how to design pwm generator circuit - ti trainingdesign notes design notes: 1. for pwm generator...
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CIRCUIT060010 CIRCUIT060010
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How to Design PWM generator circuit
CIRCUIT060010
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Circuit Description
CIRCUIT060010
Input Output Supply ViMin ViMax VoMin VoMax Vcc Vee Vref
โ2.0 V 2.0 V 50mV 5 V 5 V 0 V 2.5 V
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Design Steps
CIRCUIT060010
Input Output Supply ViMin ViMax VoMin VoMax Vcc Vee Vref
โ2.0 V 2.0 V 50mV 5 V 5 V 0 V 2.5 V
www.ti.com/circuitcookbooks
Design Steps
๐บ๐๐๐ = โ๐ 4
๐ 3= โ1๐/๐
๐ 3 = ๐ 4
๐๐_๐๐ = 1 +๐ 4
๐ 3ร
๐ 2
๐ 1 + ๐ 2ร ๐๐๐๐
๐ 1 = ๐ 2 = ๐ 3 = ๐ 4 = 10 ๐ฮฉ
CIRCUIT060010
Input Output Supply ViMin ViMax VoMin VoMax Vcc Vee Vref
โ2.0 V 2.0 V 50mV 5 V 5 V 0 V 2.5 V
www.ti.com/circuitcookbooks
Design Steps
๐๐ก๐๐ =๐ 5
๐ 6ร ๐1 = 2.1๐
๐ 5 =๐๐ก๐๐ ร ๐ 6
๐1=
2.1๐ ร 10๐ฮฉ
2.5๐= 8.42๐ฮฉ
8.42๐ฮฉ โ 8.45๐ฮฉ (๐๐ก๐๐๐๐๐๐ ๐๐๐๐ข๐)
CIRCUIT060010
Input Output Supply ViMin ViMax VoMin VoMax Vcc Vee Vref
โ2.0 V 2.0 V 50mV 5 V 5 V 0 V 2.5 V
www.ti.com/circuitcookbooks
Design Steps
๐๐ก =๐ 6
4 ร ๐ 7 ร ๐ 5 ร ๐ถ3
๐ 7 =๐ 6
4 ร ๐๐ก ร ๐ 5 ร ๐ถ3
๐ 7 =10๐ฮฉ
4 ร 500๐๐ป๐ง ร 8.45๐ฮฉ ร 100๐๐น= 5.92๐ฮฉ
5.92๐ฮฉ โ 5.9๐ฮฉ (๐๐ก๐๐๐๐๐๐ ๐๐๐๐ข๐)
CIRCUIT060010
Input Output Supply ViMin ViMax VoMin VoMax Vcc Vee Vref
โ2.0 V 2.0 V 50mV 5 V 5 V 0 V 2.5 V
www.ti.com/circuitcookbooks
Design Steps
๐๐ =1
2ฯ ร ๐ 4 ร ๐ถ1
๐ถ1 = 100๐๐น
๐๐ = 159๐๐ป๐ง
CIRCUIT060010
Input Output Supply ViMin ViMax VoMin VoMax Vcc Vee Vref
โ2.0 V 2.0 V 50mV 5 V 5 V 0 V 2.5 V
www.ti.com/circuitcookbooks
Design Steps
๐๐ =1
2ฯ ร ๐ถ2 ร๐ 1 ร ๐ 2๐ 1 + ๐ 2
๐ถ2 = 100๐๐น
๐๐ = 320๐ป๐ง
CIRCUIT060010
Input Output Supply ViMin ViMax VoMin VoMax Vcc Vee Vref
โ2.0 V 2.0 V 50mV 5 V 5 V 0 V 2.5 V
www.ti.com/circuitcookbooks
Transient Results
CIRCUIT060010
Input Output Supply ViMin ViMax VoMin VoMax Vcc Vee Vref
โ2.0 V 2.0 V 50mV 5 V 5 V 0 V 2.5 V
www.ti.com/circuitcookbooks
Design Notes
Design Notes: 1. For PWM generator circuits, use a
comparator with a push-pull output and
minimal propagation delay.
2. Select an op amp with sufficient SR, BW,
and output swing.
3. Place the pole created by C1 below the
switching frequency and well above the
audio frequency range.
CIRCUIT060010
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CIRCUIT060010 CIRCUIT060010
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