According to 101.DVN.9 of the UL standard, HVAC systems considered partial units (split systems, outdoor condenser, for example) must have safety shut-off valves factory or field installed and capable of being controlled from signal from the compressor control board. These safety valves shall be non-self-resetting, and requires a manual reset operation, and shall not be capable of remote reset.

TI collateral for designers: Damper and EEV Controller Reference Design with Power Regulation and Hall-Effect Position Sensing

Design Overview: This reference design demonstrates a dual motor drive design for damper actuators and electronic expansion valves. The multiple motor drives include one bipolar stepper motor driver, one brushless DC motor driver, operating from a 15VDC source. The design shows accurate power limiting that helps for easy qualification as a low-power circuit, defined by IEC 60335-1. This reference design incorporates a 0-10V and 4-20mA control interface for controlling the position of the valve or damper, and a TMAG5273 which is used for accurate position sensing.

Features:

• Operates at voltage ranging from 24V to 40V
• Brushless DC drive for electronic expansion device control
• Bipolar stepper drive DRV8428 efficiency > 95 %
• Single MCU control with multi-peripheral device operation through I2C and SPI
• 15W power regulation to help easy low-power circuit qualification with IEC 60335-1
• 0-10V and 4-20mA control front-end