TIDT277 April   2022

 

  1.   Description
  2.   Features
  3.   Applications
  4. 1Test Prerequisites
    1. 1.1 Voltage and Current Requirements
    2. 1.2 Considerations
    3. 1.3 Dimensions
  5. 2Testing and Results
    1. 2.1 Efficiency Graphs, all Outputs Similar Loaded
    2. 2.2 Load Regulation
    3. 2.3 Cross Regulation and Further Data For Non-Symmetrical Loading
    4. 2.4 Line Regulation at Full Load to all Outputs
    5. 2.5 Thermal Images
  6. 3Waveforms
    1. 3.1 Switching
      1. 3.1.1 Switchnode to GND
      2. 3.1.2 Diode D3
    2. 3.2 Output Voltage Ripple
    3. 3.3 Input Voltage Ripple
      1. 3.3.1 Power Stage Input
      2. 3.3.2 Between L1 and L2
      3. 3.3.3 Input Terminal
    4. 3.4 Start-Up Sequence
    5. 3.5 Shutdown Sequence

2.3 Cross Regulation and Further Data For Non-Symmetrical Loading

A B
VIN 13.5 13.506
IIN 0.1158 0.1909
+VoutU 17.27 17.29
+IoutU 0.0046 0.0045
–VoutU –4.133 –4.134
–IoutU 0.0052 0.0052
+VoutV 17.11 16.8
+IoutV 0.005 0.049
–VoutV –4.292 –3.974
–IoutV 0.0052 0.0489
+VoutW 16.74 16.78
+IoutW 0.049 0.0491
–VoutW –3.975 –3.983
–IoutW 0.0487 0.0488
PIN 1.563 2.578
Pout 1.223 2.135
Eff 0.782 0.828
Loss 0.341 0.443

A ⇒ output W full load 50 mA; output V and U 10% load, so 5 mA (one channel fully loaded).

B ⇒ output W and V full load 50 mA; output U just 10% load, so 5 mA (two channels fully loaded).

Non-symmetrical loading 10% and 100% of channels results in voltage deviation 16.74 V to 17.29 V and –3.974 V to –4.292 V.

Non-symmetrical loading individually at a channel, so different loading at + voltage and – voltage could be a problem for a virtual ground using this Zener solution. Here the load at + and – output is almost similar.

If needed, this could be improved: by increasing the voltage drop across shunt resistors R7, R8, and R9 ⇒ needs rework on R6, try 73.2 kΩ.