JAJSSI1 December 2023 TAS5827
PRODUCTION DATA
Spread spectrum modulation is a PWM modulation technique that reduces the peaks seen in EMI measurements by varying the output PWM frequency, resulting in a wider spectrum but lower level. The TAS5827 supports Spread Spectrum both of triangle and random mode.
The user needs to configure register RAMP_SS_CTRL0 Register (Offset = 6Bh) [Reset = 00h] to Enable triangle mode and enable spread spectrum, select spread spectrum frequency and range with RAMP_SS_CTRL1 Register (Offset = 6Ch) [Reset = 00h] . For 768 kHz FSW which is configured by DEVICE_CTRL1 Register (Offset = 2h) [Reset = 00h] , the spread spectrum frequency and range are described in Table 6-2.
SS_TRI_CTRL[3:0] | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
---|---|---|---|---|---|---|---|---|
Triangle Freq | 24k | 48k | ||||||
Spread Spectrum Range | 5% | 10% | 20% | 25% | 5% | 10% | 20% | 25% |
User Application example: Central Switching Frequency is 768 kHz, Triangle Frequency is 48 kHz.
Register 0x02 = 0x41 // 768 kHz Fsw, BTL Mode, 1SPW mode.
Register 0x6b = 0x03 // Enable Spread Spectrum
Register 0x6c = 0x03 // SS_CTRL[3:0]=0011, Triangle Frequency = 48 kHz, Spread Spectrum Range should be 10% (729 kHz~807 kHz)