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CHAPTER 8 16-BIT TIMER/EVENT COUNTER
By integrating 14-bit resolution PWM pulses with an external low-pass filter, they can be converted to an analogvoltage and used for electronic tuning and D/A converter applications, etc.The analog output voltage (VAN) used for D/A conversion with the configuration shown in Figure 8-14 is as follows.VAN = VREF ×
216
VREF: External switching circuit reference voltageFigure 8-14. Example of D/A Converter Configuration with PWM Outputcapture/compare register 00 (CR00) valueFigure 8-15 shows an example in which PWM output is converted to an analog voltage and used in a voltagesynthesizer type TV tuner.Figure 8-15. TV Tuner Application Circuit Example
Switching Circuit
TO0/P30
PWM
signal
V
REF
Low-Pass Filter Analog Output (V
AN
)
PD78058F, 78058FY
µ
PD78058F, 78058FY
µ
TO0/P30
V
SS
8.2 k
8.2 k
100 pF
22 k
+110 V
2SC
2352
47 k
47 k
47 k
0.22 F
µ
0.22 F
µ
0.22 F
µ
Electronic
Tuner
GND
PC574J
µ