MV1002SC

9

Operation check

Basic design

See [3.2 Component selection] on pp.9-14

See [3.3 Winding voltage supply] on pp.15-16

Determine

specification

・Adjusting the Svout capacitor ...pp.13-14

・Adjusting the resonant capacitor ...p.13

Turned on at a valley

of resonant voltage

when dimming ratio is 100%?

Do any false

detections occur in the off-time

modulation regin?

・Adjusting the CS filter ...p.12

・Adjusting the gate resistor ...p.11

・Adjusting the resonant capacitor ...p.13

・Correcting the pattern ...p.17

Is the

output current within

the allowable range?

・Adjusting the current detection resistor

...p.10

Complete the

design process

No

No

No

yes

yes

Build a power

supply

yes

3.2 Component selection

The chart below shows a design procedure, from determination of the specification to adjustment. The design

procedure provided in this section is an example of electrical design.

During the design process, be sure to comply with safety standards established by official bodies and with your company

rules.

* Repeat the operations check if a component constant changes after design has been completed.

3.2.1

MOSFET (Q1)

The MOSFET receives the voltages shown in Figure 5. The maximum applied voltage nearly equals the maximum input

voltage. In actual use, voltage spikes may occur—for instance, due to parasitic inductance of the wiring pattern. Check

with the actual apparatus and select a component with sufficient withstand voltage.

For a lighting apparatus that consumes a large amount of power, MOSFETs with low on-resistance offer advantages.

When power consumption is small, MOSFETs with small capacitance, such as Ciss and Coss, help achieve highly

efficient and advantageous dimming characteristics.

IC power consumption is the product of the input voltage and current consumption. Current consumption is the sum of

the logic current and the gate drive current. Select MOSFETs that have the lowest possible gate capacitance. (See Table

1 Recommended MOSFETs.)

CAT.No.1A0202-2E