
DS4830A User’s Guide
128
Table 14-2: Number of Slots for Each Resolution
RES_SEL[3:0] Resolution
Pulse Spreading Method
The DS4830A PWM controller uses a delta sigma algorithm to distribute the duty cycle uniformly among the slots.
For example, a 10-bit PWM output with a DCYCn value of 128 with 8-slot pulse spreading enabled (PS[1:0] = b’11)
produces a PWM output as shown in the Figure 14-5. The duty cycle of 128 in 1024 cycles (10-bit resolution) has
been divided over 8 equal slots of 16 PWM clock cycles. As duty cycle increases by a count each time the pulse
spread is implemented uniformly and the corresponding duty cycle is distributed among slots. Table 14-3 and Figure
14-5 explain this example. Example considers PWM operation in the positive polarity.
Table 14-3: Duty Cycle Distribution with 8-Slot Pulse Spreading for 10-Bit Resolution PWM Operation
Resolution
Slot 1 Slot 2 Slot 3 Slot 4 Slot 5 Slot 6 Slot 7 Slot 8
10
16
16
16
16
16
16
16
16
129
16
16
16
16
16
16
16
17
17 17 17 17 17 17 17 17
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