6 Theory

6.1 Power Electronics

Any articles concerning power electronics

6.1.1 DC-DC Voltage Converters

Articles discussing the process of converting DC to another level of DC

6.1.1.1 Boost Converter - Component Calculator

Input Parameters

VSAT Saturation voltage of the output transistor
VF Forward voltage drop of the diode
VIN Typical input voltage
VMIN The minimum voltage of the input
VOUT Desired output voltage
IOUT Desired output current
fMIN Minimum desired output switching frequency
VRIP Desired peak to peak output ripple voltage
R1 Resistor for setting VOUT

Calculated Component Values

R1 Resistor for setting VOUT
R2 Resistor for setting VOUT
R3 Switch Biasing (constant)
RPD Pull down resistor for transistor (constant)
RSC Current sense resistor
CT Timing capacitor
CO Output capacitor
LMIN Minimum inductance for output

Reference Schematic

6.1.1.2 Buck Converter - Component Calculator

Input Parameters

VSAT Saturation voltage of the output transistor
VF Forward voltage drop of the diode
VIN Typical input voltage
VMIN The minimum voltage of the input
VOUT Desired output voltage
IOUT Desired output current
fMIN Minimum desired output switching frequency
VRIP Desired peak to peak output ripple voltage
R1 Resistor for setting VOUT

Calculated Component Values

R1 Resistor for setting VOUT
R2 Resistor for setting VOUT
RPD Pull down resistor for transistor (constant)
RSC Current sense resistor
CT Timing capacitor
CO Output capacitor
LMIN Minimum inductance for output

Reference Schematic

6.1.1.3 Low Drop Out Regulators vs. Buck Converters

In this video the energy efficiencies of Low Drop Out (LDO) regulators and Buck converters is discussed. A quick graph is generated in Sage Mathematics to compare the two circuits power consumption

LDO Efficiency:

$$P_{loss}=I*(V_{in}-V_{out})$$

Where $P_{loss}$ is heat dissipation, $I$ is the current drawn on the output, $V_{in}$ is the input voltage, and $V_{out}$ is the output voltage.

Buck Efficiency:

$$P_{loss}=(1-E)*V_{out}*I$$

Where $P_{loss}$ is heat dissipation, $E$ is the calculated efficiency, $I$ is the current drawn on the output, and $V_{out}$ is the output voltage.

Sage Simulation Script:

var("Vin",latex_name="V_{in}")
var("Vout",latex_name="V_{out}")
var("I")
var("E")
Vin=17
Vout=12
E=.87
PlossLDO=I*(Vin-Vout)
PlossBuck=Vout*I*(1-E)
plot(PlossLDO,(I,0,1.5))+plot(PlossBuck,(1,0,1.5),color="red")

References: