Switching Power Supply Design Optimization By Sanjaya Maniktala Pdf
Click Here ->>> https://urluss.com/2taZN1
Output transformers are used to convert the output voltage to the appropriate value for the load. For voltages above 5,000 V, the output transformer is usually wound with an iron core, and, in the case of a flyback converter, the secondary winding is used to recharge the output capacitor after each power transfer pulse.
In low-power switching-mode supplies, the output transformer is a low-power version of the high-power transformers used in the power stage. The secondary winding is used to produce a voltage that is more than enough to drive the power transistor gate terminal. These converters usually have a current rating significantly lower than the primary current rating, to avoid overheating the winding. As a result, the output filter is often a large, heavily-potted capacitor. The output filter is usually the only part of the SMPS that can be replaced with a generic, low-cost, small-form factor component.
High-power SMPSs use switched mode power supply output transformers. The secondary winding is used to start and stop the power stage PWM cycle, providing both on-time and off-time switching.
A typical SMPS has a DC input, a rectifier (usually a diode bridge), an N-channel MOSFET (or similar device) for energy transfer (inductor or capacitor), an N-channel or P-channel MOSFET (or similar device) for driving the load, and an output filter. For low-frequency high-current power supplies, a large passive magnetic component is used to store energy, typically a ferrite or iron-core inductor. In switching-mode power supplies, the energy storage device is usually a capacitor instead of an inductor, and the term flyback converter is used for such converters.
An SMPS usually uses a PWM controller to modulate and adjust the power stage duty cycle to increase the efficiency. An SMPS may use a PWM controller for frequency control, or for both frequency and duty cycle control. However, some PWM controllers can provide only a fixed duty cycle. This is called fixed-frequency PWM.
An AC/DC power supply typically delivers either DC or AC power to the load. This power is either stepped-down (DC voltage) or rectified (AC voltage). The output voltage may be regulated (constant output voltage) or unregulated (variable output voltage). [1] A charging circuit is connected to the load, which charges a battery when the power from the AC/DC supply is not sufficient to drive the load. Once the battery is fully charged, the system shuts down.
A resonant converter (such as a resonant converter) is an SMPS that is designed to output a constant output voltage. The output voltage is constant in an area where the input power is constant (with the source current at its maximum). Since the output voltage is the same regardless of the input power, the resonant converter has a very high efficiency (i.e., the power at the output is equal to the power at the input). The output voltage is controlled by changing the resonant frequency. 827ec27edc