https://www.ti.com/ INDUSTRIAL AND AUTOMOTIVE SYSTEMS 19 www.power-mag.com Issue 3 2025 Power Electronics Europe ground differences. However, galvanic isolation is not required in this case, and the TXG8041 is a more compact and costeffective alternative. Another example of DC shift can be seen in battery packs for cordless power tools. In battery pack systems, a battery management system (BMS) is usually used to control power delivery and monitor cell condition. One common design uses a low-side FET to connect the battery negative terminal to the pack ground, which serves as the common reference for the appliance–such as a power drill. When the FET is on, the battery’s negative terminal is tied to the pack ground. When the FET is off, the battery’s negative terminal effectively floats and can drift to a different reference level than the pack ground, potentially disrupting communication between the BMS and the power drills control circuitry. Traditionally, discrete components are used to level-shift between the battery negative terminal and pack ground. However, this can be completely replaced with an integrated TXG8021 as shown in Figure 3. AC Ground Noise AC noise refers to disturbances on the ground caused by dynamic changes, resulting in a noisy or unstable ground, as shown in Figure 4. This phenomenon is often called ground bounce and can also cause signal integrity issues between systems. In mixed-signal designs, this issue can arise when interfacing high-speed digital circuits with precision analog components. Figure 5 shows an example in Test and Measurement applications where a Field Programmable Gate Array (FPGA) is referenced to digital ground and has to interface with a Digital-to-Analog Converter (DAC) that is referenced to power ground. Both grounds are ultimately connected together to establish a common reference but can be on separate ground planes on a PCB to help separate digital noise from sensitive analog circuitry. The digital side of the system can see rapid switching which can result in AC noise. Noise that carries to the power ground can introduce fluctuations in the DAC reference voltage, leading to degraded performance or distorted analog outputs. In the example below, TXG8042 is used to eliminate noisy grounds and enable the precise communication needed for accurate digital-to-analog conversion. Intentional Ground Shift Intentional ground shift is when systems deliberately use an offset ground for the benefit of the system. An example of this is topologies with a negative voltage rail. This can be seen in GaN based power stage designs which use a -50V ground in Class D audio amplifiers to increase the total voltage swing available to the amplifier output. The larger voltage swing allows the amplifier to deliver higher root mean square (RMS) power to the speaker, which translate to louder and cleaner >audio output. In the block diagram below, the TXG8010 singlechannel device can be used to bridge the offset between the MCU which sits on 0V ground and the GaN Half-Bridge Power Stage which sits on -50V. Battery stacking is also more common now as a way to support higher voltages, enabling longer runtime and improved energy capacity. This approach is frequently used in systems such as appliances, energy storage systems (ESS), and electric mobility applications. Because traditional battery monitors typically Figure 3. Cordless Power Tool with TXG Figure 5. Semiconductor Test Equipment With TXG Figure 4. AC Ground Noise
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