MA5342MS datasheet(39/64 Pages) INFINEON

39 / 64 page

Datasheet

39 of 63

V 2.1

11/2/2023

Integrated Class D Amplifier

MA5342MS

9.2

Control Loop Design

The MA5342MS allows the user to choose from numerous methods of PWM modulator implementations. In this

section, all the explanations are based on a typical application circuit of a self-oscillating

9.3

PWM Frequency

Choosing the switching frequency entails making a trade-off between many aspects. At lower switching

frequency, conduction losses in the MOSFET stage increases due to higher inductor ripple current. The output

carrier leakage in the speaker output increases. At higher switching frequency, the efficiency degrades due to

higher switching losses. Higher switching frequency supports wider audio bandwidth. The inductor ripple

decreases yet core loss might increase. For these reasons, 400kHz is chosen for a typical design example.

Self-oscillating frequency has little influence from the bus voltage and input resistance RIN. Note that the

nature of a self-oscillating PWM is for the switching frequency to decrease as PWM modulation deviates from

idling.

Table 6 summarizes suggested values of components for a given target self-oscillating frequency. The front-end

operational transconductance amplifier (OTA) output has limited voltage and current compliances. This set of

component values ensures that OTA operates within its linear region for optimal THD+N performance. In case

the target frequency is somewhere in between the frequencies listed in Table 6, simply adjust the frequency by

tweaking R1.

Table 10

External Component Values vs. Self-Oscillation Frequency

Target Self-Oscillation

Frequency (kHz)

C1=C2 (nF)

R1 (ohms)

500

2.2

200

450

2.2

165

400

2.2

141

350

2.2

124

300

2.2

115

250

2.2

102

200

4.7

41.2

150

20.0

100

14.0

4.42

MA5342MS Datasheet(PDF) 39 Page - Infineon Technologies AG

MA5342MS Datasheet(HTML) 39 Page - Infineon Technologies AG

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

Datasheet Download

Link URL