One demultiplexer application example is to use this in conjunction with amplifiers having different gain for signal segmentation processing. Figure 1-2 shows the application scenario of Smart Combiner Box (also called PV Stream Box) in solar utility power station. Smart Combiner Box is used together with central inverter in middle/large-scale PV grid-connected power generation systems. The Smart Container Box is added between the PV strings and inverter for the purpose of reduction of connection lines between PV strings and inverters, easier maintenance and higher reliability. One of the function is to monitor multi-channel string currents which usually come from current transducer (CT) or hall current sensor.

The current sensor typically has 0 to approximately 5V output or even higher up to 12V, while the recommended ADC full scale range (FSR) of the microcontroller (MCU) is usually 0 approximately 3V. So, amplifier with gain < 1 is needed to attenuate the sampling signal before going to ADC. In addition, the fact is that current sensor usually has much lower accuracy for low current measurement than that of high current measurement. And system errors and noise (such as Vos and drift of the amplifier) of the signal conditioning circuits cannot be totally avoided. To still acquire relatively high accuracy of low current measurement, attenuation of low current signal is not preferred. On the contrary, buffer or amplification is preferred. That means for different amplitude current signal from the same front-end sensor, different back-end signal conditioning circuits are needed. That leads to the signal segmentation processing example using demultiplexers, shown in Figure 1-3.

Figure 1-2 Application Scenario of Smart Combiner Box in Solar Utility Power Station

Figure 1-3 Signal Segmentation Processing Example Using Demultiplexers