A comprehensive summary of calculation formulas for 14 switching power supply topologies. Power supply engineers should save them for future use!

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A comprehensive summary of calculation formulas for 14 switching power supply topologies. Power supply engineers should save them for future use! [Copy link]

1

Buck converter power device design formula

(1): Buck converter circuit diagram:

(2): Main steady-state specifications of Buck converter:

(3): Steady-state stress of power devices:

-- Active switch S:

-- Passive switch D:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

2

Power Device Design Formulas for Boost Converters

(1): Boost converter circuit diagram:

(2): Main steady-state specifications of the Boost converter:

(3): Steady-state stress of power devices:

-- Active switch S:

- Passive switch D:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

3

Buckboost Converter Design Formula

(1): Circuit diagram of Buckboost converter:

(2): Main steady-state specifications of the Buckboost converter:

(3): Steady-state stress of power devices:

-- Active switch S:

-- Passive switch D:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

4

Design formulas of power devices in three-winding demagnetized forward converter

(1): Circuit diagram of three-winding demagnetization forward converter:

(2): Main steady-state specifications of the three-winding demagnetization forward converter:

(3): Steady-state stress of power devices:

-- Active switch S:

-- Passive switches D1, D2:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

5

Power Device Design Formulas for Diode Demagnetization Dual Forward Converters

(1): Circuit diagram of diode demagnetization dual forward converter:

(2): Main steady-state specifications of the diode demagnetization dual forward converter:

(3): Steady-state stress of power devices:

- Active switches S1, S2:

- Passive switches D1, D2:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

6

Design formulas for power devices in a tuned demagnetization forward converter

(1): Circuit diagram of the tuned demagnetization forward converter:

(2): Main steady-state specifications of the tuned demagnetization forward converter:

(3): Steady-state stress of power devices:

- Active switch S:

- Passive switches D1, D2:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

7

Design formulas for power devices in active demagnetization forward converters

(1): Circuit diagram of active demagnetization forward converter:

(2): Main steady-state specifications of active demagnetization forward converter:

(3): Steady-state stress of power devices:

-- Active switch S:

-- Passive switches D1, D2:

[color=rgb(51, 51, 51) !important]The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, its voltage tolerance can be given a suitable margin (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

8

Power device design formula for symmetrical drive half-bridge converter

(1): Circuit diagram of symmetrical drive half-bridge converter:

(2): Main steady-state specifications of symmetrical drive half-bridge converter:

(3): Steady-state stress of power devices:

- Active switches S1, S2:

-- Passive switches D1, D2:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

9

Power Device Design Formulas for Symmetrical Drive Full-Bridge Converters

(1): Circuit diagram of symmetrical drive full-bridge converter:

(2): Main steady-state specifications of symmetrical drive full-bridge converter:

(3): Steady-state stress of power devices:

-- Active switches S1 (S3), S2 (S4):

-- Passive switches D1, D2:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

10

Power Device Design Formulas for Symmetrical Drive Push-Pull Converters

(1): Circuit diagram of symmetrical drive push-pull converter:

(2): Main steady-state specifications of symmetrical drive push-pull converter:

(3): Steady-state stress of power devices:

-- Active switches S1, S2:

-- Passive switches D1, D2:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

11

Power device design formulas for symmetrical drive push-pull forward converter

(1): Circuit diagram of symmetrical drive push-pull forward converter:

(2): Main steady-state specifications of symmetrical drive push-pull forward converter:

(3): Steady-state stress of power devices:

-- Active switches S1, S2:

-- Passive switches D1, D2:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

12

Power Device Design Formulas for Asymmetric Drive Half-Bridge Converters

(1): Circuit diagram of asymmetric drive half-bridge converter:

(2): Main steady-state specifications of asymmetric drive half-bridge converter:

(3): Steady-state stress of power devices:

-- Active switches S1, S2

-- Passive switches D1, D2:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

13

Power Device Design Formulas for Symmetrically Driven Push-Pull Boost Converters

(1): Circuit diagram of symmetrical drive push-pull boost converter:

(2): Main steady-state specifications of symmetrical drive push-pull boost converter:

(3): Steady-state stress of power devices:

-- Active switches S1, S2:

-- Passive switches D1, D2:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance. It is the content of power device thermal design and will be introduced in later columns.

14

Power Device Design Formulas for Flyback Converters

(1): Circuit diagram of flyback converter:

(2): Main steady-state specifications of the flyback converter:

(3): Steady-state stress of power devices:

-- Active switch S:

-- Passive switch D:

The above formula is the voltage and current stress on the power device in steady-state operation. When selecting a power device, a suitable margin can be placed on its voltage tolerance (to ensure that the voltage peak in the worst case does not exceed this value), and the current tolerance must be determined according to the junction temperature derating requirements of the device. It is closely related to the external heat dissipation conditions and the device's on-state resistance, on-state voltage drop, junction capacitance, reverse recovery, and junction-to-shell thermal resistance, and is the content of the power device thermal design.

sanhuasr

Thank you, moderator. Can you give me the formula for calculating Vmin and Vmax?

q1233

Thanks for sharing! Thanks for sharing! Thanks for sharing! Thanks for sharing! Thanks for sharing! Thanks for sharing! Thanks for sharing! Thanks for sharing!