MB39C015 Datasheet, PDF (16/43 Pages) Cypress Semiconductor – High efficiency : 96% (Max)

MB39C015
10.2 Output voltage setting
The output voltage VOUT (VOUT1 or VOUT2) of this IC is defined by the voltage input to VREFIN (VREFIN1 or VREFIN2) . Supply the
voltage for inputting to VREFIN from an external power supply, or set the VREF output by dividing it with resistors.
The output voltage when the VREFIN voltage is set by dividing the VREF voltage with resistors is shown in the following formula.
  VOUT 3.01 × VREFIN, VREFIN
(VREF  1.30 V)
R2
R1  R2
× VREF
VREF
VREFIN
MB39C015
VREF
R1
VREFIN
R2
Note :
Refer to “ Application Circuit Examples” for the an example of this circuit.
Although the output voltage is defined according to the dividing ratio of resistance, select the resistance value so that the current
flowing through the resistance does not exceed the VREF current rating (1 mA) .
10.3 About conversion efficiency
The conversion efficiency can be improved by reducing the loss of the DC/DC converter circuit.
The total loss (PLOSS) of the DC/DC converter is roughly divided as follows :
PLOSS = PCONT + PSW + PC
PCONT
PSW
PC
: Control system circuit loss (The power used for this IC to operate, including the gate driving power for internal SW FETs)
: Switching loss (The loss caused during switching of the IC's internal SW FETs)
: Continuity loss (The loss caused when currents flow through the IC's internal SW FETs and external circuits )
Document Number: 002-08364 Rev. *A
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