor signal acquisition and switching, Electric and medical equipment safe bar.
Product series:
ISO¡¡4-20mA: 4-20Ma current loop interface IC
ISO-Ax-Px-Ox: DC Current Signal (I/V, I/I) Isolation Amplifier IC
ISO-Ux-Px-Ox: DC Voltage Signal (V/I, V/V) Isolation amplifier IC
ISO1001 /1002: Bi-directional Signal Isolation Amplifier for AC.DC
Characteristics:
Accuracy grade: 0.1, 0.2, 0.5
Linearity: <0.2% (In the whole process)
International standard signal input/output:¡¡0-10mA/0-20mA/4-20mA/0-5V/0-10V/0-±5V/1-5V
Low impedance for Input and high loading capability for output
3000V Isolation for signal input/output and power supply at the same time
Single power supply, provides the power supply on the signal input/output end
Low cost, small size and standard SIP 12 or DIP 24 packaging
Industrial level environmental temperature, fire-retarding package (UL94-V0),
General Introduction:
Signal isolation technology is the current connecting that eliminates the interface between sending end and receiving end while signal transmitting. It allows¡¡the difference between the ground or standard electrical level of sending end and receiving end can be up to thousands of voltage, it also prevent the signal from the current loop on different ground potentials.¡¡The noise from the signal ground may harm to the signal. Isolation Amplifier can separate the signal to a clean signal subsystem ground, isolates the sensor, instrument and meter or control system from the power supply, in order to keep the safety and stability of whole system.
In another case, the electrical connection between standard electrical levels can isolate and form a unsafe circuit gateway to the patients and operators.
Isolation amplifier crosses the barriers relying on no transmitters and receivers. It was used for digital signal before, but due to the linearity problem, the transformer, inter-coupler, capacitor and electric eye were needed to realize the isolation for analog signal.
Analog signal isolation: the analog signal needs to be isolated in many application circumstances. The circuit specifications of analog signal are different from the digital signal.
Usually the analog signal has the requirements for the accuracy, linearity, response frequency and noise firstly.¡¡And then follow up the requirements for power supply. The power supply needs to be high isolation, accuracy, and low noise, especially for the input grade.
¡¡¡¡
As to the interface from power supply noise, the analog signal can escape from it by modulating carrier wave. ISO 4-20Ma current loop interface IC (not powered) simplifies the analog isolation. The input signal is modulated and sent in digital way to across the barrier. The modulated signal is then received by the output part, and converter into analog signal without the ripples that exist in modulating and modulating release process.
Another problem to the signal isolation is the power consumption that the input grade needs; the key problems are input impendence and its own equivalent impendence. And output grade usually regards the enclosure and ground as the standards, the input grade usually is on another electric level. Therefore, the power supply for input grade needs to be isolated by using a single power supply (5V, 12V, 15V, 24V) instead of the Positive-Negative dual power supply.
Application Theory:
Being tested many times, the products can meet the expectation. See the graphs below:
Graph 1: Theory of Isolation Amplifier Modules.
Graph 1.1 ISO 4-20mA
Graph 1.2 ISO-1001
Graph 1.3 ISO-APO
Electric Specifications:
Typical Connection Figure:
Graph 2 is the typical connection figure for ISO-1001 isolated amplifier.
Input and output amplifier are following mode.
Here, Isolated amplifier is magnified 20 times
R1, R2 & W1 is zero circuit
R1=5.1K R2=2K W1=2K
Assistant power supply is +12VDC
R3=39K W3=10K
Graph 2. Typical Connection Figure |
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