ZSSC1750 Data Acquisition System Basis Chip (SBC) and Battery Sensor LIN-Transceiver Chip
The ZSSC1750 is a System Basis Chip (SBC) with a dual-channel ADC for battery sensing/management in automotive, industrial, and medical systems. The ZSSC1750 features an SPI interface. One of the two input channels measures the battery current IBAT via the voltage drop at the external shunt resistor. The second channel measures the battery voltage VBAT and the temperature. By simultaneously measuring VBAT and IBAT, it is possible to determine dynamically the internal resistance of the battery, Rdi, which is correlated with the state-of-health (SOH) of the battery. By integrating IBAT, it is possible to determine the state-of-charge (SOC) and the state-of-function (SOF) of the battery. During Sleep Mode, the system makes periodic measurements to monitor the discharge of the battery. Measurement cycles are controlled by user software and include various wake-up conditions. The ZSSC1750 is optimized for ultra-low power consumption drawing only 60μA or less in this mode.
For more information about the ZSSC1750, visit www.IDT.com/ZSSC1750.
Hi, I’m Josh and for today’s EEWeb Tech Lab, we will be reviewing IDT’s ZSSC1750 data acquisition system basis chip. A system basis chip is a system on a chip that integrates multiple ECU functions into a single dye and the ZSSC1750 does this by integrating a high voltage circuit, sigma delta ADCs, analog input stage, digital filtering, and a LIN transceiver into one IC. It’s designed for use with any microcontroller with a SPI interface. With the ADCs, this IC can measure lead-acid battery voltage and current at a rate of 1 kHz or more and resolution of up to 18 bits with no missing codes while still measuring temperature. Simultaneous measurement of voltage and current allows for inner resistance calculations often used for battery state of health estimation. Using a shunt, this device is capable of measuring, charging, and discharging battery current with a huge dynamic range from milliamps to thousands of amps. Accumulator registers allow accurately calculating state of charge even in operating modes when the microcontroller is asleep.
So this is the device. This is an evaluation board, but you can see right here this tiny little QFN package. It’s 6 mm by 6 mm, so very, very small form factor. It’s also a very robust little IC and so it has a robust power on reset because, in cars, it’s very, very noisy electrically and so this has to be very capable of handling any sort of surges or dips like that. This also has the capability of measuring its own internal temperature, the temperature of the IC itself. Plus if you hook up a thermistor to it, it can also measure external devices as well.
So as you look at this eval board, it’s actually three different parts here. The center part is the evaluation board specific to the 1750 but then here we have the Comboard which is what I use to hook it up to my computer. And then this is the shunt board which acts as a battery when you’re doing any of the testing like that. So all of this through the Comboard can actually hook up to my computer. I have a Windows virtual machine running right here and an IBS demonstrator application so, on this GUI, you can see different things on here. You can see some of the persistent vs the transient factors you can change in the testing itself. Plus you can change the shunt resistor and do a lot of configurations right here.
But the easiest thing about all of this is, as a GUI interface, you just come in here, you set everything you need to and you hit start. It takes a moment and then it starts emulating the connection to a lead-acid battery and shows how it would react in these certain situations. So you can actually see right now that the internal temperature is changing. It’s going up just a little bit as it actually is turning on and is self-heating a bit. But it flat lines rather quickly and I don’t anticipate, from my experiments in the past, I don’t anticipate that going any higher. But then over here, you can, again, change the external temperature, you can change the current, and you can even make certain transients in here as you need to.
Once you’re done with all of this you can just hit stop and if you want, you can save all that data into an external log basically a CSV file for further review later. So that’s just something you come down here check the box, say where you want to save it, and hit select. And so this means that you can do a large amount of the testing that you want in a lab. You don’t have to go out. You don’t have to have a battery sitting on your desk to do all this testing and you can get a very good review of exactly how this IC is going to work within your system.
The ZSSC1750 is an extremely small form factor, ultra-low power consumption IC that will help in any situation, automotive, medical, or industrial, that requires real-time monitoring of battery systems with external control with the microcontroller. To learn more about the ZSSC1750 go to www.idt.com/products/sensor-products/battery-sensor-ics/zssc1750-data-acquisition-system-basis-chip.