Rev. H 09/19

6

SID11x2K

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Figure 13. SCALE-iDriver Application Example Using a Resistor Network for Desaturation Detection.

Figure 14. SCALE-iDriver Application Example Using Diodes for Desaturation Detection.

Application Examples and Components Selection

Figures 13 and 14 show the schematic and typical components used

for a SCALE-iDriver design. In both cases the primary-side supply

voltage (V

VCC) is connected between VCC and GND pins and supported

through a supply bypass ceramic capacitor C

1 (4.7 µF typically). If the

command signal voltage level is higher than the rated IN pin voltage

(in this case 15 V) a resistive voltage divider should be used. Additional

capacitor C

F and Schmitt trigger IC1 can be used to provide input

signal filtering. The SO output has 5 V logic and the R

SO is selected

so that it does not exceed absolute maximum rated I

SO current.

The secondary-side isolated power supply (V

TOT) is connected between

VISO and COM. The positive voltage rail (V

VISO) is supported through

4.7 µF ceramic capacitors C

S21 and CS22 connected in parallel. The

negative voltage rail (V

VEE) is similarly supported through capacitors

C

S11 and CS12. The gate charge will vary according to the type of

power semiconductor switch that is being driven. Typically, C

S11 + CS12

should be at least 3 µF multiplied by the total gate charge of the

power semiconductor switch (Q

GATE) divided by 1 µC. A 10 nF capacitor

C

GXX is connected between the GH and VGXX pins.

The gate of the power semiconductor switch is connected through

resistor R

GON to the GH pin and by RGOFF to the GL pin. If the value of

R

GON is the same as RGOFF the GH pin can be connected to the GL pin

and a common gate resistor can be connected to the gate. In each

case, proper consideration needs to be given to the power dissipation

and temperature performance of the gate resistors.

To ensure gate voltage stabilization and collector current limitation

during a short-circuit, the gate is connected to the VISO pin through

a Schottky diode D

STO (for example PMEG4010).

PI-7953-092216

CGXX

10 nF

CS21

4.7 µF

CS22

4.7 µF

CS11

4.7 µF

CS12

4.7 µF

RGON

RGOFF

RVCE

330 Ω

DVCE2

DVCE1

CRES

33-330 pF

RGE

6.8 kΩ

RRES

24-62 kΩ

Gate

Emitter

Collector

IN

SO

VCC

GND

CF

SO

RSO

4.7 kΩ

R2

1 kΩ

R1

3.3 kΩ

VCC

GND

IC1

74LVC

C1

4.7 µF

Command

Signal

DSTO

SCALE-iDriver

Primary-Side

Logic

Secondary-Side

Logic

VCE

VISO

VGXX

GH

GL

VEE

COM

VTOT

+

-

FluxLink

Primary-Side

Logic

IN

SO

VCC

GND

CF

SO

RSO

4.7 kΩ

R2

1 kΩ

R1

3.3 kΩ

VCC

GND

C1

4.7 µF

Command

Signal

DCL

BAS416

PI-7954-092216

CGXX

10 nF

CS21

4.7 µF

CS22

4.7 µF

CS11

4.7 µF

CS12

4.7 µF

RGON

RGOFF

RVCE2-11

100 kΩ × 10

CRES

33 pF

RGE

6.8 kΩ

Gate

Emitter

Collector

DSTO

SCALE-iDriver

Primary-Side

Logic

Secondary-Side

Logic

RVCE

120 kΩ

VCE

VISO

VGXX

GH

GL

VEE

COM

VTOT

+

-

FluxLink

IC1

74LVC