SLVA505A February   2012  – July 2024 DRV8800 , DRV8801 , DRV8802 , DRV8803 , DRV8804 , DRV8805 , DRV8806 , DRV8811 , DRV8812 , DRV8813 , DRV8814 , DRV8818 , DRV8821 , DRV8823 , DRV8824 , DRV8828 , DRV8829 , DRV8830 , DRV8832 , DRV8832-Q1 , DRV8833 , DRV8834 , DRV8835 , DRV8836 , DRV8837 , DRV8840 , DRV8841 , DRV8842 , DRV8843 , DRV8844 , DRV8870 , DRV8871 , DRV8872

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Factors Limiting the Maximum Output Current of a Motor Driver
    1. 1.1 Thermal Limitations
    2. 1.2 Overcurrent Protection (OCP) Limitations
    3. 1.3 Silicon and Package Limitations
    4. 1.4 PCB Limitations and Thermal Management Techniques
      1. 1.4.1 Exposed Pad Packages
      2. 1.4.2 Continuous Copper Planes
      3. 1.4.3 Copper Thickness
      4. 1.4.4 Thermal Vias
      5. 1.4.5 Summary of Thermal Management Techniques
    5. 1.5 Thermal Estimations
  5. 2TI Motor Driver OCP Operation
  6. 3TI Motor Driver Data Sheet Ratings
    1. 3.1 Description
    2. 3.2 Absolute Maximum Ratings
    3. 3.3 Recommended Operating Conditions
    4. 3.4 Thermal Information
    5. 3.5 Electrical Characteristics
  7. 4References
  8. 5Revision History

1.2 Overcurrent Protection (OCP) Limitations

The motor driver IC is protected from possible damage or degradation due to excessive current by incorporating some form of overcurrent protection (OCP). Many motor driver ICs and all of TI's motor driver ICs have OCP. OCP circuits generally act to limit the output current to a level that is safe for the silicon. See Section 2 for specific information about TI's implementation.

OCP circuits may provide one or both of the following:

  • an analog current limit
  • disabling an individual FET or the entire device when some preset current level is reached

Attempting to draw more current than is allowed by the OCP circuit results in a fault or shutdown. Because of this, the OCP circuit maximum current becomes a limitation of the peak current drawn from the device. This peak current is important, for example, when considering the start-up current of a stalled DC motor.

Some devices latch in an off state after experiencing an OCP event. Other devices automatically re-start after a short delay. Refer to the device data sheet to see in which mode a particular device operates.

A deglitch circuit is implemented to allow a higher current to flow for a very short period of time. This very brief deglitch time is necessary to allow the high peak current needed to charge parasitic capacitance in the load, which can include intrawinding capacitance and also snubber capacitors typically added to DC motors reducing EMI from brush arcing.