DocID026335 Rev 1

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UM1763

Example V

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7

Example V

Figure 6. Example 04 application scheme

The goal of the fifth example is to learn how to generate a PWM signal as a function of two

comparators. In this case we want to control the PWM5 variable frequency so to keep an

analog output voltage between a high threshold and a low threshold respectively set to

410 mV and 246 mV by CPP2 and CPP3 references.

Figure 7. PWM5 variable frequency

As shown in Figure 6, in order to keep Vout over 246 mV, PWM5 is turned on when voltage

reaches the low threshold reference sensed by the DAC3 and CPP3. Also keeping Vout

under 410 mV requires the PWM5 to be turned off when voltage hits the high threshold

reference sensed by the DAC2 and CPP2. No more firmware interaction is needed as the

output control is automatically handled by the SMED 5 FSM described in Figure 7.