XC9519 datasheet(13/38 Pages) TOREX

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XC9519

Series

■

EXTERNAL COMPONENTS

<Step-up DC/DC Converter Output Voltage Setting>

The output voltage VOUTP of a step-up DC/DC converter can be set by connecting external dividing resistors RFBP1 and RFBP2.

The output voltage VOUTP is determined by the values of RFBP1 and RFBP2 as given in the equation below.

Adjust RFBP1 and RFBP2 so that (RFBP1 + RFBP2) < 500kΩ.

VOUTP = VFBP × (RFBP1 + RFBP2) / RFBP2

Set the output voltage so that V

OUTP

≧VIN + 0.2V is satisfied.

Adjust the value of the phase compensation speed-up capacitor CFBP so that f

zfp=1 / (2 × π × RFBP1) is about 40kHz, and insert several kΩ in

series as RSP. If a high output voltage is set, inserting a phase compensation speed-up capacitor may cause unstable operation.

Examples of setting CFBP and RSP are shown in the next section, “Step-up DC/DC Converter Error Amplifier External Compensation”.

【

Typical Examples】

VOUTP

RFBP1

RFBP2

4.0V

300kΩ

100kΩ

5.0V

300kΩ

75kΩ

9.0V

240kΩ

30kΩ

12.0V

330kΩ

30kΩ

15.0V

336kΩ

24kΩ

18.0V

408kΩ

24kΩ

The output voltage VOUTN of an inverting DC/DC converter can be set by connecting external dividing resistors RFBN1 and RFBN2.

The output voltage VOUTN is determined by the values of RFBN1 and RFBN2 as given in the equation below.

Adjust RFBN1 and RFBN2 so that (R

FBN1 + RFBN2) < 500kΩ.

VOUTN = - (VREF - VFBN) × RFBN1 / RFBN2

Set the output voltage so that

VIN - VOUTN+ VFN≦20.0V

(VFN : Forward voltage of external diode SBDN) is satisfied.

【

Typical Examples】

VOUTN

RFBN1

RFBN2

-4.0V

300kΩ

75kΩ

-5.0V

300kΩ

60kΩ

-9.0V

270kΩ

30kΩ

-12.0V

360kΩ

30kΩ

-15.0V

360kΩ

24kΩ

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