Keywords: Power Monitoring; I2C and SMBus Compatible; Alarm Function
SG Micro Corp has launched the SGM832 monitoring chip, which can be used for monitoring voltage, current, and power in power supply systems. The chip is compatible with I2C and SMBus interfaces and can simultaneously monitor differential voltage and bus power voltage. The chip integrates flexible register configurations that allow users to edit working modes and conversion times, set alarm functions and thresholds, and ultimately output current (A), voltage (V), and power (W) signals. The chip is packaged in environmentally friendly MSOP-10 and TDFN-3×3-10L green packages, with an operating temperature range of -40℃ to +125℃.

Figure 1 Typical Application Circuit of SGM832
Typical Features of SGM832
SG Micro Corp
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Supports independent power supply voltage from 2.7V to 5.5V;
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Single-ended bus monitoring voltage from 0V to 36V, fixed at 1.25mV LSB;
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Bidirectional differential sampling voltage from -81.92mV to +81.9175mV, fixed at 2.5μV LSB;
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8 adjustable conversion times, with separate control for bus voltage and differential voltage;
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8 adjustable conversion counts;
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16 editable address bits;
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Three adjustable working modes: continuous, triggered, and power-saving, supporting separate monitoring of bus voltage and differential voltage;
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Over/under voltage and over power warning functions for bus voltage and differential voltage.
Core Features of SGM832
SG Micro Corp
1. The SGM832 internally integrates a 05h calibration register, calculated based on the resistance value of the sampling resistor and the maximum current to be monitored. The chip calculates the actual current value from the differential voltage using the value from the 05h register, ultimately deriving the power value. In continuous mode, bus voltage and differential voltage are monitored separately through internal interleaving, and the internal logic calculation does not occupy conversion time.

Figure 2 Function Block Diagram of SGM832
2. The SGM832 features a high-precision VREF voltage and integrates a temperature compensation circuit, effectively improving temperature drift characteristics.


Figure 3 Differential Input Bias Voltage vs. Temperature
Figure 4 Bus Input Bias Voltage vs. Temperature
3. The SGM832 employs a multi-point trim scheme to reduce gain errors, effectively improving testing accuracy.


Figure 5 Differential Input Gain Error vs. Temperature
Figure 6 Bus Input Gain Error vs. Temperature
Application Cases of SGM832
SG Micro Corp
With the large-scale coverage of 5G networks and the new trends in AI development, the demand for communication and storage devices such as servers and large switches has surged, leading to explosive growth in energy consumption and operational costs of supporting equipment. Establishing an electricity consumption model through a power supply system monitoring platform for energy consumption statistics and ultimately optimizing electricity usage through analysis reports has become a mainstream solution.
Taking server platforms as an example, the system needs to monitor the power consumption of modules such as boards, fans, hard drives, network cards, and CPUs in real-time, reporting the operating conditions to the processor based on set alarm thresholds. A 2mΩ sampling resistor is placed in series on the 12V voltage rail of a single module, and VBUS collects VIN-, which is the module’s operating voltage. The maximum operating current value is 10A, and the calibration register value is calculated and input to the chip’s 05h register, allowing real-time monitoring of output voltage, current, and power values once the working mode is configured.

Figure 7 High-Side Sampling Circuit
By setting the differential voltage over-voltage warning function through the 06h register and configuring the threshold size in the 07h register, different conversion times can be set to achieve the following warning response graphs. The faster the set conversion time, the quicker the response, but the accuracy correspondingly decreases.


Figure 8 tCT = 150μs Alarm Response
Figure 9 tCT = 1.036ms Alarm Response
About SG Micro Corp
SG Micro Corp
SG Micro Corp (Beijing) Co., Ltd. (stock code 300661) focuses on the research and development and sales of high-performance, high-quality analog integrated circuits. Its products cover two major areas: signal chain and power management, with over 30 categories and more than 4600 models available for sale, all developed independently and widely used in fields such as industrial, automotive electronics, communication equipment, consumer electronics, and medical instruments, as well as emerging markets like the Internet of Things, new energy, and artificial intelligence.
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