Project Description

Project description

Please design a single-page schematic in fulfillment of the below requirements:


  1. 1. Capable of actuating a solenoid valve with the following characteristics:
    • 18 Ω coil, ~ 100mH inductance
    • 28VDC ± 4V full-power actuation; 7-10VDC power-save (“hold”) actuation. 2.
  2. Capable of arbitrarily changing solenoid valve between full-power and power-save states.
  3. Ensures valve does not turn off or de-energize when switching between states.
  4. Capable of measuring current and voltage delivered to valve by circuit.
  5. Capable of automatically disabling power to valve under an overcurrent condition (eFusing)
  6. Capable of overriding fusing circuit to keep valve on even under overcurrent condition.
  7. Assume you are provided a 28V and 10V source with arbitrarily high current sourcing ability, as well 3.3V “enable” and “mode” (full/power-save) signals from a processor.
  8. While the interfaces in #7 must be used, you may also add additional control signals/interfaces for use with your implementation (I2C, SPI, more GPIOs, etc).



Bonus tasks (implement or argue why it isn’t worth pursuing/unnecessary): 

  1. Overcurrent threshold is programmable.
  2. Include function to detect whether valve is connected (or if output is open circuit)
  3. Include function to identify temperature of solenoid, and therefore valve.
  4. Include function to identify if valve is stuck-closed or stuck-open (can happen if cryogenic)


Notional Optimizations - Aim to design the channel with the following goals and optimizations in mind:

  1. Minimal complexity – simplicity is key at ABL.
  2. Reliable – capable of withstanding rigorous thermal and vibration environments.
  3. Robust – expects possible misuse and failure modes without failing/being damaged.

Design Files

Embed Code
Component (34)


Generic Resistor (120)

C1, C4

Generic Capacitor (10uF)


Generic Capacitor (47uF)


Solenoid valve - 24 VDC, 1.2 A max

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