High-efficiency: low-emission: isolated DC/DC converter-based analog input module reference design
Description
This reference design is a simplified architecture for generating an isolated power supply for isolated amplifiers for measuring isolated voltages and currents. A fully integrated DC/DC converter with reinforced isolation operating from a 5-V input with configurable 5-V or 5.4-V output (headroom for low dropout regulator (LDO)) generates the isolated power. Shunts that are interfaced to ±50-mV input range isolation amplifiers configured as channel isolated inputs measure the current. Potential divider output interfaced to ±250-mV or ±12-V input range isolation amplifiers configured as group isolated inputs measure the voltage. The outputs of the isolation amplifiers interface directly to 24-bit delta sigma analog-to-digital converter (ADC) or are scaled to ±10 V using gain amplifiers and interfaced to 16-bit SAR ADC for performance evaluation. On-board digital diagnostics improves reliability and enhances system performance.
Features
- Generation of high efficiency isolated supply of 5 or 5.4V (LDO head room) from 4.5 to 5.5 V input providing reinforced isolationMeasures three group isolated voltage inputs with a range of 3-350V providing pin compatible basic or reinforced isolation and three isolated current inputs from 40mA-12.5A providing reinforced isolationISO224 with input range of ±12V input range connects directly to low power current transformer output as per IEC 60044-8Measurement of DC voltage and current with 1us fast fault detection comparator pathGain scaling of isolation amplifier output to ADS8588H input range of ±10V using instrumentation: precision or general purpose amplifiers Achieves ±0.2% accuracy for both voltage and current using 16-bit SAR or 24-bit delta-sigma ADC
Applications
- HVAC controller
- HVAC fluid leak detector
- Multifunction relay
- AC analog input module
- High-voltage direct current (HVDC) power transmission
Product Categories
- Isolation