Signal processing subsystem and current Input based self-power for breaker applications

The TIDA-00498 reference design features signal processing front-end and self-power block for electronic trip unit (ETU) used in circuit breakers. A FRAM based microcontroller is used for processing current inputs from signal conditioning amplifiers for 3-phase, neutral and ground current. Two gains are used to extend the range for phase current measurement.  

This reference design can also self-power using rectified current input. TIDA-00498 is designed for fast and repeatable tripping (within 30mS) for wide current and temperature range.  

Features 

• Measures three currents (phase) with input range of (0.2 to 12 I_NOMINAL ) and two current (Neutral, Earth) with (0.05 to 2 I_NOMINAL ) within ±3%
• Uses TI’s MSP430™ FRAM MCU for Fast Startup, Startup Time Including One-Cycle RMS Computation is
• Undervoltage Sense Provides Approximate 200-μs Reset Time After Power-Up
• Self-Power Supply (Rectified Current Input Based) With MOSFET-Based Shunt Regulation

Parts Include;

CSD17571Q2       30V N-Channel NexFET Power MOSFET
CSD18537NKCS  60-V, N-Channel NexFET™ Power MOSFET 
LM2903            Dual Differential Comparator 
TPS7A6533-Q1  Automotive 300-mA 40-V Low-Dropout Regulator With Ultra-Low Quiescent Current 
OPA4314          Quad, 3MHz, Low-Power, Low-Noise, RRI/O, 1.8V CMOS Operational Amplifier 
MSP430FR5969  16 MHz Ultra-Low-Power Microcontroller featuring 64 KB FRAM, 2 KB SRAM, 40 IO 
LMV551   3 MHz, Micropower RRO Amplifier 
LMT87     2.7V-Capable, 10 uA Analog Output Temperature Sensor in SC70 and TO-92 
LM8364  Micropower Undervoltage Sensing Circuits 
LM5017   7.5-100V Wide Vin, 600mA Constant On-Time Synchronous Buck Regulator 
LM4041B  Adjustable Precision Micropower Shunt Voltage Reference, 0.2% accuracy 

Learn more by downloading the reference design below