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15
Without internal series diode, this reverse current flows into PDM out and keeps the starter motor
engaged.
7.3
High Power Output 1,2,3,4 Freewheeling protection diode
The High-Power Outputs 1,2,3,4 have an internal freewheeling protection diode. The picture here down
shows what happens when a power output turns off a high inductive load:
The red line is the negative voltage spike without diode. Blue one is the clamped voltage with diode. -VF
could reach very high value: -350V, -400V are typical of solenoid loads. -VD is limited to -1V by internal
freewheeling diode.
As indicated in picture, voltage level is clamped to very low value. This action protects Power Mosfet inside
PDM avoiding complete output destruction.
**IMPORTANT**
Low and High outputs do NOT have diode protection to protect against return current (voltage?) from
inductive loads. It is recommended, if not necessary, that an external diode be used for such
outputs. Inductive load examples include relays, solenoid valves, starter solenoids, and electric motors -
including fans.
Summary of Contents for PDM 32
Page 1: ...PDM 32 User Manual VER 1 06 ...
Page 42: ...www aim sportline com PDM 32 User Guide 41 ...
Page 61: ...www aim sportline com PDM 32 User Guide 60 Appendix A Connectors and Pinout ...
Page 62: ...www aim sportline com PDM 32 User Guide 61 ...
Page 63: ...www aim sportline com PDM 32 User Guide 62 Appendix B Mechanical Drawings ...