EMC Compliant: Group Isolated: 2-Channel Binary Input Module for Wide AC/DC Input Reference Design
Description
This reference design showcases a cost-optimized architecture that improves resolution of a binary-input module. A microcontroller unit (MCU) is shared between two-input channels (group isolation) to minimize the cost per channel. Wide-input range is covered using an amplifier with gain and MCU-integrated 10-bit analog-to-digital converter (ADC) to measure within ±3% accuracy. This architecture eliminates the need for multiple hardware versions based on input voltage range as is the case with an opto-coupler based topology. A digital isolator is used to communicate the ADC code or the root-mean-square estimate of the input to the host processor. The design is tested for ESD: EFT and surge as per IEC61000-4 Level 4.
Features
- Measurement accuracy: MCU shared between two channels (group isolation) to minimize cost per channel with additional unassigned input channels for larger channel count group isolationWide-input range covered using an amplifier with two gain stagesChoice of basic or reinforced isolation between input and the host processor using digital isolatorOnboard current pulse generator (20 mA to 50 mA: 50 ms) using MCU PWM output to remove the contamination (anti-burnishing) on the binary input contacts
Applications
- Multifunction relay
- Binary input module
- Substation automation
Product Categories
- MSP430 microcontrollers