MAXQ3181: Low-Power, Active Energy, Polyphase AFE
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MAXQ3181 is a dedicated electricity measurement front end that collect and calculate polyphase voltage, current, active power and energy,and many other metering and power-quality parameters of a pholiphase load. The computed results can be retrieved by and external master through the serial interface (SPITM).
The MAXQ3181 integrates an 8-channel analog-to-digital converter (ADC) and a dedicated, high-performance MAXQ® microprocessor for computing a broad set of poly-phase multifunction energy metering parameters. Six of the input channels are dedicated to the three phase voltages and three currents. One channel is dedicated for the neutral line current monitoring, and the 8th channel is for on-chip temperature monitoring.
Features
- 0.1% Active Power and Energy Linearity Error
- 0.5% Apparent Power and Energy Linearity Error
- 0.5% Linearity Errors for RMS Voltage and RMS current
- Neutral Line current measurement
To provide flexible operation, the device provides a configurable pulse output (typically for active energy) that can be set to output any of a large array of operational parameters. MAXQ3181 include a hardware watchdog timer that is armed and periodically reset automatically during normal operation. However if an internal error of some kind causes the MAXQ3181 to lock up or enter an endless execution loop, the watchdog timer expires and triggers an automatic hardware reset. In addition to the hardware reset provided by the power-on reset and brownout reset circuits, the MAXQ3181 includes the capability to detect a low power supply on the DVDD pin and alert the master through the interrupt mechanism before a hardware reset occurs. All the operations including ADC sampling and SPI communications are synchronized to a single system clock. This clock can be obtained from one of three selectable sources: External High frequency crystal, External High frequency clock and Internal RC Oscillator.
The MAXQ3181 is packaged in a 28-pin TSSOP package and operates over the -40°C to +85°C temperature range. Three-phase power-meter reference designs are available to speed designs and reduce time-to-market. The MAXQ3181 is 100% pin compatible with the MAXQ3180, so designs can be upgraded without any circuit change.
Features from MAXQ3180 and MAXQ3181 are reported below:
Feature | MAXQ3180 | MAXQ3181 |
|---|---|---|
Active engery & power - positive/negative | V | V |
Reactive energy & power - positive/negative | V | |
V & I RMS | V | V |
Power factors, line frequency | V | V |
Neutral current monitoring | V | V |
Temperature sensor | V | V |
Phase sequence indication | V | V |
Voltage and current harmonics | V | |
Fundamental & total energy & power | V | |
Voltage phase angles | V | |
Serial interface | SPI slave | SPI slave |
Pulse output | CFP, CFQ | CFP |