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Smps
The document compares the properties of linear and SMPS power supplies. Linear power supplies are large, heavy, and have low operating costs but produce low noise. SMPS power supplies are smaller, lighter, and have higher operating costs but produce more noise. The document then describes the components and operation of a typical SMPS circuit, including the rectifier, filter capacitors, switching transistor, driver circuitry, transformers, rectifier diodes, and output filter components. It notes that a driver circuit is needed between the PWM IC and switching transistor due to the low output of the PWM IC.
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Smps
- 1. LINEAR 1) Largesize & Heavy weight 2) Transformer is Bulky 3) Low Noise * EMI 4) Regulation is 0.1 % 5) High Operating Cost 6) Bulky filter Capacitor SMPS 1) Small size & Light Weight 2) High EMI 3) Small Transformer 4) Medium Filter Cpacitor 5) High Noise 6) Regulation is 0.3 % 7) Low Operating Cost
- 2. It isPlaced after surge filter & consist of following components 1) A combination of 4 diodes This section is used to convert 230VAC to 300 VDC
- 3. 1) Theelectrolytic capacitor of higher voltage capacity C1=330µ f/ 400v, C2=330µ f/ 400v & C3=100µ f/ 400v
- 4. The Transistorsare fixed on the heat sink and hence easy to identify There is another pair of driver transistor (small size) which are used to drive switching transistor The driver transistor & switching transistor are coupled together through a small transformer called Driver Transformer
- 5. A biggerTransformer & is driven from the collector of the switching transistor
- 6. It consistsof two groups of diodes
- 7. It consistsof inductors & capacitors
- 8. IC TL494,It is used to generate the pulses of different width.It requires some esternal components like resistors,capacitors and seramic capacitors for generation of pulses
- 9. The switchingtransistor cannot be driven directly from PWM IC because o/p of PWM IC is very less .Therefore ,we need driver circuit between the switching transistor & PWM IC . The coupling of power transistor & driver transistor is done through the driver transformer.
- 10. The switchingtransistor cannot be driven directly from PWM IC because o/p of PWM IC is very less .Therefore ,we need driver circuit between the switching transistor & PWM IC . The coupling of power transistor & driver transistor is done through the driver transformer.