BD9137MUV

11/22

TSZ02201-0J3J0AJ00160-1-2

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TSZ22111

• 15 • 001

20.Nov.2014 Rev.003

4. Switching Regulator Efficiency

Efficiency ŋ may be expressed by the equation shown below:

Efficiency may be improved by reducing the switching regulator power dissipation factors Pd

α as follows:

Dissipation factors:

(1)

where:

(2)

Gate Charge/Discharge Dissipation：Pd(Gate)

where:

f is the switching frequency.

V is the gate driving voltage of FET.

(3)

Switching Dissipation：Pd(SW)

where:

(4)

ESR Dissipation of Capacitor：Pd(ESR)

where:

ESR is the equivalent series.

(5)

Operating Current Dissipation of IC：Pd(IC)

where:

 

%

100

100

100























Pd

P

P

P

P

I

V

I

V

OUT

OUT

IN

OUT

IN

IN

OUT

OUT

 





ON

COIL

OUT

R

R

I

R

I

Pd







2

2

 

DRIVE

OUT

RSS

IN

I

f

I

C

V

SW

Pd









2





ESR

I

ESR

Pd

RMS





2

 

CC

IN

I

V

IC

Pd









2

V

f

C

Gate

Pd

gs





