SLVAE59A February   2019  – April 2022 DRV8242-Q1 , DRV8243-Q1 , DRV8244-Q1 , DRV8245-Q1 , DRV8343-Q1 , DRV8702-Q1 , DRV8702D-Q1 , DRV8703-Q1 , DRV8703D-Q1 , DRV8803 , DRV8804 , DRV8805 , DRV8806 , DRV8860 , DRV8873 , DRV8873-Q1 , DRV8874 , DRV8874-Q1 , DRV8876 , DRV8876-Q1 , DRV8935 , DRV8955

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Types of Solenoids
  3. 2Solenoid Driving Typologies
    1. 2.1 Low-Side and High-Side Configuration
    2. 2.2 Half-Bridge and H-Bridge Driver Configurations
  4. 3Basics of Driving Solenoid Loads
    1. 3.1 Current Control
    2. 3.2 Fast Discharging Circuits
      1. 3.2.1 Freewheeling and Clamping
      2. 3.2.2 Passive Voltage Clamping
  5. 4DRV Motor Driver Features for Solenoid Driving
    1. 4.1 Current Sensing and Regulation Solutions
    2. 4.2 Independent Low-/High-Side Driving
    3. 4.3 Half-Bridge Driving
    4. 4.4 Integrated and Gate Driver H-Bridges
  6. 5Summary
  7. 6Revision History

3.2 Fast Discharging Circuits

Some applications require fast turn on/off rates of a solenoid. Recirculating load current in opposing MOSFET may not be enough to decay the current fast enough, which can cause a delay in the plunger releasing.

To implement a fast discharge circuit, the driver circuit must generate a large voltage opposite to the solenoid that can quickly decay the recirculation current to zero. The higher opposing voltage, the faster the current decay. These fast discharging circuits can be made using an H-bridge, Zener or Transient-voltage-suppression (TVS) diode, a Voltage Dependent Resistor (varistor).