SLVSAH5E December 2010 – May 2019 TPS57114-Q1
The following formulas show how to estimate the IC power dissipation under continuous-conduction mode (CCM) operation. The power dissipation of the IC (PT) includes conduction loss (P(con)), dead-time loss (P(d)), switching loss (P(SW)), gate-drive loss (P(gd)), and supply-current loss (P(q)).
IO is the output current (A).
rDS(on)(Temp) is the on-resistance of the high-side MOSFET with given temperature (Ω).
VI is the input voltage (V).
f(SW) is the switching frequency (Hz).
For a given TA,
For a given TJ(max) = 150°C
PT is the total device power dissipation (W).
TA is the ambient temperature (°C).
TJ is the junction temperature (°C).
RθJA is the thermal resistance of the package (°C/W).
TJ(max) is maximum junction temperature (°C).
TA(max) is maximum ambient temperature (°C).
There are additional power losses in the regulator circuit due to the inductor ac and dc losses and trace resistance that impact the overall efficiency of the regulator.