MV1012SC

13

3.2.8

Vcc pin smoothing capacitor (C3)

C3 is a capacitor used to stabilize the power supply voltage of the Vcc pin. Check the Vcc pin voltage waveform and

select a capacitor with capacitance of 0.1 uF or more. A very large capacitance value will length start times. Check with

the actual apparatus.

3.2.9

REF pin capacitor (C5)

C5 is a capacitor used to prevent unintended noise-induced operations. The capacitance of the capacitor should be

around 1000 pF. For dimming methods, see Section 5 [Dimming characteristics] on page 19.

3.2.10 Svin pin capacitor (C9)

C9 is a capacitor used to prevent unintended noise-induced operations. The capacitance of the capacitor should be

around 1000 pF.

3.2.11 Resonant capacitor (Cr)

In addition to enabling adjustments of the resonant period, Cr will reduce switching-off noise. However, note that it may

also increase switching-on noise. If Cr is too large, dimming characteristics and efficiency may be degraded. We

recommend against using this capacitor. If you wish to use it, make adjustments with the actual apparatus to minimize

capacitance.

3.2.12 Input capacitor (C1) and Output capacitor (C2)

Select input and output capacitors after considering allowable ripple current, life, output holding time, etc. The ripple

current of a capacitor is calculated by the following formulas:

Ripple current of input capacitor

Ripple current of output capacitor

Where D represents the switching duty cycle.

D is obtained using the formula, D = Vo/Vi, based on the relationship between input and output voltages.

In the case of an input capacitor, ripple currents are added from input circuit devices, such as the full wave rectifier and

PFC. Consider these as well when selecting the capacitor.

3.2.13 Svout pin capacitor (C8)

C8 is a capacitor used to adjust the delay shown in Figure 7 and to the on-timing. For a discussion of adjusting

on-timing using C8, see [Additional explanation of resonant period in quasi-resonant operation] on page 14.

C8 also prevents unintended noise-induced operations. Adjust the capacitance to around 10 to 100 pF with the actual

apparatus.

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

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

 





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4

D

3

1

D

Ip

Iripin

3

Io

Iripout

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CAT.No.1A0602-1E