4.2.2 Open Loop with Current Limit Test

Below are the steps for testing the Open Loop with Current Limit operation of the CIP Hybrid Power Starter Kit.

  1. Remove programming interface. Place CH1 oscilloscope probe to PWM_HS test point, CH2 oscilloscope probe to PWM_LS test point, CH3 oscilloscope probe to CT_CS test point, and CH4 oscilloscope probe to VOUT test point.
  2. Connect DC supply (set to 6V) and LOAD (set to 2A). Power-up the board. PWM_HS, PWM_LS and CT_CS signals and VOUT can be monitored.
  3. Increasing VIN increases VOUT, but duty cycle is decreases because the CT_CS signal is touching the PRG signal at the defined slope.
    Figure 4-19. PRG Effect on CT_CS Signal and PWM Duty Cycle
  4. Increasing the load will decrease VOUT, since the duty cycle is being limited by the CT_CS signal touching the PRG signal.