SLVAE69 July   2019 TPS568215 , TPS56C215

 

  1.   Expand Buck Converter Minimum Input Voltage with External VCC Bias
    1.     Trademarks
    2. 1 TPS56C215 Introduction
    3. 2 12 V / 5 V O-ring supply for DDR application
    4. 3 Schematic and Bench Results
      1. 3.1 Efficiency Comparison
      2. 3.2 Bench Waveforms
    5. 4 Conclusion
    6. 5 References

3 Schematic and Bench Results

The detail schematic of external VREG5 Biased TPS56C215 schematic is shown in Figure 4.

Fig4-External-VREG5-Biased-TPS56C215.pngFigure 4. External VREG5 Biased TPS56C215 Schematic

The system level parameters are shown in Table 1.

Table 1. System Parameters

Parameter Example Value
12 V Input Voltage Rail, V 12 12 VDC
5 V Input Voltage Rail, V 5 5 VDC
VREG5 Supply, VDD 5 VDC
Output VPP Voltage, VOUT 2.5 VDC
Maximum Output Current, IO_MAX 12 A
Switching Frequency, FSW 800 kHz
Output Inductor, Lf 470 nH
Output Capacitor, COUT 47uFx4