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- High Resolution, Startup Analog Front End for Air Circuit Breaker Design Guide (Rev. B)
(PDF 3740 KB)
09 Sep 2016 486 views
The TIDA-00661 reference design features signal processing front-end subsystem for electronic trip units (ETU) used in air circuit breakers (ACB) or molded case circuit breakers (MCCB). This subsystem consists of Delta-Sigma ADC with 24-Bit resolution and fast startup (< 3ms), ±2.5V regulator, FRAM-based microcontroller (MCU) for interfacing to ADC and processing the inputs. The subsystem is designed to start-up, compute full-cycle RMS current, make decisions, and provide trip signal to the solenoid within 30 ms.
- Measurement of AC input from 10V to 750V and 50mA to 25A within ±1% with fixed gain
- Voltage and Current inputs are interfaced to a 24-Bit Delta-Sigma ADC with Fast startup (< 3ms)
- DC-DC converters configured in Fly-Buck configuration to generate supply output (2W/ 8W)
- Provides option to measure 3 earth fault current inputs with a single gain opamp interfaced to 12-Bit internal ADC of MCU
- On-Board potential divider provided to measure the AC input voltage and Burden resistors are provided to connect external CT secondary input for current measurement
- Regulators generate 3.3V and 5V (MCU and ADC board), ±2.5V and 3V (ADC analog supply)