SLUAAN0 December   2022 TPS62933F

 

  1.   Designing a Simple and Low-Cost Flybuck Solution With the TPS62933F
  2.   Trademarks
  3. 1Introduction
  4. 2Flybuck Converter Device Overview
    1. 2.1 Operation Description
    2. 2.2 Equations for Maximum Output Current
  5. 3Design Flybuck With TPS62933F
    1. 3.1 Primary Voltage and Turns Ratio
    2. 3.2 Feedback Resistor
    3. 3.3 Rectifier Diode
    4. 3.4 Primary Inductance
    5. 3.5 Primary Turns
    6. 3.6 Input and Output Capacitor
    7. 3.7 Pre-Load
    8. 3.8 Factors Affecting Voltage Regulation
    9. 3.9 Avoiding Low-Side Sink Current Limit
  6. 4Experimental Results
  7. 5Conclusion
  8. 6References

3 Design Flybuck With TPS62933F

Figure 3-1 shows the design example with the typical flybuck circuit, using the synchronous buck regulator TPS62933F from TI.

Figure 3-1 TPS62933F Two Output Isolated Buck Solution

Table 3-1 lists the design specification.

Table 3-1 Design Parameters
Design ParameterExample Value
Input voltage range (VIN)10 V to 24 V
Primary output voltage (VOUT1)5 V
Positive isolated output voltage (VOUT2)12 V
Negative isolated output voltage (VOUT3)–12 V
Primary load current (IOUT1)1 A
Positive isolated load current (IOUT2)0.2 A
Negative isolated load current (IOUT3)0.2 A
Switching frequency (fsw)500 kHz

In this example, one primary output and two isolated outputs are obtained. We will begin with the buck converter component calculations and qualify the steps for the isolated configuration.