MC33153

11

MOTOROLA ANALOG IC DEVICE DATA

APPLICATION INFORMATION

Figure 34 shows a basic IGBT driver application. When

driven from an optoisolator, an input pull up resistor is

required. This resistor value should be set to bias the output

transistor at the desired current. A decoupling capacitor

should be placed close to the IC to minimize switching noise.

A bootstrap diode may be used for a floating supply. If the

protection features are not required, then both the Fault

Blanking/Desaturation and Current Sense Inputs should both

be connected to the Kelvin Ground (Pin 2). When used with a

single supply, the Kelvin Ground and VEE pins should be

connected together. Separate gate resistors are

recommended to optimize the turn–on and turn–off drive.

Figure 34. Basic Application

7

4

3

2

1

5

8

6

Fault

Input

Desat/

Blank

Output

Sense

Gnd

VEE

VCC

MC33153

18 V

B+

Bootstrap

Figure 35. Dual Supply Application

7

4

3

2

1

5

8

6

Fault

Input

Desat/

Blank

Output

Sense

Gnd

VEE

VCC

MC33153

15 V

–5.0 V

When used in a dual supply application as in Figure 35, the

Kelvin Ground should be connected to the emitter of the

IGBT. If the protection features are not used, then both the

Fault Blanking/Desaturation and the Current Sense Inputs

should be connected to Ground. The input optoisolator

should always be referenced to VEE.

If desaturation protection is desired, a high voltage diode

is connected to the Fault Blanking/Desaturation pin. The

blanking capacitor should be connected from the

Desaturation pin to the VEE pin. If a dual supply is used, the

blanking capacitor should be connected to the Kelvin

Ground. The Current Sense Input should be tied high

because the two comparator outputs are ANDed together.

Although the reverse voltage on collector of the IGBT is

clamped to the emitter by the free–wheeling diode, there is

normally considerable inductance within the package itself. A

small resistor in series with the diode can be used to protect

the IC from reverse voltage transients.

Figure 36. Desaturation Application

7

4

3

2

1

5

8

6

Fault

Input

Desat/

Blank

Output

Sense

Gnd

VEE

VCC

MC33153

18 V

CBlank

When using sense IGBTs or a sense resistor, the sense

voltage is applied to the Current Sense Input. The sense trip

voltages are referenced to the Kelvin Ground pin. The sense

voltage is very small, typically about 65 mV, and sensitive to

noise. Therefore, the sense and ground return conductors

should be routed as a differential pair. An RC filter is useful in

filtering any high frequency noise. A blanking capacitor is

connected from the blanking pin to VEE. The stray

capacitance on the blanking pin provides a very small level of

blanking if left open. The blanking pin should not be grounded

when using current sensing, that would disable the sense.

The blanking pin should never be tied high, that would short

out the clamp transistor.

Figure 37. Sense IGBT Application

7

4

3

2

1

5

8

6

Fault

Input

Desat/

Blank

Output

Sense

Gnd

VEE

VCC

MC33153

18 V