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Constant Current Sink

Introduction

  1. Using MOSFET Safe Operating Area Curves in Your Design (TI AN)

Resources

  • Constant Current load (analog control loop MOSFET, OpAmp, current sense feedback loop)
  • Low-side (simpler) versus high-side current sense
  • Constant-current discharge
  • Measure battery voltage
  • Measure discharge current
  • Cut-off voltage
  • Temperature sensing
  • Discharge profiles
  • Reverse polarity protection
  • Input fuse

Notes

  • A precision current sink can by created with a transistor, amplifier, and voltage reference.
  • Thing of FET as a transconductance device, with gate-sourcve voltage programming the drain current.
  • Transconductance g_m is the ratio of i_d/V_gs.
  • The gate of a MOSFET is insulated from the drain source channel
  • The drain-source resistance is programmed by the gate-source voltage.
  • https://www.youtube.com/watch?v=3xp6C67hwsE
    • FET IRFP260N (Quad)