CFG_DPM register bit field definitions.
The CFG_DPM register configures the Detection of Plunger Movement (DPM) algorithm parameters. DPM settings are global and apply to all channels.
Register Layout
| Bits | Field | Description |
| 31:21 | RSVD | Reserved (write 0) |
| 20:16 | RSVD | Reserved (write 0) |
| 15 | RSVD | Reserved (write 0) |
| 14:8 | DPM_ISTART[6:0] | Starting current for DPM monitoring |
| 7:4 | DPM_TDEB[3:0] | DPM debounce time |
| 3:0 | DPM_IPTH[3:0] | DPM current dip threshold |
DPM Algorithm Parameters
- ISTART: Starting current for DPM monitoring
- ISTART = DPM_ISTART[6:0] × (IFS / 127)
- Set ISTART just below the minimum current where the plunger movement dip is expected
- TDEB: Debounce time (minimum dip duration to be recognized)
- TDEB = DPM_TDEB[3:0] / fCHOP
- Lower values = more sensitive (may false-trigger on noise)
- Higher values = less sensitive (may miss valid dips)
- IPTH: Current dip threshold (minimum dip amplitude)
- IPTH = DPM_IPTH[3:0] × (IFS / 127)
- Lower values = more sensitive
- Higher values = less sensitive
DPM Algorithm Behavior
The DPM algorithm monitors current above ISTART until either:
- The programmed IHIT level is reached, OR
- The HIT time (tHIT) ends
A valid plunger movement is detected if:
- A current dip with amplitude > IPTH occurs, AND
- The dip duration > TDEB
If no valid dip is detected, a DPM fault is signaled (if DPM_EN is set for that channel and M_DPM is not masked).
- Note
- DPM accuracy becomes less reliable if the dip is not pronounced enough.
-
The current slope above ISTART must be slower than 700mA/ms for reliable detection (to allow the internal ADC to track).
-
Per datasheet section "Detection of Plunger Movement (DPM)" and "Detection of Plunger Movement Register Description (CFG_DPM)".
