Switch power adapter switch power adapter with 4 kinds of modulation mode
Now a lot of places are used to power this thing, whether in which field.
Today then I will take you more understanding about the switch power adapter 4 kinds of modulation mode, estimates that were not many people know.
Then with the power adapter manufacturer in shenzhen to see what are the four kinds of modulation mode: 1, the pulse density modulation (' product data management (PDM), namely, pulse modulation.
Its characteristic is pulse width is constant value, by adjusting the voltage pulse number.
It USES the technology of zero voltage, can significantly reduce the wastage of the power switch tube.
2, pulse width modulation PWM for short, namely pulse width modulation.
Its characteristics switch cycle is constant value, by adjusting the pulse width to change the duty ratio, attain the goal of voltage regulation.
Its core type PWM controller.
Pulse width modulation and the application of switching power supply is more common, the space is larger than the adjusting range, PWM can also and the main system clock in sync.
3, mixed modulation it is (1), the combination of the two ways .
Switching cycle and pulse width is not fixed, are adjustable.
It contains a PWM controller and PFM controller.
4, pulse frequency modulation (' PFM, namely pulse frequency modulation.
Characterized by a pulse width is constant value, by adjusting the switching frequency to change the duty ratio, attain the goal of voltage regulation.
Its core is the PFM controller.
Pulse frequency modulation switch power supply, especially suitable for portable devices, it can under the condition of low duty ratio, low frequency, reduce the control chip of the static current.
From the above four kinds of modulation mode, switch power modulation method has two major categories: adjustable width and frequency modulation.
The width is adjusting the duty ratio (
The energy transfer time and waveform cycle than Ton/T)
To adjust the output voltage (
It should be pointed out that, PWM controller can be used as an independent integrated circuit, can also be integrated in the switching voltage stabilizer, or in the monolithic switch power supply.
Among them, the switching voltage stabilizer belongs to DC/DC converter, switching power supply for AC/DC converter.