Expert Talk: What is a Power Converter (SMPS)?

Open online SPICE simulator circuit link: learn_power_converter_220V_overview_startup.tsc


A power converter transfers electric energy from a given source (input) to an energy sink (load)
in a well regulated manner. Infineon products and solutions help designer to achieve this task in an
easy, efficient and safe way. An energy source can be the power grid (AC) or a battery (DC).
Energy sink (Load) can be resistive (heater, LED), capacitive (bulb), inductive (motor, valve)
or a combination of them (CPU, FPGA).

Converter Types
- AC-AC: Transformer
- AC-DC: Rectifier
- DC-DC: Topologies like buck, boost, buck-boost, flyback, etc.
- DC-AC: Inverter (Motor, Solar)

Converter Realization
- Linear regulators: use semiconductor components in linear mode: low efficiency, bigger size, but low EMI noise
- Switching regulators: use components in swiched mode: higher efficiency, smaller size, but high EMI noise
- Power path: converts energy from the input source to the output load
- Control path: controls the power path for well regulated transfer, highest efficiency and stable operation

Example: Swiched mode power supply (SMPS) for charging adapter
set your CCM converter spec in the Interpreter window on the left, click on Run to calculate the parts and simulate it
- Input: 170 VAC
- Output: 12 VDC
- Current: 1 A

Circuit on the left: Flyback converter with two stages
- AC-DC Converter: Rectifier stage
- DC-DC Converter: Flyback topology

Important Note (Disclaimer)
This is an idealized circuit for learning and experimental use. Test carefully when using calculated values for real hardware.

Expert talk: how to design a Power Converter?

+

{1. click here to set application parameters}
{2. click on "Run" to calculate components}
{3. click on "OK" and Simulate Transient }

{Input voltages [V]}
V_in_ac:= 170 {use 100... 300}
V_in_dc:= 0.9*V_in_ac {after rectification}
V_in_dc=[153]
{Output voltage [V]}
V_out:= 12 {set smaller than V_in_dc}

{Output current [A]}
I_out:= 1 {use 1 .. 4}
R_load:= V_out/I_out
R_load=[12]

{Transformer}
N1:= 10 {Primary winding}
N2:= 1 {Secondary winding}
Ratio:= -N2/N1 {voltage Ratio}
Ratio=[-100m]
{=== Control settings: change with care ! ===}
{Switching frequency [Hz]}
fs:= 50k {use 100k .. 300k}
{Duty cycle}
Duty:= 1/(1+(V_in_dc/V_out*N2/N1))
Duty=[439.5604m]
L_INIT:= (V_out*I_out)/V_in_dc { DC value}
C0_INIT:= V_in_dc {capacitor DC value}
C_INIT:= V_out
T:=1/fs
T_on:= Duty*T
T_off:=T-T_on
ControlT2:=T_on
ControlT4:=T_off
{Calculate components for CCM}
L_crcm:= ((1-Duty)^2*R_load)/(2*fs*(N2/N1)^2)
L_crcm=[3.7691m]
L:= 2*L_crcm
L=[7.5382m]
R_crcm:= (2*L*fs*(N2/N1)^2)/(1-Duty)^2
R_crcm=[24]

AC-DC Converter (Rectifier)

Flyback Topology (DC-DC)



Technical Assistance
Other circuits

Infineon MOSFET Finder,https://www.infineon.com/cms/en/tools/solution-finder/product-finder/mosfet-finder/)
\a(Power Selection Guide,https://www.infineon.com/dgdl/Infineon-Power_and_Sensing_Selection_Guide_2018-SG-v00_00-EN.pdf?fileId=5546d4625607bd13015621522aa012cb)
\a(Automotive Power Guide


Explore DC-DC topologies