SNOSAS1B November   2010  – September 2025 LMD18200QML

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Functional Diagram
  6. 5 Absolute Maximum Ratings
  7. 6 Operating Ratings
  8. 7 Quality Conformance Inspection
  9. 8 LMD18200 Electrical Characteristics DC Parameters
  10. 9 Typical Performance Characteristics
  11. 10Test Circuit
    1. 10.1 Switching Time Definitions
  12. 11Pinout Description
    1. 11.1 Application Information
      1. 11.1.1 TYPES OF PWM SIGNALS
      2. 11.1.2 SIGNAL TRANSITION REQUIREMENTS
      3. 11.1.3 USING THE CURRENT SENSE OUTPUT
      4. 11.1.4 USING THE THERMAL WARNING FLAG
      5. 11.1.5 SUPPLY BYPASSING
      6. 11.1.6 CURRENT LIMITING
      7. 11.1.7 INTERNAL CHARGE PUMP AND USE OF BOOTSTRAP CAPACITORS
      8. 11.1.8 INTERNAL PROTECTION DIODES
    2. 11.2 Typical Applications
      1. 11.2.1 FIXED OFF-TIME CONTROL
      2. 11.2.2 TORQUE REGULATION
      3. 11.2.3 VELOCITY REGULATION
  13. 12Revision History

11.2.1 FIXED OFF-TIME CONTROL

This circuit controls the current through the motor by applying an average voltage equal to zero to the motor terminals for a fixed period of time, whenever the current through the motor exceeds the commanded current. This action causes the motor current to vary slightly about an externally controlled average level. The duration of the Off-period is adjusted by the resistor and capacitor combination of the LM555. In this circuit the Sign/Magnitude mode of operation is implemented (see Section 11.1.1).

LMD18200QML Fixed Off-Time ControlFigure 11-6 Fixed Off-Time Control
LMD18200QML Switching WaveformsFigure 11-7 Switching Waveforms