SLVSFV5C July 2023 – July 2025 DRV8262
PRODUCTION DATA
Spread spectrum or frequency dithering is used to reduce the effect of EMI by converting a narrowband signal into a wideband signal, which spreads the energy across multiple frequencies. Figure 6-3 illustrates how manipulating the clock frequency over time has the effect of spreading the energy.
In the context of the DRV8262, the frequencies of the internal clock for digital circuits (10MHz typical) and the clock for charge pump (357kHz typical) are manipulated to reduce the peak energy and is distributed to other frequencies and harmonics. Spread spectrum combined with output slew rate control minimize the radiated emissions from the device and help pass strict EMI standards.
When the DRV8262 is powered up, spread spectrum is enabled. There are many ways to implement spread spectrum. The DRV8262 uses the triangular analog modulation profile. Figure 6-4 and Figure 6-5 shows the spread spectrum profiles of the internal digital clock and the charge pump clock around the respective center frequencies. The digital clock varies by equal amounts over 14 steps between 9MHz and 11MHz.
Figure 6-5 Triangular Spread Spectrum of
Charge Pump Clock