SNVAA80 July   2024 LM5177

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Reverse Current Operation
  6. 3Design Considerations
  7. 4Pin Configurations
    1. 4.1 Other Pin Configurations
      1. 4.1.1 MODE Pin
      2. 4.1.2 IMONOUT
  8. 5Application Measurements
  9. 6Summary
  10. 7References

5 Application Measurements

To verify that the designed controllers for the MODE pin work correctly, tests are conducted using the LM5177 Buck-Boost Controller Evaluation Module. The results, displayed in Figure 5-1 through Figure 5-4, demonstrate a smooth shift from constant current to constant voltage charging of the storage element when using the MODE pin control. However, a small hysteresis, caused by the switching delay of the MOSFET, is noticeable during the transitions between FPWM and PSM modes, leading to a minor ripple in the charging voltage. An initial bias of 5V is applied to the storage element to bypass the internal low voltage protection of the controller. When the storage voltage reaches the desired voltages, the reference voltage from the voltage divider circuit rises to 1.24V, causing the cathode voltage of the TLV431 to drop from VCC to 1.8V.

LM5177, LM5177X Constant Voltage Charging Figure 5-1 Constant Voltage Charging
LM5177, LM5177X Constant Voltage Charging and Discharging Figure 5-2 Constant Voltage Charging and Discharging
LM5177, LM5177X Constant Voltage Charging With Supply Current Figure 5-3 Constant Voltage Charging With Supply Current
LM5177, LM5177X Constant Voltage Charging and Discharging With Supply Current Figure 5-4 Constant Voltage Charging and Discharging With Supply Current