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TDA8932B Datasheet(PDF) 22 Page - NXP Semiconductors |
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TDA8932B Datasheet(HTML) 22 Page - NXP Semiconductors |
22 / 48 page ![]() TDA8932B_4 © NXP B.V. 2008. All rights reserved. Product data sheet Rev. 04 — 18 December 2008 22 of 48 NXP Semiconductors TDA8932B Class-D audio amplifier 14. Application information 14.1 Output power estimation The output power Po at THD+N = 0.5 %, just before clipping, for the SE and BTL configuration can be estimated using Equation 2 and Equation 3. SE configuration: (2) BTL configuration: (3) Where: VP = supply voltage VDDP1 − VSSP1 (V) or VDDP2 − VSSP2 (V) RL = load impedance (Ω) RDSon = on-resistance power switch (Ω) Rs = series resistance output inductor (Ω) RESR = equivalent series resistance SE capacitor (Ω) tw(min) = minimum pulse width (s); 80 ns typical fosc = oscillator frequency (Hz); 320 kHz typical with Rosc = 39 kΩ The output power Po at THD+N = 10 % can be estimated by: (4) Figure 8 and Figure 9 show the estimated output power at THD+N = 0.5 % and THD+N = 10 % as a function of the supply voltage for SE and BTL configurations at different load impedances. The output power is calculated with: RDSon = 0.15 Ω (at Tj =25 °C), Rs = 0.05 Ω, RESR = 0.05 Ω and IO(ocp) = 4 A (minimum). P o 0.5% () R L R L R DSon R s R ESR ++ + ---------------------------------------------------------- 1t wmin () – f osc × () × V P × 2 8R L × ------------------------------------------------------------------------------------------------------------------------------------------- = P o 0.5% () R L R L 2 + R DSon R s + () × ------------------------------------------------------ 1t wmin () – f osc × () × V P × 2 2R L × -------------------------------------------------------------------------------------------------------------------------------------- = P o10% () 1.25 P o 0.5% () × = |
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